package engine

import (
	"context"
	"time"

	"github.com/Monibuca/utils/v3/codec"
	"github.com/pkg/errors"
)

// Subscriber 订阅者实体定义
type Subscriber struct {
	context.Context
	*Stream       `json:"-"`
	ID            string
	TotalDrop     int //总丢帧
	TotalPacket   int
	Type          string
	BufferLength  int
	Delay         uint32
	SubscribeTime time.Time
	cancel        context.CancelFunc
	Sign          string
	OffsetTime    uint32
	startTime     uint32
	OnAudio       func(pack AudioPack) `json:"-"`
	OnVideo       func(pack VideoPack) `json:"-"`
}

// IsClosed 检查订阅者是否已经关闭
func (s *Subscriber) IsClosed() bool {
	return s.Context != nil && s.Err() != nil
}

// Close 关闭订阅者
func (s *Subscriber) Close() {
	if s.cancel != nil {
		s.UnSubscribe(s)
		s.cancel()
	}
}
func (r *Subscriber) GetVideoTrack(codec string) *VideoTrack {
	if !config.EnableVideo {
		return nil
	}
	r.videoRW.RLock()
	defer r.videoRW.RUnlock()
	return r.VideoTracks[codec]
}
func (s *Subscriber) GetAudioTrack(codecs ...string) (at *AudioTrack) {
	if !config.EnableAudio {
		return nil
	}
	if HasTranscoder {
		s.audioRW.Lock()
		defer s.audioRW.Unlock()
	} else {
		s.audioRW.RLock()
		defer s.audioRW.RUnlock()
	}
	for _, codec := range codecs {
		if at, ok := s.AudioTracks[codec]; ok {
			return at
		}
	}
	if HasTranscoder {
		at = s.AddAudioTrack(codecs[0], nil)
		at.SoundFormat = codec.Codec2SoundFormat[codecs[0]]
		TriggerHook(Hook{HOOK_REQUEST_TRANSAUDIO, &TransCodeReq{s, codecs[0]}})
	}
	return
}

//Subscribe 开始订阅 将Subscriber与Stream关联
func (s *Subscriber) Subscribe(streamPath string) error {
	if FindStream(streamPath) == nil {
		return errors.Errorf("Stream not found:%s", streamPath)
	}
	GetStream(streamPath).Subscribe(s)
	if s.Context == nil {
		return errors.Errorf("stream not exist:%s", streamPath)
	}
	return nil
}

//Play 开始播放
func (s *Subscriber) Play(ctx context.Context, at *AudioTrack, vt *VideoTrack) {
	defer s.Close()
	if vt == nil && at == nil {
		return
	}
	if vt == nil {
		s.PlayAudio(ctx, at)
		return
	} else if at == nil {
		s.PlayVideo(ctx, vt)
		return
	}
	select {
	case <-vt.WaitFirst: //等待获取到第一个关键帧
	case <-s.Context.Done():
		return
	case <-ctx.Done(): //可能等不到关键帧就退出了
		return
	}
	vr := vt.Buffer.SubRing(vt.FirstScreen) //从关键帧开始读取，首屏秒开
	vr.Current.Wait()                       //等到RingBuffer可读
	ar := at.Buffer.SubRing(at.Buffer.Index)
	ar.Current.Wait()
	dropping := false //是否处于丢帧中
	send_audio := func() {
		s.OnAudio(ar.Current.AudioPack)
		if at.Buffer.Index-ar.Index > 128 {
			dropping = true
		}
	}
	send_video := func() {
		s.OnVideo(vr.Current.VideoPack)
		if vt.Buffer.Index-vr.Index > 128 {
			dropping = true
		}
	}
	for ctx.Err() == nil && s.Context.Err() == nil {
		if ar.Current.Timestamp > vr.Current.Timestamp || ar.Current.Timestamp == 0 {
			if !dropping {
				send_video()
			} else if vr.Current.NalType == codec.NALU_IDR_Picture {
				dropping = false
			}
			vr.NextR()
		} else {
			if !dropping {
				send_audio()
			}
			ar.NextR()
		}
	}
}
func (s *Subscriber) PlayAudio(ctx context.Context, at *AudioTrack) {
	ring := at.Buffer.SubRing(at.Buffer.Index)
	ring.Current.Wait()
	droped := 0
	var action, send func()
	drop := func() {
		if at.Buffer.Index-ring.Index < 10 {
			action = send
		} else {
			droped++
		}
	}
	send = func() {
		s.OnAudio(ring.Current.AudioPack)

		//s.BufferLength = pIndex - ring.Index
		//s.Delay = s.AVRing.Timestamp - packet.Timestamp
		if at.Buffer.Index-ring.Index > 128 {
			action = drop
		}
	}
	for action = send; ctx.Err() == nil && s.Context.Err() == nil; ring.NextR() {
		action()
	}
}

func (s *Subscriber) PlayVideo(ctx context.Context, vt *VideoTrack) {
	select {
	case <-vt.WaitFirst:
	case <-s.Context.Done():
		return
	case <-ctx.Done(): //可能等不到关键帧就退出了
		return
	}
	ring := vt.Buffer.SubRing(vt.FirstScreen)
	ring.Current.Wait()
	droped := 0
	var action, send func()
	drop := func() {
		if ring.Current.NalType == codec.NALU_IDR_Picture {
			action = send
		} else {
			droped++
		}
	}
	send = func() {
		s.OnVideo(ring.Current.VideoPack)
		pIndex := vt.Buffer.Index
		//s.BufferLength = pIndex - ring.Index
		//s.Delay = s.AVRing.Timestamp - packet.Timestamp
		if pIndex-ring.Index > 128 {
			action = drop
		}
	}
	for action = send; ctx.Err() == nil && s.Context.Err() == nil; ring.NextR() {
		action()
	}
}