package player

import (
	"context"
	"errors"
	"io"
	"os"
	"os/exec"
	"path/filepath"
)

type VLC struct {
	session    *exec.Cmd
	ctx        context.Context
	cancelFunc context.CancelFunc
	wr         *writer
}

func NewVLC(ctx context.Context) (Player, error) {
	r := new(VLC)

	if err := r.Available(ctx); err != nil {
		return nil, err
	}

	return r, nil
}

func (p *VLC) Available(ctx context.Context) error {
	p.ctx, p.cancelFunc = context.WithCancel(ctx)

	home, err := os.UserHomeDir()
	if err != nil {
		return err
	}

	var (
		paths = []string{
			filepath.Join("/", "Applications", "VLC.app", "Contents", "MacOS", "VLC"),
			filepath.Join("/", "Applications", "VLC.app", "Contents", "MacOS", "vlc"),
			filepath.Join("/", "Applications", "MacPorts", "VLC.app", "Contents", "MacOS", "VLC"),
			filepath.Join("/", "Applications", "MacPorts", "VLC.app", "Contents", "MacOS", "vlc"),
			filepath.Join(home, "Applications", "VLC.app", "Contents", "MacOS", "vlc"),
			filepath.Join(home, "Applications", "VLC.app", "Contents", "MacOS", "vlc"),
		}
		f *os.File
		s os.FileInfo
	)

	for _, path := range paths {
		if f, err = os.Open(path); err != nil {
			continue
		}

		if s, err = f.Stat(); err != nil {
			continue
		}

		if s.IsDir() {
			continue
		}

		p.session = exec.CommandContext(p.ctx, path, "-")
		return nil
	}

	return errors.New("could not find installed VLC player")
}

func (p *VLC) Start(stop chan error) error {
	if p.session == nil {
		return errors.New("illegal state: player session was not established")
	}

	var (
		pipe io.WriteCloser
		err  error
	)

	if pipe, err = p.session.StdinPipe(); err != nil {
		return err
	}

	if err = p.session.Start(); err != nil {
		return err
	}

	p.wr = Writer(pipe)
	go p.wr.Run(stop)

	return nil
}

func (p *VLC) Write(d []byte) error {
	if p.wr == nil {
		return io.ErrClosedPipe
	}

	return p.wr.Write(d)
}

func (p *VLC) Close() error {
	if p.cancelFunc != nil {
		p.cancelFunc()
	}

	if p.wr != nil {
		_ = p.wr.Close()
	}

	p.session = nil
	return nil
}