package middleware

import (
	"git.noahlan.cn/noahlan/nnet"
	"git.noahlan.cn/noahlan/nnet/conn"
	"git.noahlan.cn/noahlan/nnet/event"
	"git.noahlan.cn/noahlan/nnet/packet"
	rt "git.noahlan.cn/noahlan/nnet/router"
	"git.noahlan.cn/noahlan/ntool/nlog"
	"sync/atomic"
	"time"
)

type HeartbeatMiddleware struct {
	lastAt   int64
	interval time.Duration
	hbdFn    func(conn *conn.Connection) []byte
}

func WithHeartbeat(interval time.Duration, hbdFn func(conn *conn.Connection) []byte) nnet.RunOption {
	m := &HeartbeatMiddleware{
		lastAt:   time.Now().Unix(),
		interval: interval,
		hbdFn:    hbdFn,
	}
	if hbdFn == nil {
		nlog.Error("dataFn must not be nil")
		panic("dataFn must not be nil")
	}

	var startFn event.OnConnectedFn = func(nc *conn.Connection) {
		ticker := time.NewTicker(m.interval)

		defer func() {
			ticker.Stop()
		}()

		for {
			select {
			case <-ticker.C:
				deadline := time.Now().Add(-2 * m.interval).Unix()
				if atomic.LoadInt64(&m.lastAt) < deadline {
					nlog.Errorf("Heartbeat timeout, LastTime=%d, Deadline=%d", atomic.LoadInt64(&m.lastAt), deadline)
					break
				}
				err := nc.SendBytes(m.hbdFn(nc))
				if err != nil {
					nlog.Errorf("Heartbeat err: %v", err)
					return
				}
			}
		}
	}

	return func(ngin *nnet.Engine) {
		ngin.EventManager().RegisterEvent(event.EvtOnConnected, startFn)

		ngin.Use(func(next rt.HandlerFunc) rt.HandlerFunc {
			return func(conn *conn.Connection, pkg packet.IPacket) {
				m.handle(conn, pkg)

				next(conn, pkg)
			}
		})
	}
}

func (m *HeartbeatMiddleware) handle(_ *conn.Connection, _ packet.IPacket) {
	atomic.StoreInt64(&m.lastAt, time.Now().Unix())
}