package claude

import (
	"errors"
	"fmt"
	"io"
	"net/http"
	"one-api/dto"
	"one-api/relay/channel"
	relaycommon "one-api/relay/common"
	"one-api/setting/model_setting"
	"one-api/types"
	"strings"

	"github.com/gin-gonic/gin"
)

const (
	RequestModeCompletion = 1
	RequestModeMessage    = 2
)

type Adaptor struct {
	RequestMode int
}

func (a *Adaptor) ConvertGeminiRequest(*gin.Context, *relaycommon.RelayInfo, *dto.GeminiChatRequest) (any, error) {
	//TODO implement me
	return nil, errors.New("not implemented")
}

func (a *Adaptor) ConvertClaudeRequest(c *gin.Context, info *relaycommon.RelayInfo, request *dto.ClaudeRequest) (any, error) {
	return request, nil
}

func (a *Adaptor) ConvertAudioRequest(c *gin.Context, info *relaycommon.RelayInfo, request dto.AudioRequest) (io.Reader, error) {
	//TODO implement me
	return nil, errors.New("not implemented")
}

func (a *Adaptor) ConvertImageRequest(c *gin.Context, info *relaycommon.RelayInfo, request dto.ImageRequest) (any, error) {
	//TODO implement me
	return nil, errors.New("not implemented")
}

func (a *Adaptor) Init(info *relaycommon.RelayInfo) {
	if strings.HasPrefix(info.UpstreamModelName, "claude-2") || strings.HasPrefix(info.UpstreamModelName, "claude-instant") {
		a.RequestMode = RequestModeCompletion
	} else {
		a.RequestMode = RequestModeMessage
	}
}

func (a *Adaptor) GetRequestURL(info *relaycommon.RelayInfo) (string, error) {
	if a.RequestMode == RequestModeMessage {
		return fmt.Sprintf("%s/v1/messages", info.ChannelBaseUrl), nil
	} else {
		return fmt.Sprintf("%s/v1/complete", info.ChannelBaseUrl), nil
	}
}

func (a *Adaptor) SetupRequestHeader(c *gin.Context, req *http.Header, info *relaycommon.RelayInfo) error {
	if model_setting.GetGlobalSettings().PassThroughRequestEnabled || info.ChannelSetting.PassThroughBodyEnabled {
		userAgent := c.Request.Header.Get("User-Agent")
		
		// 智能请求头策略：检测客户端类型并决定处理方式
		if isClaudeCode(userAgent) || isKillcode(userAgent) {
			// Claude Code 和 killcode: 完全透传原始请求头
			for key, values := range c.Request.Header {
				keyLower := strings.ToLower(key)
				if keyLower == "host" || keyLower == "content-length" || keyLower == "connection" {
					continue
				}
				for _, value := range values {
					req.Add(key, value)
				}
			}
		} else {
			// 其他客户端: 伪装成 killcode 格式以绕过上游限制
			setupKillcodeHeaders(c, req)
		}
		
		// 保险：确保 User-Agent 一定存在，避免显示 Go-http-client/2.0
		if req.Get("User-Agent") == "" {
			req.Set("User-Agent", "B2/JS 0.51.0")
		}
	} else {
		// 非穿透模式：使用通用设置
		channel.SetupApiRequestHeader(info, c, req)
	}
	
	// 无论哪种模式都需要设置正确的API密钥
	req.Set("x-api-key", info.ApiKey)
	
	if !model_setting.GetGlobalSettings().PassThroughRequestEnabled && !info.ChannelSetting.PassThroughBodyEnabled {
		// 非穿透模式才强制设置这些头
		anthropicVersion := c.Request.Header.Get("anthropic-version")
		if anthropicVersion == "" {
			anthropicVersion = "2023-06-01"
		}
		req.Set("anthropic-version", anthropicVersion)
		model_setting.GetClaudeSettings().WriteHeaders(info.OriginModelName, req)
	}
	return nil
}

// isClaudeCode 检测是否为 Claude Code 客户端
func isClaudeCode(userAgent string) bool {
	return strings.Contains(userAgent, "claude-cli")
}

// isKillcode 检测是否为 killcode 客户端
func isKillcode(userAgent string) bool {
	return strings.Contains(userAgent, "B2/JS") || strings.Contains(userAgent, "X-Stainless")
}

// setupKillcodeHeaders 设置 killcode 风格的请求头，用于伪装其他客户端
func setupKillcodeHeaders(c *gin.Context, req *http.Header) {
	// 基础头部
	req.Set("User-Agent", "B2/JS 0.51.0")
	req.Set("Connection", "keep-alive")
	req.Set("Accept", "application/json")
	req.Set("Accept-Encoding", "br, gzip, deflate")
	req.Set("Content-Type", "application/json")
	
	// Stainless SDK 特有头部
	req.Set("X-Stainless-Retry-Count", "0")
	req.Set("X-Stainless-Timeout", "600")
	req.Set("X-Stainless-Lang", "js")
	req.Set("X-Stainless-Package-Version", "0.51.0")
	req.Set("X-Stainless-OS", "Windows")
	req.Set("X-Stainless-Arch", "x64")
	req.Set("X-Stainless-Runtime", "node")
	req.Set("X-Stainless-Runtime-Version", "v20.19.1")
	
	// 保留重要的原始头部
	if anthropicVersion := c.Request.Header.Get("anthropic-version"); anthropicVersion != "" {
		req.Set("anthropic-version", anthropicVersion)
	} else {
		req.Set("anthropic-version", "2023-06-01")
	}
	
	if anthropicBeta := c.Request.Header.Get("anthropic-beta"); anthropicBeta != "" {
		req.Set("anthropic-beta", anthropicBeta)
	}
	
	// 其他辅助头部
	req.Set("accept-language", "*")
	req.Set("sec-fetch-mode", "cors")
}

func (a *Adaptor) ConvertOpenAIRequest(c *gin.Context, info *relaycommon.RelayInfo, request *dto.GeneralOpenAIRequest) (any, error) {
	if request == nil {
		return nil, errors.New("request is nil")
	}
	if a.RequestMode == RequestModeCompletion {
		return RequestOpenAI2ClaudeComplete(*request), nil
	} else {
		return RequestOpenAI2ClaudeMessage(c, *request)
	}
}

func (a *Adaptor) ConvertRerankRequest(c *gin.Context, relayMode int, request dto.RerankRequest) (any, error) {
	return nil, nil
}

func (a *Adaptor) ConvertEmbeddingRequest(c *gin.Context, info *relaycommon.RelayInfo, request dto.EmbeddingRequest) (any, error) {
	//TODO implement me
	return nil, errors.New("not implemented")
}

func (a *Adaptor) ConvertOpenAIResponsesRequest(c *gin.Context, info *relaycommon.RelayInfo, request dto.OpenAIResponsesRequest) (any, error) {
	// TODO implement me
	return nil, errors.New("not implemented")
}

func (a *Adaptor) DoRequest(c *gin.Context, info *relaycommon.RelayInfo, requestBody io.Reader) (any, error) {
	return channel.DoApiRequest(a, c, info, requestBody)
}

func (a *Adaptor) DoResponse(c *gin.Context, resp *http.Response, info *relaycommon.RelayInfo) (usage any, err *types.NewAPIError) {
	if info.IsStream {
		return ClaudeStreamHandler(c, resp, info, a.RequestMode)
	} else {
		return ClaudeHandler(c, resp, info, a.RequestMode)
	}
	return
}

func (a *Adaptor) GetModelList() []string {
	return ModelList
}

func (a *Adaptor) GetChannelName() string {
	return ChannelName
}