Add Docker support with CI/CD workflow and usage instructions

- Added `.github/workflows/docker-image.yml` for automated Docker image build and push on version tags.
- Created `Dockerfile` to containerize the application.
- Updated README with instructions for running the application using Docker.

.github/workflows/docker-image.yml

@@ -0,0 +1,42 @@
+name: docker-image
+
+on:
+  push:
+    tags:
+      - v*
+
+env:
+  APP_NAME: CLIProxyAPI
+  DOCKERHUB_REPO: eceasy/cli-proxy-api
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      - name: Login to DockerHub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - name: Generate App Version
+        run: echo APP_VERSION=`git describe --tags --always` >> $GITHUB_ENV
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          platforms: |
+            linux/amd64
+            linux/arm64
+          push: true
+          build-args: |
+            APP_NAME=${{ env.APP_NAME }}
+            APP_VERSION=${{ env.APP_VERSION }}
+          tags: |
+            ${{ env.DOCKERHUB_REPO }}:latest
+            ${{ env.DOCKERHUB_REPO }}:${{ env.APP_VERSION }}

.goreleaser.yml

@@ -8,4 +8,10 @@ builds:
       - amd64
       - arm64
     main: ./cmd/server/
-    binary: cli-proxy-api
+    binary: cli-proxy-api
+archives:
+  - id: "cli-proxy-api"
+    files:
+      - LICENSE
+      - README.md
+      - config.yaml

Dockerfile

@@ -0,0 +1,23 @@
+FROM golang:1.24-alpine AS builder
+
+WORKDIR /app
+
+COPY go.mod go.sum ./
+
+RUN go mod download
+
+COPY . .
+
+RUN CGO_ENABLED=0 GOOS=linux go build -o ./CLIProxyAPI ./cmd/server/
+
+FROM alpine:3.22.0
+
+RUN mkdir /CLIProxyAPI
+
+COPY --from=builder ./app/CLIProxyAPI /CLIProxyAPI/CLIProxyAPI
+
+WORKDIR /CLIProxyAPI
+
+EXPOSE 8317
+
+CMD ["./CLIProxyAPI"]

README.md

@@ -1,15 +1,17 @@
 # CLI Proxy API
 
-A proxy server that provides an OpenAI-compatible API interface for CLI. This allows you to use CLI models with tools and libraries designed for the OpenAI API.
+A proxy server that provides an OpenAI/Gemini/Claude compatible API interface for CLI. This allows you to use CLI models with tools and libraries designed for the OpenAI/Gemini/Claude API.
 
 ## Features
 
-- OpenAI-compatible API endpoints for CLI models
+- OpenAI/Gemini/Claude compatible API endpoints for CLI models
 - Support for both streaming and non-streaming responses
 - Function calling/tools support
 - Multimodal input support (text and images)
 - Multiple account support with load balancing
 - Simple CLI authentication flow
+- Support for Generative Language API Key
+- Support Gemini CLI with multiple account load balancing
 
 ## Installation
 
@@ -134,7 +136,7 @@ console.log(response.choices[0].message.content);
 
 - gemini-2.5-pro
 - gemini-2.5-flash
-- And various preview versions
+- And it automates switching to various preview versions
 
 ## Configuration
 
@@ -146,13 +148,14 @@ The server uses a YAML configuration file (`config.yaml`) located in the project
 
 ### Configuration Options
 
-| Parameter   | Type     | Default            | Description                                                                                  |
-|-------------|----------|--------------------|----------------------------------------------------------------------------------------------|
-| `port`      | integer  | 8317               | The port number on which the server will listen                                              |
-| `auth_dir`  | string   | "~/.cli-proxy-api" | Directory where authentication tokens are stored. Supports using `~` for home directory      |
-| `proxy-url` | string   | ""                 | Proxy url, support socks5/http/https protocol, example: socks5://user:pass@192.168.1.1:1080/ |
-| `debug`     | boolean  | false              | Enable debug mode for verbose logging                                                        |
-| `api_keys`  | string[] | []                 | List of API keys that can be used to authenticate requests                                   |
+| Parameter                     | Type     | Default            | Description                                                                                  |
+|-------------------------------|----------|--------------------|----------------------------------------------------------------------------------------------|
+| `port`                        | integer  | 8317               | The port number on which the server will listen                                              |
+| `auth-dir`                    | string   | "~/.cli-proxy-api" | Directory where authentication tokens are stored. Supports using `~` for home directory      |
+| `proxy-url`                   | string   | ""                 | Proxy url, support socks5/http/https protocol, example: socks5://user:pass@192.168.1.1:1080/ |
+| `debug`                       | boolean  | false              | Enable debug mode for verbose logging                                                        |
+| `api-keys`                    | string[] | []                 | List of API keys that can be used to authenticate requests                                   |
+| `generative-language-api-key` | string[] | []                 | List of Generative Language API keys                                                         |
 
 ### Example Configuration File
 
@@ -161,29 +164,68 @@ The server uses a YAML configuration file (`config.yaml`) located in the project
 port: 8317
 
 # Authentication directory (supports ~ for home directory)
-auth_dir: "~/.cli-proxy-api"
+auth-dir: "~/.cli-proxy-api"
 
 # Enable debug logging
 debug: false
 
 # API keys for authentication
-api_keys:
+api-keys:
   - "your-api-key-1"
   - "your-api-key-2"
+
+# API keys for official Generative Language API
+generative-language-api-key:
+  - "AIzaSy...01"
+  - "AIzaSy...02"
+  - "AIzaSy...03"
+  - "AIzaSy...04"
 ```
 
 ### Authentication Directory
 
-The `auth_dir` parameter specifies where authentication tokens are stored. When you run the login command, the application will create JSON files in this directory containing the authentication tokens for your Google accounts. Multiple accounts can be used for load balancing.
+The `auth-dir` parameter specifies where authentication tokens are stored. When you run the login command, the application will create JSON files in this directory containing the authentication tokens for your Google accounts. Multiple accounts can be used for load balancing.
 
 ### API Keys
 
-The `api_keys` parameter allows you to define a list of API keys that can be used to authenticate requests to your proxy server. When making requests to the API, you can include one of these keys in the `Authorization` header:
+The `api-keys` parameter allows you to define a list of API keys that can be used to authenticate requests to your proxy server. When making requests to the API, you can include one of these keys in the `Authorization` header:
 
