package websocket

import (
	"errors"
	"log"
	"net/http"
	"strconv"
	"strings"

	"github.com/2930134478/AI-CS/backend/repository"
	"github.com/2930134478/AI-CS/backend/service"
	"github.com/2930134478/AI-CS/backend/utils"
	"github.com/gin-gonic/gin"
	"github.com/gorilla/websocket"
	"gorm.io/gorm"
)

var upgrader = websocket.Upgrader{
	ReadBufferSize:  1024,
	WriteBufferSize: 1024,
	// 允许跨域连接
	CheckOrigin: func(r *http.Request) bool {
		return true
	},
}

// HandleWebSocket 处理 WebSocket 连接
func HandleWebSocket(hub *Hub, userRepo *repository.UserRepository, conversationService *service.ConversationService) gin.HandlerFunc {
	return func(c *gin.Context) {
		// 从查询参数获取对话ID
		conversationIDStr := c.Query("conversation_id")
		if conversationIDStr == "" {
			c.JSON(http.StatusBadRequest, gin.H{"error": "conversation_id 不能为空"})
			return
		}

		conversationID, err := strconv.ParseUint(conversationIDStr, 10, 32)
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "无效的 conversation_id"})
			return
		}

		// 从查询参数获取是否是访客（默认为 true，因为默认是访客连接）
		isVisitorStr := c.DefaultQuery("is_visitor", "true")
		isVisitor := isVisitorStr == "true" || isVisitorStr == "1"

		// 从查询参数获取客服ID（如果是客服连接，需要传递 agent_id）
		var agentID uint
		if !isVisitor {
			agentIDStr := c.Query("agent_id")
			if agentIDStr == "" {
				c.JSON(http.StatusBadRequest, gin.H{"error": "agent_id 不能为空"})
				return
			}
			parsed, parseErr := strconv.ParseUint(agentIDStr, 10, 32)
			if parseErr != nil || parsed == 0 {
				c.JSON(http.StatusBadRequest, gin.H{"error": "无效的 agent_id"})
				return
			}
			agentID = uint(parsed)
			wsToken := c.Query("ws_token")
			if !utils.ValidateWSToken(wsToken, agentID) {
				c.JSON(http.StatusUnauthorized, gin.H{"error": "ws_token 无效或已过期"})
				return
			}
			if userRepo != nil {
				user, userErr := userRepo.GetByID(agentID)
				if userErr != nil || user == nil {
					c.JSON(http.StatusUnauthorized, gin.H{"error": "客服身份无效"})
					return
				}
				if user.Role != "admin" && user.Role != "agent" {
					c.JSON(http.StatusForbidden, gin.H{"error": "仅客服账号允许建立该连接"})
					return
				}
			}
		} else if conversationService != nil {
			accessToken := strings.TrimSpace(c.Query("access_token"))
			if accessToken == "" {
				accessToken = strings.TrimSpace(c.GetHeader("X-Conversation-Token"))
			}
			if err := conversationService.ValidateVisitorAccessToken(uint(conversationID), accessToken); err != nil {
				if errors.Is(err, gorm.ErrRecordNotFound) {
					c.JSON(http.StatusNotFound, gin.H{"error": "会话不存在"})
				} else {
					c.JSON(http.StatusUnauthorized, gin.H{"error": "access_token 无效或缺失"})
				}
				return
			}
		}

		// 升级 HTTP 连接为 WebSocket 连接
		conn, err := upgrader.Upgrade(c.Writer, c.Request, nil)
		if err != nil {
			log.Printf("WebSocket 升级失败: %v", err)
			return
		}

		// 创建客户端
		client := NewClient(hub, conn, uint(conversationID), isVisitor, agentID)

		// 注册客户端到 Hub
		client.hub.register <- client

		// 启动两个 goroutine：
		// 1. ReadPump：从客户端读取消息（主要是心跳包）
		// 2. WritePump：向客户端发送消息
		go client.WritePump()
		go client.ReadPump()

		log.Printf("✅ WebSocket 连接已建立: 对话ID=%d, 是访客=%v", conversationID, isVisitor)
	}
}