package vidplayback

import (
	"bytes"
	"encoding/binary"
	"fmt"
	"image"
	"image/color"
	"image/draw"
	"log"
	"math/rand"
	"time"

	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/canvas"
	"fyne.io/fyne/v2/widget"
	"github.com/zergon321/reisen"
)

var _ fyne.WidgetRenderer = (*vidPlaybackRenderer)(nil)

const (
	width            = 1280
	height           = 720
	frameBufferSize  = 1024
	sampleRate       = 44100
	channelCount     = 2
	bitDepth         = 8
	sampleBufferSize = 32 * channelCount * bitDepth * 1024
)

// player holds all the data
// necessary for playing video.
type player struct {
	pix         *image.NRGBA
	ticker      <-chan time.Time
	errs        <-chan error
	frameBuffer <-chan *image.RGBA
	last        time.Time
	deltaTime   float64
	paused      bool
	wid         *VidPlayback
}

func (p *player) readVideoAndAudio(media *reisen.Media) (<-chan *image.RGBA, <-chan [2]float64, chan error, error) {
	frameBuffer := make(chan *image.RGBA, frameBufferSize)
	sampleBuffer := make(chan [2]float64, sampleBufferSize)
	errs := make(chan error)

	err := media.OpenDecode()

	if err != nil {
		return nil, nil, nil, err
	}

	videoStream := media.VideoStreams()[0]
	err = videoStream.Open()

	if err != nil {
		return nil, nil, nil, err
	}

	audioStream := media.AudioStreams()[0]
	err = audioStream.Open()

	if err != nil {
		return nil, nil, nil, err
	}

	go func() {
		for {
			packet, gotPacket, err := media.ReadPacket()

			if err != nil {
				go func(err error) {
					errs <- err
				}(err)
			}

			if !gotPacket {
				break
			}

			switch packet.Type() {
			case reisen.StreamVideo:
				s := media.Streams()[packet.StreamIndex()].(*reisen.VideoStream)
				videoFrame, gotFrame, err := s.ReadVideoFrame()

				if err != nil {
					go func(err error) {
						errs <- err
					}(err)
				}

				if !gotFrame {
					break
				}

				if videoFrame == nil {
					continue
				}

				frameBuffer <- videoFrame.Image()

			case reisen.StreamAudio:
				s := media.Streams()[packet.StreamIndex()].(*reisen.AudioStream)
				audioFrame, gotFrame, err := s.ReadAudioFrame()

				if err != nil {
					go func(err error) {
						errs <- err
					}(err)
				}

				if !gotFrame {
					break
				}

				if audioFrame == nil {
					continue
				}

				// Turn the raw byte data into
				// audio samples of type [2]float64.
				reader := bytes.NewReader(audioFrame.Data())

				// See the README.md file for
				// detailed scheme of the sample structure.
				for reader.Len() > 0 {
					sample := [2]float64{0, 0}
					var result float64
					err = binary.Read(reader, binary.LittleEndian, &result)

					if err != nil {
						go func(err error) {
							errs <- err
						}(err)
					}

					sample[0] = result

					err = binary.Read(reader, binary.LittleEndian, &result)

					if err != nil {
						go func(err error) {
							errs <- err
						}(err)
					}

					sample[1] = result
					sampleBuffer <- sample
				}
			}
		}

		videoStream.Close()
		audioStream.Close()
		media.CloseDecode()
		close(frameBuffer)
		close(sampleBuffer)
		close(errs)
	}()

	return frameBuffer, sampleBuffer, errs, nil
}

// Starts reading samples and frames
// of the media file.
func (p *player) open(fname string) error {
	fmt.Printf("Opening %s...\n", fname)
	// Sprite for drawing video frames.
	p.pix = image.NewNRGBA(image.Rect(0, 0, width, height))

	// Open the media file.
	media, err := reisen.NewMedia(fname)

	if err != nil {
		fmt.Printf("Open error %s\n", err.Error())
		return err
	}

	// Get the FPS for playing
	// video frames.
	videoFPS, _ := media.Streams()[0].FrameRate()
	fmt.Printf("FPS %d\n", videoFPS)
	if videoFPS == 0 {
		fmt.Printf("Assuming 60fps as FPS was 0.\n")
		videoFPS = 60
	}

