package logic

import (
	"context"
	"slowwildws/internal/constants"
	"slowwildws/internal/svc"
	"slowwildws/internal/types"
	"sync"
	"time"

	"github.com/gorilla/websocket"
	"github.com/zeromicro/go-zero/core/logx"
)

type ConnectionLogic struct {
	logx.Logger
	ctx               context.Context
	svcCtx            *svc.ServiceContext
	conn              *websocket.Conn
	idleMu            sync.Mutex                // 超时锁
	idle              time.Time                 // 闲置时间
	maxConnectionIdle time.Duration             // 最大闲置时间，也就是空闲时间
	messageMu         sync.Mutex                // 消息锁
	readMessageList   []*types.Message          // 读取消息队列
	readMessageSeq    map[string]*types.Message // 读取消息序列化
	done              chan struct{}             // 结束方法
	message           chan *types.Message       //消息通道
}

func NewConnectionLogic(ctx context.Context, svcCtx *svc.ServiceContext, conn *websocket.Conn) *ConnectionLogic {
	return &ConnectionLogic{
		Logger:            logx.WithContext(ctx),
		ctx:               ctx,
		svcCtx:            svcCtx,
		conn:              conn,
		idle:              time.Now(),
		maxConnectionIdle: time.Duration(svcCtx.Config.MaxConnectionIdle) * time.Second,
		done:              make(chan struct{}),
		readMessageList:   make([]*types.Message, 0, 2),
		readMessageSeq:    make(map[string]*types.Message, 2),
		message:           make(chan *types.Message, 1), // 给容量为1的话可以确保收发顺序
	}
}

// 关闭连接
func (c *ConnectionLogic) Close() error {
	select {
	case <-c.done:
	default:
		close(c.done)
	}
	return c.conn.Close()
}

// 读取消息
func (c *ConnectionLogic) ReadMessage() (messageType int, p []byte, err error) {
	// 这里不能先获取锁，因为会被阻塞住，下面这个获取消息的方法是阻塞的，会导致锁一直得不到释放
	messageType, p, err = c.conn.ReadMessage()
	c.idleMu.Lock()
	defer func() {
		c.idleMu.Unlock()
	}()
	c.idle = time.Now()
	return
}

// 写消息
func (c *ConnectionLogic) WriteMessage(messageType int, data []byte) error {
	c.idleMu.Lock()
	defer func() {
		c.idleMu.Unlock()
	}()
	err := c.conn.WriteMessage(messageType, data)
	c.idle = time.Now()
	return err
}

// 心跳检测
func (c *ConnectionLogic) Keepalive() {
	idlerTimer := time.NewTimer(c.maxConnectionIdle)
	defer idlerTimer.Stop()

	for {
		select {
		case <-idlerTimer.C:
			c.idleMu.Lock()
			idle := c.idle
			if idle.IsZero() {
				idlerTimer.Reset(c.maxConnectionIdle)
				c.idleMu.Unlock()
				continue
			}
			val := c.maxConnectionIdle - time.Since(idle)
			if val <= 0 {
				c.idleMu.Unlock()
				c.Close()
				return
			}
			idlerTimer.Reset(val)
			c.idleMu.Unlock()
		case <-c.done:
			return

		}
	}
}

// 添加消息到队列中
func (c *ConnectionLogic) appendMsgMq(msg *types.Message) {
	c.messageMu.Lock()
	defer c.messageMu.Unlock()

	if m, ok := c.readMessageSeq[msg.Id]; ok {
		// 已经有消息记录，该消息已经有ack确认
		if len(c.readMessageList) == 0 {
			// 队列中没有该消息
			return
		}
		if m.AckSeq >= msg.AckSeq {
			// 没有进行ack确认，或者重复
			return
		}
		c.readMessageSeq[msg.Id] = msg
		return
	}
	// 还没有进行ack确认，避免客户端重复发送多余的ack消息
	if msg.FrameType == constants.FrameAck {
		return
	}
	c.readMessageList = append(c.readMessageList, msg)
	c.readMessageSeq[msg.Id] = msg
}