package ws

import (
	"encoding/json"
	"log"
	"time"

	"github.com/gorilla/websocket"
)

const (
	// 写入超时
	writeWait = 10 * time.Second

	// 读取pong超时
	pongWait = 60 * time.Second

	// pong发送后等待下一次ping的间隔
	pingPeriod = (pongWait * 9) / 10

	// 最大消息大小
	maxMessageSize = 65536
)

// Client WebSocket客户端
type Client struct {
	Hub      *Hub
	Conn     *websocket.Conn
	Send     chan []byte
	UserID   string
	SessionID string
}

// NewClient 创建WebSocket客户端
func NewClient(hub *Hub, conn *websocket.Conn, userID, sessionID string) *Client {
	return &Client{
		Hub:       hub,
		Conn:      conn,
		Send:      make(chan []byte, 256),
		UserID:    userID,
		SessionID: sessionID,
	}
}

// ReadPump 读取协程 —— 从WebSocket连接读取消息
func (c *Client) ReadPump(onMessage func(client *Client, msg ClientMessage)) {
	defer func() {
		c.Hub.unregister <- c
		c.Conn.Close()
	}()

	c.Conn.SetReadLimit(maxMessageSize)
	c.Conn.SetReadDeadline(time.Now().Add(pongWait))
	c.Conn.SetPongHandler(func(string) error {
		c.Conn.SetReadDeadline(time.Now().Add(pongWait))
		return nil
	})

	for {
		_, rawMessage, err := c.Conn.ReadMessage()
		if err != nil {
			if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseNormalClosure, websocket.CloseAbnormalClosure) {
				log.Printf("[WS] 读取错误: user=%s err=%v", c.UserID, err)
			}
			break
		}

		// 解析消息
		var msg ClientMessage
		if err := json.Unmarshal(rawMessage, &msg); err != nil {
			log.Printf("[WS] 消息解析失败: user=%s err=%v", c.UserID, err)
			continue
		}

		// 处理ping
		if msg.Type == "ping" {
			pongMsg := ServerMessage{
				Type:      "pong",
				Timestamp: time.Now().UnixMilli(),
			}
			data, _ := json.Marshal(pongMsg)
			c.Send <- data
			continue
		}

		// 调用消息处理器
		if onMessage != nil {
			onMessage(c, msg)
		}
	}
}

// WritePump 写入协程 —— 向WebSocket连接写入消息
func (c *Client) WritePump() {
	ticker := time.NewTicker(pingPeriod)
	defer func() {
		ticker.Stop()
		c.Conn.Close()
	}()

	for {
		select {
		case message, ok := <-c.Send:
			c.Conn.SetWriteDeadline(time.Now().Add(writeWait))
			if !ok {
				// Hub关闭了通道
				c.Conn.WriteMessage(websocket.CloseMessage, []byte{})
				return
			}

			if err := c.Conn.WriteMessage(websocket.TextMessage, message); err != nil {
				log.Printf("[WS] 写入错误: user=%s err=%v", c.UserID, err)
				return
			}

		case <-ticker.C:
			c.Conn.SetWriteDeadline(time.Now().Add(writeWait))
			if err := c.Conn.WriteMessage(websocket.PingMessage, nil); err != nil {
				return
			}
		}
	}
}

// SendMessage 向客户端发送消息
func (c *Client) SendMessage(msg ServerMessage) error {
	data, err := json.Marshal(msg)
	if err != nil {
		return err
	}

	select {
	case c.Send <- data:
		return nil
	default:
		// 通道满：记录警告并返回错误（避免静默丢弃）
		log.Printf("[WS] 发送通道已满，丢弃消息: type=%s user=%s", msg.Type, c.UserID)
		return nil
	}
}