package main

import (
	"git.gammaspectra.live/S.O.N.G/Kirika/audio"
	"git.gammaspectra.live/S.O.N.G/Kirika/audio/format"
	"git.gammaspectra.live/S.O.N.G/Kirika/audio/format/aac"
	"git.gammaspectra.live/S.O.N.G/Kirika/audio/format/flac"
	"git.gammaspectra.live/S.O.N.G/Kirika/audio/format/mp3"
	"git.gammaspectra.live/S.O.N.G/Kirika/audio/format/opus"
	"git.gammaspectra.live/S.O.N.G/Kirika/audio/packetizer"
	"io"
	"log"
	"sync"
)

type HeaderEntry struct {
	Name  string `json:"name"`
	Value string `json:"value"`
}

type ListenerInformation struct {
	Mount   string        `json:"mount"`
	Path    string        `json:"path"`
	Headers []HeaderEntry `json:"headers"`
}

type StreamListener struct {
	Information ListenerInformation
	Start       func(packets []packetizer.Packet) error
	Write       func(packet packetizer.Packet) error
	Close       func()
}
type StreamMount struct {
	Mount      string
	MimeType   string
	Packetizer packetizer.Packetizer

	listeners     []*StreamListener
	listenersLock sync.Mutex
	keepBuffer    []packetizer.Packet
}

func NewStreamMount(source audio.Source, mount string, codec string, container string, bitrate interface{}) *StreamMount {
	var encoderFormat format.Encoder
	options := make(map[string]interface{})
	var mimeType string

	reader, writer := io.Pipe()
	var packetizerEntry packetizer.Packetizer

	switch codec {
	case "opus":
		encoderFormat = opus.NewFormat()
		if bitrate != nil {
			options["bitrate"] = bitrate
		}
		mimeType = "audio/ogg;codecs=opus"
		packetizerEntry = packetizer.NewOggPacketizer(reader)
	case "mp3":
		encoderFormat = mp3.NewFormat()
		if bitrate != nil {
			options["bitrate"] = bitrate
		}
		mimeType = "audio/mpeg;codecs=mp3"
		packetizerEntry = packetizer.NewMp3Packetizer(reader)
	case "flac":
		encoderFormat = flac.NewFormat()
		if bitrate != nil {
			options["bitdepth"] = bitrate
		}
		options["compression_level"] = 8
		mimeType = "audio/flac"
		packetizerEntry = packetizer.NewFLACPacketizer(reader)
	case "aac":
		encoderFormat = aac.NewFormat()
		if bitrate != nil {
			options["bitrate"] = bitrate
		}
		mimeType = "audio/aac"
		packetizerEntry = packetizer.NewAdtsPacketizer(reader)
	case "he-aacv2":
		encoderFormat = aac.NewFormat()
		if bitrate != nil {
			options["bitrate"] = bitrate
		}
		options["mode"] = "hev2"
		mimeType = "audio/aac"
		packetizerEntry = packetizer.NewAdtsPacketizer(reader)
	}

	if encoderFormat == nil {
		switch container {
		case "ogg":
			encoderFormat = opus.NewFormat()
			if bitrate != nil {
				options["bitrate"] = bitrate
			}
			mimeType = "audio/ogg;codecs=opus"
			packetizerEntry = packetizer.NewOggPacketizer(reader)
		case "mp3":
			encoderFormat = mp3.NewFormat()
			if bitrate != nil {
				options["bitrate"] = bitrate
			}
			mimeType = "audio/mpeg;codecs=mp3"
			packetizerEntry = packetizer.NewMp3Packetizer(reader)
		case "flac":
			encoderFormat = flac.NewFormat()
			if bitrate != nil {
				options["bitdepth"] = bitrate
			}
			options["compression_level"] = 8
			mimeType = "audio/flac"
			packetizerEntry = packetizer.NewFLACPacketizer(reader)
		case "adts", "aac":
			encoderFormat = aac.NewFormat()
			if bitrate != nil {
				options["bitrate"] = bitrate
			}
			mimeType = "audio/aac"
			packetizerEntry = packetizer.NewAdtsPacketizer(reader)
		}
	}

	if encoderFormat == nil || packetizerEntry == nil {
		return nil
	}

	if opusFormat, ok := encoderFormat.(opus.Format); ok {
		go func() {
			defer writer.Close()
			if err := opusFormat.Encode(audio.NewResampleFilter(opus.FixedSampleRate, audio.Linear, 0).Process(source), writer, options); err != nil {
				log.Panic(err)
			}
		}()
	} else {
		go func() {
			defer writer.Close()
			if err := encoderFormat.Encode(source, writer, options); err != nil {
				log.Panic(err)
			}
		}()
	}

	return &StreamMount{
		Mount:      mount,
		MimeType:   mimeType,
		Packetizer: packetizerEntry,
	}
}

func (m *StreamMount) removeDiscard() {
	for i, p := range m.keepBuffer {
		if p.KeepMode() == packetizer.Discard {
			m.keepBuffer = append(m.keepBuffer[:i], m.keepBuffer[i+1:]...)
			m.removeDiscard()
			break
		}
	}
}

func (m *StreamMount) removeKeepLast() {
	for i, p := range m.keepBuffer {
		if p.KeepMode() == packetizer.KeepLast {
			m.keepBuffer = append(m.keepBuffer[:i], m.keepBuffer[i+1:]...)
			m.removeKeepLast()
			break
		}
	}
}

func (m *StreamMount) removeGroupKeep() {
	for i, p := range m.keepBuffer {
		if p.KeepMode() == packetizer.GroupKeep {
			m.keepBuffer = append(m.keepBuffer[:i], m.keepBuffer[i+1:]...)
			m.removeGroupKeep()
			break
		}
	}
}

func (m *StreamMount) AddListener(listener *StreamListener) {
	m.listenersLock.Lock()
	defer m.listenersLock.Unlock()
	m.listeners = append(m.listeners, listener)
}

func (m *StreamMount) GetListeners() (entries []*ListenerInformation) {
	m.listenersLock.Lock()
	defer m.listenersLock.Unlock()
	for _, l := range m.listeners {
		entries = append(entries, &l.Information)
	}

	return
}

func (m *StreamMount) Process() {
	defer func() {
		m.listenersLock.Lock()
		for _, l := range m.listeners {
			l.Close()
		}
		m.listeners = m.listeners[:0]
		m.listenersLock.Unlock()
	}()
	var toRemove []int
	for {
		packet := m.Packetizer.GetPacket()
		if packet == nil {
			return
		}

		//TODO: do this via goroutine messaging?
		for i, l := range m.listeners {
			if l.Start != nil {
				l.Start(m.keepBuffer)
				l.Start = nil
			}
			if l.Write(packet) != nil {
				toRemove = append(toRemove, i)
				l.Close()
			}
		}

		if len(toRemove) > 0 {
			m.listenersLock.Lock()
			//TODO: remove more than one per iteration
			for _, i := range toRemove {
				m.listeners = append(m.listeners[:i], m.listeners[i+1:]...)
				break
			}
			m.listenersLock.Unlock()
			toRemove = toRemove[:0]
		}

		m.removeDiscard() //always remove discards

		switch packet.KeepMode() {
		case packetizer.KeepLast:
			m.removeKeepLast()
			fallthrough
		case packetizer.Keep:
			m.keepBuffer = append(m.keepBuffer, packet)
		case packetizer.GroupKeep:
			m.keepBuffer = append(m.keepBuffer, packet)
		case packetizer.GroupDiscard:
			m.removeGroupKeep()
		case packetizer.Discard:
			m.keepBuffer = append(m.keepBuffer, packet)

		}

	}

}