//go:build linux
// +build linux

package service

import (
	"archive/tar"
	"errors"
	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/canvas"
	"fyne.io/fyne/v2/lang"
	"fyne.io/fyne/v2/widget"
	"git.kor-elf.net/kor-elf/gui-for-ffmpeg/internal/application"
	"github.com/ulikunitz/xz"
	"io"
	"net/http"
	"os"
	"path/filepath"
)

func startDownload(app application.AppContract, progressBar *widget.ProgressBar, progressMessage *canvas.Text, save func(ffmpegPath string, ffprobePath string, ffplayPath string) error) error {
	var err error

	dir, err := localSharePath()
	if err != nil {
		return err
	}
	dir = filepath.Join(dir, "fyne", app.FyneApp().UniqueID())
	err = os.MkdirAll(dir, 0755)
	if err != nil {
		return err
	}

	fyne.Do(func() {
		progressMessage.Text = lang.L("downloadRun")
		progressMessage.Refresh()
	})
	err = downloadFile(dir+"/ffmpeg.tar.xz", "https://github.com/BtbN/FFmpeg-Builds/releases/download/latest/ffmpeg-master-latest-linux64-gpl.tar.xz", progressBar)
	if err != nil {
		return err
	}

	fyne.Do(func() {
		progressMessage.Text = lang.L("unzipRun")
		progressMessage.Refresh()
	})
	err = unTarXz(dir+"/ffmpeg.tar.xz", dir, progressBar)
	if err != nil {
		return err
	}
	_ = os.Remove(dir + "/ffmpeg.tar.xz")

	fyne.Do(func() {
		progressMessage.Text = lang.L("testFF")
		progressMessage.Refresh()
	})

	err = save(
		dir+"/ffmpeg-master-latest-linux64-gpl/bin/ffmpeg",
		dir+"/ffmpeg-master-latest-linux64-gpl/bin/ffprobe",
		dir+"/ffmpeg-master-latest-linux64-gpl/bin/ffplay",
	)
	if err != nil {
		return err
	}

	fyne.Do(func() {
		progressMessage.Text = lang.L("completedQueue")
		progressMessage.Refresh()
	})

	return nil
}

func localSharePath() (string, error) {
	xdgDataHome := os.Getenv("XDG_DATA_HOME")
	if xdgDataHome != "" {
		return xdgDataHome, nil
	}
	homeDir, err := os.UserHomeDir()
	if err != nil {
		return "", err
	}
	return filepath.Join(homeDir, ".local", "share"), nil
}

func downloadFile(filepath string, url string, progressBar *widget.ProgressBar) (err error) {
	progressBar.Value = 0
	progressBar.Max = 100

	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return err
	}
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	f, err := os.OpenFile(filepath, os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		return err
	}
	defer f.Close()

	buf := make([]byte, 32*1024)
	var downloaded int64
	for {
		n, err := resp.Body.Read(buf)
		if err != nil {
			if err == io.EOF {
				break
			}
			return err
		}
		if n > 0 {
			f.Write(buf[:n])
			downloaded += int64(n)
			progressBar.Value = float64(downloaded) / float64(resp.ContentLength) * 100
			fyne.Do(func() {
				progressBar.Refresh()
			})
		}
	}
	return nil
}

func unTarXz(fileTar string, directory string, progressBar *widget.ProgressBar) error {
	progressBar.Value = 0
	progressBar.Max = 100

	fyne.Do(func() {
		progressBar.Refresh()
	})

	f, err := os.Open(fileTar)
	if err != nil {
		return err
	}
	defer f.Close()

	xzReader, err := xz.NewReader(f)
	if err != nil {
		return err
	}

	tarReader := tar.NewReader(xzReader)

	totalFiles := 0
	for {
		_, err := tarReader.Next()
		if err == io.EOF {
			break
		}
		if err != nil {
			return err
		}
		totalFiles++
	}

	// Rewind back to the beginning of the file to re-process
	_, err = f.Seek(0, 0)
	if err != nil {
		return err
	}

	xzReader, err = xz.NewReader(f)
	if err != nil {
		return err
	}

	tarReader = tar.NewReader(xzReader)

	// We count the number of files already unpacked
	unpackedFiles := 0

	for {
		header, err := tarReader.Next()
		if err == io.EOF {
			break
		}
		if err != nil {
			return err
		}

		targetPath := filepath.Join(directory, header.Name)
		switch header.Typeflag {
		case tar.TypeDir:
			err := os.MkdirAll(targetPath, 0755)
			if err != nil {
				return err
			}
		case tar.TypeReg:
			outFile, err := os.Create(targetPath)
			if err != nil {
				return err
			}
			defer outFile.Close()

			_, err = io.Copy(outFile, tarReader)

			if err != nil {
				return err
			}
		default:
			return errors.New("unsupported file type")
		}

		unpackedFiles++
		progressBar.Value = float64(unpackedFiles) / float64(totalFiles) * 100
		fyne.Do(func() {
			progressBar.Refresh()
		})
	}

	ffmpegPath := filepath.Join(directory, "ffmpeg-master-latest-linux64-gpl", "bin", "ffmpeg")
	err = os.Chmod(ffmpegPath, 0755)
	if err != nil {
		return err
	}

	ffprobePath := filepath.Join(directory, "ffmpeg-master-latest-linux64-gpl", "bin", "ffprobe")
	err = os.Chmod(ffprobePath, 0755)
	if err != nil {
		return err
	}

	ffplayPath := filepath.Join(directory, "ffmpeg-master-latest-linux64-gpl", "bin", "ffplay")
	err = os.Chmod(ffplayPath, 0755)
	if err != nil {
		return err
	}

	return nil
}