package api

import (
	"context"
	"encoding/json"
	"log"
	"net/http"
	"sync"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/gorilla/websocket"

	"git.pyer.club/kingecg/gotidb/pkg/manager"
	"git.pyer.club/kingecg/gotidb/pkg/model"
)

// WebSocketServer WebSocket服务
type WebSocketServer struct {
	dataManager *manager.DataManager
	router      *gin.Engine
	server      *http.Server
	clients     map[*websocket.Conn]bool
	clientsLock sync.RWMutex
	upgrader    websocket.Upgrader
}

// SubscriptionRequest 订阅请求
type SubscriptionRequest struct {
	DeviceID   string            `json:"device_id"`
	MetricCode string            `json:"metric_code"`
	Labels     map[string]string `json:"labels"`
}

// DataChangeEvent 数据变更事件
type DataChangeEvent struct {
	DeviceID   string            `json:"device_id"`
	MetricCode string            `json:"metric_code"`
	Labels     map[string]string `json:"labels"`
	Timestamp  time.Time         `json:"timestamp"`
	Value      interface{}       `json:"value"`
}

// NewWebSocketServer 创建一个新的WebSocket服务
func NewWebSocketServer(dataManager *manager.DataManager) *WebSocketServer {
	router := gin.Default()

	server := &WebSocketServer{
		dataManager: dataManager,
		router:      router,
		clients:     make(map[*websocket.Conn]bool),
		upgrader: websocket.Upgrader{
			CheckOrigin: func(r *http.Request) bool {
				return true // 允许所有来源的WebSocket连接
			},
		},
	}

	server.setupRoutes()

	// 注册数据变更回调
	dataManager.RegisterCallback(server.handleDataChange)

	return server
}

// setupRoutes 设置路由
func (s *WebSocketServer) setupRoutes() {
	// WebSocket连接
	s.router.GET("/ws", s.handleWebSocket)
}

// handleWebSocket 处理WebSocket连接
func (s *WebSocketServer) handleWebSocket(c *gin.Context) {
	// 升级HTTP连接为WebSocket连接
	conn, err := s.upgrader.Upgrade(c.Writer, c.Request, nil)
	if err != nil {
		log.Printf("Failed to upgrade connection: %v", err)
		return
	}

	// 注册客户端
	s.clientsLock.Lock()
	s.clients[conn] = true
	s.clientsLock.Unlock()

	// 处理客户端消息
	go s.handleClient(conn)
}

// handleClient 处理客户端消息
func (s *WebSocketServer) handleClient(conn *websocket.Conn) {
	defer func() {
		// 关闭连接
		conn.Close()

		// 移除客户端
		s.clientsLock.Lock()
		delete(s.clients, conn)
		s.clientsLock.Unlock()
	}()

	// 读取客户端消息
	for {
		_, message, err := conn.ReadMessage()
		if err != nil {
			if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseAbnormalClosure) {
				log.Printf("WebSocket error: %v", err)
			}
			break
		}

		// 解析订阅请求
		var req SubscriptionRequest
		if err := json.Unmarshal(message, &req); err != nil {
			log.Printf("Failed to parse subscription request: %v", err)
			continue
		}

		// 处理订阅请求
		// TODO: 实现订阅逻辑
	}
}

// handleDataChange 处理数据变更
func (s *WebSocketServer) handleDataChange(id model.DataPointID, value model.DataValue) {
	// 创建数据变更事件
	event := DataChangeEvent{
		DeviceID:   id.DeviceID,
		MetricCode: id.MetricCode,
		Labels:     id.Labels,
		Timestamp:  value.Timestamp,
		Value:      value.Value,
	}

	// 序列化事件
	data, err := json.Marshal(event)
	if err != nil {
		log.Printf("Failed to marshal data change event: %v", err)
		return
	}

	// 广播事件
	s.clientsLock.RLock()
	for client := range s.clients {
		if err := client.WriteMessage(websocket.TextMessage, data); err != nil {
			log.Printf("Failed to send data change event: %v", err)
			client.Close()
			delete(s.clients, client)
		}
	}
	s.clientsLock.RUnlock()
}

// Start 启动WebSocket服务
func (s *WebSocketServer) Start(addr string) error {
	s.server = &http.Server{
		Addr:    addr,
		Handler: s.router,
	}

	return s.server.ListenAndServe()
}

// Stop 停止WebSocket服务
func (s *WebSocketServer) Stop(ctx context.Context) error {
	return s.server.Shutdown(ctx)
}