package service

import (
	"context"
	"fmt"
	"sync"
	"time"

	"github.com/flipped-aurora/gin-vue-admin/server/global"
	"github.com/flipped-aurora/gin-vue-admin/server/plugin/volcengine/model/request"
	"github.com/flipped-aurora/gin-vue-admin/server/plugin/volcengine/model/response"
	"github.com/google/uuid"
	"github.com/volcengine/volcengine-go-sdk/service/arkruntime"
	"github.com/volcengine/volcengine-go-sdk/service/arkruntime/model"
	"go.uber.org/zap"
)

type LLMService struct {
	client         *arkruntime.Client
	activeSessions sync.Map // requestID -> context.CancelFunc
}

var LLMServiceApp = new(LLMService)

// InitVolcengineClient 初始化火山引擎客户端
func (l *LLMService) InitVolcengineClient() error {
	config := global.GVA_CONFIG.Volcengine

	// 验证配置
	if config.AccessKey == "" || config.SecretKey == "" {
		return fmt.Errorf("volcengine access key or secret key is empty")
	}

	// 创建ARK Runtime客户端
	l.client = arkruntime.NewClientWithAkSk(config.AccessKey, config.SecretKey)

	global.GVA_LOG.Info("Volcengine client initialized successfully")
	return nil
}

// ChatCompletion 非流式聊天完成
func (l *LLMService) ChatCompletion(req request.ChatRequest) (*response.ChatResponse, error) {
	if l.client == nil {
		if err := l.InitVolcengineClient(); err != nil {
			return nil, err
		}
	}

	// 生成请求ID
	if req.RequestID == "" {
		req.RequestID = uuid.New().String()
	}

	// 转换消息格式
	messages := make([]*model.ChatCompletionMessage, len(req.Messages))
	for i, msg := range req.Messages {
		messages[i] = &model.ChatCompletionMessage{
			Role: msg.Role,
			Content: &model.ChatCompletionMessageContent{
				StringValue: &msg.Content,
			},
		}
	}

	// 设置模型
	modelName := req.Model
	if modelName == "" {
		modelName = global.GVA_CONFIG.Volcengine.DefaultModel
	}

	// 创建请求
	chatReq := &model.ChatCompletionRequest{
		Model:    modelName,
		Messages: messages,
	}

	// 设置可选参数
	if req.Temperature > 0 {
		chatReq.Temperature = float32(req.Temperature)
	}
	if req.MaxTokens > 0 {
		chatReq.MaxTokens = req.MaxTokens
	}
	if req.TopP > 0 {
		chatReq.TopP = float32(req.TopP)
	}

	// 创建上下文
	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
	defer cancel()

	// 存储取消函数
	l.activeSessions.Store(req.RequestID, cancel)
	defer l.activeSessions.Delete(req.RequestID)

	// 调用API
	resp, err := l.client.CreateChatCompletion(ctx, chatReq)
	if err != nil {
		global.GVA_LOG.Error("Chat completion failed", zap.Error(err), zap.String("requestID", req.RequestID))
		return nil, fmt.Errorf("chat completion failed: %w", err)
	}

	// 转换响应格式
	chatResp := &response.ChatResponse{
		ID:      req.RequestID,
		Object:  "chat.completion",
		Created: time.Now().Unix(),
		Model:   modelName,
		Choices: make([]response.Choice, len(resp.Choices)),
	}

	for i, choice := range resp.Choices {
		messageContent := ""
		if choice.Message.Content != nil && choice.Message.Content.StringValue != nil {
			messageContent = *choice.Message.Content.StringValue
		}

		chatResp.Choices[i] = response.Choice{
			Index: i,
			Message: response.Message{
				Role:    choice.Message.Role,
				Content: messageContent,
			},
			FinishReason: string(choice.FinishReason),
		}
	}

	// 设置使用量统计
	chatResp.Usage = &response.Usage{
		PromptTokens:     resp.Usage.PromptTokens,
		CompletionTokens: resp.Usage.CompletionTokens,
		TotalTokens:      resp.Usage.TotalTokens,
	}

	global.GVA_LOG.Info("Chat completion successful", zap.String("requestID", req.RequestID))
	return chatResp, nil
}

// StreamChatCompletion 流式聊天完成
func (l *LLMService) StreamChatCompletion(req request.ChatRequest, eventChan chan<- response.StreamEvent) error {
	if l.client == nil {
		if err := l.InitVolcengineClient(); err != nil {
			return err
		}
	}

	// 生成请求ID
	if req.RequestID == "" {
		req.RequestID = uuid.New().String()
	}

	// 转换消息格式
	messages := make([]*model.ChatCompletionMessage, len(req.Messages))
	for i, msg := range req.Messages {
		messages[i] = &model.ChatCompletionMessage{
			Role: msg.Role,
			Content: &model.ChatCompletionMessageContent{
				StringValue: &msg.Content,
			},
		}
	}