 ```
 Authorization: Bearer your-api-key-1
 ```
 
+### Official Generative Language API
+
+The `generative-language-api-key` parameter allows you to define a list of API keys that can be used to authenticate requests to the official Generative Language API.
+
+## Gemini CLI with multiple account load balancing
+
+Start CLI Proxy API server, and then set the `CODE_ASSIST_ENDPOINT` environment variable to the URL of the CLI Proxy API server.
+
+```bash
+export CODE_ASSIST_ENDPOINT="http://127.0.0.1:8317"
+```
+
+The server will relay the `loadCodeAssist`, `onboardUser`, and `countTokens` requests. And automatically load balance the text generation requests between the multiple accounts.
+
+> [!NOTE]  
+> This feature only allows local access because I couldn't find a way to authenticate the requests.   
+> I hardcoded `127.0.0.1` into the load balancing.
+
+## Run with Docker
+
+Run the following command to login: 
+
+```bash
+docker run --rm -p 8085:8085 -v /path/to/your/config.yaml:/CLIProxyAPI/config.yaml -v /path/to/your/auth-dir:/root/.cli-proxy-api eceasy/cli-proxy-api:latest /CLIProxyAPI/CLIProxyAPI --login
+```
+
+Run the following command to start the server:
+
+```bash
+docker run --rm -p 8317:8317 -v /path/to/your/config.yaml:/CLIProxyAPI/config.yaml -v /path/to/your/auth-dir:/root/.cli-proxy-api eceasy/cli-proxy-api:latest
+```
+
 ## Contributing
 
 Contributions are welcome! Please feel free to submit a Pull Request.

cmd/server/main.go

@@ -12,9 +12,11 @@ import (
 	"strings"
 )
 
+// LogFormatter defines a custom log format for logrus.
 type LogFormatter struct {
 }
 
+// Format renders a single log entry.
 func (m *LogFormatter) Format(entry *log.Entry) ([]byte, error) {
 	var b *bytes.Buffer
 	if entry.Buffer != nil {
@@ -25,33 +27,42 @@ func (m *LogFormatter) Format(entry *log.Entry) ([]byte, error) {
 
 	timestamp := entry.Time.Format("2006-01-02 15:04:05")
 	var newLog string
+	// Customize the log format to include timestamp, level, caller file/line, and message.
 	newLog = fmt.Sprintf("[%s] [%s] [%s:%d] %s\n", timestamp, entry.Level, path.Base(entry.Caller.File), entry.Caller.Line, entry.Message)
 
 	b.WriteString(newLog)
 	return b.Bytes(), nil
 }
 
+// init initializes the logger configuration.
 func init() {
+	// Set logger output to standard output.
 	log.SetOutput(os.Stdout)
+	// Enable reporting the caller function's file and line number.
 	log.SetReportCaller(true)
+	// Set the custom log formatter.
 	log.SetFormatter(&LogFormatter{})
 }
 
+// main is the entry point of the application.
 func main() {
 	var login bool
 	var projectID string
 	var configPath string
 
+	// Define command-line flags.
 	flag.BoolVar(&login, "login", false, "Login Google Account")
 	flag.StringVar(&projectID, "project_id", "", "Project ID")
 	flag.StringVar(&configPath, "config", "", "Configure File Path")
 
+	// Parse the command-line flags.
 	flag.Parse()
 
 	var err error
 	var cfg *config.Config
 	var wd string
 
+	// Load configuration from the specified path or the default path.
 	if configPath != "" {
 		cfg, err = config.LoadConfig(configPath)
 	} else {
@@ -65,12 +76,14 @@ func main() {
 		log.Fatalf("failed to load config: %v", err)
 	}
 
+	// Set the log level based on the configuration.
 	if cfg.Debug {
 		log.SetLevel(log.DebugLevel)
 	} else {
 		log.SetLevel(log.InfoLevel)
 	}
 
+	// Expand the tilde (~) in the auth directory path to the user's home directory.
 	if strings.HasPrefix(cfg.AuthDir, "~") {
 		home, errUserHomeDir := os.UserHomeDir()
 		if errUserHomeDir != nil {
@@ -85,6 +98,7 @@ func main() {
 		}
 	}
 
+	// Either perform login or start the service based on the 'login' flag.
 	if login {
 		cmd.DoLogin(cfg, projectID)
 	} else {

config.yaml

@@ -1,7 +1,15 @@
 port: 8317
-auth_dir: "~/.cli-proxy-api"
-debug: false
+auth-dir: "~/.cli-proxy-api"
+debug: true
 proxy-url: ""
-api_keys:
+quota-exceeded:
+  switch-project: true
+  switch-preview-model: true
+api-keys:
   - "12345"
-  - "23456"
+  - "23456"
+generative-language-api-key:
+  - "AIzaSy...01"
+  - "AIzaSy...02"
+  - "AIzaSy...03"
+  - "AIzaSy...04"

internal/api/claude-code-handlers.go

@@ -0,0 +1,234 @@
+package api
+
+import (
+	"context"
+	"fmt"
+	"github.com/gin-gonic/gin"
+	"github.com/luispater/CLIProxyAPI/internal/api/translator"
+	"github.com/luispater/CLIProxyAPI/internal/client"
+	log "github.com/sirupsen/logrus"
+	"net/http"
+	"strings"
+	"time"
+)
+
+// ClaudeMessages handles Claude-compatible streaming chat completions.
+// This function implements a sophisticated client rotation and quota management system
+// to ensure high availability and optimal resource utilization across multiple backend clients.
+func (h *APIHandlers) ClaudeMessages(c *gin.Context) {
+	// Extract raw JSON data from the incoming request
+	rawJson, err := c.GetRawData()
+	// If data retrieval fails, return a 400 Bad Request error.
+	if err != nil {
+		c.JSON(http.StatusBadRequest, ErrorResponse{
+			Error: ErrorDetail{
+				Message: fmt.Sprintf("Invalid request: %v", err),
+				Type:    "invalid_request_error",
+			},
+		})
+		return
+	}
+
+	// Set up Server-Sent Events (SSE) headers for streaming response
+	// These headers are essential for maintaining a persistent connection
+	// and enabling real-time streaming of chat completions
+	c.Header("Content-Type", "text/event-stream")
+	c.Header("Cache-Control", "no-cache")
+	c.Header("Connection", "keep-alive")
+	c.Header("Access-Control-Allow-Origin", "*")
+
+	// Get the http.Flusher interface to manually flush the response.
+	// This is crucial for streaming as it allows immediate sending of data chunks
+	flusher, ok := c.Writer.(http.Flusher)
+	if !ok {
+		c.JSON(http.StatusInternalServerError, ErrorResponse{
+			Error: ErrorDetail{
+				Message: "Streaming not supported",
+				Type:    "server_error",
+			},
+		})
+		return
+	}
+
+	// Parse and prepare the Claude request, extracting model name, system instructions,
+	// conversation contents, and available tools from the raw JSON
+	modelName, systemInstruction, contents, tools := translator.PrepareClaudeRequest(rawJson)
+
+	// Map Claude model names to corresponding Gemini models
+	// This allows the proxy to handle Claude API calls using Gemini backend
+	if modelName == "claude-sonnet-4-20250514" {
+		modelName = "gemini-2.5-pro"
+	} else if modelName == "claude-3-5-haiku-20241022" {
+		modelName = "gemini-2.5-flash"
+	}
+
+	// Create a cancellable context for the backend client request
+	// This allows proper cleanup and cancellation of ongoing requests
+	cliCtx, cliCancel := context.WithCancel(context.Background())
+	var cliClient *client.Client
+	defer func() {
+		// Ensure the client's mutex is unlocked on function exit.
+		// This prevents deadlocks and ensures proper resource cleanup
+		if cliClient != nil {
+			cliClient.RequestMutex.Unlock()
+		}
+	}()
+
+	// Main client rotation loop with quota management
+	// This loop implements a sophisticated load balancing and failover mechanism
+outLoop:
+	for {
+		// Thread-safe client index rotation to distribute load evenly
+		// This ensures fair usage across all available clients
+		mutex.Lock()
+		startIndex := lastUsedClientIndex
+		currentIndex := (startIndex + 1) % len(h.cliClients)
+		lastUsedClientIndex = currentIndex
+		mutex.Unlock()
+
+		// Build a list of available clients, starting from the next client in rotation
+		// This implements round-robin load balancing while filtering out quota-exceeded clients
+		reorderedClients := make([]*client.Client, 0)
+		for i := 0; i < len(h.cliClients); i++ {
+			cliClient = h.cliClients[(startIndex+1+i)%len(h.cliClients)]
+
+			// Skip clients that have exceeded their quota for the requested model
+			if cliClient.IsModelQuotaExceeded(modelName) {
+				// Log different messages based on authentication method (API key vs account)
+				if cliClient.GetGenerativeLanguageAPIKey() == "" {
+					log.Debugf("Model %s is quota exceeded for account %s, project id: %s", modelName, cliClient.GetEmail(), cliClient.GetProjectID())
+				} else {
+					log.Debugf("Model %s is quota exceeded for generative language API Key: %s", modelName, cliClient.GetGenerativeLanguageAPIKey())
+				}
+
+				cliClient = nil
+				continue
+			}
+			reorderedClients = append(reorderedClients, cliClient)
+		}
+
+		// If all clients have exceeded quota, return a 429 Too Many Requests error
+		if len(reorderedClients) == 0 {
+			c.Status(429)
+			_, _ = fmt.Fprint(c.Writer, fmt.Sprintf(`{"error":{"code":429,"message":"All the models of '%s' are quota exceeded","status":"RESOURCE_EXHAUSTED"}}`, modelName))
+			flusher.Flush()
+			cliCancel()
+			return
+		}
+
+		// Attempt to acquire a lock on an available client using non-blocking TryLock
+		// This prevents blocking when a client is busy with another request
+		locked := false
+		for i := 0; i < len(reorderedClients); i++ {
+			cliClient = reorderedClients[i]
+			if cliClient.RequestMutex.TryLock() {
+				locked = true
+				break
+			}
+		}
+
+		// If no client is immediately available, fall back to blocking on the first client
+		// This ensures the request will eventually be processed
+		if !locked {
+			cliClient = h.cliClients[0]
+			cliClient.RequestMutex.Lock()
+		}
+
+		// Determine the authentication method being used by the selected client
+		// This affects how responses are formatted and logged
+		isGlAPIKey := false
+		if glAPIKey := cliClient.GetGenerativeLanguageAPIKey(); glAPIKey != "" {
+			log.Debugf("Request use generative language API Key: %s", glAPIKey)
+			isGlAPIKey = true
+		} else {
+			log.Debugf("Request use account: %s, project id: %s", cliClient.GetEmail(), cliClient.GetProjectID())
+		}
+		// Initiate streaming communication with the backend client
+		// This returns two channels: one for response chunks and one for errors
+
+		includeThoughts := false
+		if userAgent, hasKey := c.Request.Header["User-Agent"]; hasKey {
+			includeThoughts = !strings.Contains(userAgent[0], "claude-cli")
+		}
+
+		respChan, errChan := cliClient.SendMessageStream(cliCtx, rawJson, modelName, systemInstruction, contents, tools, includeThoughts)
+
+		// Track response state for proper Claude format conversion
+		hasFirstResponse := false
+		responseType := 0
+		responseIndex := 0
+
+		// Main streaming loop - handles multiple concurrent events using Go channels
+		// This select statement manages four different types of events simultaneously
+		for {
+			select {
+			// Case 1: Handle client disconnection
+			// Detects when the HTTP client has disconnected and cleans up resources
+			case <-c.Request.Context().Done():
+				if c.Request.Context().Err().Error() == "context canceled" {
+					log.Debugf("Client disconnected: %v", c.Request.Context().Err())
+					cliCancel() // Cancel the backend request to prevent resource leaks
+					return
+				}
+
+			// Case 2: Process incoming response chunks from the backend
+			// This handles the actual streaming data from the AI model
+			case chunk, okStream := <-respChan:
+				if !okStream {
+					// Stream has ended - send the final message_stop event
+					// This follows the Claude API specification for stream termination
+					_, _ = c.Writer.Write([]byte(`event: message_stop`))
+					_, _ = c.Writer.Write([]byte("\n"))
+					_, _ = c.Writer.Write([]byte(`data: {"type":"message_stop"}`))
+					_, _ = c.Writer.Write([]byte("\n\n\n"))
+
+					flusher.Flush()
+					cliCancel()
+					return
+				} else {
+					// Convert the backend response to Claude-compatible format
+					// This translation layer ensures API compatibility
+					claudeFormat := translator.ConvertCliToClaude(chunk, isGlAPIKey, hasFirstResponse, &responseType, &responseIndex)
+					if claudeFormat != "" {
+						_, _ = c.Writer.Write([]byte(claudeFormat))
+						flusher.Flush() // Immediately send the chunk to the client
+					}
+					hasFirstResponse = true
+				}
+
+			// Case 3: Handle errors from the backend
+			// This manages various error conditions and implements retry logic
+			case errInfo, okError := <-errChan:
+				if okError {
+					// Special handling for quota exceeded errors
+					// If configured, attempt to switch to a different project/client
+					if errInfo.StatusCode == 429 && h.cfg.QuotaExceeded.SwitchProject {
+						continue outLoop // Restart the client selection process
+					} else {
+						// Forward other errors directly to the client
+						c.Status(errInfo.StatusCode)
+						_, _ = fmt.Fprint(c.Writer, errInfo.Error.Error())
+						flusher.Flush()
+						cliCancel()
+					}
+					return
+				}
+
+			// Case 4: Send periodic keep-alive signals
+			// Prevents connection timeouts during long-running requests
+			case <-time.After(500 * time.Millisecond):
+				if hasFirstResponse {
+					// Send a ping event to maintain the connection
+					// This is especially important for slow AI model responses
+					output := "event: ping\n"
+					output = output + `data: {"type": "ping"}`
+					output = output + "\n\n\n"
+					_, _ = c.Writer.Write([]byte(output))
+
+					flusher.Flush()
+				}
+			}
+		}
+	}
+
+}

internal/api/cli-handlers.go

@@ -0,0 +1,239 @@
+package api
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"github.com/gin-gonic/gin"
+	"github.com/luispater/CLIProxyAPI/internal/client"
+	"github.com/luispater/CLIProxyAPI/internal/util"
+	log "github.com/sirupsen/logrus"
+	"github.com/tidwall/gjson"
+	"github.com/tidwall/sjson"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+)
+
+func (h *APIHandlers) CLIHandler(c *gin.Context) {
+	if !strings.HasPrefix(c.Request.RemoteAddr, "127.0.0.1:") {
+		c.JSON(http.StatusForbidden, ErrorResponse{
+			Error: ErrorDetail{
+				Message: "CLI reply only allow local access",
+				Type:    "forbidden",
+			},
+		})
+		return
+	}
+
+	rawJson, _ := c.GetRawData()
+	requestRawURI := c.Request.URL.Path
+	if requestRawURI == "/v1internal:generateContent" {
+		h.internalGenerateContent(c, rawJson)
+	} else if requestRawURI == "/v1internal:streamGenerateContent" {
+		h.internalStreamGenerateContent(c, rawJson)
+	} else {
+		reqBody := bytes.NewBuffer(rawJson)
+		req, err := http.NewRequest("POST", fmt.Sprintf("https://cloudcode-pa.googleapis.com%s", c.Request.URL.RequestURI()), reqBody)
+		if err != nil {
+			c.JSON(http.StatusBadRequest, ErrorResponse{
+				Error: ErrorDetail{
+					Message: fmt.Sprintf("Invalid request: %v", err),
+					Type:    "invalid_request_error",
+				},
+			})
+			return
+		}
+		for key, value := range c.Request.Header {
+			req.Header[key] = value
+		}
+
+		httpClient, err := util.SetProxy(h.cfg, &http.Client{})
+		if err != nil {
+			log.Fatalf("set proxy failed: %v", err)
+		}
+
+		resp, err := httpClient.Do(req)
+		if err != nil {
+			c.JSON(http.StatusBadRequest, ErrorResponse{
+				Error: ErrorDetail{
+					Message: fmt.Sprintf("Invalid request: %v", err),
+					Type:    "invalid_request_error",
+				},
+			})
+			return
+		}
+
+		if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+			defer func() {
+				if err = resp.Body.Close(); err != nil {
+					log.Printf("warn: failed to close response body: %v", err)
+				}
+			}()
+			bodyBytes, _ := io.ReadAll(resp.Body)
+
+			c.JSON(http.StatusBadRequest, ErrorResponse{
+				Error: ErrorDetail{
+					Message: string(bodyBytes),
+					Type:    "invalid_request_error",
+				},
+			})
+			return
+		}
+
+		defer func() {
+			_ = resp.Body.Close()
+		}()
+
+		for key, value := range resp.Header {
+			c.Header(key, value[0])
+		}
+		output, err := io.ReadAll(resp.Body)
+		if err != nil {
+			log.Errorf("Failed to read response body: %v", err)
+			return
+		}
+		_, _ = c.Writer.Write(output)
+	}
+}
+
+func (h *APIHandlers) internalStreamGenerateContent(c *gin.Context, rawJson []byte) {
+	// Get the http.Flusher interface to manually flush the response.
+	flusher, ok := c.Writer.(http.Flusher)
+	if !ok {
+		c.JSON(http.StatusInternalServerError, ErrorResponse{
+			Error: ErrorDetail{
+				Message: "Streaming not supported",
+				Type:    "server_error",
+			},
+		})
+		return
+	}
+
+	modelResult := gjson.GetBytes(rawJson, "model")
+	modelName := modelResult.String()
+
+	cliCtx, cliCancel := context.WithCancel(context.Background())
+	var cliClient *client.Client
+	defer func() {
+		// Ensure the client's mutex is unlocked on function exit.
+		if cliClient != nil {
+			cliClient.RequestMutex.Unlock()
+		}
+	}()
+
+outLoop:
+	for {
+		var errorResponse *client.ErrorMessage
+		cliClient, errorResponse = h.getClient(modelName)
+		if errorResponse != nil {
+			c.Status(errorResponse.StatusCode)
+			_, _ = fmt.Fprint(c.Writer, errorResponse.Error)
+			flusher.Flush()
+			cliCancel()
+			return
+		}
+
+		if glAPIKey := cliClient.GetGenerativeLanguageAPIKey(); glAPIKey != "" {
+			log.Debugf("Request use generative language API Key: %s", glAPIKey)
+		} else {
+			log.Debugf("Request use account: %s, project id: %s", cliClient.GetEmail(), cliClient.GetProjectID())
+		}
+		// Send the message and receive response chunks and errors via channels.
+		respChan, errChan := cliClient.SendRawMessageStream(cliCtx, rawJson)
+		hasFirstResponse := false
+		for {
+			select {
+			// Handle client disconnection.
+			case <-c.Request.Context().Done():
+				if c.Request.Context().Err().Error() == "context canceled" {
+					log.Debugf("Client disconnected: %v", c.Request.Context().Err())
+					cliCancel() // Cancel the backend request.
+					return
+				}
+			// Process incoming response chunks.
+			case chunk, okStream := <-respChan:
+				if !okStream {
+					cliCancel()
+					return
+				} else {
+					hasFirstResponse = true
+					if cliClient.GetGenerativeLanguageAPIKey() != "" {
+						chunk, _ = sjson.SetRawBytes(chunk, "response", chunk)
+					}
+					_, _ = c.Writer.Write([]byte("data: "))
+					_, _ = c.Writer.Write(chunk)
+					_, _ = c.Writer.Write([]byte("\n\n"))
+					flusher.Flush()
+				}
+			// Handle errors from the backend.
+			case err, okError := <-errChan:
+				if okError {
+					if err.StatusCode == 429 && h.cfg.QuotaExceeded.SwitchProject {
+						continue outLoop
+					} else {
+						c.Status(err.StatusCode)
+						_, _ = fmt.Fprint(c.Writer, err.Error.Error())
+						flusher.Flush()
+						cliCancel()
+					}
+					return
+				}
+			// Send a keep-alive signal to the client.
+			case <-time.After(500 * time.Millisecond):
+				if hasFirstResponse {
+					_, _ = c.Writer.Write([]byte("\n"))
+					flusher.Flush()
+				}
+			}
+		}
+	}
+}
+
+func (h *APIHandlers) internalGenerateContent(c *gin.Context, rawJson []byte) {
+	c.Header("Content-Type", "application/json")
+
+	modelResult := gjson.GetBytes(rawJson, "model")
+	modelName := modelResult.String()
+	cliCtx, cliCancel := context.WithCancel(context.Background())
+	var cliClient *client.Client
+	defer func() {
+		if cliClient != nil {
+			cliClient.RequestMutex.Unlock()
+		}
+	}()
+
+	for {
+		var errorResponse *client.ErrorMessage
+		cliClient, errorResponse = h.getClient(modelName)
+		if errorResponse != nil {
+			c.Status(errorResponse.StatusCode)
+			_, _ = fmt.Fprint(c.Writer, errorResponse.Error)
+			cliCancel()
+			return
+		}
+
+		if glAPIKey := cliClient.GetGenerativeLanguageAPIKey(); glAPIKey != "" {
+			log.Debugf("Request use generative language API Key: %s", glAPIKey)
+		} else {
+			log.Debugf("Request use account: %s, project id: %s", cliClient.GetEmail(), cliClient.GetProjectID())
+		}
+
+		resp, err := cliClient.SendRawMessage(cliCtx, rawJson)
+		if err != nil {
+			if err.StatusCode == 429 && h.cfg.QuotaExceeded.SwitchProject {
+				continue
+			} else {
+				c.Status(err.StatusCode)
+				_, _ = c.Writer.Write([]byte(err.Error.Error()))
+				cliCancel()
+			}
+			break
+		} else {
+			_, _ = c.Writer.Write(resp)
+			cliCancel()
+			break
+		}
+	}
+}

internal/api/gemini-handlers.go

@@ -0,0 +1,242 @@
+package api
+
+import (
+	"context"
+	"fmt"
+	"github.com/gin-gonic/gin"
+	"github.com/luispater/CLIProxyAPI/internal/api/translator"
+	"github.com/luispater/CLIProxyAPI/internal/client"
+	log "github.com/sirupsen/logrus"
+	"github.com/tidwall/gjson"
+	"github.com/tidwall/sjson"
+	"net/http"
+	"strings"
+	"time"
+)
+
+func (h *APIHandlers) GeminiHandler(c *gin.Context) {
+	var person struct {
+		Action string `uri:"action" binding:"required"`
+	}
+	if err := c.ShouldBindUri(&person); err != nil {
+		c.JSON(http.StatusBadRequest, ErrorResponse{
+			Error: ErrorDetail{
+				Message: fmt.Sprintf("Invalid request: %v", err),
+				Type:    "invalid_request_error",
+			},
+		})
+		return
+	}
+	action := strings.Split(person.Action, ":")
+	if len(action) != 2 {
+		c.JSON(http.StatusNotFound, ErrorResponse{
+			Error: ErrorDetail{
+				Message: fmt.Sprintf("%s not found.", c.Request.URL.Path),
+				Type:    "invalid_request_error",
+			},
+		})
+		return
+	}
+
+	modelName := action[0]
+	method := action[1]
+	rawJson, _ := c.GetRawData()
+	rawJson, _ = sjson.SetBytes(rawJson, "model", []byte(modelName))
+
+	if method == "generateContent" {
+		h.geminiGenerateContent(c, rawJson)
+	} else if method == "streamGenerateContent" {
+		h.geminiStreamGenerateContent(c, rawJson)
+	}
+}
+
+func (h *APIHandlers) geminiStreamGenerateContent(c *gin.Context, rawJson []byte) {
+	// Get the http.Flusher interface to manually flush the response.
+	flusher, ok := c.Writer.(http.Flusher)
+	if !ok {
+		c.JSON(http.StatusInternalServerError, ErrorResponse{
+			Error: ErrorDetail{
+				Message: "Streaming not supported",
+				Type:    "server_error",
+			},
+		})
+		return
+	}
+
+	modelResult := gjson.GetBytes(rawJson, "model")
+	modelName := modelResult.String()
+
+	cliCtx, cliCancel := context.WithCancel(context.Background())
+	var cliClient *client.Client
+	defer func() {
+		// Ensure the client's mutex is unlocked on function exit.
+		if cliClient != nil {
+			cliClient.RequestMutex.Unlock()
+		}
+	}()
+
+outLoop:
+	for {
+		var errorResponse *client.ErrorMessage
+		cliClient, errorResponse = h.getClient(modelName)
+		if errorResponse != nil {
+			c.Status(errorResponse.StatusCode)
+			_, _ = fmt.Fprint(c.Writer, errorResponse.Error)
+			flusher.Flush()
+			cliCancel()
+			return
+		}
+
+		template := `{"project":"","request":{},"model":""}`
+		template, _ = sjson.SetRaw(template, "request", string(rawJson))
+		template, _ = sjson.Set(template, "model", gjson.Get(template, "request.model").String())
+		template, _ = sjson.Delete(template, "request.model")
+
+		template, errFixCLIToolResponse := translator.FixCLIToolResponse(template)
+		if errFixCLIToolResponse != nil {
+			c.JSON(http.StatusInternalServerError, ErrorResponse{
+				Error: ErrorDetail{
+					Message: errFixCLIToolResponse.Error(),
+					Type:    "server_error",
+				},
+			})
+			cliCancel()
+			return
+		}
+
+		systemInstructionResult := gjson.Get(template, "request.system_instruction")
+		if systemInstructionResult.Exists() {
+			template, _ = sjson.SetRaw(template, "request.systemInstruction", systemInstructionResult.Raw)
+			template, _ = sjson.Delete(template, "request.system_instruction")
+		}
+		rawJson = []byte(template)
+
+		if glAPIKey := cliClient.GetGenerativeLanguageAPIKey(); glAPIKey != "" {
+			log.Debugf("Request use generative language API Key: %s", glAPIKey)
+		} else {
+			log.Debugf("Request use account: %s, project id: %s", cliClient.GetEmail(), cliClient.GetProjectID())
+		}
+
+		// Send the message and receive response chunks and errors via channels.
+		respChan, errChan := cliClient.SendRawMessageStream(cliCtx, rawJson)
