package main

import (
	"container/list"
	"log"
	"time"

	"github.com/faiface/beep"
	"github.com/kataras/go-events"

	"dndmusicbot/ffmpeg"
	discordspeaker "dndmusicbot/speaker"
)

type Ambiance struct {
	Type string
	URL  string
}

func init() {
	app.ambiance = beep.Mixer{}
	discordspeaker.Play(&app.ambiance)

	app.queue = new(Queue)
	app.queue.list = list.New()
	app.queue.Events = app.events
	discordspeaker.Play(app.queue)

	log.Println("queue.go done.")
}

type Song struct {
	Title    string
	Channel  string
	VideoID  string
	Length   time.Duration
	PCM      *ffmpeg.PCM
	Playlist Playlist
	DLuri    string
}

func (s *Song) NewStream() (err error) {
	s.PCM, err = ffmpeg.NewPCM(s.DLuri, sampleRate, channels)
	return
}

type Queue struct {
	Events  events.EventEmmiter
	playing bool
	yt      VideoInfo
	list    *list.List
	current *list.Element
}

func (q Queue) IsPlaying() bool {
	return q.playing
}

func (q *Queue) Play() {
	q.playing = true
	if q.list.Len() > 0 {
		play := q.list.Front()
		q.current = play
		app.events.Emit("song_start")
	}
}

func (q *Queue) Add(s *Song) {
	el := q.list.PushBack(s)
	if el == q.list.Front() {
		q.Play()
	}
}

func (q Queue) QLen() int {
	return q.list.Len()
}

func (q Queue) Current() *Song {
	if q.current == nil {
		return new(Song)
	}
	return q.current.Value.(*Song)
}

func (q *Queue) Reset() {
	q.playing = false

	q.current = nil
	q.list = q.list.Init()
}

func (q *Queue) Next() {
	if q.current == nil {
		return
	}
	next := q.current.Next()
	if next == nil {
		next = q.list.Front()
	}

	pcm := next.Value.(*Song).PCM
	if pcm != nil && pcm.Position() != 0 {
		err := next.Value.(*Song).NewStream()
		log.Println(err)
	}

	q.current = next
	return
}

func (q *Queue) Prev() {
	if q.current == nil {
		return
	}

	prev := q.current.Prev()
	if prev == nil {
		prev = q.list.Back()
	}

	err := prev.Value.(*Song).NewStream()
	if err != nil {
		log.Println(err)
	}
	q.current = prev

	return
}

func (q *Queue) Preload() {
}

func (q *Queue) Stream(samples [][2]float64) (n int, ok bool) {
	if q.current != nil && !q.current.Value.(*Song).PCM.Player.Started {
		q.current.Value.(*Song).PCM.Player.Start()
	}
	// We use the filled variable to track how many samples we've
	// successfully filled already. We loop until all samples are filled.
	filled := 0

	for filled < len(samples) {
		// There are no streamers in the queue, so we stream silence.
		if q.current == nil || q.list.Len() == 0 {
			for i := range samples[filled:] {
				samples[i][0] = 0
				samples[i][1] = 0
			}
			break
		}

		// We stream from the first streamer in the queue.
		n, ok := q.current.Value.(*Song).PCM.Stream(samples[filled:])
		// If it's drained, we pop it from the queue, thus continuing with
		// the next streamer.
		if !ok {
			q.Next()
			q.Events.Emit("song_over", nil)
		}
		// We update the number of filled samples.
		filled += n
	}
	return len(samples), true
}

func (q *Queue) Err() error {
	return nil
}

func (q *Queue) Position() int {
	if q.current == nil || q.current.Value.(*Song).PCM == nil {
		return 0
	}

	return q.current.Value.(*Song).PCM.Position()
}

func (q Queue) Len() int {
	if q.current == nil {
		return 0
	}

	return int(q.current.Value.(*Song).Length.Milliseconds())
}