package api

import (
	"fmt"
	"io"
	"time"

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

type LLMApi struct{}

// ChatCompletion
// @Tags      Volcengine
// @Summary   LLM聊天完成
// @Security  ApiKeyAuth
// @accept    application/json
// @Produce   application/json
// @Param     data  body      request.ChatRequest                    true  "聊天请求参数"
// @Success   200   {object}  response.Response{data=volcengineResponse.ChatResponse}  "聊天响应"
// @Router    /volcengine/llm/chat [post]
func (l *LLMApi) ChatCompletion(c *gin.Context) {
	var chatReq request.ChatRequest
	err := c.ShouldBindJSON(&chatReq)
	if err != nil {
		response.FailWithMessage(err.Error(), c)
		return
	}

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

	// 根据stream参数选择响应模式
	if chatReq.Stream {
		// 流式响应 (SSE)
		l.handleStreamResponse(c, chatReq)
	} else {
		// 普通JSON响应
		l.handleNormalResponse(c, chatReq)
	}
}

// handleNormalResponse 处理普通JSON响应
func (l *LLMApi) handleNormalResponse(c *gin.Context, chatReq request.ChatRequest) {
	resp, err := service.LLMServiceApp.ChatCompletion(chatReq)
	if err != nil {
		global.GVA_LOG.Error("聊天完成失败!", zap.Error(err), zap.String("requestID", chatReq.RequestID))
		response.FailWithMessage("聊天完成失败: "+err.Error(), c)
		return
	}

	global.GVA_LOG.Info("聊天完成成功", zap.String("requestID", chatReq.RequestID))
	response.OkWithDetailed(resp, "聊天完成成功", c)
}

// handleStreamResponse 处理流式响应 (SSE)
func (l *LLMApi) handleStreamResponse(c *gin.Context, chatReq request.ChatRequest) {
	// 设置SSE响应头
	c.Header("Content-Type", "text/event-stream")
	c.Header("Cache-Control", "no-cache")
	c.Header("Connection", "keep-alive")
	c.Header("Access-Control-Allow-Origin", "*")
	c.Header("Access-Control-Allow-Headers", "Cache-Control")

	// 创建事件通道
	eventChan := make(chan volcengineResponse.StreamEvent, 100)
	defer close(eventChan)

	// 启动流式处理
	go func() {
		err := service.LLMServiceApp.StreamChatCompletion(chatReq, eventChan)
		if err != nil {
			global.GVA_LOG.Error("流式聊天失败!", zap.Error(err), zap.String("requestID", chatReq.RequestID))
			eventChan <- volcengineResponse.StreamEvent{
				Event: "error",
				Data: volcengineResponse.ChatResponse{
					ID: chatReq.RequestID,
					Error: &volcengineResponse.APIError{
						Code:    "stream_error",
						Message: err.Error(),
						Type:    "internal_error",
					},
				},
			}
		}
	}()

	// 发送流式数据
	c.Stream(func(w io.Writer) bool {
		select {
		case event, ok := <-eventChan:
			if !ok {
				return false
			}

			switch event.Event {
			case "message":
				// 发送消息事件
				c.SSEvent("message", event.Data)
			case "error":
				// 发送错误事件
				c.SSEvent("error", event.Data)
				return false
			case "done":
				// 发送完成事件
				c.SSEvent("done", event.Data)
				return false
			}
			return true
		case <-time.After(30 * time.Second):
			// 超时处理
			c.SSEvent("error", volcengineResponse.ChatResponse{
				ID: chatReq.RequestID,
				Error: &volcengineResponse.APIError{
					Code:    "timeout",
					Message: "Stream timeout",
					Type:    "timeout_error",
				},
			})
			return false
		}
	})
}

// StopGeneration
// @Tags      Volcengine
// @Summary   停止LLM生成
// @Security  ApiKeyAuth
// @accept    application/json
// @Produce   application/json
// @Param     data  body      request.StopRequest                     true  "停止请求参数"
// @Success   200   {object}  response.Response{data=volcengineResponse.StopResponse}  "停止响应"
// @Router    /volcengine/llm/stop [post]
func (l *LLMApi) StopGeneration(c *gin.Context) {
	var stopReq request.StopRequest
	err := c.ShouldBindJSON(&stopReq)
	if err != nil {
		response.FailWithMessage(err.Error(), c)
		return
	}

	resp, err := service.LLMServiceApp.StopGeneration(stopReq)
	if err != nil {
		global.GVA_LOG.Error("停止生成失败!", zap.Error(err), zap.String("requestID", stopReq.RequestID))
		response.FailWithMessage("停止生成失败: "+err.Error(), c)
		return
	}

	if resp.Success {
		global.GVA_LOG.Info("停止生成成功", zap.String("requestID", stopReq.RequestID))
		response.OkWithDetailed(resp, "停止生成成功", c)
	} else {
		global.GVA_LOG.Warn("停止生成失败", zap.String("requestID", stopReq.RequestID), zap.String("reason", resp.Message))
		response.FailWithDetailed(resp, resp.Message, c)
	}
}

// GetActiveSessionsCount
// @Tags      Volcengine
// @Summary   获取活跃会话数量
// @Security  ApiKeyAuth
// @Produce   application/json
// @Success   200   {object}  response.Response{data=int}  "活跃会话数量"
// @Router    /volcengine/llm/sessions [get]
func (l *LLMApi) GetActiveSessionsCount(c *gin.Context) {
	count := service.LLMServiceApp.GetActiveSessionsCount()
	response.OkWithDetailed(gin.H{"count": count}, fmt.Sprintf("当前活跃会话数量: %d", count), c)
}