package ws

import (
	"errors"
	"eta/eta_api/utils"
	"github.com/gorilla/websocket"
	"sync"
	"time"
)

// Session 会话结构
type Session struct {
	Id          string
	UserId      int
	Conn        *websocket.Conn
	LastActive  time.Time
	Latency     *LatencyMeasurer
	History     []string
	CloseChan   chan struct{}
	MessageChan chan *Message
	mu          sync.RWMutex
	sessionOnce sync.Once
}
type Message struct {
	MessageType string
	message     []byte
}

// readPump 处理读操作
func (s *Session) readPump() {
	defer manager.RemoveSession(s.Id)
	s.Conn.SetReadLimit(maxMessageSize)
	_ = s.Conn.SetReadDeadline(time.Now().Add(60 * time.Second))
	for {
		_, message, err := s.Conn.ReadMessage()
		if err != nil {
			handleCloseError(err)
			return
		}
		// 更新活跃时间
		s.UpdateActivity()
		// 处理消息
		if err = manager.HandleMessage(s.UserId, s.Id, message); err != nil {
			//写应答
			_ = s.writeWithTimeout(&Message{
				MessageType: "error",
				message:     []byte(err.Error()),
			})
		}
	}
}

// UpdateActivity 跟新最近活跃时间
func (s *Session) UpdateActivity() {
	s.mu.Lock()
	defer s.mu.Unlock()
	s.LastActive = time.Now()
}

func (s *Session) Close() {
	s.sessionOnce.Do(func() {
		// 控制关闭顺序
		close(s.CloseChan)
		close(s.MessageChan)
		s.forceClose()
	})
}

// 带超时的安全写入
func (s *Session) writeWithTimeout(msg *Message) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	if s.Conn == nil {
		return errors.New("connection closed")
	}
	// 设置写超时
	if err := s.Conn.SetWriteDeadline(time.Now().Add(writeWaitTimeout)); err != nil {
		return err
	}
	return s.Conn.WriteMessage(websocket.TextMessage, msg.message)
}

// writePump 处理写操作
func (s *Session) writePump() {
	ticker := time.NewTicker(basePingInterval)
	defer func() {
		manager.RemoveSession(s.Id)
		ticker.Stop()
	}()
	for {
		select {
		case message, ok := <-s.MessageChan:
			if !ok {
				return
			}
			_ = s.writeWithTimeout(message)
		case <-ticker.C:
			_ = s.Latency.SendPing(s.Conn)
			ticker.Reset(s.Latency.lastLatency)
		case <-s.CloseChan:
			return
		}
	}
}
func handleCloseError(err error) {
	if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway) {
		var wsErr *websocket.CloseError
		if !errors.As(err, &wsErr) {
			utils.FileLog.Error("未知错误 %s", err.Error())
		} else {
			switch wsErr.Code {
			case websocket.CloseNormalClosure:
				utils.FileLog.Info("正常关闭连接")
			default:
				utils.FileLog.Error("关闭代码:%d:%s", wsErr.Code, wsErr.Text)
			}
		}
	}
}

// 强制关闭连接
func (s *Session) forceClose() {
	// 添加互斥锁保护
	s.mu.Lock()
	defer s.mu.Unlock()
	// 发送关闭帧
	_ = s.Conn.WriteControl(websocket.CloseMessage,
		websocket.FormatCloseMessage(websocket.ClosePolicyViolation, "heartbeat failed"),
		time.Now().Add(5*time.Second))
	_ = s.Conn.Close()
	s.Conn = nil // 标记连接已关闭
	utils.FileLog.Info("连接已强制关闭",
		"user", s.UserId,
		"session", s.Id)
}

func NewSession(userId int, sessionId string, conn *websocket.Conn) (session *Session) {
	session = &Session{
		UserId:      userId,
		Id:          sessionId,
		Conn:        conn,
		History:     []string{},
		LastActive:  time.Now(),
		CloseChan:   make(chan struct{}),
		MessageChan: make(chan *Message, 10),
	}
	session.Latency = SetupLatencyMeasurement(conn)
	go session.readPump()
	go session.writePump()
	return
}