package executor

import (
	"bufio"
	"bytes"
	"context"
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"

	claudeauth "github.com/router-for-me/CLIProxyAPI/v6/internal/auth/claude"
	"github.com/router-for-me/CLIProxyAPI/v6/internal/config"
	"github.com/router-for-me/CLIProxyAPI/v6/internal/misc"
	cliproxyauth "github.com/router-for-me/CLIProxyAPI/v6/sdk/cliproxy/auth"
	cliproxyexecutor "github.com/router-for-me/CLIProxyAPI/v6/sdk/cliproxy/executor"
	sdktranslator "github.com/router-for-me/CLIProxyAPI/v6/sdk/translator"
	log "github.com/sirupsen/logrus"
	"github.com/tidwall/sjson"
)

// ClaudeExecutor is a stateless executor for Anthropic Claude over the messages API.
// If api_key is unavailable on auth, it falls back to legacy via ClientAdapter.
type ClaudeExecutor struct {
	cfg *config.Config
}

func NewClaudeExecutor(cfg *config.Config) *ClaudeExecutor { return &ClaudeExecutor{cfg: cfg} }

func (e *ClaudeExecutor) Identifier() string { return "claude" }

func (e *ClaudeExecutor) PrepareRequest(_ *http.Request, _ *cliproxyauth.Auth) error { return nil }

func (e *ClaudeExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, req cliproxyexecutor.Request, opts cliproxyexecutor.Options) (cliproxyexecutor.Response, error) {
	apiKey, baseURL := claudeCreds(auth)
	if apiKey == "" {
		return NewClientAdapter("claude").Execute(ctx, auth, req, opts)
	}
	if baseURL == "" {
		baseURL = "https://api.anthropic.com"
	}
	from := opts.SourceFormat
	to := sdktranslator.FromString("claude")
	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), false)

	if !strings.HasPrefix(req.Model, "claude-3-5-haiku") {
		body, _ = sjson.SetRawBytes(body, "system", []byte(misc.ClaudeCodeInstructions))
	}

	url := fmt.Sprintf("%s/v1/messages?beta=true", baseURL)
	recordAPIRequest(ctx, e.cfg, body)
	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
	if err != nil {
		return cliproxyexecutor.Response{}, err
	}
	applyClaudeHeaders(httpReq, apiKey, false)

	httpClient := &http.Client{}
	if rt, ok := ctx.Value("cliproxy.roundtripper").(http.RoundTripper); ok && rt != nil {
		httpClient.Transport = rt
	}
	resp, err := httpClient.Do(httpReq)
	if err != nil {
		return cliproxyexecutor.Response{}, err
	}
	defer func() { _ = resp.Body.Close() }()
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		b, _ := io.ReadAll(resp.Body)
		appendAPIResponseChunk(ctx, e.cfg, b)
		log.Debugf("request error, error status: %d, error body: %s", resp.StatusCode, string(b))
		return cliproxyexecutor.Response{}, statusErr{code: resp.StatusCode, msg: string(b)}
	}
	data, err := io.ReadAll(resp.Body)
	if err != nil {
		return cliproxyexecutor.Response{}, err
	}
	appendAPIResponseChunk(ctx, e.cfg, data)
	var param any
	out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, data, &param)
	return cliproxyexecutor.Response{Payload: []byte(out)}, nil
}

func (e *ClaudeExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Auth, req cliproxyexecutor.Request, opts cliproxyexecutor.Options) (<-chan cliproxyexecutor.StreamChunk, error) {
	apiKey, baseURL := claudeCreds(auth)
	if apiKey == "" {
		return NewClientAdapter("claude").ExecuteStream(ctx, auth, req, opts)
	}
	if baseURL == "" {
		baseURL = "https://api.anthropic.com"
	}
	from := opts.SourceFormat
	to := sdktranslator.FromString("claude")
	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), true)
	body, _ = sjson.SetRawBytes(body, "system", []byte(misc.ClaudeCodeInstructions))

	url := fmt.Sprintf("%s/v1/messages?beta=true", baseURL)
	recordAPIRequest(ctx, e.cfg, body)
	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
	if err != nil {
		return nil, err
	}
	applyClaudeHeaders(httpReq, apiKey, true)