+		for {
+			select {
+			// Handle client disconnection.
+			case <-c.Request.Context().Done():
+				if c.Request.Context().Err().Error() == "context canceled" {
+					log.Debugf("Client disconnected: %v", c.Request.Context().Err())
+					cliCancel() // Cancel the backend request.
+					return
+				}
+			// Process incoming response chunks.
+			case chunk, okStream := <-respChan:
+				if !okStream {
+					cliCancel()
+					return
+				} else {
+					if cliClient.GetGenerativeLanguageAPIKey() == "" {
+						responseResult := gjson.GetBytes(chunk, "response")
+						if responseResult.Exists() {
+							chunk = []byte(responseResult.Raw)
+						}
+					}
+					_, _ = c.Writer.Write([]byte("data: "))
+					_, _ = c.Writer.Write(chunk)
+					_, _ = c.Writer.Write([]byte("\n\n"))
+					flusher.Flush()
+				}
+			// Handle errors from the backend.
+			case err, okError := <-errChan:
+				if okError {
+					if err.StatusCode == 429 && h.cfg.QuotaExceeded.SwitchProject {
+						continue outLoop
+					} else {
+						c.Status(err.StatusCode)
+						_, _ = fmt.Fprint(c.Writer, err.Error.Error())
+						flusher.Flush()
+						cliCancel()
+					}
+					return
+				}
+			// Send a keep-alive signal to the client.
+			case <-time.After(500 * time.Millisecond):
+			}
+		}
+	}
+}
+
+func (h *APIHandlers) geminiGenerateContent(c *gin.Context, rawJson []byte) {
+	c.Header("Content-Type", "application/json")
+
+	modelResult := gjson.GetBytes(rawJson, "model")
+	modelName := modelResult.String()
+	cliCtx, cliCancel := context.WithCancel(context.Background())
+	var cliClient *client.Client
+	defer func() {
+		if cliClient != nil {
+			cliClient.RequestMutex.Unlock()
+		}
+	}()
+
+	for {
+		var errorResponse *client.ErrorMessage
+		cliClient, errorResponse = h.getClient(modelName)
+		if errorResponse != nil {
+			c.Status(errorResponse.StatusCode)
+			_, _ = fmt.Fprint(c.Writer, errorResponse.Error)
+			cliCancel()
+			return
+		}
+
+		template := `{"project":"","request":{},"model":""}`
+		template, _ = sjson.SetRaw(template, "request", string(rawJson))
+		template, _ = sjson.Set(template, "model", gjson.Get(template, "request.model").String())
+		template, _ = sjson.Delete(template, "request.model")
+
+		template, errFixCLIToolResponse := translator.FixCLIToolResponse(template)
+		if errFixCLIToolResponse != nil {
+			c.JSON(http.StatusInternalServerError, ErrorResponse{
+				Error: ErrorDetail{
+					Message: errFixCLIToolResponse.Error(),
+					Type:    "server_error",
+				},
+			})
+			cliCancel()
+			return
+		}
+
+		systemInstructionResult := gjson.Get(template, "request.system_instruction")
+		if systemInstructionResult.Exists() {
+			template, _ = sjson.SetRaw(template, "request.systemInstruction", systemInstructionResult.Raw)
+			template, _ = sjson.Delete(template, "request.system_instruction")
+		}
+		rawJson = []byte(template)
+
+		if glAPIKey := cliClient.GetGenerativeLanguageAPIKey(); glAPIKey != "" {
+			log.Debugf("Request use generative language API Key: %s", glAPIKey)
+		} else {
+			log.Debugf("Request use account: %s, project id: %s", cliClient.GetEmail(), cliClient.GetProjectID())
+		}
+		resp, err := cliClient.SendRawMessage(cliCtx, rawJson)
+		if err != nil {
+			if err.StatusCode == 429 && h.cfg.QuotaExceeded.SwitchProject {
+				continue
+			} else {
+				c.Status(err.StatusCode)
+				_, _ = c.Writer.Write([]byte(err.Error.Error()))
+				cliCancel()
+			}
+			break
+		} else {
+			if cliClient.GetGenerativeLanguageAPIKey() == "" {
+				responseResult := gjson.GetBytes(resp, "response")
+				if responseResult.Exists() {
+					resp = []byte(responseResult.Raw)
+				}
+			}
+			_, _ = c.Writer.Write(resp)
+			cliCancel()
+			break
+		}
+	}
+}

internal/api/handlers.go

@@ -2,14 +2,13 @@ package api
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
+	"github.com/luispater/CLIProxyAPI/internal/api/translator"
 	"github.com/luispater/CLIProxyAPI/internal/client"
+	"github.com/luispater/CLIProxyAPI/internal/config"
 	log "github.com/sirupsen/logrus"
 	"github.com/tidwall/gjson"
-	"github.com/tidwall/sjson"
 	"net/http"
-	"strings"
 	"sync"
 	"time"
 
@@ -21,63 +20,27 @@ var (
 	lastUsedClientIndex = 0
 )
 
-// APIHandlers contains the handlers for API endpoints
+// APIHandlers contains the handlers for API endpoints.
+// It holds a pool of clients to interact with the backend service.
 type APIHandlers struct {
 	cliClients []*client.Client
-	debug      bool
+	cfg        *config.Config
 }
 
-// NewAPIHandlers creates a new API handlers instance
-func NewAPIHandlers(cliClients []*client.Client, debug bool) *APIHandlers {
+// NewAPIHandlers creates a new API handlers instance.
+// It takes a slice of clients and a debug flag as input.
+func NewAPIHandlers(cliClients []*client.Client, cfg *config.Config) *APIHandlers {
 	return &APIHandlers{
 		cliClients: cliClients,
-		debug:      debug,
+		cfg:        cfg,
 	}
 }
 
+// Models handles the /v1/models endpoint.
+// It returns a hardcoded list of available AI models.
 func (h *APIHandlers) Models(c *gin.Context) {
 	c.JSON(http.StatusOK, gin.H{
 		"data": []map[string]any{
-			{
-				"id":                    "gemini-2.5-pro-preview-05-06",
-				"object":                "model",
-				"version":               "2.5-preview-05-06",
-				"name":                  "Gemini 2.5 Pro Preview 05-06",
-				"description":           "Preview release (May 6th, 2025) of Gemini 2.5 Pro",
-				"context_length":        1048576,
-				"max_completion_tokens": 65536,
-				"supported_parameters": []string{
-					"tools",
-					"temperature",
-					"top_p",
-					"top_k",
-				},
-				"temperature":    1,
-				"topP":           0.95,
-				"topK":           64,
-				"maxTemperature": 2,
-				"thinking":       true,
-			},
-			{
-				"id":                    "gemini-2.5-pro-preview-06-05",
-				"object":                "model",
-				"version":               "2.5-preview-06-05",
-				"name":                  "Gemini 2.5 Pro Preview",
-				"description":           "Preview release (June 5th, 2025) of Gemini 2.5 Pro",
-				"context_length":        1048576,
-				"max_completion_tokens": 65536,
-				"supported_parameters": []string{
-					"tools",
-					"temperature",
-					"top_p",
-					"top_k",
-				},
-				"temperature":    1,
-				"topP":           0.95,
-				"topK":           64,
-				"maxTemperature": 2,
-				"thinking":       true,
-			},
 			{
 				"id":                    "gemini-2.5-pro",
 				"object":                "model",
@@ -98,46 +61,6 @@ func (h *APIHandlers) Models(c *gin.Context) {
 				"maxTemperature": 2,
 				"thinking":       true,
 			},
-			{
-				"id":                    "gemini-2.5-flash-preview-04-17",
-				"object":                "model",
-				"version":               "2.5-preview-04-17",
-				"name":                  "Gemini 2.5 Flash Preview 04-17",
-				"description":           "Preview release (April 17th, 2025) of Gemini 2.5 Flash",
-				"context_length":        1048576,
-				"max_completion_tokens": 65536,
-				"supported_parameters": []string{
-					"tools",
-					"temperature",
-					"top_p",
-					"top_k",
-				},
-				"temperature":    1,
-				"topP":           0.95,
-				"topK":           64,
-				"maxTemperature": 2,
-				"thinking":       true,
-			},
-			{
-				"id":                    "gemini-2.5-flash-preview-05-20",
-				"object":                "model",
-				"version":               "2.5-preview-05-20",
-				"name":                  "Gemini 2.5 Flash Preview 05-20",
-				"description":           "Preview release (April 17th, 2025) of Gemini 2.5 Flash",
-				"context_length":        1048576,
-				"max_completion_tokens": 65536,
-				"supported_parameters": []string{
-					"tools",
-					"temperature",
-					"top_p",
-					"top_k",
-				},
-				"temperature":    1,
-				"topP":           0.95,
-				"topK":           64,
-				"maxTemperature": 2,
-				"thinking":       true,
-			},
 			{
 				"id":                    "gemini-2.5-flash",
 				"object":                "model",
@@ -162,241 +85,35 @@ func (h *APIHandlers) Models(c *gin.Context) {
 	})
 }
 
-// ChatCompletions handles the /v1/chat/completions endpoint
-func (h *APIHandlers) ChatCompletions(c *gin.Context) {
-	rawJson, err := c.GetRawData()
-	// If data retrieval fails, return 400 error
-	if err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": fmt.Sprintf("Invalid request: %v", err), "code": 400})
-		return
-	}
-
-	streamResult := gjson.GetBytes(rawJson, "stream")
-	if streamResult.Type == gjson.True {
-		h.handleStreamingResponse(c, rawJson)
-	} else {
-		h.handleNonStreamingResponse(c, rawJson)
-	}
-}
-
-func (h *APIHandlers) prepareRequest(rawJson []byte) (string, []client.Content, []client.ToolDeclaration) {
-	// log.Debug(string(rawJson))
-	modelName := "gemini-2.5-pro"
-	modelResult := gjson.GetBytes(rawJson, "model")
-	if modelResult.Type == gjson.String {
-		modelName = modelResult.String()
-	}
-
-	contents := make([]client.Content, 0)
-	messagesResult := gjson.GetBytes(rawJson, "messages")
-	if messagesResult.IsArray() {
-		messagesResults := messagesResult.Array()
-		for i := 0; i < len(messagesResults); i++ {
-			messageResult := messagesResults[i]
-			roleResult := messageResult.Get("role")
-			contentResult := messageResult.Get("content")
-			if roleResult.Type == gjson.String {
-				if roleResult.String() == "system" {
-					if contentResult.Type == gjson.String {
-						contents = append(contents, client.Content{Role: "user", Parts: []client.Part{{Text: contentResult.String()}}})
-					} else if contentResult.IsObject() {
-						contentTypeResult := contentResult.Get("type")
-						if contentTypeResult.Type == gjson.String && contentTypeResult.String() == "text" {
-							contentTextResult := contentResult.Get("text")
-							if contentTextResult.Type == gjson.String {
-								contents = append(contents, client.Content{Role: "user", Parts: []client.Part{{Text: contentTextResult.String()}}})
-								contents = append(contents, client.Content{Role: "model", Parts: []client.Part{{Text: "Understood. I will follow these instructions and use my tools to assist you."}}})
-							}
-						}
-					}
-				} else if roleResult.String() == "user" {
-					if contentResult.Type == gjson.String {
-						contents = append(contents, client.Content{Role: "user", Parts: []client.Part{{Text: contentResult.String()}}})
-					} else if contentResult.IsObject() {
-						contentTypeResult := contentResult.Get("type")
-						if contentTypeResult.Type == gjson.String && contentTypeResult.String() == "text" {
-							contentTextResult := contentResult.Get("text")
-							if contentTextResult.Type == gjson.String {
-								contents = append(contents, client.Content{Role: "user", Parts: []client.Part{{Text: contentTextResult.String()}}})
-							}
-						}
-					} else if contentResult.IsArray() {
-						contentItemResults := contentResult.Array()
-						parts := make([]client.Part, 0)
-						for j := 0; j < len(contentItemResults); j++ {
-							contentItemResult := contentItemResults[j]
-							contentTypeResult := contentItemResult.Get("type")
-							if contentTypeResult.Type == gjson.String && contentTypeResult.String() == "text" {
-								contentTextResult := contentItemResult.Get("text")
-								if contentTextResult.Type == gjson.String {
-									parts = append(parts, client.Part{Text: contentTextResult.String()})
-								}
-							} else if contentTypeResult.Type == gjson.String && contentTypeResult.String() == "image_url" {
-								imageURLResult := contentItemResult.Get("image_url.url")
-								if imageURLResult.Type == gjson.String {
-									imageURL := imageURLResult.String()
-									if len(imageURL) > 5 {
-										imageURLs := strings.SplitN(imageURL[5:], ";", 2)
-										if len(imageURLs) == 2 {
-											if len(imageURLs[1]) > 7 {
-												parts = append(parts, client.Part{InlineData: &client.InlineData{
-													MimeType: imageURLs[0],
-													Data:     imageURLs[1][7:],
-												}})
-											}
-										}
-									}
-								}
-							} else if contentTypeResult.Type == gjson.String && contentTypeResult.String() == "file" {
-								filenameResult := contentItemResult.Get("file.filename")
-								fileDataResult := contentItemResult.Get("file.file_data")
-								if filenameResult.Type == gjson.String && fileDataResult.Type == gjson.String {
-									filename := filenameResult.String()
-									splitFilename := strings.Split(filename, ".")
-									ext := splitFilename[len(splitFilename)-1]
-
-									mimeType, ok := MimeTypes[ext]
-									if !ok {
-										log.Warnf("Unknown file name extension '%s' at index %d, skipping file", ext, j)
-										continue
-									}
-
-									parts = append(parts, client.Part{InlineData: &client.InlineData{
-										MimeType: mimeType,
-										Data:     fileDataResult.String(),
-									}})
-								}
-							}
-						}
-						contents = append(contents, client.Content{Role: "user", Parts: parts})
-					}
-				} else if roleResult.String() == "assistant" {
-					if contentResult.Type == gjson.String {
-						contents = append(contents, client.Content{Role: "model", Parts: []client.Part{{Text: contentResult.String()}}})
-					} else if contentResult.IsObject() {
-						contentTypeResult := contentResult.Get("type")
-						if contentTypeResult.Type == gjson.String && contentTypeResult.String() == "text" {
-							contentTextResult := contentResult.Get("text")
-							if contentTextResult.Type == gjson.String {
-								contents = append(contents, client.Content{Role: "user", Parts: []client.Part{{Text: contentTextResult.String()}}})
-							}
-						}
-					} else if !contentResult.Exists() || contentResult.Type == gjson.Null {
-						toolCallsResult := messageResult.Get("tool_calls")
-						if toolCallsResult.IsArray() {
-							tcsResult := toolCallsResult.Array()
-							for j := 0; j < len(tcsResult); j++ {
-								tcResult := tcsResult[j]
-								functionNameResult := tcResult.Get("function.name")
-								functionArguments := tcResult.Get("function.arguments")
-								if functionNameResult.Exists() && functionNameResult.Type == gjson.String && functionArguments.Exists() && functionArguments.Type == gjson.String {
-									var args map[string]any
-									err := json.Unmarshal([]byte(functionArguments.String()), &args)
-									if err == nil {
-										contents = append(contents, client.Content{
-											Role: "model", Parts: []client.Part{
-												{
-													FunctionCall: &client.FunctionCall{
-														Name: functionNameResult.String(),
-														Args: args,
-													},
-												},
-											},
-										})
-									}
-								}
-							}
-						}
-					}
-				} else if roleResult.String() == "tool" {
-					toolCallIDResult := messageResult.Get("tool_call_id")
-					if toolCallIDResult.Exists() && toolCallIDResult.Type == gjson.String {
-						if contentResult.Type == gjson.String {
-							functionResponse := client.FunctionResponse{Name: toolCallIDResult.String(), Response: map[string]interface{}{"result": contentResult.String()}}
-							contents = append(contents, client.Content{Role: "tool", Parts: []client.Part{{FunctionResponse: &functionResponse}}})
-						} else if contentResult.IsObject() {
-							contentTypeResult := contentResult.Get("type")
-							if contentTypeResult.Type == gjson.String && contentTypeResult.String() == "text" {
-								contentTextResult := contentResult.Get("text")
-								if contentTextResult.Type == gjson.String {
-									functionResponse := client.FunctionResponse{Name: toolCallIDResult.String(), Response: map[string]interface{}{"result": contentResult.String()}}
-									contents = append(contents, client.Content{Role: "tool", Parts: []client.Part{{FunctionResponse: &functionResponse}}})
-								}
-							}
-						}
-					}
-				}
-			}
-		}
-	}
-
-	var tools []client.ToolDeclaration
-	toolsResult := gjson.GetBytes(rawJson, "tools")
-	if toolsResult.IsArray() {
-		tools = make([]client.ToolDeclaration, 1)
-		tools[0].FunctionDeclarations = make([]any, 0)
-		toolsResults := toolsResult.Array()
-		for i := 0; i < len(toolsResults); i++ {
-			toolTypeResult := toolsResults[i].Get("type")
-			if toolTypeResult.Type != gjson.String || toolTypeResult.String() != "function" {
-				continue
-			}
-			functionTypeResult := toolsResults[i].Get("function")
-			if functionTypeResult.Exists() && functionTypeResult.IsObject() {
-				var functionDeclaration any
-				err := json.Unmarshal([]byte(functionTypeResult.Raw), &functionDeclaration)
-				if err == nil {
-					tools[0].FunctionDeclarations = append(tools[0].FunctionDeclarations, functionDeclaration)
-				}
-			}
-		}
-	} else {
-		tools = make([]client.ToolDeclaration, 0)
-	}
-	return modelName, contents, tools
-}
-
-// handleNonStreamingResponse handles non-streaming responses
-func (h *APIHandlers) handleNonStreamingResponse(c *gin.Context, rawJson []byte) {
-	c.Header("Content-Type", "application/json")
-
-	// Handle streaming manually
-	flusher, ok := c.Writer.(http.Flusher)
-	if !ok {
-		c.JSON(http.StatusInternalServerError, ErrorResponse{
-			Error: ErrorDetail{
-				Message: "Streaming not supported",
-				Type:    "server_error",
-			},
-		})
-		return
-	}
-
-	modelName, contents, tools := h.prepareRequest(rawJson)
-	cliCtx, cliCancel := context.WithCancel(context.Background())
+func (h *APIHandlers) getClient(modelName string) (*client.Client, *client.ErrorMessage) {
 	var cliClient *client.Client
-	defer func() {
-		if cliClient != nil {
-			cliClient.RequestMutex.Unlock()
-		}
-	}()
 
-	// Lock the mutex to update the last used page index
+	// Lock the mutex to update the last used client index
 	mutex.Lock()
 	startIndex := lastUsedClientIndex
 	currentIndex := (startIndex + 1) % len(h.cliClients)
 	lastUsedClientIndex = currentIndex
 	mutex.Unlock()
 
-	// Reorder the pages to start from the last used index
-	reorderedPages := make([]*client.Client, len(h.cliClients))
+	// Reorder the client to start from the last used index
+	reorderedClients := make([]*client.Client, 0)
 	for i := 0; i < len(h.cliClients); i++ {
-		reorderedPages[i] = h.cliClients[(startIndex+1+i)%len(h.cliClients)]
+		cliClient = h.cliClients[(startIndex+1+i)%len(h.cliClients)]
+		if cliClient.IsModelQuotaExceeded(modelName) {
+			log.Debugf("Model %s is quota exceeded for account %s, project id: %s", modelName, cliClient.GetEmail(), cliClient.GetProjectID())
+			cliClient = nil
+			continue
+		}
+		reorderedClients = append(reorderedClients, cliClient)
+	}
+
+	if len(reorderedClients) == 0 {
+		return nil, &client.ErrorMessage{StatusCode: 429, Error: fmt.Errorf(`{"error":{"code":429,"message":"All the models of '%s' are quota exceeded","status":"RESOURCE_EXHAUSTED"}}`, modelName)}
 	}
 
 	locked := false
-	for i := 0; i < len(reorderedPages); i++ {
-		cliClient = reorderedPages[i]
+	for i := 0; i < len(reorderedClients); i++ {
+		cliClient = reorderedClients[i]
 		if cliClient.RequestMutex.TryLock() {
 			locked = true
 			break
@@ -407,43 +124,84 @@ func (h *APIHandlers) handleNonStreamingResponse(c *gin.Context, rawJson []byte)
 		cliClient.RequestMutex.Lock()
 	}
 
-	log.Debugf("Request use account: %s, project id: %s", cliClient.GetEmail(), cliClient.GetProjectID())
-	jsonTemplate := `{"id":"","object":"chat.completion","created":123456,"model":"model","choices":[{"index":0,"message":{"role":"assistant","content":null,"reasoning_content":null,"tool_calls":null},"finish_reason":null,"native_finish_reason":null}]}`
-	respChan, errChan := cliClient.SendMessageStream(cliCtx, rawJson, modelName, contents, tools)
+	return cliClient, nil
+}
+
+// ChatCompletions handles the /v1/chat/completions endpoint.
+// It determines whether the request is for a streaming or non-streaming response
+// and calls the appropriate handler.
+func (h *APIHandlers) ChatCompletions(c *gin.Context) {
+	rawJson, err := c.GetRawData()
+	// If data retrieval fails, return a 400 Bad Request error.
+	if err != nil {
+		c.JSON(http.StatusBadRequest, ErrorResponse{
+			Error: ErrorDetail{
+				Message: fmt.Sprintf("Invalid request: %v", err),
+				Type:    "invalid_request_error",
+			},
+		})
+		return
+	}
+
+	// Check if the client requested a streaming response.
+	streamResult := gjson.GetBytes(rawJson, "stream")
+	if streamResult.Type == gjson.True {
+		h.handleStreamingResponse(c, rawJson)
+	} else {
+		h.handleNonStreamingResponse(c, rawJson)
+	}
+}
+
+// handleNonStreamingResponse handles non-streaming chat completion responses.
+// It selects a client from the pool, sends the request, and aggregates the response
+// before sending it back to the client.
+func (h *APIHandlers) handleNonStreamingResponse(c *gin.Context, rawJson []byte) {
+	c.Header("Content-Type", "application/json")
+
+	modelName, systemInstruction, contents, tools := translator.PrepareRequest(rawJson)
+	cliCtx, cliCancel := context.WithCancel(context.Background())
+	var cliClient *client.Client
+	defer func() {
+		if cliClient != nil {
+			cliClient.RequestMutex.Unlock()
+		}
+	}()
+
 	for {
-		select {
-		case <-c.Request.Context().Done():
-			if c.Request.Context().Err().Error() == "context canceled" {
-				log.Debugf("Client disconnected: %v", c.Request.Context().Err())
-				cliCancel()
-				return
-			}
-		case chunk, okStream := <-respChan:
-			if !okStream {
-				_, _ = fmt.Fprint(c.Writer, jsonTemplate)
-				flusher.Flush()
-				cliCancel()
-				return
+		var errorResponse *client.ErrorMessage
+		cliClient, errorResponse = h.getClient(modelName)
+		if errorResponse != nil {
+			c.Status(errorResponse.StatusCode)
+			_, _ = fmt.Fprint(c.Writer, errorResponse.Error)
+			cliCancel()
+			return
+		}
+
+		isGlAPIKey := false
+		if glAPIKey := cliClient.GetGenerativeLanguageAPIKey(); glAPIKey != "" {
+			log.Debugf("Request use generative language API Key: %s", glAPIKey)
+			isGlAPIKey = true
+		} else {
+			log.Debugf("Request use account: %s, project id: %s", cliClient.GetEmail(), cliClient.GetProjectID())
+		}
+
+		resp, err := cliClient.SendMessage(cliCtx, rawJson, modelName, systemInstruction, contents, tools)
+		if err != nil {
+			if err.StatusCode == 429 && h.cfg.QuotaExceeded.SwitchProject {
+				continue
 			} else {
-				jsonTemplate = h.convertCliToOpenAINonStream(jsonTemplate, chunk)
-			}
-		case err, okError := <-errChan:
-			if okError {
 				c.Status(err.StatusCode)
-				_, _ = fmt.Fprint(c.Writer, err.Error.Error())
-				flusher.Flush()
-				// c.JSON(http.StatusInternalServerError, ErrorResponse{
-				// 	Error: ErrorDetail{
-				// 		Message: err.Error(),
-				// 		Type:    "server_error",
-				// 	},
-				// })
+				_, _ = c.Writer.Write([]byte(err.Error.Error()))
 				cliCancel()
-				return
 			}
-		case <-time.After(500 * time.Millisecond):
-			_, _ = c.Writer.Write([]byte("\n"))
-			flusher.Flush()
+			break
+		} else {
+			openAIFormat := translator.ConvertCliToOpenAINonStream(resp, time.Now().Unix(), isGlAPIKey)
+			if openAIFormat != "" {
+				_, _ = c.Writer.Write([]byte(openAIFormat))
+			}
+			cliCancel()
+			break
 		}
 	}
 }
@@ -455,7 +213,7 @@ func (h *APIHandlers) handleStreamingResponse(c *gin.Context, rawJson []byte) {
 	c.Header("Connection", "keep-alive")
 	c.Header("Access-Control-Allow-Origin", "*")
 
-	// Handle streaming manually
+	// Get the http.Flusher interface to manually flush the response.
 	flusher, ok := c.Writer.(http.Flusher)
 	if !ok {