	// 设置模型
	modelName := req.Model
	if modelName == "" {
		modelName = global.GVA_CONFIG.Volcengine.DefaultModel
	}

	// 创建流式请求
	chatReq := &model.ChatCompletionRequest{
		Model:    modelName,
		Messages: messages,
		Stream:   true,
	}

	// 设置可选参数
	if req.Temperature > 0 {
		chatReq.Temperature = float32(req.Temperature)
	}
	if req.MaxTokens > 0 {
		chatReq.MaxTokens = req.MaxTokens
	}
	if req.TopP > 0 {
		chatReq.TopP = float32(req.TopP)
	}

	// 创建上下文
	ctx, cancel := context.WithTimeout(context.Background(), 300*time.Second) // 流式响应需要更长时间
	defer cancel()

	// 存储取消函数
	l.activeSessions.Store(req.RequestID, cancel)
	defer l.activeSessions.Delete(req.RequestID)

	// 调用流式API
	stream_resp, err := l.client.CreateChatCompletionStream(ctx, chatReq)
	if err != nil {
		global.GVA_LOG.Error("Stream chat completion failed", zap.Error(err), zap.String("requestID", req.RequestID))
		return fmt.Errorf("stream chat completion failed: %w", err)
	}
	defer stream_resp.Close()

	// 处理流式响应
	for {
		select {
		case <-ctx.Done():
			// 上下文取消
			eventChan <- response.StreamEvent{
				Event: "error",
				Data: response.ChatResponse{
					ID: req.RequestID,
					Error: &response.APIError{
						Code:    "context_cancelled",
						Message: "Request was cancelled",
						Type:    "request_cancelled",
					},
				},
			}
			return ctx.Err()
		default:
			// 接收流式数据
			recv, err := stream_resp.Recv()
			if err != nil {
				if err.Error() == "EOF" {
					// 流结束
					eventChan <- response.StreamEvent{
						Event: "done",
						Data: response.ChatResponse{
							ID:     req.RequestID,
							Object: "chat.completion.chunk",
						},
					}
					global.GVA_LOG.Info("Stream chat completion finished", zap.String("requestID", req.RequestID))
					return nil
				}
				global.GVA_LOG.Error("Stream receive error", zap.Error(err), zap.String("requestID", req.RequestID))
				eventChan <- response.StreamEvent{
					Event: "error",
					Data: response.ChatResponse{
						ID: req.RequestID,
						Error: &response.APIError{
							Code:    "stream_error",
							Message: err.Error(),
							Type:    "stream_error",
						},
					},
				}
				return err
			}

			// 转换并发送响应
			chatResp := response.ChatResponse{
				ID:      req.RequestID,
				Object:  "chat.completion.chunk",
				Created: time.Now().Unix(),
				Model:   modelName,
				Choices: make([]response.Choice, len(recv.Choices)),
			}

			for i, choice := range recv.Choices {
				chatResp.Choices[i] = response.Choice{
					Index: i,
					Delta: response.Message{
						Role:    choice.Delta.Role,
						Content: choice.Delta.Content,
					},
				}
				if choice.FinishReason != "" {
					chatResp.Choices[i].FinishReason = string(choice.FinishReason)
				}
			}

			eventChan <- response.StreamEvent{
				Event: "message",
				Data:  chatResp,
			}
		}
	}
}

// StopGeneration 停止生成
func (l *LLMService) StopGeneration(req request.StopRequest) (*response.StopResponse, error) {
	// 查找并取消对应的请求
	if cancelFunc, ok := l.activeSessions.Load(req.RequestID); ok {
		if cancel, ok := cancelFunc.(context.CancelFunc); ok {
			cancel()
			l.activeSessions.Delete(req.RequestID)

			global.GVA_LOG.Info("Request stopped successfully", zap.String("requestID", req.RequestID))
			return &response.StopResponse{
				Success:   true,
				Message:   "Request stopped successfully",
				RequestID: req.RequestID,
				StoppedAt: time.Now().Unix(),
			}, nil
		}
	}

	global.GVA_LOG.Warn("Request not found or already completed", zap.String("requestID", req.RequestID))
	return &response.StopResponse{
		Success:   false,
		Message:   "Request not found or already completed",
		RequestID: req.RequestID,
		StoppedAt: time.Now().Unix(),
	}, nil
}

// GetActiveSessionsCount 获取活跃会话数量
func (l *LLMService) GetActiveSessionsCount() int {
	count := 0
	l.activeSessions.Range(func(key, value interface{}) bool {
		count++
		return true
	})
	return count
}