	// SPF for frame ticker.
	spf := 1.0 / float64(videoFPS)
	frameDuration, err := time.
		ParseDuration(fmt.Sprintf("%fs", spf))

	if err != nil {
		fmt.Printf("Error %s\n", err.Error())
		return err
	}

	// Start decoding streams.
	var sampleSource <-chan [2]float64
	p.frameBuffer, sampleSource,
		p.errs, err = p.readVideoAndAudio(media)

	if err != nil {
		fmt.Printf("Error %s\n", err.Error())
		return err
	}

	// Start playing audio samples.
	//speaker.Play(p.streamSamples(sampleSource))
	// nooope.
	_ = sampleSource

	p.ticker = time.Tick(frameDuration)

	// Setup metrics.
	p.last = time.Now()
	return nil
}

func (p *player) update(screen *canvas.Image) error {
	// Compute dt.
	p.deltaTime = time.Since(p.last).Seconds()
	p.last = time.Now()

	// Check for incoming errors.
	select {
	case err, ok := <-p.errs:
		if ok {
			fmt.Printf("Error %s\n", err.Error())
			return err
		}

	default:
	}

	// Read video frames and draw them.
	select {
	case <-p.ticker:
		frame, ok := <-p.frameBuffer

		if ok {
			p.pix.Pix = frame.Pix
			screen.Refresh()
			fmt.Print(".")
			p.wid.Refresh()
		}

	default:
	}

	return nil
}

type VidPlayback struct {
	widget.BaseWidget
	VideoFilename string

	play player
}

func NewVidPlayback() *VidPlayback {
	v := &VidPlayback{}
	v.play.wid = v
	return v
}

func (v *VidPlayback) Resize(s fyne.Size) {
	v.BaseWidget.Resize(s)
}

func (v *VidPlayback) CreateRenderer() fyne.WidgetRenderer {
	return newVidPlaybackRenderer(v)
}

func (v *VidPlayback) Play() {
	_ = v.play.open(v.VideoFilename)
	v.play.paused = false
}

type vidPlaybackRenderer struct {
	vidPlayback  *VidPlayback
	currentframe *canvas.Image
}

func newVidPlaybackRenderer(v *VidPlayback) *vidPlaybackRenderer {
	renderer := &vidPlaybackRenderer{
		vidPlayback: v,
	}
	i := image.NewRGBA(image.Rect(0, 0, 640, 480))
	for x := 0; x < 640; x++ {
		for y := 0; y < 480; y++ {
			lum := uint8(rand.Float32() * 255)
			i.Set(x, y, color.RGBA{lum, lum, lum, 255})
		}
	}
	renderer.currentframe = canvas.NewImageFromImage(i)
	go func() {
		for {
			if v.play.paused {
				time.Sleep(time.Millisecond * 8)
				continue
			}

			err := v.play.update(renderer.currentframe)
			if err != nil {
				log.Println("Error playing:", err)
			}
		}
	}()
	return renderer
}

func (r *vidPlaybackRenderer) Objects() []fyne.CanvasObject {
	return []fyne.CanvasObject{r.currentframe}
}

func (r *vidPlaybackRenderer) Layout(s fyne.Size) {
	r.currentframe.Resize(s)
}

func (r *vidPlaybackRenderer) MinSize() fyne.Size {
	return fyne.NewSize(200, 200)
}

func (r *vidPlaybackRenderer) Refresh() {

	b := r.currentframe.Image.Bounds()
	fmt.Print("*")
	m := image.NewRGBA(image.Rect(0, 0, b.Dx(), b.Dy()))
	draw.Draw(m, m.Bounds(), r.currentframe.Image, b.Min, draw.Src)

	for x := 0; x < b.Dx(); x++ {
		for y := 0; y < b.Dy(); y++ {
			lum := uint8(rand.Float32() * 255)
			m.Set(x, y, color.RGBA{lum, lum, lum, 255})
		}
	}
	fmt.Print("+")
	r.currentframe.Image = m
	r.currentframe.Refresh()
}

func (r *vidPlaybackRenderer) Destroy() {
} // Called when the renderer is destroyed