 		c.JSON(http.StatusInternalServerError, ErrorResponse{
@@ -466,265 +224,86 @@ func (h *APIHandlers) handleStreamingResponse(c *gin.Context, rawJson []byte) {
 		})
 		return
 	}
-	modelName, contents, tools := h.prepareRequest(rawJson)
+
+	// Prepare the request for the backend client.
+	modelName, systemInstruction, contents, tools := translator.PrepareRequest(rawJson)
 	cliCtx, cliCancel := context.WithCancel(context.Background())
 	var cliClient *client.Client
 	defer func() {
+		// Ensure the client's mutex is unlocked on function exit.
 		if cliClient != nil {
 			cliClient.RequestMutex.Unlock()
 		}
 	}()
 
-	// Lock the mutex to update the last used page index
-	mutex.Lock()
-	startIndex := lastUsedClientIndex
-	currentIndex := (startIndex + 1) % len(h.cliClients)
-	lastUsedClientIndex = currentIndex
-	mutex.Unlock()
-
-	// Reorder the pages to start from the last used index
-	reorderedPages := make([]*client.Client, len(h.cliClients))
-	for i := 0; i < len(h.cliClients); i++ {
-		reorderedPages[i] = h.cliClients[(startIndex+1+i)%len(h.cliClients)]
-	}
-
-	locked := false
-	for i := 0; i < len(reorderedPages); i++ {
-		cliClient = reorderedPages[i]
-		if cliClient.RequestMutex.TryLock() {
-			locked = true
-			break
-		}
-	}
-	if !locked {
-		cliClient = h.cliClients[0]
-		cliClient.RequestMutex.Lock()
-	}
-
-	log.Debugf("Request use account: %s, project id: %s", cliClient.GetEmail(), cliClient.GetProjectID())
-	respChan, errChan := cliClient.SendMessageStream(cliCtx, rawJson, modelName, contents, tools)
+outLoop:
 	for {
-		select {
-		case <-c.Request.Context().Done():
-			if c.Request.Context().Err().Error() == "context canceled" {
-				log.Debugf("Client disconnected: %v", c.Request.Context().Err())
-				cliCancel()
-				return
-			}
-		case chunk, okStream := <-respChan:
-			if !okStream {
-				_, _ = fmt.Fprintf(c.Writer, "data: [DONE]\n\n")
-				flusher.Flush()
-				cliCancel()
-				return
-			} else {
-				openAIFormat := h.convertCliToOpenAI(chunk)
-				if openAIFormat != "" {
-					_, _ = fmt.Fprintf(c.Writer, "data: %s\n\n", openAIFormat)
+		var errorResponse *client.ErrorMessage
+		cliClient, errorResponse = h.getClient(modelName)
+		if errorResponse != nil {
+			c.Status(errorResponse.StatusCode)
+			_, _ = fmt.Fprint(c.Writer, errorResponse.Error)
+			flusher.Flush()
+			cliCancel()
+			return
+		}
+
+		isGlAPIKey := false
+		if glAPIKey := cliClient.GetGenerativeLanguageAPIKey(); glAPIKey != "" {
+			log.Debugf("Request use generative language API Key: %s", glAPIKey)
+			isGlAPIKey = true
+		} else {
+			log.Debugf("Request use account: %s, project id: %s", cliClient.GetEmail(), cliClient.GetProjectID())
+		}
+		// Send the message and receive response chunks and errors via channels.
+		respChan, errChan := cliClient.SendMessageStream(cliCtx, rawJson, modelName, systemInstruction, contents, tools)
+		hasFirstResponse := false
+		for {
+			select {
+			// Handle client disconnection.
+			case <-c.Request.Context().Done():
+				if c.Request.Context().Err().Error() == "context canceled" {
+					log.Debugf("Client disconnected: %v", c.Request.Context().Err())
+					cliCancel() // Cancel the backend request.
+					return
+				}
+			// Process incoming response chunks.
+			case chunk, okStream := <-respChan:
+				if !okStream {
+					// Stream is closed, send the final [DONE] message.
+					_, _ = fmt.Fprintf(c.Writer, "data: [DONE]\n\n")
+					flusher.Flush()
+					cliCancel()
+					return
+				} else {
+					// Convert the chunk to OpenAI format and send it to the client.
+					hasFirstResponse = true
+					openAIFormat := translator.ConvertCliToOpenAI(chunk, time.Now().Unix(), isGlAPIKey)
+					if openAIFormat != "" {
+						_, _ = fmt.Fprintf(c.Writer, "data: %s\n\n", openAIFormat)
+						flusher.Flush()
+					}
+				}
+			// Handle errors from the backend.
+			case err, okError := <-errChan:
+				if okError {
+					if err.StatusCode == 429 && h.cfg.QuotaExceeded.SwitchProject {
+						continue outLoop
+					} else {
+						c.Status(err.StatusCode)
+						_, _ = fmt.Fprint(c.Writer, err.Error.Error())
+						flusher.Flush()
+						cliCancel()
+					}
+					return
+				}
+			// Send a keep-alive signal to the client.
+			case <-time.After(500 * time.Millisecond):
+				if hasFirstResponse {
+					_, _ = c.Writer.Write([]byte(": CLI-PROXY-API PROCESSING\n\n"))
 					flusher.Flush()
 				}
 			}
-		case err, okError := <-errChan:
-			if okError {
-				c.Status(err.StatusCode)
-				_, _ = fmt.Fprint(c.Writer, err.Error.Error())
-				flusher.Flush()
-				// c.JSON(http.StatusInternalServerError, ErrorResponse{
-				// 	Error: ErrorDetail{
-				// 		Message: err.Error(),
-				// 		Type:    "server_error",
-				// 	},
-				// })
-				cliCancel()
-				return
-			}
-		case <-time.After(500 * time.Millisecond):
-			_, _ = c.Writer.Write([]byte(": CLI-PROXY-API PROCESSING\n\n"))
-			flusher.Flush()
 		}
 	}
 }
-
-func (h *APIHandlers) convertCliToOpenAI(rawJson []byte) string {
-	// log.Debugf(string(rawJson))
-	template := `{"id":"","object":"chat.completion.chunk","created":12345,"model":"model","choices":[{"index":0,"delta":{"role":null,"content":null,"reasoning_content":null,"tool_calls":null},"finish_reason":null,"native_finish_reason":null}]}`
-
-	modelVersionResult := gjson.GetBytes(rawJson, "response.modelVersion")
-	if modelVersionResult.Exists() && modelVersionResult.Type == gjson.String {
-		template, _ = sjson.Set(template, "model", modelVersionResult.String())
-	}
-
-	createTimeResult := gjson.GetBytes(rawJson, "response.createTime")
-	if createTimeResult.Exists() && createTimeResult.Type == gjson.String {
-		t, err := time.Parse(time.RFC3339Nano, createTimeResult.String())
-		var unixTimestamp int64
-		if err == nil {
-			unixTimestamp = t.Unix()
-		} else {
-			unixTimestamp = time.Now().Unix()
-		}
-		template, _ = sjson.Set(template, "created", unixTimestamp)
-	}
-
-	responseIdResult := gjson.GetBytes(rawJson, "response.responseId")
-	if responseIdResult.Exists() && responseIdResult.Type == gjson.String {
-		template, _ = sjson.Set(template, "id", responseIdResult.String())
-	}
-
-	finishReasonResult := gjson.GetBytes(rawJson, "response.candidates.0.finishReason")
-	if finishReasonResult.Exists() && finishReasonResult.Type == gjson.String {
-		template, _ = sjson.Set(template, "choices.0.finish_reason", finishReasonResult.String())
-		template, _ = sjson.Set(template, "choices.0.native_finish_reason", finishReasonResult.String())
-	}
-
-	usageResult := gjson.GetBytes(rawJson, "response.usageMetadata")
-	candidatesTokenCountResult := usageResult.Get("candidatesTokenCount")
-	if candidatesTokenCountResult.Exists() && candidatesTokenCountResult.Type == gjson.Number {
-		template, _ = sjson.Set(template, "usage.completion_tokens", candidatesTokenCountResult.Int())
-	}
-	totalTokenCountResult := usageResult.Get("totalTokenCount")
-	if totalTokenCountResult.Exists() && totalTokenCountResult.Type == gjson.Number {
-		template, _ = sjson.Set(template, "usage.total_tokens", totalTokenCountResult.Int())
-	}
-	thoughtsTokenCountResult := usageResult.Get("thoughtsTokenCount")
-	promptTokenCountResult := usageResult.Get("promptTokenCount")
-	if promptTokenCountResult.Exists() && promptTokenCountResult.Type == gjson.Number {
-		if thoughtsTokenCountResult.Exists() && thoughtsTokenCountResult.Type == gjson.Number {
-			template, _ = sjson.Set(template, "usage.prompt_tokens", promptTokenCountResult.Int()+thoughtsTokenCountResult.Int())
-		} else {
-			template, _ = sjson.Set(template, "usage.prompt_tokens", promptTokenCountResult.Int())
-		}
-	}
-	if thoughtsTokenCountResult.Exists() && thoughtsTokenCountResult.Type == gjson.Number {
-		template, _ = sjson.Set(template, "usage.completion_tokens_details.reasoning_tokens", thoughtsTokenCountResult.Int())
-	}
-
-	partResult := gjson.GetBytes(rawJson, "response.candidates.0.content.parts.0")
-	partTextResult := partResult.Get("text")
-	functionCallResult := partResult.Get("functionCall")
-
-	if partTextResult.Exists() && partTextResult.Type == gjson.String {
-		partThoughtResult := partResult.Get("thought")
-		if partThoughtResult.Exists() && partThoughtResult.Type == gjson.True {
-			template, _ = sjson.Set(template, "choices.0.delta.reasoning_content", partTextResult.String())
-		} else {
-			template, _ = sjson.Set(template, "choices.0.delta.content", partTextResult.String())
-		}
-		template, _ = sjson.Set(template, "choices.0.delta.role", "assistant")
-	} else if functionCallResult.Exists() {
-		functionCallTemplate := `[{"id": "","type": "function","function": {"name": "","arguments": ""}}]`
-		fcNameResult := functionCallResult.Get("name")
-		if fcNameResult.Exists() && fcNameResult.Type == gjson.String {
-			functionCallTemplate, _ = sjson.Set(functionCallTemplate, "0.id", fcNameResult.String())
-			functionCallTemplate, _ = sjson.Set(functionCallTemplate, "0.function.name", fcNameResult.String())
-		}
-		fcArgsResult := functionCallResult.Get("args")
-		if fcArgsResult.Exists() && fcArgsResult.IsObject() {
-			functionCallTemplate, _ = sjson.Set(functionCallTemplate, "0.function.arguments", fcArgsResult.Raw)
-		}
-		template, _ = sjson.Set(template, "choices.0.delta.role", "assistant")
-		template, _ = sjson.SetRaw(template, "choices.0.delta.tool_calls", functionCallTemplate)
-	} else {
-		return ""
-	}
-
-	return template
-}
-
-func (h *APIHandlers) convertCliToOpenAINonStream(template string, rawJson []byte) string {
-	modelVersionResult := gjson.GetBytes(rawJson, "response.modelVersion")
-	if modelVersionResult.Exists() && modelVersionResult.Type == gjson.String {
-		template, _ = sjson.Set(template, "model", modelVersionResult.String())
-	}
-
-	createTimeResult := gjson.GetBytes(rawJson, "response.createTime")
-	if createTimeResult.Exists() && createTimeResult.Type == gjson.String {
-		t, err := time.Parse(time.RFC3339Nano, createTimeResult.String())
-		var unixTimestamp int64
-		if err == nil {
-			unixTimestamp = t.Unix()
-		} else {
-			unixTimestamp = time.Now().Unix()
-		}
-		template, _ = sjson.Set(template, "created", unixTimestamp)
-	}
-
-	responseIdResult := gjson.GetBytes(rawJson, "response.responseId")
-	if responseIdResult.Exists() && responseIdResult.Type == gjson.String {
-		template, _ = sjson.Set(template, "id", responseIdResult.String())
-	}
-
-	finishReasonResult := gjson.GetBytes(rawJson, "response.candidates.0.finishReason")
-	if finishReasonResult.Exists() && finishReasonResult.Type == gjson.String {
-		template, _ = sjson.Set(template, "choices.0.finish_reason", finishReasonResult.String())
-		template, _ = sjson.Set(template, "choices.0.native_finish_reason", finishReasonResult.String())
-	}
-
-	usageResult := gjson.GetBytes(rawJson, "response.usageMetadata")
-	candidatesTokenCountResult := usageResult.Get("candidatesTokenCount")
-	if candidatesTokenCountResult.Exists() && candidatesTokenCountResult.Type == gjson.Number {
-		template, _ = sjson.Set(template, "usage.completion_tokens", candidatesTokenCountResult.Int())
-	}
-	totalTokenCountResult := usageResult.Get("totalTokenCount")
-	if totalTokenCountResult.Exists() && totalTokenCountResult.Type == gjson.Number {
-		template, _ = sjson.Set(template, "usage.total_tokens", totalTokenCountResult.Int())
-	}
-	thoughtsTokenCountResult := usageResult.Get("thoughtsTokenCount")
-	promptTokenCountResult := usageResult.Get("promptTokenCount")
-	if promptTokenCountResult.Exists() && promptTokenCountResult.Type == gjson.Number {
-		if thoughtsTokenCountResult.Exists() && thoughtsTokenCountResult.Type == gjson.Number {
-			template, _ = sjson.Set(template, "usage.prompt_tokens", promptTokenCountResult.Int()+thoughtsTokenCountResult.Int())
-		} else {
-			template, _ = sjson.Set(template, "usage.prompt_tokens", promptTokenCountResult.Int())
-		}
-	}
-	if thoughtsTokenCountResult.Exists() && thoughtsTokenCountResult.Type == gjson.Number {
-		template, _ = sjson.Set(template, "usage.completion_tokens_details.reasoning_tokens", thoughtsTokenCountResult.Int())
-	}
-
-	partResult := gjson.GetBytes(rawJson, "response.candidates.0.content.parts.0")
-	partTextResult := partResult.Get("text")
-	functionCallResult := partResult.Get("functionCall")
-
-	if partTextResult.Exists() && partTextResult.Type == gjson.String {
-		partThoughtResult := partResult.Get("thought")
-		if partThoughtResult.Exists() && partThoughtResult.Type == gjson.True {
-			reasoningContentResult := gjson.Get(template, "choices.0.message.reasoning_content")
-			if reasoningContentResult.Type == gjson.String {
-				template, _ = sjson.Set(template, "choices.0.message.reasoning_content", reasoningContentResult.String()+partTextResult.String())
-			} else {
-				template, _ = sjson.Set(template, "choices.0.message.reasoning_content", partTextResult.String())
-			}
-		} else {
-			reasoningContentResult := gjson.Get(template, "choices.0.message.content")
-			if reasoningContentResult.Type == gjson.String {
-				template, _ = sjson.Set(template, "choices.0.message.content", reasoningContentResult.String()+partTextResult.String())
-			} else {
-				template, _ = sjson.Set(template, "choices.0.message.content", partTextResult.String())
-			}
-		}
-		template, _ = sjson.Set(template, "choices.0.message.role", "assistant")
-	} else if functionCallResult.Exists() {
-		toolCallsResult := gjson.Get(template, "choices.0.message.tool_calls")
-		if !toolCallsResult.Exists() || toolCallsResult.Type == gjson.Null {
-			template, _ = sjson.SetRaw(template, "choices.0.message.tool_calls", `[]`)
-		}
-
-		functionCallItemTemplate := `{"id": "","type": "function","function": {"name": "","arguments": ""}}`
-		fcNameResult := functionCallResult.Get("name")
-		if fcNameResult.Exists() && fcNameResult.Type == gjson.String {
-			functionCallItemTemplate, _ = sjson.Set(functionCallItemTemplate, "id", fcNameResult.String())
-			functionCallItemTemplate, _ = sjson.Set(functionCallItemTemplate, "function.name", fcNameResult.String())
-		}
-		fcArgsResult := functionCallResult.Get("args")
-		if fcArgsResult.Exists() && fcArgsResult.IsObject() {
-			functionCallItemTemplate, _ = sjson.Set(functionCallItemTemplate, "function.arguments", fcArgsResult.Raw)
-		}
-		template, _ = sjson.Set(template, "choices.0.message.role", "assistant")
-		template, _ = sjson.SetRaw(template, "choices.0.message.tool_calls.-1", functionCallItemTemplate)
-	} else {
-		return ""
-	}
-
-	return template
-}

internal/api/models.go

@@ -1,13 +1,18 @@
 package api
 
-// ErrorResponse represents an error response
+// ErrorResponse represents a standard error response format for the API.
+// It contains a single ErrorDetail field.
 type ErrorResponse struct {
 	Error ErrorDetail `json:"error"`
 }
 
-// ErrorDetail represents error details
+// ErrorDetail provides specific information about an error that occurred.
+// It includes a human-readable message, an error type, and an optional error code.
 type ErrorDetail struct {
+	// A human-readable message providing more details about the error.
 	Message string `json:"message"`
-	Type    string `json:"type"`
-	Code    string `json:"code,omitempty"`
+	// The type of error that occurred (e.g., "invalid_request_error").
+	Type string `json:"type"`
+	// A short code identifying the error, if applicable.
+	Code string `json:"code,omitempty"`
 }

internal/api/server.go

@@ -6,35 +6,31 @@ import (
 	"fmt"
 	"github.com/gin-gonic/gin"
 	"github.com/luispater/CLIProxyAPI/internal/client"
+	"github.com/luispater/CLIProxyAPI/internal/config"
 	log "github.com/sirupsen/logrus"
 	"net/http"
 	"strings"
 )
 
-// Server represents the API server
+// Server represents the main API server.
+// It encapsulates the Gin engine, HTTP server, handlers, and configuration.
 type Server struct {
 	engine   *gin.Engine
 	server   *http.Server
 	handlers *APIHandlers
-	cfg      *ServerConfig
+	cfg      *config.Config
 }
 
-// ServerConfig contains configuration for the API server
-type ServerConfig struct {
-	Port    string
-	Debug   bool
-	ApiKeys []string
-}
-
-// NewServer creates a new API server instance
-func NewServer(config *ServerConfig, cliClients []*client.Client) *Server {
+// NewServer creates and initializes a new API server instance.
+// It sets up the Gin engine, middleware, routes, and handlers.
+func NewServer(cfg *config.Config, cliClients []*client.Client) *Server {
 	// Set gin mode
-	if !config.Debug {
+	if !cfg.Debug {
 		gin.SetMode(gin.ReleaseMode)
 	}
 
 	// Create handlers
-	handlers := NewAPIHandlers(cliClients, config.Debug)
+	handlers := NewAPIHandlers(cliClients, cfg)
 
 	// Create gin engine
 	engine := gin.New()
@@ -48,7 +44,7 @@ func NewServer(config *ServerConfig, cliClients []*client.Client) *Server {
 	s := &Server{
 		engine:   engine,
 		handlers: handlers,
-		cfg:      config,
+		cfg:      cfg,
 	}
 
 	// Setup routes
@@ -56,14 +52,15 @@ func NewServer(config *ServerConfig, cliClients []*client.Client) *Server {
 
 	// Create HTTP server
 	s.server = &http.Server{
-		Addr:    ":" + config.Port,
+		Addr:    fmt.Sprintf(":%d", cfg.Port),
 		Handler: engine,
 	}
 
 	return s
 }
 
-// setupRoutes configures the API routes
+// setupRoutes configures the API routes for the server.
+// It defines the endpoints and associates them with their respective handlers.
 func (s *Server) setupRoutes() {
 	// OpenAI compatible API routes
 	v1 := s.engine.Group("/v1")
@@ -71,6 +68,15 @@ func (s *Server) setupRoutes() {
 	{
 		v1.GET("/models", s.handlers.Models)
 		v1.POST("/chat/completions", s.handlers.ChatCompletions)
+		v1.POST("/messages", s.handlers.ClaudeMessages)
+	}
+
+	// Gemini compatible API routes
+	v1beta := s.engine.Group("/v1beta")
+	v1beta.Use(AuthMiddleware(s.cfg))
+	{
+		v1beta.GET("/models", s.handlers.Models)
+		v1beta.POST("/models/:action", s.handlers.GeminiHandler)
 	}
 
 	// Root endpoint
@@ -84,13 +90,16 @@ func (s *Server) setupRoutes() {
 			},
 		})
 	})
+	s.engine.POST("/v1internal:method", s.handlers.CLIHandler)
+
 }
 
-// Start starts the API server
+// Start begins listening for and serving HTTP requests.
+// It's a blocking call and will only return on an unrecoverable error.
 func (s *Server) Start() error {
 	log.Debugf("Starting API server on %s", s.server.Addr)
 
-	// Start the HTTP server
+	// Start the HTTP server.
 	if err := s.server.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
 		return fmt.Errorf("failed to start HTTP server: %v", err)
 	}
@@ -98,11 +107,12 @@ func (s *Server) Start() error {
 	return nil
 }
 
-// Stop gracefully stops the API server
+// Stop gracefully shuts down the API server without interrupting any
+// active connections.
 func (s *Server) Stop(ctx context.Context) error {
 	log.Debug("Stopping API server...")
 
-	// Shutdown the HTTP server
+	// Shutdown the HTTP server.
 	if err := s.server.Shutdown(ctx); err != nil {
 		return fmt.Errorf("failed to shutdown HTTP server: %v", err)
 	}
@@ -111,7 +121,8 @@ func (s *Server) Stop(ctx context.Context) error {
 	return nil
 }
 
-// corsMiddleware adds CORS headers
+// corsMiddleware returns a Gin middleware handler that adds CORS headers
+// to every response, allowing cross-origin requests.
 func corsMiddleware() gin.HandlerFunc {
 	return func(c *gin.Context) {
 		c.Header("Access-Control-Allow-Origin", "*")
@@ -127,8 +138,9 @@ func corsMiddleware() gin.HandlerFunc {
 	}
 }
 
-// AuthMiddleware authenticates requests using API keys
-func AuthMiddleware(cfg *ServerConfig) gin.HandlerFunc {
+// AuthMiddleware returns a Gin middleware handler that authenticates requests
+// using API keys. If no API keys are configured, it allows all requests.
+func AuthMiddleware(cfg *config.Config) gin.HandlerFunc {
 	return func(c *gin.Context) {
 		if len(cfg.ApiKeys) == 0 {
 			c.Next()
@@ -137,7 +149,9 @@ func AuthMiddleware(cfg *ServerConfig) gin.HandlerFunc {
 
 		// Get the Authorization header
 		authHeader := c.GetHeader("Authorization")
-		if authHeader == "" {
+		authHeaderGoogle := c.GetHeader("X-Goog-Api-Key")
+		authHeaderAnthropic := c.GetHeader("X-Api-Key")
+		if authHeader == "" && authHeaderGoogle == "" && authHeaderAnthropic == "" {
 			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
 				"error": "Missing API key",
 			})
@@ -156,7 +170,7 @@ func AuthMiddleware(cfg *ServerConfig) gin.HandlerFunc {
 		// Find the API key in the in-memory list
 		var foundKey string
 		for i := range cfg.ApiKeys {
-			if cfg.ApiKeys[i] == apiKey {
+			if cfg.ApiKeys[i] == apiKey || cfg.ApiKeys[i] == authHeaderGoogle || cfg.ApiKeys[i] == authHeaderAnthropic {
 				foundKey = cfg.ApiKeys[i]
 				break
 			}

internal/api/translator/mime-type.go

@@ -1,5 +1,7 @@
-package api
+package translator
 
+// MimeTypes is a comprehensive map of file extensions to their corresponding MIME types.
+// This is used to identify the type of file being uploaded or processed.
 var MimeTypes = map[string]string{
 	"ez":          "application/andrew-inset",
 	"aw":          "application/applixware",

internal/api/translator/request.go

@@ -0,0 +1,544 @@
+package translator
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"github.com/tidwall/sjson"
+	"strings"
+
+	"github.com/luispater/CLIProxyAPI/internal/client"
+	log "github.com/sirupsen/logrus"
+	"github.com/tidwall/gjson"
+)
+
+// PrepareRequest translates a raw JSON request from an OpenAI-compatible format
+// to the internal format expected by the backend client. It parses messages,
+// roles, content types (text, image, file), and tool calls.
+func PrepareRequest(rawJson []byte) (string, *client.Content, []client.Content, []client.ToolDeclaration) {
+	// Extract the model name from the request, defaulting to "gemini-2.5-pro".
+	modelName := "gemini-2.5-pro"
+	modelResult := gjson.GetBytes(rawJson, "model")
+	if modelResult.Type == gjson.String {
+		modelName = modelResult.String()
+	}
+
+	// Initialize data structures for processing conversation messages
+	// contents: stores the processed conversation history
+	// systemInstruction: stores system-level instructions separate from conversation
+	contents := make([]client.Content, 0)
+	var systemInstruction *client.Content
+	messagesResult := gjson.GetBytes(rawJson, "messages")
+
+	// Pre-process tool responses to create a lookup map
+	// This first pass collects all tool responses so they can be matched with their corresponding calls
+	toolItems := make(map[string]*client.FunctionResponse)
+	if messagesResult.IsArray() {
+		messagesResults := messagesResult.Array()
+		for i := 0; i < len(messagesResults); i++ {
+			messageResult := messagesResults[i]
+			roleResult := messageResult.Get("role")
+			if roleResult.Type != gjson.String {
+				continue
+			}
+			contentResult := messageResult.Get("content")
+
+			// Extract tool responses for later matching with function calls
+			if roleResult.String() == "tool" {
+				toolCallID := messageResult.Get("tool_call_id").String()
+				if toolCallID != "" {
+					var responseData string
+					// Handle both string and object-based tool response formats
+					if contentResult.Type == gjson.String {
+						responseData = contentResult.String()
+					} else if contentResult.IsObject() && contentResult.Get("type").String() == "text" {
+						responseData = contentResult.Get("text").String()
+					}
+
+					// Clean up tool call ID by removing timestamp suffix
+					// This normalizes IDs for consistent matching between calls and responses
+					toolCallIDs := strings.Split(toolCallID, "-")