	httpClient := &http.Client{Timeout: 0}
	if rt, ok := ctx.Value("cliproxy.roundtripper").(http.RoundTripper); ok && rt != nil {
		httpClient.Transport = rt
	}
	resp, err := httpClient.Do(httpReq)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		defer func() { _ = resp.Body.Close() }()
		b, _ := io.ReadAll(resp.Body)
		appendAPIResponseChunk(ctx, e.cfg, b)
		log.Debugf("request error, error status: %d, error body: %s", resp.StatusCode, string(b))
		return nil, statusErr{code: resp.StatusCode, msg: string(b)}
	}
	out := make(chan cliproxyexecutor.StreamChunk)
	go func() {
		defer close(out)
		defer func() { _ = resp.Body.Close() }()
		scanner := bufio.NewScanner(resp.Body)
		buf := make([]byte, 1024*1024)
		scanner.Buffer(buf, 1024*1024)
		var param any
		for scanner.Scan() {
			line := scanner.Bytes()
			appendAPIResponseChunk(ctx, e.cfg, line)
			chunks := sdktranslator.TranslateStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, bytes.Clone(line), &param)
			for i := range chunks {
				out <- cliproxyexecutor.StreamChunk{Payload: []byte(chunks[i])}
			}
		}
		if err = scanner.Err(); err != nil {
			out <- cliproxyexecutor.StreamChunk{Err: err}
		}
	}()
	return out, nil
}

func (e *ClaudeExecutor) Refresh(ctx context.Context, auth *cliproxyauth.Auth) (*cliproxyauth.Auth, error) {
	log.Debugf("claude executor: refresh called")
	if auth == nil {
		return nil, fmt.Errorf("claude executor: auth is nil")
	}
	var refreshToken string
	if auth.Metadata != nil {
		if v, ok := auth.Metadata["refresh_token"].(string); ok && v != "" {
			refreshToken = v
		}
	}
	if refreshToken == "" {
		return auth, nil
	}
	svc := claudeauth.NewClaudeAuth(e.cfg)
	td, err := svc.RefreshTokens(ctx, refreshToken)
	if err != nil {
		return nil, err
	}
	if auth.Metadata == nil {
		auth.Metadata = make(map[string]any)
	}
	auth.Metadata["access_token"] = td.AccessToken
	if td.RefreshToken != "" {
		auth.Metadata["refresh_token"] = td.RefreshToken
	}
	auth.Metadata["email"] = td.Email
	auth.Metadata["expired"] = td.Expire
	auth.Metadata["type"] = "claude"
	now := time.Now().Format(time.RFC3339)
	auth.Metadata["last_refresh"] = now
	return auth, nil
}

func applyClaudeHeaders(r *http.Request, apiKey string, stream bool) {
	r.Header.Set("Authorization", "Bearer "+apiKey)
	r.Header.Set("Content-Type", "application/json")
	r.Header.Set("Anthropic-Version", "2023-06-01")
	r.Header.Set("Anthropic-Dangerous-Direct-Browser-Access", "true")
	r.Header.Set("Anthropic-Beta", "claude-code-20250219,oauth-2025-04-20,interleaved-thinking-2025-05-14,fine-grained-tool-streaming-2025-05-14")
	r.Header.Set("Connection", "keep-alive")
	r.Header.Set("User-Agent", "claude-cli/1.0.83 (external, cli)")
	r.Header.Set("Accept-Encoding", "gzip, deflate, br, zstd")
	r.Header.Set("X-App", "cli")
	r.Header.Set("X-Stainless-Helper-Method", "stream")
	r.Header.Set("X-Stainless-Retry-Count", "0")
	r.Header.Set("X-Stainless-Runtime-Version", "v24.3.0")
	r.Header.Set("X-Stainless-Package-Version", "0.55.1")
	r.Header.Set("X-Stainless-Runtime", "node")
	r.Header.Set("X-Stainless-Lang", "js")
	r.Header.Set("X-Stainless-Arch", "arm64")
	r.Header.Set("X-Stainless-Os", "MacOS")
	r.Header.Set("X-Stainless-Timeout", "60")
	if stream {
		r.Header.Set("Accept", "text/event-stream")
		return
	}
	r.Header.Set("Accept", "application/json")
}

func claudeCreds(a *cliproxyauth.Auth) (apiKey, baseURL string) {
	if a == nil {
		return "", ""
	}
	if a.Attributes != nil {
		apiKey = a.Attributes["api_key"]
		baseURL = a.Attributes["base_url"]
	}
	if apiKey == "" && a.Metadata != nil {
		if v, ok := a.Metadata["access_token"].(string); ok {
			apiKey = v
		}
	}
	return
}