Add token refresh handling for 401 responses across clients

- Implemented `RefreshTokens` method in client interfaces and Gemini clients.
- Updated handlers to call `RefreshTokens` on 401 responses and retry requests if token refresh succeeds.
- Enhanced error handling and retry logic to accommodate token refresh flow.

internal/api/handlers/claude/code_handlers.go

@@ -197,6 +197,14 @@ outLoop:
 						log.Debugf("http status code %d, switch client, %s", errInfo.StatusCode, util.HideAPIKey(cliClient.GetEmail()))
 						retryCount++
 						continue outLoop
+					case 401:
+						log.Debugf("unauthorized request, try to refresh token, %s", util.HideAPIKey(cliClient.GetEmail()))
+						err := cliClient.RefreshTokens(cliCtx)
+						if err != nil {
+							log.Debugf("refresh token failed, switch client, %s", util.HideAPIKey(cliClient.GetEmail()))
+						}
+						retryCount++
+						continue outLoop
 					default:
 						// Forward other errors directly to the client
 						c.Status(errInfo.StatusCode)

internal/api/handlers/gemini/gemini-cli_handlers.go

@@ -275,6 +275,14 @@ func (h *GeminiCLIAPIHandler) handleInternalGenerateContent(c *gin.Context, rawJ
 				log.Debugf("http status code %d, switch client", err.StatusCode)
 				retryCount++
 				continue
+			case 401:
+				log.Debugf("unauthorized request, try to refresh token, %s", util.HideAPIKey(cliClient.GetEmail()))
+				errRefreshTokens := cliClient.RefreshTokens(cliCtx)
+				if errRefreshTokens != nil {
+					log.Debugf("refresh token failed, switch client, %s", util.HideAPIKey(cliClient.GetEmail()))
+				}
+				retryCount++
+				continue
 			default:
 				// Forward other errors directly to the client
 				c.Status(err.StatusCode)

internal/api/handlers/gemini/gemini_handlers.go

@@ -17,6 +17,7 @@ import (
 	. "github.com/luispater/CLIProxyAPI/internal/constant"
 	"github.com/luispater/CLIProxyAPI/internal/interfaces"
 	"github.com/luispater/CLIProxyAPI/internal/registry"
+	"github.com/luispater/CLIProxyAPI/internal/util"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -387,6 +388,14 @@ func (h *GeminiAPIHandler) handleGenerateContent(c *gin.Context, modelName strin
 				log.Debugf("http status code %d, switch client", err.StatusCode)
 				retryCount++
 				continue
+			case 401:
+				log.Debugf("unauthorized request, try to refresh token, %s", util.HideAPIKey(cliClient.GetEmail()))
+				errRefreshTokens := cliClient.RefreshTokens(cliCtx)
+				if errRefreshTokens != nil {
+					log.Debugf("refresh token failed, switch client, %s", util.HideAPIKey(cliClient.GetEmail()))
+				}
+				retryCount++
+				continue
 			default:
 				// Forward other errors directly to the client
 				c.Status(err.StatusCode)

internal/api/handlers/openai/openai_handlers.go

@@ -18,6 +18,7 @@ import (
 	. "github.com/luispater/CLIProxyAPI/internal/constant"
 	"github.com/luispater/CLIProxyAPI/internal/interfaces"
 	"github.com/luispater/CLIProxyAPI/internal/registry"
+	"github.com/luispater/CLIProxyAPI/internal/util"
 	log "github.com/sirupsen/logrus"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"
@@ -409,6 +410,14 @@ func (h *OpenAIAPIHandler) handleNonStreamingResponse(c *gin.Context, rawJSON []
 				log.Debugf("http status code %d, switch client", err.StatusCode)
 				retryCount++
 				continue
+			case 401:
+				log.Debugf("unauthorized request, try to refresh token, %s", util.HideAPIKey(cliClient.GetEmail()))
+				errRefreshTokens := cliClient.RefreshTokens(cliCtx)
+				if errRefreshTokens != nil {
+					log.Debugf("refresh token failed, switch client, %s", util.HideAPIKey(cliClient.GetEmail()))
+				}
+				retryCount++
+				continue
 			default:
 				// Forward other errors directly to the client
 				c.Status(err.StatusCode)

internal/client/gemini-cli_client.go

@@ -860,3 +860,8 @@ func (c *GeminiCLIClient) GetUserAgent() string {
 func (c *GeminiCLIClient) GetRequestMutex() *sync.Mutex {
 	return nil
 }
+
+func (c *GeminiCLIClient) RefreshTokens(ctx context.Context) error {
+	// API keys don't need refreshing
+	return nil
+}

internal/client/gemini_client.go

@@ -434,3 +434,8 @@ func (c *GeminiClient) GetUserAgent() string {
 func (c *GeminiClient) GetRequestMutex() *sync.Mutex {
 	return nil
 }
+
+func (c *GeminiClient) RefreshTokens(ctx context.Context) error {
+	// API keys don't need refreshing
+	return nil
+}

internal/interfaces/client.go

@@ -51,4 +51,6 @@ type Client interface {
 
 	// Provider returns the name of the AI service provider (e.g., "gemini", "claude").
 	Provider() string
+
+	RefreshTokens(ctx context.Context) error
 }