+					strings.Join(toolCallIDs, "-")
+					newToolCallID := strings.Join(toolCallIDs[:len(toolCallIDs)-1], "-")
+
+					// Create function response object with normalized ID and response data
+					functionResponse := client.FunctionResponse{Name: newToolCallID, Response: map[string]interface{}{"result": responseData}}
+					toolItems[toolCallID] = &functionResponse
+				}
+			}
+		}
+	}
+
+	if messagesResult.IsArray() {
+		messagesResults := messagesResult.Array()
+		for i := 0; i < len(messagesResults); i++ {
+			messageResult := messagesResults[i]
+			roleResult := messageResult.Get("role")
+			contentResult := messageResult.Get("content")
+			if roleResult.Type != gjson.String {
+				continue
+			}
+
+			switch roleResult.String() {
+			// System messages are converted to a user message followed by a model's acknowledgment.
+			case "system":
+				if contentResult.Type == gjson.String {
+					systemInstruction = &client.Content{Role: "user", Parts: []client.Part{{Text: contentResult.String()}}}
+				} else if contentResult.IsObject() {
+					// Handle object-based system messages.
+					if contentResult.Get("type").String() == "text" {
+						systemInstruction = &client.Content{Role: "user", Parts: []client.Part{{Text: contentResult.Get("text").String()}}}
+					}
+				}
+			// User messages can contain simple text or a multi-part body.
+			case "user":
+				if contentResult.Type == gjson.String {
+					contents = append(contents, client.Content{Role: "user", Parts: []client.Part{{Text: contentResult.String()}}})
+				} else if contentResult.IsArray() {
+					// Handle multi-part user messages (text, images, files).
+					contentItemResults := contentResult.Array()
+					parts := make([]client.Part, 0)
+					for j := 0; j < len(contentItemResults); j++ {
+						contentItemResult := contentItemResults[j]
+						contentTypeResult := contentItemResult.Get("type")
+						switch contentTypeResult.String() {
+						case "text":
+							parts = append(parts, client.Part{Text: contentItemResult.Get("text").String()})
+						case "image_url":
+							// Parse data URI for images.
+							imageURL := contentItemResult.Get("image_url.url").String()
+							if len(imageURL) > 5 {
+								imageURLs := strings.SplitN(imageURL[5:], ";", 2)
+								if len(imageURLs) == 2 && len(imageURLs[1]) > 7 {
+									parts = append(parts, client.Part{InlineData: &client.InlineData{
+										MimeType: imageURLs[0],
+										Data:     imageURLs[1][7:],
+									}})
+								}
+							}
+						case "file":
+							// Handle file attachments by determining MIME type from extension.
+							filename := contentItemResult.Get("file.filename").String()
+							fileData := contentItemResult.Get("file.file_data").String()
+							ext := ""
+							if split := strings.Split(filename, "."); len(split) > 1 {
+								ext = split[len(split)-1]
+							}
+							if mimeType, ok := MimeTypes[ext]; ok {
+								parts = append(parts, client.Part{InlineData: &client.InlineData{
+									MimeType: mimeType,
+									Data:     fileData,
+								}})
+							} else {
+								log.Warnf("Unknown file name extension '%s' at index %d, skipping file", ext, j)
+							}
+						}
+					}
+					contents = append(contents, client.Content{Role: "user", Parts: parts})
+				}
+			// Assistant messages can contain text responses or tool calls
+			// In the internal format, assistant messages are converted to "model" role
+			case "assistant":
+				if contentResult.Type == gjson.String {
+					// Simple text response from the assistant
+					contents = append(contents, client.Content{Role: "model", Parts: []client.Part{{Text: contentResult.String()}}})
+				} else if !contentResult.Exists() || contentResult.Type == gjson.Null {
+					// Handle complex tool calls made by the assistant
+					// This processes function calls and matches them with their responses
+					functionIDs := make([]string, 0)
+					toolCallsResult := messageResult.Get("tool_calls")
+					if toolCallsResult.IsArray() {
+						parts := make([]client.Part, 0)
+						tcsResult := toolCallsResult.Array()
+
+						// Process each tool call in the assistant's message
+						for j := 0; j < len(tcsResult); j++ {
+							tcResult := tcsResult[j]
+
+							// Extract function call details
+							functionID := tcResult.Get("id").String()
+							functionIDs = append(functionIDs, functionID)
+
+							functionName := tcResult.Get("function.name").String()
+							functionArgs := tcResult.Get("function.arguments").String()
+
+							// Parse function arguments from JSON string to map
+							var args map[string]any
+							if err := json.Unmarshal([]byte(functionArgs), &args); err == nil {
+								parts = append(parts, client.Part{
+									FunctionCall: &client.FunctionCall{
+										Name: functionName,
+										Args: args,
+									},
+								})
+							}
+						}
+
+						// Add the model's function calls to the conversation
+						if len(parts) > 0 {
+							contents = append(contents, client.Content{
+								Role: "model", Parts: parts,
+							})
+
+							// Create a separate tool response message with the collected responses
+							// This matches function calls with their corresponding responses
+							toolParts := make([]client.Part, 0)
+							for _, functionID := range functionIDs {
+								if functionResponse, ok := toolItems[functionID]; ok {
+									toolParts = append(toolParts, client.Part{FunctionResponse: functionResponse})
+								}
+							}
+							// Add the tool responses as a separate message in the conversation
+							contents = append(contents, client.Content{Role: "tool", Parts: toolParts})
+						}
+					}
+				}
+			}
+		}
+	}
+
+	// Translate the tool declarations from the request.
+	var tools []client.ToolDeclaration
+	toolsResult := gjson.GetBytes(rawJson, "tools")
+	if toolsResult.IsArray() {
+		tools = make([]client.ToolDeclaration, 1)
+		tools[0].FunctionDeclarations = make([]any, 0)
+		toolsResults := toolsResult.Array()
+		for i := 0; i < len(toolsResults); i++ {
+			toolResult := toolsResults[i]
+			if toolResult.Get("type").String() == "function" {
+				functionTypeResult := toolResult.Get("function")
+				if functionTypeResult.Exists() && functionTypeResult.IsObject() {
+					var functionDeclaration any
+					if err := json.Unmarshal([]byte(functionTypeResult.Raw), &functionDeclaration); err == nil {
+						tools[0].FunctionDeclarations = append(tools[0].FunctionDeclarations, functionDeclaration)
+					}
+				}
+			}
+		}
+	} else {
+		tools = make([]client.ToolDeclaration, 0)
+	}
+
+	return modelName, systemInstruction, contents, tools
+}
+
+// FunctionCallGroup represents a group of function calls and their responses
+type FunctionCallGroup struct {
+	ModelContent    map[string]interface{}
+	FunctionCalls   []gjson.Result
+	ResponsesNeeded int
+}
+
+// FixCLIToolResponse performs sophisticated tool response format conversion and grouping.
+// This function transforms the CLI tool response format by intelligently grouping function calls
+// with their corresponding responses, ensuring proper conversation flow and API compatibility.
+// It converts from a linear format (1.json) to a grouped format (2.json) where function calls
+// and their responses are properly associated and structured.
+func FixCLIToolResponse(input string) (string, error) {
+	// Parse the input JSON to extract the conversation structure
+	parsed := gjson.Parse(input)
+
+	// Extract the contents array which contains the conversation messages
+	contents := parsed.Get("request.contents")
+	if !contents.Exists() {
+		return input, fmt.Errorf("contents not found in input")
+	}
+
+	// Initialize data structures for processing and grouping
+	var newContents []interface{}          // Final processed contents array
+	var pendingGroups []*FunctionCallGroup // Groups awaiting completion with responses
+	var collectedResponses []gjson.Result  // Standalone responses to be matched
+
+	// Process each content object in the conversation
+	// This iterates through messages and groups function calls with their responses
+	contents.ForEach(func(key, value gjson.Result) bool {
+		role := value.Get("role").String()
+		parts := value.Get("parts")
+
+		// Check if this content has function responses
+		var responsePartsInThisContent []gjson.Result
+		parts.ForEach(func(_, part gjson.Result) bool {
+			if part.Get("functionResponse").Exists() {
+				responsePartsInThisContent = append(responsePartsInThisContent, part)
+			}
+			return true
+		})
+
+		// If this content has function responses, collect them
+		if len(responsePartsInThisContent) > 0 {
+			collectedResponses = append(collectedResponses, responsePartsInThisContent...)
+
+			// Check if any pending groups can be satisfied
+			for i := len(pendingGroups) - 1; i >= 0; i-- {
+				group := pendingGroups[i]
+				if len(collectedResponses) >= group.ResponsesNeeded {
+					// Take the needed responses for this group
+					groupResponses := collectedResponses[:group.ResponsesNeeded]
+					collectedResponses = collectedResponses[group.ResponsesNeeded:]
+
+					// Create merged function response content
+					var responseParts []interface{}
+					for _, response := range groupResponses {
+						var responseMap map[string]interface{}
+						errUnmarshal := json.Unmarshal([]byte(response.Raw), &responseMap)
+						if errUnmarshal != nil {
+							log.Warnf("failed to unmarshal function response: %v\n", errUnmarshal)
+							continue
+						}
+						responseParts = append(responseParts, responseMap)
+					}
+
+					if len(responseParts) > 0 {
+						functionResponseContent := map[string]interface{}{
+							"parts": responseParts,
+							"role":  "function",
+						}
+						newContents = append(newContents, functionResponseContent)
+					}
+
+					// Remove this group as it's been satisfied
+					pendingGroups = append(pendingGroups[:i], pendingGroups[i+1:]...)
+					break
+				}
+			}
+
+			return true // Skip adding this content, responses are merged
+		}
+
+		// If this is a model with function calls, create a new group
+		if role == "model" {
+			var functionCallsInThisModel []gjson.Result
+			parts.ForEach(func(_, part gjson.Result) bool {
+				if part.Get("functionCall").Exists() {
+					functionCallsInThisModel = append(functionCallsInThisModel, part)
+				}
+				return true
+			})
+
+			if len(functionCallsInThisModel) > 0 {
+				// Add the model content
+				var contentMap map[string]interface{}
+				errUnmarshal := json.Unmarshal([]byte(value.Raw), &contentMap)
+				if errUnmarshal != nil {
+					log.Warnf("failed to unmarshal model content: %v\n", errUnmarshal)
+					return true
+				}
+				newContents = append(newContents, contentMap)
+
+				// Create a new group for tracking responses
+				group := &FunctionCallGroup{
+					ModelContent:    contentMap,
+					FunctionCalls:   functionCallsInThisModel,
+					ResponsesNeeded: len(functionCallsInThisModel),
+				}
+				pendingGroups = append(pendingGroups, group)
+			} else {
+				// Regular model content without function calls
+				var contentMap map[string]interface{}
+				errUnmarshal := json.Unmarshal([]byte(value.Raw), &contentMap)
+				if errUnmarshal != nil {
+					log.Warnf("failed to unmarshal content: %v\n", errUnmarshal)
+					return true
+				}
+				newContents = append(newContents, contentMap)
+			}
+		} else {
+			// Non-model content (user, etc.)
+			var contentMap map[string]interface{}
+			errUnmarshal := json.Unmarshal([]byte(value.Raw), &contentMap)
+			if errUnmarshal != nil {
+				log.Warnf("failed to unmarshal content: %v\n", errUnmarshal)
+				return true
+			}
+			newContents = append(newContents, contentMap)
+		}
+
+		return true
+	})
+
+	// Handle any remaining pending groups with remaining responses
+	for _, group := range pendingGroups {
+		if len(collectedResponses) >= group.ResponsesNeeded {
+			groupResponses := collectedResponses[:group.ResponsesNeeded]
+			collectedResponses = collectedResponses[group.ResponsesNeeded:]
+
+			var responseParts []interface{}
+			for _, response := range groupResponses {
+				var responseMap map[string]interface{}
+				errUnmarshal := json.Unmarshal([]byte(response.Raw), &responseMap)
+				if errUnmarshal != nil {
+					log.Warnf("failed to unmarshal function response: %v\n", errUnmarshal)
+					continue
+				}
+				responseParts = append(responseParts, responseMap)
+			}
+
+			if len(responseParts) > 0 {
+				functionResponseContent := map[string]interface{}{
+					"parts": responseParts,
+					"role":  "function",
+				}
+				newContents = append(newContents, functionResponseContent)
+			}
+		}
+	}
+
+	// Update the original JSON with the new contents
+	result := input
+	newContentsJSON, _ := json.Marshal(newContents)
+	result, _ = sjson.Set(result, "request.contents", json.RawMessage(newContentsJSON))
+
+	return result, nil
+}
+
+func PrepareClaudeRequest(rawJson []byte) (string, *client.Content, []client.Content, []client.ToolDeclaration) {
+	var pathsToDelete []string
+	root := gjson.ParseBytes(rawJson)
+	walk(root, "", "additionalProperties", &pathsToDelete)
+	walk(root, "", "$schema", &pathsToDelete)
+
+	var err error
+	for _, p := range pathsToDelete {
+		rawJson, err = sjson.DeleteBytes(rawJson, p)
+		if err != nil {
+			continue
+		}
+	}
+	rawJson = bytes.Replace(rawJson, []byte(`"url":{"type":"string","format":"uri",`), []byte(`"url":{"type":"string",`), -1)
+
+	// log.Debug(string(rawJson))
+	modelName := "gemini-2.5-pro"
+	modelResult := gjson.GetBytes(rawJson, "model")
+	if modelResult.Type == gjson.String {
+		modelName = modelResult.String()
+	}
+
+	contents := make([]client.Content, 0)
+
+	var systemInstruction *client.Content
+
+	systemResult := gjson.GetBytes(rawJson, "system")
+	if systemResult.IsArray() {
+		systemResults := systemResult.Array()
+		systemInstruction = &client.Content{Role: "user", Parts: []client.Part{}}
+		for i := 0; i < len(systemResults); i++ {
+			systemPromptResult := systemResults[i]
+			systemTypePromptResult := systemPromptResult.Get("type")
+			if systemTypePromptResult.Type == gjson.String && systemTypePromptResult.String() == "text" {
+				systemPrompt := systemPromptResult.Get("text").String()
+				systemPart := client.Part{Text: systemPrompt}
+				systemInstruction.Parts = append(systemInstruction.Parts, systemPart)
+			}
+		}
+		if len(systemInstruction.Parts) == 0 {
+			systemInstruction = nil
+		}
+	}
+
+	messagesResult := gjson.GetBytes(rawJson, "messages")
+	if messagesResult.IsArray() {
+		messageResults := messagesResult.Array()
+		for i := 0; i < len(messageResults); i++ {
+			messageResult := messageResults[i]
+			roleResult := messageResult.Get("role")
+			if roleResult.Type != gjson.String {
+				continue
+			}
+			role := roleResult.String()
+			if role == "assistant" {
+				role = "model"
+			}
+			clientContent := client.Content{Role: role, Parts: []client.Part{}}
+
+			contentsResult := messageResult.Get("content")
+			if contentsResult.IsArray() {
+				contentResults := contentsResult.Array()
+				for j := 0; j < len(contentResults); j++ {
+					contentResult := contentResults[j]
+					contentTypeResult := contentResult.Get("type")
+					if contentTypeResult.Type == gjson.String && contentTypeResult.String() == "text" {
+						prompt := contentResult.Get("text").String()
+						clientContent.Parts = append(clientContent.Parts, client.Part{Text: prompt})
+					} else if contentTypeResult.Type == gjson.String && contentTypeResult.String() == "tool_use" {
+						functionName := contentResult.Get("name").String()
+						functionArgs := contentResult.Get("input").String()
+						var args map[string]any
+						if err = json.Unmarshal([]byte(functionArgs), &args); err == nil {
+							clientContent.Parts = append(clientContent.Parts, client.Part{
+								FunctionCall: &client.FunctionCall{
+									Name: functionName,
+									Args: args,
+								},
+							})
+						}
+					} else if contentTypeResult.Type == gjson.String && contentTypeResult.String() == "tool_result" {
+						toolCallID := contentResult.Get("tool_use_id").String()
+						if toolCallID != "" {
+							funcName := toolCallID
+							toolCallIDs := strings.Split(toolCallID, "-")
+							if len(toolCallIDs) > 1 {
+								funcName = strings.Join(toolCallIDs[0:len(toolCallIDs)-1], "-")
+							}
+							responseData := contentResult.Get("content").String()
+							functionResponse := client.FunctionResponse{Name: funcName, Response: map[string]interface{}{"result": responseData}}
+							clientContent.Parts = append(clientContent.Parts, client.Part{FunctionResponse: &functionResponse})
+						}
+					}
+				}
+				contents = append(contents, clientContent)
+			} else if contentsResult.Type == gjson.String {
+				prompt := contentsResult.String()
+				contents = append(contents, client.Content{Role: role, Parts: []client.Part{{Text: prompt}}})
+			}
+		}
+	}
+
+	var tools []client.ToolDeclaration
+	toolsResult := gjson.GetBytes(rawJson, "tools")
+	if toolsResult.IsArray() {
+		tools = make([]client.ToolDeclaration, 1)
+		tools[0].FunctionDeclarations = make([]any, 0)
+		toolsResults := toolsResult.Array()
+		for i := 0; i < len(toolsResults); i++ {
+			toolResult := toolsResults[i]
+			inputSchemaResult := toolResult.Get("input_schema")
+			if inputSchemaResult.Exists() && inputSchemaResult.IsObject() {
+				inputSchema := inputSchemaResult.Raw
+				inputSchema, _ = sjson.Delete(inputSchema, "additionalProperties")
+				inputSchema, _ = sjson.Delete(inputSchema, "$schema")
+
+				tool, _ := sjson.Delete(toolResult.Raw, "input_schema")
+				tool, _ = sjson.SetRaw(tool, "parameters", inputSchema)
+				var toolDeclaration any
+				if err = json.Unmarshal([]byte(tool), &toolDeclaration); err == nil {
+					tools[0].FunctionDeclarations = append(tools[0].FunctionDeclarations, toolDeclaration)
+				}
+			}
+		}
+	} else {
+		tools = make([]client.ToolDeclaration, 0)
+	}
+
+	return modelName, systemInstruction, contents, tools
+}
+
+func walk(value gjson.Result, path, field string, pathsToDelete *[]string) {
+	switch value.Type {
+	case gjson.JSON:
+		value.ForEach(func(key, val gjson.Result) bool {
+			var childPath string
+			if path == "" {
+				childPath = key.String()
+			} else {
+				childPath = path + "." + key.String()
+			}
+			if key.String() == field {
+				*pathsToDelete = append(*pathsToDelete, childPath)
+			}
+			walk(val, childPath, field, pathsToDelete)
+			return true
+		})
+	case gjson.String, gjson.Number, gjson.True, gjson.False, gjson.Null:
+	}
+}

internal/api/translator/response.go

@@ -0,0 +1,382 @@
+package translator
+
+import (
+	"bytes"
+	"fmt"
+	"time"
+
+	"github.com/tidwall/gjson"
+	"github.com/tidwall/sjson"
+)
+
+// ConvertCliToOpenAI translates a single chunk of a streaming response from the
+// backend client format to the OpenAI Server-Sent Events (SSE) format.
+// It returns an empty string if the chunk contains no useful data.
+func ConvertCliToOpenAI(rawJson []byte, unixTimestamp int64, isGlAPIKey bool) string {
+	if isGlAPIKey {
+		rawJson, _ = sjson.SetRawBytes(rawJson, "response", rawJson)
+	}
+
+	// Initialize the OpenAI SSE template.
+	template := `{"id":"","object":"chat.completion.chunk","created":12345,"model":"model","choices":[{"index":0,"delta":{"role":null,"content":null,"reasoning_content":null,"tool_calls":null},"finish_reason":null,"native_finish_reason":null}]}`
+
+	// Extract and set the model version.
+	if modelVersionResult := gjson.GetBytes(rawJson, "response.modelVersion"); modelVersionResult.Exists() {
+		template, _ = sjson.Set(template, "model", modelVersionResult.String())
+	}
+
+	// Extract and set the creation timestamp.
+	if createTimeResult := gjson.GetBytes(rawJson, "response.createTime"); createTimeResult.Exists() {
+		t, err := time.Parse(time.RFC3339Nano, createTimeResult.String())
+		if err == nil {
+			unixTimestamp = t.Unix()
+		}
+		template, _ = sjson.Set(template, "created", unixTimestamp)
+	} else {
+		template, _ = sjson.Set(template, "created", unixTimestamp)
+	}
+
+	// Extract and set the response ID.
+	if responseIdResult := gjson.GetBytes(rawJson, "response.responseId"); responseIdResult.Exists() {
+		template, _ = sjson.Set(template, "id", responseIdResult.String())
+	}
+
+	// Extract and set the finish reason.
+	if finishReasonResult := gjson.GetBytes(rawJson, "response.candidates.0.finishReason"); finishReasonResult.Exists() {
+		template, _ = sjson.Set(template, "choices.0.finish_reason", finishReasonResult.String())
+		template, _ = sjson.Set(template, "choices.0.native_finish_reason", finishReasonResult.String())
+	}
+
+	// Extract and set usage metadata (token counts).
+	if usageResult := gjson.GetBytes(rawJson, "response.usageMetadata"); usageResult.Exists() {
+		if candidatesTokenCountResult := usageResult.Get("candidatesTokenCount"); candidatesTokenCountResult.Exists() {
+			template, _ = sjson.Set(template, "usage.completion_tokens", candidatesTokenCountResult.Int())
+		}
+		if totalTokenCountResult := usageResult.Get("totalTokenCount"); totalTokenCountResult.Exists() {
+			template, _ = sjson.Set(template, "usage.total_tokens", totalTokenCountResult.Int())
+		}
+		promptTokenCount := usageResult.Get("promptTokenCount").Int()
+		thoughtsTokenCount := usageResult.Get("thoughtsTokenCount").Int()
+		template, _ = sjson.Set(template, "usage.prompt_tokens", promptTokenCount+thoughtsTokenCount)
+		if thoughtsTokenCount > 0 {
+			template, _ = sjson.Set(template, "usage.completion_tokens_details.reasoning_tokens", thoughtsTokenCount)
+		}
+	}
+
+	// Process the main content part of the response.
+	partsResult := gjson.GetBytes(rawJson, "response.candidates.0.content.parts")
+	if partsResult.IsArray() {
+		partResults := partsResult.Array()
+		for i := 0; i < len(partResults); i++ {
+			partResult := partResults[i]
+			partTextResult := partResult.Get("text")
+			functionCallResult := partResult.Get("functionCall")
+
+			if partTextResult.Exists() {
+				// Handle text content, distinguishing between regular content and reasoning/thoughts.
+				if partResult.Get("thought").Bool() {
+					template, _ = sjson.Set(template, "choices.0.delta.reasoning_content", partTextResult.String())
+				} else {
+					template, _ = sjson.Set(template, "choices.0.delta.content", partTextResult.String())
+				}
+				template, _ = sjson.Set(template, "choices.0.delta.role", "assistant")
+			} else if functionCallResult.Exists() {
+				// Handle function call content.
+				toolCallsResult := gjson.Get(template, "choices.0.delta.tool_calls")
+				if !toolCallsResult.Exists() || !toolCallsResult.IsArray() {
+					template, _ = sjson.SetRaw(template, "choices.0.delta.tool_calls", `[]`)
+				}
+
+				functionCallTemplate := `{"id": "","type": "function","function": {"name": "","arguments": ""}}`
+				fcName := functionCallResult.Get("name").String()
+				functionCallTemplate, _ = sjson.Set(functionCallTemplate, "id", fmt.Sprintf("%s-%d", fcName, time.Now().UnixNano()))
+				functionCallTemplate, _ = sjson.Set(functionCallTemplate, "function.name", fcName)
+				if fcArgsResult := functionCallResult.Get("args"); fcArgsResult.Exists() {
+					functionCallTemplate, _ = sjson.Set(functionCallTemplate, "function.arguments", fcArgsResult.Raw)
+				}
+				template, _ = sjson.Set(template, "choices.0.delta.role", "assistant")
+				template, _ = sjson.SetRaw(template, "choices.0.message.tool_calls.-1", functionCallTemplate)
+			}
+		}
+	}
+
+	return template
+}
+
+// ConvertCliToOpenAINonStream aggregates response from the backend client
+// convert a single, non-streaming OpenAI-compatible JSON response.
+func ConvertCliToOpenAINonStream(rawJson []byte, unixTimestamp int64, isGlAPIKey bool) string {
+	if isGlAPIKey {
+		rawJson, _ = sjson.SetRawBytes(rawJson, "response", rawJson)
+	}
+	template := `{"id":"","object":"chat.completion","created":123456,"model":"model","choices":[{"index":0,"message":{"role":"assistant","content":null,"reasoning_content":null,"tool_calls":null},"finish_reason":null,"native_finish_reason":null}]}`
+	if modelVersionResult := gjson.GetBytes(rawJson, "response.modelVersion"); modelVersionResult.Exists() {
+		template, _ = sjson.Set(template, "model", modelVersionResult.String())
+	}
+
+	if createTimeResult := gjson.GetBytes(rawJson, "response.createTime"); createTimeResult.Exists() {
+		t, err := time.Parse(time.RFC3339Nano, createTimeResult.String())
+		if err == nil {
+			unixTimestamp = t.Unix()
+		}
+		template, _ = sjson.Set(template, "created", unixTimestamp)
+	} else {
+		template, _ = sjson.Set(template, "created", unixTimestamp)
+	}
+
+	if responseIdResult := gjson.GetBytes(rawJson, "response.responseId"); responseIdResult.Exists() {
+		template, _ = sjson.Set(template, "id", responseIdResult.String())
+	}
+
+	if finishReasonResult := gjson.GetBytes(rawJson, "response.candidates.0.finishReason"); finishReasonResult.Exists() {
+		template, _ = sjson.Set(template, "choices.0.finish_reason", finishReasonResult.String())
+		template, _ = sjson.Set(template, "choices.0.native_finish_reason", finishReasonResult.String())
+	}
+
+	if usageResult := gjson.GetBytes(rawJson, "response.usageMetadata"); usageResult.Exists() {
+		if candidatesTokenCountResult := usageResult.Get("candidatesTokenCount"); candidatesTokenCountResult.Exists() {
+			template, _ = sjson.Set(template, "usage.completion_tokens", candidatesTokenCountResult.Int())
+		}
+		if totalTokenCountResult := usageResult.Get("totalTokenCount"); totalTokenCountResult.Exists() {
+			template, _ = sjson.Set(template, "usage.total_tokens", totalTokenCountResult.Int())
+		}
+		promptTokenCount := usageResult.Get("promptTokenCount").Int()
+		thoughtsTokenCount := usageResult.Get("thoughtsTokenCount").Int()
+		template, _ = sjson.Set(template, "usage.prompt_tokens", promptTokenCount+thoughtsTokenCount)
+		if thoughtsTokenCount > 0 {
+			template, _ = sjson.Set(template, "usage.completion_tokens_details.reasoning_tokens", thoughtsTokenCount)
+		}
+	}
+
+	// Process the main content part of the response.
+	partsResult := gjson.GetBytes(rawJson, "response.candidates.0.content.parts")
+	if partsResult.IsArray() {
+		partsResults := partsResult.Array()
+		for i := 0; i < len(partsResults); i++ {
+			partResult := partsResults[i]
+			partTextResult := partResult.Get("text")
+			functionCallResult := partResult.Get("functionCall")
+
+			if partTextResult.Exists() {
+				// Append text content, distinguishing between regular content and reasoning.
+				if partResult.Get("thought").Bool() {
+					template, _ = sjson.Set(template, "choices.0.message.reasoning_content", partTextResult.String())
+				} else {
+					template, _ = sjson.Set(template, "choices.0.message.content", partTextResult.String())
+				}
+				template, _ = sjson.Set(template, "choices.0.message.role", "assistant")
+			} else if functionCallResult.Exists() {
+				// Append function call content to the tool_calls array.
+				toolCallsResult := gjson.Get(template, "choices.0.message.tool_calls")
+				if !toolCallsResult.Exists() || !toolCallsResult.IsArray() {
+					template, _ = sjson.SetRaw(template, "choices.0.message.tool_calls", `[]`)
+				}
+				functionCallItemTemplate := `{"id": "","type": "function","function": {"name": "","arguments": ""}}`
+				fcName := functionCallResult.Get("name").String()
+				functionCallItemTemplate, _ = sjson.Set(functionCallItemTemplate, "id", fmt.Sprintf("%s-%d", fcName, time.Now().UnixNano()))
+				functionCallItemTemplate, _ = sjson.Set(functionCallItemTemplate, "function.name", fcName)
+				if fcArgsResult := functionCallResult.Get("args"); fcArgsResult.Exists() {
+					functionCallItemTemplate, _ = sjson.Set(functionCallItemTemplate, "function.arguments", fcArgsResult.Raw)
+				}
+				template, _ = sjson.Set(template, "choices.0.message.role", "assistant")
+				template, _ = sjson.SetRaw(template, "choices.0.message.tool_calls.-1", functionCallItemTemplate)
+			} else {
+				// If no usable content is found, return an empty string.
+				return ""
+			}
+		}
+	}
+
+	return template
+}
+
+// ConvertCliToClaude performs sophisticated streaming response format conversion.
+// This function implements a complex state machine that translates backend client responses
+// into Claude-compatible Server-Sent Events (SSE) format. It manages different response types
+// and handles state transitions between content blocks, thinking processes, and function calls.
+//
+// Response type states: 0=none, 1=content, 2=thinking, 3=function
+// The function maintains state across multiple calls to ensure proper SSE event sequencing.
+func ConvertCliToClaude(rawJson []byte, isGlAPIKey, hasFirstResponse bool, responseType, responseIndex *int) string {
+	// Normalize the response format for different API key types
+	// Generative Language API keys have a different response structure
+	if isGlAPIKey {
+		rawJson, _ = sjson.SetRawBytes(rawJson, "response", rawJson)
+	}
+
+	// Track whether tools are being used in this response chunk
+	usedTool := false
+	output := ""
+
+	// Initialize the streaming session with a message_start event
+	// This is only sent for the very first response chunk
+	if !hasFirstResponse {
+		output = "event: message_start\n"
+
+		// Create the initial message structure with default values
+		// This follows the Claude API specification for streaming message initialization
+		messageStartTemplate := `{"type": "message_start", "message": {"id": "msg_1nZdL29xx5MUA1yADyHTEsnR8uuvGzszyY", "type": "message", "role": "assistant", "content": [], "model": "claude-3-5-sonnet-20241022", "stop_reason": null, "stop_sequence": null, "usage": {"input_tokens": 0, "output_tokens": 0}}}`
+
+		// Override default values with actual response metadata if available
+		if modelVersionResult := gjson.GetBytes(rawJson, "response.modelVersion"); modelVersionResult.Exists() {
+			messageStartTemplate, _ = sjson.Set(messageStartTemplate, "message.model", modelVersionResult.String())
+		}
+		if responseIdResult := gjson.GetBytes(rawJson, "response.responseId"); responseIdResult.Exists() {
+			messageStartTemplate, _ = sjson.Set(messageStartTemplate, "message.id", responseIdResult.String())
+		}
+		output = output + fmt.Sprintf("data: %s\n\n\n", messageStartTemplate)
+	}
+
+	// Process the response parts array from the backend client
+	// Each part can contain text content, thinking content, or function calls
+	partsResult := gjson.GetBytes(rawJson, "response.candidates.0.content.parts")
+	if partsResult.IsArray() {
+		partResults := partsResult.Array()
+		for i := 0; i < len(partResults); i++ {
+			partResult := partResults[i]
+
+			// Extract the different types of content from each part
+			partTextResult := partResult.Get("text")
+			functionCallResult := partResult.Get("functionCall")
+
+			// Handle text content (both regular content and thinking)
+			if partTextResult.Exists() {
+				// Process thinking content (internal reasoning)
+				if partResult.Get("thought").Bool() {
+					// Continue existing thinking block
+					if *responseType == 2 {
+						output = output + "event: content_block_delta\n"
+						data, _ := sjson.Set(fmt.Sprintf(`{"type":"content_block_delta","index":%d,"delta":{"type":"thinking_delta","thinking":""}}`, *responseIndex), "delta.thinking", partTextResult.String())
+						output = output + fmt.Sprintf("data: %s\n\n\n", data)
+					} else {
+						// Transition from another state to thinking
+						// First, close any existing content block
+						if *responseType != 0 {
+							if *responseType == 2 {
+								output = output + "event: content_block_delta\n"
+								output = output + fmt.Sprintf(`data: {"type":"content_block_delta","index":%d,"delta":{"type":"signature_delta","signature":null}}`, *responseIndex)
+								output = output + "\n\n\n"
+							}
+							output = output + "event: content_block_stop\n"
+							output = output + fmt.Sprintf(`data: {"type":"content_block_stop","index":%d}`, *responseIndex)
+							output = output + "\n\n\n"
+							*responseIndex++
+						}
+
+						// Start a new thinking content block
+						output = output + "event: content_block_start\n"
+						output = output + fmt.Sprintf(`data: {"type":"content_block_start","index":%d,"content_block":{"type":"thinking","thinking":""}}`, *responseIndex)
+						output = output + "\n\n\n"
+						output = output + "event: content_block_delta\n"
+						data, _ := sjson.Set(fmt.Sprintf(`{"type":"content_block_delta","index":%d,"delta":{"type":"thinking_delta","thinking":""}}`, *responseIndex), "delta.thinking", partTextResult.String())
+						output = output + fmt.Sprintf("data: %s\n\n\n", data)
+						*responseType = 2 // Set state to thinking
+					}
+				} else {
+					// Process regular text content (user-visible output)
+					// Continue existing text block
+					if *responseType == 1 {
+						output = output + "event: content_block_delta\n"
+						data, _ := sjson.Set(fmt.Sprintf(`{"type":"content_block_delta","index":%d,"delta":{"type":"text_delta","text":""}}`, *responseIndex), "delta.text", partTextResult.String())
+						output = output + fmt.Sprintf("data: %s\n\n\n", data)
+					} else {
+						// Transition from another state to text content
+						// First, close any existing content block
+						if *responseType != 0 {
+							if *responseType == 2 {
+								output = output + "event: content_block_delta\n"
+								output = output + fmt.Sprintf(`data: {"type":"content_block_delta","index":%d,"delta":{"type":"signature_delta","signature":null}}`, *responseIndex)
+								output = output + "\n\n\n"
+							}
+							output = output + "event: content_block_stop\n"
+							output = output + fmt.Sprintf(`data: {"type":"content_block_stop","index":%d}`, *responseIndex)
+							output = output + "\n\n\n"
+							*responseIndex++
+						}
+
+						// Start a new text content block
+						output = output + "event: content_block_start\n"
+						output = output + fmt.Sprintf(`data: {"type":"content_block_start","index":%d,"content_block":{"type":"text","text":""}}`, *responseIndex)
+						output = output + "\n\n\n"
+						output = output + "event: content_block_delta\n"
+						data, _ := sjson.Set(fmt.Sprintf(`{"type":"content_block_delta","index":%d,"delta":{"type":"text_delta","text":""}}`, *responseIndex), "delta.text", partTextResult.String())
+						output = output + fmt.Sprintf("data: %s\n\n\n", data)
+						*responseType = 1 // Set state to content
+					}
+				}
+			} else if functionCallResult.Exists() {
+				// Handle function/tool calls from the AI model
+				// This processes tool usage requests and formats them for Claude API compatibility
+				usedTool = true
+				fcName := functionCallResult.Get("name").String()
+
+				// Handle state transitions when switching to function calls
+				// Close any existing function call block first
+				if *responseType == 3 {
+					output = output + "event: content_block_stop\n"
+					output = output + fmt.Sprintf(`data: {"type":"content_block_stop","index":%d}`, *responseIndex)
+					output = output + "\n\n\n"
+					*responseIndex++
+					*responseType = 0
+				}
+
+				// Special handling for thinking state transition
+				if *responseType == 2 {
+					output = output + "event: content_block_delta\n"
+					output = output + fmt.Sprintf(`data: {"type":"content_block_delta","index":%d,"delta":{"type":"signature_delta","signature":null}}`, *responseIndex)
+					output = output + "\n\n\n"
+				}
+
+				// Close any other existing content block
+				if *responseType != 0 {
+					output = output + "event: content_block_stop\n"
+					output = output + fmt.Sprintf(`data: {"type":"content_block_stop","index":%d}`, *responseIndex)
+					output = output + "\n\n\n"
+					*responseIndex++
+				}
+
+				// Start a new tool use content block
+				// This creates the structure for a function call in Claude format
+				output = output + "event: content_block_start\n"
+
+				// Create the tool use block with unique ID and function details
+				data := fmt.Sprintf(`{"type":"content_block_start","index":%d,"content_block":{"type":"tool_use","id":"","name":"","input":{}}}`, *responseIndex)
+				data, _ = sjson.Set(data, "content_block.id", fmt.Sprintf("%s-%d", fcName, time.Now().UnixNano()))
+				data, _ = sjson.Set(data, "content_block.name", fcName)
+				output = output + fmt.Sprintf("data: %s\n\n\n", data)
+
+				if fcArgsResult := functionCallResult.Get("args"); fcArgsResult.Exists() {
+					output = output + "event: content_block_delta\n"
+					data, _ = sjson.Set(fmt.Sprintf(`{"type":"content_block_delta","index":%d,"delta":{"type":"input_json_delta","partial_json":""}}`, *responseIndex), "delta.partial_json", fcArgsResult.Raw)
+					output = output + fmt.Sprintf("data: %s\n\n\n", data)
+				}
+				*responseType = 3
+			}
+		}
+	}
+
+	usageResult := gjson.GetBytes(rawJson, "response.usageMetadata")
+	if usageResult.Exists() && bytes.Contains(rawJson, []byte(`"finishReason"`)) {
+		if candidatesTokenCountResult := usageResult.Get("candidatesTokenCount"); candidatesTokenCountResult.Exists() {
+			output = output + "event: content_block_stop\n"
+			output = output + fmt.Sprintf(`data: {"type":"content_block_stop","index":%d}`, *responseIndex)
+			output = output + "\n\n\n"
+
+			output = output + "event: message_delta\n"
+			output = output + `data: `
+
+			template := `{"type":"message_delta","delta":{"stop_reason":"end_turn","stop_sequence":null},"usage":{"input_tokens":0,"output_tokens":0}}`
+			if usedTool {
+				template = `{"type":"message_delta","delta":{"stop_reason":"tool_use","stop_sequence":null},"usage":{"input_tokens":0,"output_tokens":0}}`
+			}
+
+			thoughtsTokenCount := usageResult.Get("thoughtsTokenCount").Int()
+			template, _ = sjson.Set(template, "usage.output_tokens", candidatesTokenCountResult.Int()+thoughtsTokenCount)
+			template, _ = sjson.Set(template, "usage.input_tokens", usageResult.Get("promptTokenCount").Int())
+
+			output = output + template + "\n\n\n"
+		}
+	}
+
+	return output
+}

internal/auth/auth.go

@@ -5,17 +5,18 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"github.com/luispater/CLIProxyAPI/internal/config"
-	log "github.com/sirupsen/logrus"
-	"github.com/skratchdot/open-golang/open"
-	"github.com/tidwall/gjson"
-	"golang.org/x/net/proxy"
 	"io"
 	"net"
 	"net/http"
 	"net/url"
 	"time"
 
+	"github.com/luispater/CLIProxyAPI/internal/config"
+	log "github.com/sirupsen/logrus"
+	"github.com/skratchdot/open-golang/open"
+	"github.com/tidwall/gjson"
+	"golang.org/x/net/proxy"
+
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
 )
@@ -33,76 +34,78 @@ var (
 	}
 )
 
-// GetAuthenticatedClient configures and returns an HTTP client with OAuth2 tokens.
-// It handles the entire flow: loading, refreshing, and fetching new tokens.
+// GetAuthenticatedClient configures and returns an HTTP client ready for making authenticated API calls.
+// It manages the entire OAuth2 flow, including handling proxies, loading existing tokens,
+// initiating a new web-based OAuth flow if necessary, and refreshing tokens.
 func GetAuthenticatedClient(ctx context.Context, ts *TokenStorage, cfg *config.Config) (*http.Client, error) {
+	// Configure proxy settings for the HTTP client if a proxy URL is provided.
 	proxyURL, err := url.Parse(cfg.ProxyUrl)
 	if err == nil {
+		var transport *http.Transport
 		if proxyURL.Scheme == "socks5" {
+			// Handle SOCKS5 proxy.
 			username := proxyURL.User.Username()
 			password, _ := proxyURL.User.Password()
-			auth := &proxy.Auth{
-				User:     username,
-				Password: password,
-			}
+			auth := &proxy.Auth{User: username, Password: password}
 			dialer, errSOCKS5 := proxy.SOCKS5("tcp", proxyURL.Host, auth, proxy.Direct)
 			if errSOCKS5 != nil {
 				log.Fatalf("create SOCKS5 dialer failed: %v", errSOCKS5)
 			}
-
-			transport := &http.Transport{
-				DialContext: func(ctx context.Context, network, addr string) (c net.Conn, err error) {
+			transport = &http.Transport{
+				DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
 					return dialer.Dial(network, addr)
 				},
 			}
-			proxyClient := &http.Client{
-				Transport: transport,
-			}
-
-			ctx = context.WithValue(ctx, oauth2.HTTPClient, proxyClient)
 		} else if proxyURL.Scheme == "http" || proxyURL.Scheme == "https" {
-			transport := &http.Transport{
-				Proxy: http.ProxyURL(proxyURL),
-			}
-			proxyClient := &http.Client{
-				Transport: transport,
-			}
+			// Handle HTTP/HTTPS proxy.
+			transport = &http.Transport{Proxy: http.ProxyURL(proxyURL)}
+		}
+
+		if transport != nil {
+			proxyClient := &http.Client{Transport: transport}
 			ctx = context.WithValue(ctx, oauth2.HTTPClient, proxyClient)
 		}
 	}
 
+	// Configure the OAuth2 client.
 	conf := &oauth2.Config{
 		ClientID:     oauthClientID,
 		ClientSecret: oauthClientSecret,
-		RedirectURL:  "http://localhost:8085/oauth2callback", // Placeholder, will be updated
+		RedirectURL:  "http://localhost:8085/oauth2callback", // This will be used by the local server.
 		Scopes:       oauthScopes,
 		Endpoint:     google.Endpoint,
 	}
 
 	var token *oauth2.Token
 
+	// If no token is found in storage, initiate the web-based OAuth flow.
 	if ts.Token == nil {
 		log.Info("Could not load token from file, starting OAuth flow.")
 		token, err = getTokenFromWeb(ctx, conf)
 		if err != nil {
 			return nil, fmt.Errorf("failed to get token from web: %w", err)
 		}
-		newTs, errSaveTokenToFile := createTokenStorage(ctx, conf, token, ts.ProjectID)
-		if errSaveTokenToFile != nil {
-			log.Errorf("Warning: failed to save token to file: %v", err)
-			return nil, errSaveTokenToFile
+		// After getting a new token, create a new token storage object with user info.
+		newTs, errCreateTokenStorage := createTokenStorage(ctx, conf, token, ts.ProjectID)
+		if errCreateTokenStorage != nil {
+			log.Errorf("Warning: failed to create token storage: %v", errCreateTokenStorage)
+			return nil, errCreateTokenStorage
 		}
 		*ts = *newTs
 	}
+
+	// Unmarshal the stored token into an oauth2.Token object.
 	tsToken, _ := json.Marshal(ts.Token)
 	if err = json.Unmarshal(tsToken, &token); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to unmarshal token: %w", err)
 	}
 
+	// Return an HTTP client that automatically handles token refreshing.
 	return conf.Client(ctx, token), nil
 }
 
-// createTokenStorage creates a token storage.
+// createTokenStorage creates a new TokenStorage object. It fetches the user's email
+// using the provided token and populates the storage structure.
 func createTokenStorage(ctx context.Context, config *oauth2.Config, token *oauth2.Token, projectID string) (*TokenStorage, error) {
 	httpClient := config.Client(ctx, token)
 	req, err := http.NewRequestWithContext(ctx, "GET", "https://www.googleapis.com/oauth2/v1/userinfo?alt=json", nil)
@@ -117,7 +120,9 @@ func createTokenStorage(ctx context.Context, config *oauth2.Config, token *oauth
 		return nil, fmt.Errorf("failed to execute request: %w", err)
 	}
 	defer func() {
-		_ = resp.Body.Close()
+		if err = resp.Body.Close(); err != nil {
+			log.Printf("warn: failed to close response body: %v", err)
+		}
 	}()
 
 	bodyBytes, _ := io.ReadAll(resp.Body)
@@ -154,7 +159,10 @@ func createTokenStorage(ctx context.Context, config *oauth2.Config, token *oauth
 	return &ts, nil
 }
 
-// getTokenFromWeb starts a local server to handle the OAuth2 flow.
+// getTokenFromWeb initiates the web-based OAuth2 authorization flow.
+// It starts a local HTTP server to listen for the callback from Google's auth server,
+// opens the user's browser to the authorization URL, and exchanges the received
+// authorization code for an access token.
 func getTokenFromWeb(ctx context.Context, config *oauth2.Config) (*oauth2.Token, error) {
 	// Use a channel to pass the authorization code from the HTTP handler to the main function.
 	codeChan := make(chan string)

internal/auth/models.go

@@ -1,9 +1,17 @@
 package auth
 
+// TokenStorage defines the structure for storing OAuth2 token information,
+// along with associated user and project details. This data is typically
+// serialized to a JSON file for persistence.
 type TokenStorage struct {
-	Token     any    `json:"token"`
+	// Token holds the raw OAuth2 token data, including access and refresh tokens.
+	Token any `json:"token"`
+	// ProjectID is the Google Cloud Project ID associated with this token.
 	ProjectID string `json:"project_id"`
-	Email     string `json:"email"`
-	Auto      bool   `json:"auto"`
-	Checked   bool   `json:"checked"`
+	// Email is the email address of the authenticated user.
+	Email string `json:"email"`
+	// Auto indicates if the project ID was automatically selected.
+	Auto bool `json:"auto"`
+	// Checked indicates if the associated Cloud AI API has been verified as enabled.
+	Checked bool `json:"checked"`
 }

internal/client/client.go

@@ -6,12 +6,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"github.com/luispater/CLIProxyAPI/internal/auth"
-	"github.com/luispater/CLIProxyAPI/internal/config"
-	log "github.com/sirupsen/logrus"
-	"github.com/tidwall/gjson"
-	"github.com/tidwall/sjson"
-	"golang.org/x/oauth2"
 	"io"
 	"net/http"
 	"os"
@@ -20,28 +14,53 @@ import (
 	"strings"
 	"sync"
 	"time"
+
+	"github.com/luispater/CLIProxyAPI/internal/auth"
+	"github.com/luispater/CLIProxyAPI/internal/config"
+	log "github.com/sirupsen/logrus"
+	"github.com/tidwall/gjson"
+	"github.com/tidwall/sjson"
+	"golang.org/x/oauth2"
 )
 
 const (
 	codeAssistEndpoint = "https://cloudcode-pa.googleapis.com"
 	apiVersion         = "v1internal"
 	pluginVersion      = "0.1.9"
+
+	glEndPoint   = "https://generativelanguage.googleapis.com/"
+	glApiVersion = "v1beta"
+)
+
+var (
+	previewModels = map[string][]string{
+		"gemini-2.5-pro":   {"gemini-2.5-pro-preview-05-06", "gemini-2.5-pro-preview-06-05"},
+		"gemini-2.5-flash": {"gemini-2.5-flash-preview-04-17", "gemini-2.5-flash-preview-05-20"},
+	}
 )
 
 // Client is the main client for interacting with the CLI API.
 type Client struct {
-	httpClient   *http.Client
-	RequestMutex sync.Mutex
-	tokenStorage *auth.TokenStorage
-	cfg          *config.Config
+	httpClient         *http.Client
+	RequestMutex       sync.Mutex
+	tokenStorage       *auth.TokenStorage
+	cfg                *config.Config
+	modelQuotaExceeded map[string]*time.Time
+	glAPIKey           string
 }
 
 // NewClient creates a new CLI API client.
-func NewClient(httpClient *http.Client, ts *auth.TokenStorage, cfg *config.Config) *Client {
+func NewClient(httpClient *http.Client, ts *auth.TokenStorage, cfg *config.Config, glAPIKey ...string) *Client {
+	var glKey string
+	if len(glAPIKey) > 0 {
+		glKey = glAPIKey[0]
+	}
 	return &Client{
-		httpClient:   httpClient,
-		tokenStorage: ts,
-		cfg:          cfg,
+		httpClient:         httpClient,
+		tokenStorage:       ts,
+		cfg:                cfg,
+		modelQuotaExceeded: make(map[string]*time.Time),
+		glAPIKey:           glKey,
 	}
 }
 
@@ -70,7 +89,14 @@ func (c *Client) GetEmail() string {
 }
 
 func (c *Client) GetProjectID() string {
-	return c.tokenStorage.ProjectID
+	if c.tokenStorage != nil {
+		return c.tokenStorage.ProjectID
+	}
+	return ""
+}
+
+func (c *Client) GetGenerativeLanguageAPIKey() string {
+	return c.glAPIKey
 }
 
 // SetupUser performs the initial user onboarding and setup.
@@ -186,6 +212,7 @@ func (c *Client) makeAPIRequest(ctx context.Context, endpoint, method string, bo
 	metadataStr := getClientMetadataString()
 	req.Header.Set("Content-Type", "application/json")
 	req.Header.Set("User-Agent", getUserAgent())
+	req.Header.Set("X-Goog-Api-Client", "gl-node/22.17.0")
 	req.Header.Set("Client-Metadata", metadataStr)
 	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", token.AccessToken))
 
@@ -194,7 +221,9 @@ func (c *Client) makeAPIRequest(ctx context.Context, endpoint, method string, bo
 		return fmt.Errorf("failed to execute request: %w", err)
 	}
 	defer func() {
-		_ = resp.Body.Close()
+		if err = resp.Body.Close(); err != nil {
+			log.Printf("warn: failed to close response body: %v", err)
+		}
 	}()
 
 	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
@@ -211,8 +240,8 @@ func (c *Client) makeAPIRequest(ctx context.Context, endpoint, method string, bo
 	return nil
 }
 
-// StreamAPIRequest handles making streaming requests to the CLI API endpoints.
-func (c *Client) StreamAPIRequest(ctx context.Context, endpoint string, body interface{}) (io.ReadCloser, *ErrorMessage) {
+// APIRequest handles making requests to the CLI API endpoints.
+func (c *Client) APIRequest(ctx context.Context, endpoint string, body interface{}, stream bool) (io.ReadCloser, *ErrorMessage) {
 	var jsonBody []byte
 	var err error
 	if byteBody, ok := body.([]byte); ok {
@@ -223,49 +252,394 @@ func (c *Client) StreamAPIRequest(ctx context.Context, endpoint string, body int
 			return nil, &ErrorMessage{500, fmt.Errorf("failed to marshal request body: %w", err)}
 		}
 	}
+
+	var url string
+	if c.glAPIKey == "" {
+		// Add alt=sse for streaming
+		url = fmt.Sprintf("%s/%s:%s", codeAssistEndpoint, apiVersion, endpoint)
+		if stream {
+			url = url + "?alt=sse"
+		}
+	} else {
+		modelResult := gjson.GetBytes(jsonBody, "model")
+		url = fmt.Sprintf("%s/%s/models/%s:%s", glEndPoint, glApiVersion, modelResult.String(), endpoint)
+		if stream {
+			url = url + "?alt=sse"
+		}
+		jsonBody = []byte(gjson.GetBytes(jsonBody, "request").Raw)
+		systemInstructionResult := gjson.GetBytes(jsonBody, "systemInstruction")
+		if systemInstructionResult.Exists() {
+			jsonBody, _ = sjson.SetRawBytes(jsonBody, "system_instruction", []byte(systemInstructionResult.Raw))
+			jsonBody, _ = sjson.DeleteBytes(jsonBody, "systemInstruction")
+			jsonBody, _ = sjson.DeleteBytes(jsonBody, "session_id")
+		}
+	}
+
 	// log.Debug(string(jsonBody))
 	reqBody := bytes.NewBuffer(jsonBody)
 
-	// Add alt=sse for streaming
-	url := fmt.Sprintf("%s/%s:%s?alt=sse", codeAssistEndpoint, apiVersion, endpoint)
-
 	req, err := http.NewRequestWithContext(ctx, "POST", url, reqBody)
 	if err != nil {
-		return nil, &ErrorMessage{500, fmt.Errorf("failed to create request: %w", err)}
-	}
-
-	token, err := c.httpClient.Transport.(*oauth2.Transport).Source.Token()
-	if err != nil {
-		return nil, &ErrorMessage{500, fmt.Errorf("failed to get token: %w", err)}
+		return nil, &ErrorMessage{500, fmt.Errorf("failed to create request: %v", err)}
 	}
 
 	// Set headers
 	metadataStr := getClientMetadataString()
 	req.Header.Set("Content-Type", "application/json")
-	req.Header.Set("User-Agent", getUserAgent())
-	req.Header.Set("Client-Metadata", metadataStr)
-	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", token.AccessToken))
+	if c.glAPIKey == "" {
+		token, errToken := c.httpClient.Transport.(*oauth2.Transport).Source.Token()
+		if errToken != nil {
+			return nil, &ErrorMessage{500, fmt.Errorf("failed to get token: %v", errToken)}
+		}
+		req.Header.Set("User-Agent", getUserAgent())
+		req.Header.Set("X-Goog-Api-Client", "gl-node/22.17.0")
+		req.Header.Set("Client-Metadata", metadataStr)
+		req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", token.AccessToken))
+	} else {
+		req.Header.Set("x-goog-api-key", c.glAPIKey)
+	}
 
 	resp, err := c.httpClient.Do(req)
 	if err != nil {
-		return nil, &ErrorMessage{500, fmt.Errorf("failed to execute request: %w", err)}
+		return nil, &ErrorMessage{500, fmt.Errorf("failed to execute request: %v", err)}
 	}
 
 	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
 		defer func() {
-			_ = resp.Body.Close()
+			if err = resp.Body.Close(); err != nil {
+				log.Printf("warn: failed to close response body: %v", err)
+			}
 		}()
 		bodyBytes, _ := io.ReadAll(resp.Body)
-
+		// log.Debug(string(jsonBody))
 		return nil, &ErrorMessage{resp.StatusCode, fmt.Errorf(string(bodyBytes))}
-		// return nil, fmt.Errorf("api streaming request failed with status %d: %s", resp.StatusCode, string(bodyBytes))
 	}
 
 	return resp.Body, nil
 }
 
-// SendMessageStream handles a single conversational turn, including tool calls.
-func (c *Client) SendMessageStream(ctx context.Context, rawJson []byte, model string, contents []Content, tools []ToolDeclaration) (<-chan []byte, <-chan *ErrorMessage) {
+// SendMessage handles a single conversational turn, including tool calls.
+func (c *Client) SendMessage(ctx context.Context, rawJson []byte, model string, systemInstruction *Content, contents []Content, tools []ToolDeclaration) ([]byte, *ErrorMessage) {
+	request := GenerateContentRequest{
+		Contents: contents,
+		GenerationConfig: GenerationConfig{
+			ThinkingConfig: GenerationConfigThinkingConfig{
+				IncludeThoughts: true,
+			},
+		},
+	}
+
+	request.SystemInstruction = systemInstruction
+
+	request.Tools = tools
+
+	requestBody := map[string]interface{}{
+		"project": c.GetProjectID(), // Assuming ProjectID is available
+		"request": request,
+		"model":   model,
+	}
+
+	byteRequestBody, _ := json.Marshal(requestBody)
+
+	// log.Debug(string(byteRequestBody))
+
+	reasoningEffortResult := gjson.GetBytes(rawJson, "reasoning_effort")
+	if reasoningEffortResult.String() == "none" {
+		byteRequestBody, _ = sjson.DeleteBytes(byteRequestBody, "request.generationConfig.thinkingConfig.include_thoughts")
+		byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", 0)
+	} else if reasoningEffortResult.String() == "auto" {
+		byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", -1)
+	} else if reasoningEffortResult.String() == "low" {
+		byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", 1024)
+	} else if reasoningEffortResult.String() == "medium" {
+		byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", 8192)
+	} else if reasoningEffortResult.String() == "high" {
+		byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", 24576)
+	} else {
+		byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", -1)
+	}
+
+	temperatureResult := gjson.GetBytes(rawJson, "temperature")
+	if temperatureResult.Exists() && temperatureResult.Type == gjson.Number {
+		byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.temperature", temperatureResult.Num)
+	}
+
+	topPResult := gjson.GetBytes(rawJson, "top_p")
+	if topPResult.Exists() && topPResult.Type == gjson.Number {
+		byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.topP", topPResult.Num)
+	}
+
+	topKResult := gjson.GetBytes(rawJson, "top_k")
+	if topKResult.Exists() && topKResult.Type == gjson.Number {
+		byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.topK", topKResult.Num)
+	}
+
+	modelName := model
+	// log.Debug(string(byteRequestBody))
+	for {
+		if c.isModelQuotaExceeded(modelName) {
+			if c.cfg.QuotaExceeded.SwitchPreviewModel && c.glAPIKey == "" {
+				modelName = c.getPreviewModel(model)
+				if modelName != "" {
+					log.Debugf("Model %s is quota exceeded. Switch to preview model %s", model, modelName)
+					byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "model", modelName)
+					continue
+				}
+			}
+			return nil, &ErrorMessage{
+				StatusCode: 429,
+				Error:      fmt.Errorf(`{"error":{"code":429,"message":"All the models of '%s' are quota exceeded","status":"RESOURCE_EXHAUSTED"}}`, model),
+			}
+		}
+
+		respBody, err := c.APIRequest(ctx, "generateContent", byteRequestBody, false)
+		if err != nil {
+			if err.StatusCode == 429 {
+				now := time.Now()
+				c.modelQuotaExceeded[modelName] = &now
+				if c.cfg.QuotaExceeded.SwitchPreviewModel && c.glAPIKey == "" {
+					continue
+				}
+			}
+			return nil, err
+		}
+		delete(c.modelQuotaExceeded, modelName)
+		bodyBytes, errReadAll := io.ReadAll(respBody)
+		if errReadAll != nil {
+			return nil, &ErrorMessage{StatusCode: 500, Error: errReadAll}
+		}
+		return bodyBytes, nil
+	}
+}
+
+// SendMessageStream handles streaming conversational turns with comprehensive parameter management.
+// This function implements a sophisticated streaming system that supports tool calls, reasoning modes,
+// quota management, and automatic model fallback. It returns two channels for asynchronous communication:
+// one for streaming response data and another for error handling.
+func (c *Client) SendMessageStream(ctx context.Context, rawJson []byte, model string, systemInstruction *Content, contents []Content, tools []ToolDeclaration, includeThoughts ...bool) (<-chan []byte, <-chan *ErrorMessage) {
+	// Define the data prefix used in Server-Sent Events streaming format
+	dataTag := []byte("data: ")
+
+	// Create channels for asynchronous communication
+	// errChan: delivers error messages during streaming
+	// dataChan: delivers response data chunks
+	errChan := make(chan *ErrorMessage)
+	dataChan := make(chan []byte)
+
+	// Launch a goroutine to handle the streaming process asynchronously
+	// This allows the function to return immediately while processing continues in the background
+	go func() {
+		// Ensure channels are properly closed when the goroutine exits
+		defer close(errChan)
+		defer close(dataChan)
+
+		// Configure thinking/reasoning capabilities
+		// Default to including thoughts unless explicitly disabled
+		includeThoughtsFlag := true
+		if len(includeThoughts) > 0 {
+			includeThoughtsFlag = includeThoughts[0]
+		}
+
+		// Build the base request structure for the Gemini API
+		// This includes conversation contents and generation configuration
+		request := GenerateContentRequest{
+			Contents: contents,
+			GenerationConfig: GenerationConfig{
+				ThinkingConfig: GenerationConfigThinkingConfig{
+					IncludeThoughts: includeThoughtsFlag,
+				},
+			},
+		}
+
+		// Add system instructions if provided
+		// System instructions guide the AI's behavior and response style
+		request.SystemInstruction = systemInstruction
+
+		// Add available tools for function calling capabilities
+		// Tools allow the AI to perform actions beyond text generation
+		request.Tools = tools
+
+		// Construct the complete request body with project context
+		// The project ID is essential for proper API routing and billing
+		requestBody := map[string]interface{}{
+			"project": c.GetProjectID(), // Project ID for API routing and quota management
+			"request": request,
+			"model":   model,
+		}
+
+		// Serialize the request body to JSON for API transmission
+		byteRequestBody, _ := json.Marshal(requestBody)
+
+		// Parse and configure reasoning effort levels from the original request
+		// This maps Claude-style reasoning effort parameters to Gemini's thinking budget system
+		reasoningEffortResult := gjson.GetBytes(rawJson, "reasoning_effort")
+		if reasoningEffortResult.String() == "none" {
+			// Disable thinking entirely for fastest responses
+			byteRequestBody, _ = sjson.DeleteBytes(byteRequestBody, "request.generationConfig.thinkingConfig.include_thoughts")
+			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", 0)
+		} else if reasoningEffortResult.String() == "auto" {
+			// Let the model decide the appropriate thinking budget automatically
+			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", -1)
+		} else if reasoningEffortResult.String() == "low" {
+			// Minimal thinking for simple tasks (1KB thinking budget)
+			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", 1024)
+		} else if reasoningEffortResult.String() == "medium" {
+			// Moderate thinking for complex tasks (8KB thinking budget)
+			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", 8192)
+		} else if reasoningEffortResult.String() == "high" {
+			// Maximum thinking for very complex tasks (24KB thinking budget)
+			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", 24576)
+		} else {
+			// Default to automatic thinking budget if no specific level is provided
+			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", -1)
+		}
+
+		// Configure temperature parameter for response randomness control
+		// Temperature affects the creativity vs consistency trade-off in responses
+		temperatureResult := gjson.GetBytes(rawJson, "temperature")
+		if temperatureResult.Exists() && temperatureResult.Type == gjson.Number {
+			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.temperature", temperatureResult.Num)
+		}
+
+		// Configure top-p parameter for nucleus sampling
+		// Controls the cumulative probability threshold for token selection
+		topPResult := gjson.GetBytes(rawJson, "top_p")
+		if topPResult.Exists() && topPResult.Type == gjson.Number {
+			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.topP", topPResult.Num)
+		}
+
+		// Configure top-k parameter for limiting token candidates
+		// Restricts the model to consider only the top K most likely tokens
+		topKResult := gjson.GetBytes(rawJson, "top_k")
+		if topKResult.Exists() && topKResult.Type == gjson.Number {
+			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.topK", topKResult.Num)
+		}
+
+		// Initialize model name for quota management and potential fallback
+		modelName := model
+		var stream io.ReadCloser
+
+		// Quota management and model fallback loop
+		// This loop handles quota exceeded scenarios and automatic model switching
+		for {
+			// Check if the current model has exceeded its quota
+			if c.isModelQuotaExceeded(modelName) {
+				// Attempt to switch to a preview model if configured and using account auth
+				if c.cfg.QuotaExceeded.SwitchPreviewModel && c.glAPIKey == "" {
+					modelName = c.getPreviewModel(model)
+					if modelName != "" {
+						log.Debugf("Model %s is quota exceeded. Switch to preview model %s", model, modelName)
+						// Update the request body with the new model name
+						byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "model", modelName)
+						continue // Retry with the preview model
+					}
+				}
+				// If no fallback is available, return a quota exceeded error
+				errChan <- &ErrorMessage{
+					StatusCode: 429,
+					Error:      fmt.Errorf(`{"error":{"code":429,"message":"All the models of '%s' are quota exceeded","status":"RESOURCE_EXHAUSTED"}}`, model),
+				}
+				return
+			}
+
+			// Attempt to establish a streaming connection with the API
+			var err *ErrorMessage
+			stream, err = c.APIRequest(ctx, "streamGenerateContent", byteRequestBody, true)
+			if err != nil {
+				// Handle quota exceeded errors by marking the model and potentially retrying
+				if err.StatusCode == 429 {
+					now := time.Now()
+					c.modelQuotaExceeded[modelName] = &now // Mark model as quota exceeded
+					// If preview model switching is enabled, retry the loop
+					if c.cfg.QuotaExceeded.SwitchPreviewModel && c.glAPIKey == "" {
+						continue
+					}
+				}
+				// Forward other errors to the error channel
+				errChan <- err
+				return
+			}
+			// Clear any previous quota exceeded status for this model
+			delete(c.modelQuotaExceeded, modelName)
+			break // Successfully established connection, exit the retry loop
+		}
+
+		// Process the streaming response using a scanner
+		// This handles the Server-Sent Events format from the API
+		scanner := bufio.NewScanner(stream)
+		for scanner.Scan() {
+			line := scanner.Bytes()
+			// Filter and forward only data lines (those prefixed with "data: ")
+			// This extracts the actual JSON content from the SSE format
+			if bytes.HasPrefix(line, dataTag) {
+				dataChan <- line[6:] // Remove "data: " prefix and send the JSON content
+			}
+		}
+
+		// Handle any scanning errors that occurred during stream processing
+		if errScanner := scanner.Err(); errScanner != nil {
+			// Send a 500 Internal Server Error for scanning failures
+			errChan <- &ErrorMessage{500, errScanner}
+			_ = stream.Close()
+			return
+		}
+
+		// Ensure the stream is properly closed to prevent resource leaks
+		_ = stream.Close()
+	}()
+
+	// Return the channels immediately for asynchronous communication
+	// The caller can read from these channels while the goroutine processes the request
+	return dataChan, errChan
+}
+
+// SendRawMessage handles a single conversational turn, including tool calls.
+func (c *Client) SendRawMessage(ctx context.Context, rawJson []byte) ([]byte, *ErrorMessage) {
+	if c.glAPIKey == "" {
+		rawJson, _ = sjson.SetBytes(rawJson, "project", c.GetProjectID())
+	}
+
+	modelResult := gjson.GetBytes(rawJson, "model")
+	model := modelResult.String()
+	modelName := model
+	for {
+		if c.isModelQuotaExceeded(modelName) {
+			if c.cfg.QuotaExceeded.SwitchPreviewModel && c.glAPIKey == "" {
+				modelName = c.getPreviewModel(model)
+				if modelName != "" {
+					log.Debugf("Model %s is quota exceeded. Switch to preview model %s", model, modelName)
+					rawJson, _ = sjson.SetBytes(rawJson, "model", modelName)
+					continue
+				}
+			}
+			return nil, &ErrorMessage{
+				StatusCode: 429,
+				Error:      fmt.Errorf(`{"error":{"code":429,"message":"All the models of '%s' are quota exceeded","status":"RESOURCE_EXHAUSTED"}}`, model),
+			}
+		}
+
+		respBody, err := c.APIRequest(ctx, "generateContent", rawJson, false)
+		if err != nil {
+			if err.StatusCode == 429 {
+				now := time.Now()
+				c.modelQuotaExceeded[modelName] = &now
+				if c.cfg.QuotaExceeded.SwitchPreviewModel && c.glAPIKey == "" {
+					continue
+				}
+			}
+			return nil, err
+		}
+		delete(c.modelQuotaExceeded, modelName)
+		bodyBytes, errReadAll := io.ReadAll(respBody)
+		if errReadAll != nil {
+			return nil, &ErrorMessage{StatusCode: 500, Error: errReadAll}
+		}
+		return bodyBytes, nil
+	}
+}
+
+// SendRawMessageStream handles a single conversational turn, including tool calls.
+func (c *Client) SendRawMessageStream(ctx context.Context, rawJson []byte) (<-chan []byte, <-chan *ErrorMessage) {
 	dataTag := []byte("data: ")
 	errChan := make(chan *ErrorMessage)
 	dataChan := make(chan []byte)
@@ -273,77 +647,56 @@ func (c *Client) SendMessageStream(ctx context.Context, rawJson []byte, model st
 		defer close(errChan)
 		defer close(dataChan)
 
-		request := GenerateContentRequest{
-			Contents: contents,
-			GenerationConfig: GenerationConfig{
-				ThinkingConfig: GenerationConfigThinkingConfig{
-					IncludeThoughts: true,
-				},
-			},
-		}
-		request.Tools = tools
-
-		requestBody := map[string]interface{}{
-			"project": c.tokenStorage.ProjectID, // Assuming ProjectID is available
-			"request": request,
-			"model":   model,
+		if c.glAPIKey == "" {
+			rawJson, _ = sjson.SetBytes(rawJson, "project", c.GetProjectID())
 		}
 
-		byteRequestBody, _ := json.Marshal(requestBody)
-
-		// log.Debug(string(byteRequestBody))
-
-		reasoningEffortResult := gjson.GetBytes(rawJson, "reasoning_effort")
-		if reasoningEffortResult.String() == "none" {
-			byteRequestBody, _ = sjson.DeleteBytes(byteRequestBody, "request.generationConfig.thinkingConfig.include_thoughts")
-			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", 0)
-		} else if reasoningEffortResult.String() == "auto" {
-			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", -1)
-		} else if reasoningEffortResult.String() == "low" {
-			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", 1024)
-		} else if reasoningEffortResult.String() == "medium" {
-			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", 8192)
-		} else if reasoningEffortResult.String() == "high" {
-			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", 24576)
-		} else {
-			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.thinkingConfig.thinkingBudget", -1)
-		}
-
-		temperatureResult := gjson.GetBytes(rawJson, "temperature")
-		if temperatureResult.Exists() && temperatureResult.Type == gjson.Number {
-			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.temperature", temperatureResult.Num)
-		}
-
-		topPResult := gjson.GetBytes(rawJson, "top_p")
-		if topPResult.Exists() && topPResult.Type == gjson.Number {
-			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.topP", topPResult.Num)
-		}
-
-		topKResult := gjson.GetBytes(rawJson, "top_k")
-		if topKResult.Exists() && topKResult.Type == gjson.Number {
-			byteRequestBody, _ = sjson.SetBytes(byteRequestBody, "request.generationConfig.topK", topKResult.Num)
-		}
-
-		// log.Debug(string(byteRequestBody))
-
-		stream, err := c.StreamAPIRequest(ctx, "streamGenerateContent", byteRequestBody)
-		if err != nil {
-			// log.Println(err)
-			errChan <- err
-			return
+		modelResult := gjson.GetBytes(rawJson, "model")
+		model := modelResult.String()
+		modelName := model
+		var stream io.ReadCloser
+		for {
+			if c.isModelQuotaExceeded(modelName) {
+				if c.cfg.QuotaExceeded.SwitchPreviewModel && c.glAPIKey == "" {
+					modelName = c.getPreviewModel(model)
+					if modelName != "" {
+						log.Debugf("Model %s is quota exceeded. Switch to preview model %s", model, modelName)
+						rawJson, _ = sjson.SetBytes(rawJson, "model", modelName)
+						continue
+					}
+				}
+				errChan <- &ErrorMessage{
+					StatusCode: 429,
+					Error:      fmt.Errorf(`{"error":{"code":429,"message":"All the models of '%s' are quota exceeded","status":"RESOURCE_EXHAUSTED"}}`, model),
+				}
+				return
+			}
+			var err *ErrorMessage
+			stream, err = c.APIRequest(ctx, "streamGenerateContent", rawJson, true)
+			if err != nil {
+				if err.StatusCode == 429 {
+					now := time.Now()
+					c.modelQuotaExceeded[modelName] = &now
+					if c.cfg.QuotaExceeded.SwitchPreviewModel && c.glAPIKey == "" {
+						continue
+					}
+				}
+				errChan <- err
+				return
+			}
+			delete(c.modelQuotaExceeded, modelName)
+			break
 		}
 
 		scanner := bufio.NewScanner(stream)
 		for scanner.Scan() {
 			line := scanner.Bytes()
-			// log.Printf("Received stream chunk: %s", line)
 			if bytes.HasPrefix(line, dataTag) {
 				dataChan <- line[6:]
 			}
 		}
 
 		if errScanner := scanner.Err(); errScanner != nil {
-			// log.Println(err)
 			errChan <- &ErrorMessage{500, errScanner}
 			_ = stream.Close()
 			return
@@ -355,6 +708,41 @@ func (c *Client) SendMessageStream(ctx context.Context, rawJson []byte, model st
 	return dataChan, errChan
 }
 
+func (c *Client) isModelQuotaExceeded(model string) bool {
+	if lastExceededTime, hasKey := c.modelQuotaExceeded[model]; hasKey {
+		duration := time.Now().Sub(*lastExceededTime)
+		if duration > 30*time.Minute {
+			return false
+		}
+		return true
+	}
+	return false
+}
+
+func (c *Client) getPreviewModel(model string) string {
+	if models, hasKey := previewModels[model]; hasKey {
+		for i := 0; i < len(models); i++ {
+			if !c.isModelQuotaExceeded(models[i]) {
+				return models[i]
+			}
+		}
+	}
+	return ""
+}
+
+func (c *Client) IsModelQuotaExceeded(model string) bool {
+	if c.isModelQuotaExceeded(model) {
+		if c.cfg.QuotaExceeded.SwitchPreviewModel {
+			return c.getPreviewModel(model) == ""
+		}
+		return true
+	}
+	return false
+}
+
+// CheckCloudAPIIsEnabled sends a simple test request to the API to verify
+// that the Cloud AI API is enabled for the user's project. It provides
+// an activation URL if the API is disabled.
 func (c *Client) CheckCloudAPIIsEnabled() (bool, error) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer func() {
@@ -363,79 +751,78 @@ func (c *Client) CheckCloudAPIIsEnabled() (bool, error) {
 	}()
 	c.RequestMutex.Lock()
 
-	requestBody := `{"project":"%s","request":{"contents":[{"role":"user","parts":[{"text":"Be concise. What is the capital of France?"}]}],"generationConfig":{"thinkingConfig":{"include_thoughts":false,"thinkingBudget":0}}},"model":"gemini-2.5-flash"}`
-	requestBody = fmt.Sprintf(requestBody, c.tokenStorage.ProjectID)
-	// log.Debug(requestBody)
-	stream, err := c.StreamAPIRequest(ctx, "streamGenerateContent", []byte(requestBody))
+	// A simple request to test the API endpoint.
+	requestBody := fmt.Sprintf(`{"project":"%s","request":{"contents":[{"role":"user","parts":[{"text":"Be concise. What is the capital of France?"}]}],"generationConfig":{"thinkingConfig":{"include_thoughts":false,"thinkingBudget":0}}},"model":"gemini-2.5-flash"}`, c.tokenStorage.ProjectID)
+
+	stream, err := c.APIRequest(ctx, "streamGenerateContent", []byte(requestBody), true)
 	if err != nil {
+		// If a 403 Forbidden error occurs, it likely means the API is not enabled.
 		if err.StatusCode == 403 {
 			errJson := err.Error.Error()
-			codeResult := gjson.Get(errJson, "error.code")
-			if codeResult.Exists() && codeResult.Type == gjson.Number {
-				if codeResult.Int() == 403 {
-					activationUrlResult := gjson.Get(errJson, "error.details.0.metadata.activationUrl")
-					if activationUrlResult.Exists() {
-						log.Warnf(
-							"\n\nPlease activate your account with this url:\n\n%s\n And execute this command again:\n%s --login --project_id %s",
-							activationUrlResult.String(),
-							os.Args[0],
-							c.tokenStorage.ProjectID,
-						)
-					}
+			// Check for a specific error code and extract the activation URL.
+			if gjson.Get(errJson, "error.code").Int() == 403 {
+				activationUrl := gjson.Get(errJson, "error.details.0.metadata.activationUrl").String()
+				if activationUrl != "" {
+					log.Warnf(
+						"\n\nPlease activate your account with this url:\n\n%s\n And execute this command again:\n%s --login --project_id %s",
+						activationUrl,
+						os.Args[0],
+						c.tokenStorage.ProjectID,
+					)
 				}
 			}
 			return false, nil
 		}
 		return false, err.Error
 	}
+	defer func() {
+		_ = stream.Close()
+	}()
 
+	// We only need to know if the request was successful, so we can drain the stream.
 	scanner := bufio.NewScanner(stream)
 	for scanner.Scan() {
-		line := scanner.Text()
-		if !strings.HasPrefix(line, "data: ") {
-			continue
-		}
+		// Do nothing, just consume the stream.
 	}
 
-	if scannerErr := scanner.Err(); scannerErr != nil {
-		_ = stream.Close()
-	} else {
-		_ = stream.Close()
-	}
-
-	return true, nil
+	return scanner.Err() == nil, scanner.Err()
 }
 
+// GetProjectList fetches a list of Google Cloud projects accessible by the user.
 func (c *Client) GetProjectList(ctx context.Context) (*GCPProject, error) {
 	token, err := c.httpClient.Transport.(*oauth2.Transport).Source.Token()
+	if err != nil {
+		return nil, fmt.Errorf("failed to get token: %w", err)
+	}
+
 	req, err := http.NewRequestWithContext(ctx, "GET", "https://cloudresourcemanager.googleapis.com/v1/projects", nil)
 	if err != nil {
-		return nil, fmt.Errorf("could not get project list: %v", err)
+		return nil, fmt.Errorf("could not create project list request: %v", err)
 	}
-	req.Header.Set("Content-Type", "application/json")
 	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", token.AccessToken))
 
 	resp, err := c.httpClient.Do(req)
 	if err != nil {
-		return nil, fmt.Errorf("failed to execute request: %w", err)
+		return nil, fmt.Errorf("failed to execute project list request: %w", err)
 	}
 	defer func() {
 		_ = resp.Body.Close()
 	}()
 
-	bodyBytes, _ := io.ReadAll(resp.Body)
 	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
-		return nil, fmt.Errorf("get user info request failed with status %d: %s", resp.StatusCode, string(bodyBytes))
+		bodyBytes, _ := io.ReadAll(resp.Body)
+		return nil, fmt.Errorf("project list request failed with status %d: %s", resp.StatusCode, string(bodyBytes))
 	}
 
 	var project GCPProject
-	err = json.Unmarshal(bodyBytes, &project)
-	if err != nil {
+	if err = json.NewDecoder(resp.Body).Decode(&project); err != nil {
 		return nil, fmt.Errorf("failed to unmarshal project list: %w", err)
 	}
 	return &project, nil
 }
 
+// SaveTokenToFile serializes the client's current token storage to a JSON file.
+// The filename is constructed from the user's email and project ID.
 func (c *Client) SaveTokenToFile() error {
 	if err := os.MkdirAll(c.cfg.AuthDir, 0700); err != nil {
 		return fmt.Errorf("failed to create directory: %v", err)
@@ -457,17 +844,19 @@ func (c *Client) SaveTokenToFile() error {
 	return nil
 }
 
-// getClientMetadata returns metadata about the client environment.
+// getClientMetadata returns a map of metadata about the client environment,
+// such as IDE type, platform, and plugin version.
 func getClientMetadata() map[string]string {
 	return map[string]string{
-		"ideType":       "IDE_UNSPECIFIED",
-		"platform":      getPlatform(),
-		"pluginType":    "GEMINI",
-		"pluginVersion": pluginVersion,
+		"ideType":    "IDE_UNSPECIFIED",
+		"platform":   "PLATFORM_UNSPECIFIED",
+		"pluginType": "GEMINI",
+		// "pluginVersion": pluginVersion,
 	}
 }
 
-// getClientMetadataString returns the metadata as a comma-separated string.
+// getClientMetadataString returns the client metadata as a single,
+// comma-separated string, which is required for the 'Client-Metadata' header.
 func getClientMetadataString() string {
 	md := getClientMetadata()
 	parts := make([]string, 0, len(md))
@@ -477,11 +866,14 @@ func getClientMetadataString() string {
 	return strings.Join(parts, ",")
 }
 
+// getUserAgent constructs the User-Agent string for HTTP requests.
 func getUserAgent() string {
-	return fmt.Sprintf(fmt.Sprintf("GeminiCLI/%s (%s; %s)", pluginVersion, runtime.GOOS, runtime.GOARCH))
+	// return fmt.Sprintf("GeminiCLI/%s (%s; %s)", pluginVersion, runtime.GOOS, runtime.GOARCH)
+	return "google-api-nodejs-client/9.15.1"
 }
 
-// getPlatform returns the OS and architecture in the format expected by the API.
+// getPlatform determines the operating system and architecture and formats
+// it into a string expected by the backend API.
 func getPlatform() string {
 	goOS := runtime.GOOS
 	arch := runtime.GOARCH

internal/client/models.go

@@ -2,17 +2,23 @@ package client
 
 import "time"
 
+// ErrorMessage encapsulates an error with an associated HTTP status code.
 type ErrorMessage struct {
 	StatusCode int
 	Error      error
 }
 
+// GCPProject represents the response structure for a Google Cloud project list request.
 type GCPProject struct {
 	Projects []GCPProjectProjects `json:"projects"`
 }
+
+// GCPProjectLabels defines the labels associated with a GCP project.
 type GCPProjectLabels struct {
 	GenerativeLanguage string `json:"generative-language"`
 }
+
+// GCPProjectProjects contains details about a single Google Cloud project.
 type GCPProjectProjects struct {
 	ProjectNumber  string           `json:"projectNumber"`
 	ProjectID      string           `json:"projectId"`
@@ -22,12 +28,14 @@ type GCPProjectProjects struct {
 	CreateTime     time.Time        `json:"createTime"`
 }
 
+// Content represents a single message in a conversation, with a role and parts.
 type Content struct {
 	Role  string `json:"role"`
 	Parts []Part `json:"parts"`
 }
 
-// Part represents a single part of a message's content.
+// Part represents a distinct piece of content within a message, which can be
+// text, inline data (like an image), a function call, or a function response.
 type Part struct {
 	Text             string            `json:"text,omitempty"`
 	InlineData       *InlineData       `json:"inlineData,omitempty"`
@@ -35,46 +43,49 @@ type Part struct {
 	FunctionResponse *FunctionResponse `json:"functionResponse,omitempty"`
 }
 
+// InlineData represents base64-encoded data with its MIME type.
 type InlineData struct {
 	MimeType string `json:"mime_type,omitempty"`
 	Data     string `json:"data,omitempty"`
 }
 
-// FunctionCall represents a tool call requested by the model.
+// FunctionCall represents a tool call requested by the model, including the
+// function name and its arguments.
 type FunctionCall struct {
 	Name string                 `json:"name"`
 	Args map[string]interface{} `json:"args"`
 }
 
-// FunctionResponse represents the result of a tool execution.
+// FunctionResponse represents the result of a tool execution, sent back to the model.
 type FunctionResponse struct {
 	Name     string                 `json:"name"`
 	Response map[string]interface{} `json:"response"`
 }
 
-// GenerateContentRequest is the request payload for the streamGenerateContent endpoint.
+// GenerateContentRequest is the top-level request structure for the streamGenerateContent endpoint.
 type GenerateContentRequest struct {
-	Contents         []Content         `json:"contents"`
-	Tools            []ToolDeclaration `json:"tools,omitempty"`
-	GenerationConfig `json:"generationConfig"`
+	SystemInstruction *Content          `json:"systemInstruction,omitempty"`
+	Contents          []Content         `json:"contents"`
+	Tools             []ToolDeclaration `json:"tools,omitempty"`
+	GenerationConfig  `json:"generationConfig"`
 }
 
-// GenerationConfig defines model generation parameters.
+// GenerationConfig defines parameters that control the model's generation behavior.
 type GenerationConfig struct {
 	ThinkingConfig GenerationConfigThinkingConfig `json:"thinkingConfig,omitempty"`
 	Temperature    float64                        `json:"temperature,omitempty"`
 	TopP           float64                        `json:"topP,omitempty"`
 	TopK           float64                        `json:"topK,omitempty"`
-	// Temperature, TopP, TopK, etc. can be added here.
 }
 
+// GenerationConfigThinkingConfig specifies configuration for the model's "thinking" process.
 type GenerationConfigThinkingConfig struct {
+	// IncludeThoughts determines whether the model should output its reasoning process.
 	IncludeThoughts bool `json:"include_thoughts,omitempty"`
 }
 
-// ToolDeclaration is the structure for declaring tools to the API.
-// For now, we'll assume a simple structure. A more complete implementation
-// would mirror the OpenAPI schema definition.
+// ToolDeclaration defines the structure for declaring tools (like functions)
+// that the model can call.
 type ToolDeclaration struct {
 	FunctionDeclarations []interface{} `json:"functionDeclarations"`
 }

internal/cmd/login.go

@@ -9,6 +9,9 @@ import (
 	"os"
 )
 
+// DoLogin handles the entire user login and setup process.
+// It authenticates the user, sets up the user's project, checks API enablement,
+// and saves the token for future use.
 func DoLogin(cfg *config.Config, projectID string) {
 	var err error
 	var ts auth.TokenStorage
@@ -16,9 +19,8 @@ func DoLogin(cfg *config.Config, projectID string) {
 		ts.ProjectID = projectID
 	}
 
-	// 2. Initialize authenticated HTTP Client
+	// Initialize an authenticated HTTP client. This will trigger the OAuth flow if necessary.
 	clientCtx := context.Background()
-
 	log.Info("Initializing authentication...")
 	httpClient, errGetClient := auth.GetAuthenticatedClient(clientCtx, &ts, cfg)
 	if errGetClient != nil {
@@ -27,51 +29,57 @@ func DoLogin(cfg *config.Config, projectID string) {
 	}
 	log.Info("Authentication successful.")
 
-	// 3. Initialize CLI Client
+	// Initialize the API client.
 	cliClient := client.NewClient(httpClient, &ts, cfg)
+
+	// Perform the user setup process.
 	err = cliClient.SetupUser(clientCtx, ts.Email, projectID)
 	if err != nil {
+		// Handle the specific case where a project ID is required but not provided.
 		if err.Error() == "failed to start user onboarding, need define a project id" {
-			log.Error("failed to start user onboarding")
+			log.Error("Failed to start user onboarding: A project ID is required.")
+			// Fetch and display the user's available projects to help them choose one.
 			project, errGetProjectList := cliClient.GetProjectList(clientCtx)
 			if errGetProjectList != nil {
-				log.Fatalf("failed to complete user setup: %v", err)
+				log.Fatalf("Failed to get project list: %v", err)
 			} else {
-				log.Infof("Your account %s needs specify a project id.", ts.Email)
+				log.Infof("Your account %s needs to specify a project ID.", ts.Email)
 				log.Info("========================================================================")
-				for i := 0; i < len(project.Projects); i++ {
-					log.Infof("Project ID: %s", project.Projects[i].ProjectID)
-					log.Infof("Project Name: %s", project.Projects[i].Name)
-					log.Info("========================================================================")
+				for _, p := range project.Projects {
+					log.Infof("Project ID: %s", p.ProjectID)
+					log.Infof("Project Name: %s", p.Name)
+					log.Info("------------------------------------------------------------------------")
 				}
-				log.Infof("Please run this command to login again:\n\n%s --login --project_id <project_id>\n", os.Args[0])
+				log.Infof("Please run this command to login again with a specific project:\n\n%s --login --project_id <project_id>\n", os.Args[0])
 			}
 		} else {
-			// Log as a warning because in some cases, the CLI might still be usable
-			// or the user might want to retry setup later.
-			log.Fatalf("failed to complete user setup: %v", err)
+			log.Fatalf("Failed to complete user setup: %v", err)
 		}
-	} else {
-		auto := projectID == ""
-		cliClient.SetIsAuto(auto)
+		return // Exit after handling the error.
+	}
 
-		if !cliClient.IsChecked() && !cliClient.IsAuto() {
-			isChecked, checkErr := cliClient.CheckCloudAPIIsEnabled()
-			if checkErr != nil {
-				log.Fatalf("failed to check cloud api is enabled: %v", checkErr)
-				return
-			}
-			cliClient.SetIsChecked(isChecked)
-		}
+	// If setup is successful, proceed to check API status and save the token.
+	auto := projectID == ""
+	cliClient.SetIsAuto(auto)
 
-		if !cliClient.IsChecked() && !cliClient.IsAuto() {
+	// If the project was not automatically selected, check if the Cloud AI API is enabled.
+	if !cliClient.IsChecked() && !cliClient.IsAuto() {
+		isChecked, checkErr := cliClient.CheckCloudAPIIsEnabled()
+		if checkErr != nil {
+			log.Fatalf("Failed to check if Cloud AI API is enabled: %v", checkErr)
 			return
 		}
-
-		err = cliClient.SaveTokenToFile()
-		if err != nil {
-			log.Fatal(err)
+		cliClient.SetIsChecked(isChecked)
+		// If the check fails (returns false), the CheckCloudAPIIsEnabled function
+		// will have already printed instructions, so we can just exit.
+		if !isChecked {
 			return
 		}
 	}
+
+	// Save the successfully obtained and verified token to a file.
+	err = cliClient.SaveTokenToFile()
+	if err != nil {
+		log.Fatalf("Failed to save token to file: %v", err)
+	}
 }

internal/cmd/run.go

@@ -3,13 +3,14 @@ package cmd
 import (
 	"context"
 	"encoding/json"
-	"fmt"
 	"github.com/luispater/CLIProxyAPI/internal/api"
 	"github.com/luispater/CLIProxyAPI/internal/auth"
 	"github.com/luispater/CLIProxyAPI/internal/client"
 	"github.com/luispater/CLIProxyAPI/internal/config"
+	"github.com/luispater/CLIProxyAPI/internal/util"
 	log "github.com/sirupsen/logrus"
 	"io/fs"
+	"net/http"
 	"os"
 	"os/signal"
 	"path/filepath"
@@ -18,20 +19,18 @@ import (
 	"time"
 )
 
+// StartService initializes and starts the main API proxy service.
+// It loads all available authentication tokens, creates a pool of clients,
+// starts the API server, and handles graceful shutdown signals.
 func StartService(cfg *config.Config) {
-	// Create API server configuration
-	apiConfig := &api.ServerConfig{
-		Port:    fmt.Sprintf("%d", cfg.Port),
-		Debug:   cfg.Debug,
-		ApiKeys: cfg.ApiKeys,
-	}
-
+	// Create a pool of API clients, one for each token file found.
 	cliClients := make([]*client.Client, 0)
 	err := filepath.Walk(cfg.AuthDir, func(path string, info fs.FileInfo, err error) error {
 		if err != nil {
 			return err
 		}
 
+		// Process only JSON files in the auth directory.
 		if !info.IsDir() && strings.HasSuffix(info.Name(), ".json") {
 			log.Debugf("Loading token from: %s", path)
 			f, errOpen := os.Open(path)
@@ -42,58 +41,75 @@ func StartService(cfg *config.Config) {
 				_ = f.Close()
 			}()
 
+			// Decode the token storage file.
 			var ts auth.TokenStorage
 			if err = json.NewDecoder(f).Decode(&ts); err == nil {
-				// 2. Initialize authenticated HTTP Client
+				// For each valid token, create an authenticated client.
 				clientCtx := context.Background()
-
-				log.Info("Initializing authentication...")
+				log.Info("Initializing authentication for token...")
 				httpClient, errGetClient := auth.GetAuthenticatedClient(clientCtx, &ts, cfg)
 				if errGetClient != nil {
-					log.Fatalf("failed to get authenticated client: %v", errGetClient)
+					// Log fatal will exit, but we return the error for completeness.
+					log.Fatalf("failed to get authenticated client for token %s: %v", path, errGetClient)
 					return errGetClient
 				}
 				log.Info("Authentication successful.")
 
-				// 3. Initialize CLI Client
+				// Add the new client to the pool.
 				cliClient := client.NewClient(httpClient, &ts, cfg)
 				cliClients = append(cliClients, cliClient)
 			}
 		}
 		return nil
 	})
-
-	// Create API server
-	apiServer := api.NewServer(apiConfig, cliClients)
-	log.Infof("Starting API server on port %s", apiConfig.Port)
-	if err = apiServer.Start(); err != nil {
-		log.Fatalf("API server failed to start: %v", err)
-		return
+	if err != nil {
+		log.Fatalf("Error walking auth directory: %v", err)
 	}
 
-	// Set up graceful shutdown
+	if len(cfg.GlAPIKey) > 0 {
+		for i := 0; i < len(cfg.GlAPIKey); i++ {
+			httpClient, errSetProxy := util.SetProxy(cfg, &http.Client{})
+			if errSetProxy != nil {
+				log.Fatalf("set proxy failed: %v", errSetProxy)
+			}
+
+			log.Debug("Initializing with Generative Language API key...")
+			cliClient := client.NewClient(httpClient, nil, cfg, cfg.GlAPIKey[i])
+			cliClients = append(cliClients, cliClient)
+		}
+	}
+
+	// Create and start the API server with the pool of clients.
+	apiServer := api.NewServer(cfg, cliClients)
+	log.Infof("Starting API server on port %d", cfg.Port)
+	if err = apiServer.Start(); err != nil {
+		log.Fatalf("API server failed to start: %v", err)
+	}
+
+	// Set up a channel to listen for OS signals for graceful shutdown.
 	sigChan := make(chan os.Signal, 1)
 	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
 
+	// Main loop to wait for shutdown signal.
 	for {
 		select {
 		case <-sigChan:
 			log.Debugf("Received shutdown signal. Cleaning up...")
 
-			// Create shutdown context
+			// Create a context with a timeout for the shutdown process.
 			ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
-			_ = ctx // Mark ctx as used to avoid error, as apiServer.Stop(ctx) is commented out
+			_ = cancel
 
-			// Stop API server
+			// Stop the API server gracefully.
 			if err = apiServer.Stop(ctx); err != nil {
 				log.Debugf("Error stopping API server: %v", err)
 			}
-			cancel()
 
 			log.Debugf("Cleanup completed. Exiting...")
 			os.Exit(0)
 		case <-time.After(5 * time.Second):
-
+			// This case is currently empty and acts as a periodic check.
+			// It could be used for periodic tasks in the future.
 		}
 	}
 }

internal/config/config.go

@@ -6,33 +6,46 @@ import (
 	"os"
 )
 
-// Config represents the application's configuration
+// Config represents the application's configuration, loaded from a YAML file.
 type Config struct {
-	Port     int      `yaml:"port"`
-	AuthDir  string   `yaml:"auth_dir"`
-	Debug    bool     `yaml:"debug"`
-	ProxyUrl string   `yaml:"proxy-url"`
-	ApiKeys  []string `yaml:"api_keys"`
+	// Port is the network port on which the API server will listen.
+	Port int `yaml:"port"`
+	// AuthDir is the directory where authentication token files are stored.
+	AuthDir string `yaml:"auth-dir"`
+	// Debug enables or disables debug-level logging and other debug features.
+	Debug bool `yaml:"debug"`
+	// ProxyUrl is the URL of an optional proxy server to use for outbound requests.
+	ProxyUrl string `yaml:"proxy-url"`
+	// ApiKeys is a list of keys for authenticating clients to this proxy server.
+	ApiKeys []string `yaml:"api-keys"`
+	// QuotaExceeded defines the behavior when a quota is exceeded.
+	QuotaExceeded ConfigQuotaExceeded `yaml:"quota-exceeded"`
+	// GlAPIKey is the API key for the generative language API.
+	GlAPIKey []string `yaml:"generative-language-api-key"`
 }
 
-// / LoadConfig loads the configuration from the specified file
+type ConfigQuotaExceeded struct {
+	// SwitchProject indicates whether to automatically switch to another project when a quota is exceeded.
+	SwitchProject bool `yaml:"switch-project"`
+	// SwitchPreviewModel indicates whether to automatically switch to a preview model when a quota is exceeded.
+	SwitchPreviewModel bool `yaml:"switch-preview-model"`
+}
+
+// LoadConfig reads a YAML configuration file from the given path,
+// unmarshals it into a Config struct, and returns it.
 func LoadConfig(configFile string) (*Config, error) {
-	// Read the configuration file
+	// Read the entire configuration file into memory.
 	data, err := os.ReadFile(configFile)
-	// If reading the file fails
 	if err != nil {
-		// Return an error
 		return nil, fmt.Errorf("failed to read config file: %w", err)
 	}
 
-	// Parse the YAML data
+	// Unmarshal the YAML data into the Config struct.
 	var config Config
-	// If parsing the YAML data fails
 	if err = yaml.Unmarshal(data, &config); err != nil {
-		// Return an error
 		return nil, fmt.Errorf("failed to parse config file: %w", err)
 	}
 
-	// Return the configuration
+	// Return the populated configuration struct.
 	return &config, nil
 }

internal/util/proxy.go

@@ -0,0 +1,37 @@
+package util
+
+import (
+	"context"
+	"github.com/luispater/CLIProxyAPI/internal/config"
+	"golang.org/x/net/proxy"
+	"net"
+	"net/http"
+	"net/url"
+)
+
+func SetProxy(cfg *config.Config, httpClient *http.Client) (*http.Client, error) {
+	var transport *http.Transport
+	proxyURL, errParse := url.Parse(cfg.ProxyUrl)
+	if errParse == nil {
+		if proxyURL.Scheme == "socks5" {
+			username := proxyURL.User.Username()
+			password, _ := proxyURL.User.Password()
+			proxyAuth := &proxy.Auth{User: username, Password: password}
+			dialer, errSOCKS5 := proxy.SOCKS5("tcp", proxyURL.Host, proxyAuth, proxy.Direct)
+			if errSOCKS5 != nil {
+				return nil, errSOCKS5
+			}
+			transport = &http.Transport{
+				DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
+					return dialer.Dial(network, addr)
+				},
+			}
+		} else if proxyURL.Scheme == "http" || proxyURL.Scheme == "https" {
+			transport = &http.Transport{Proxy: http.ProxyURL(proxyURL)}
+		}
+	}
+	if transport != nil {
+		httpClient.Transport = transport
+	}
+	return httpClient, nil
+}