Add FFmpeg utilities configuration UI and automated downloading

Introduce a new UI for configuring FFmpeg, FFprobe, and FFplay paths with file selection and error handling. Add platform-specific logic for downloading and extracting FFmpeg binaries directly within the application, improving user experience.

internal/ffmpeg/download/service/download_windows.go

@@ -0,0 +1,175 @@
+//go:build windows
+// +build windows
+
+package service
+
+import (
+	"archive/zip"
+	"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"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+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 := os.Getenv("APPDATA")
+	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.zip", "https://github.com/BtbN/FFmpeg-Builds/releases/download/latest/ffmpeg-master-latest-win64-gpl.zip", progressBar)
+	if err != nil {
+		return err
+	}
+
+	fyne.Do(func() {
+		progressMessage.Text = lang.L("unzipRun")
+		progressMessage.Refresh()
+	})
+	err = unZip(dir+"/ffmpeg.zip", dir, progressBar)
+	if err != nil {
+		return err
+	}
+	_ = os.Remove(dir + "/ffmpeg.zip")
+
+	fyne.Do(func() {
+		progressMessage.Text = lang.L("testFF")
+		progressMessage.Refresh()
+	})
+	err = save(
+		dir+"/ffmpeg-master-latest-win64-gpl/bin/ffmpeg.exe",
+		dir+"/ffmpeg-master-latest-win64-gpl/bin/ffprobe.exe",
+		dir+"/ffmpeg-master-latest-win64-gpl/bin/ffplay.exe",
+	)
+	if err != nil {
+		return err
+	}
+
+	fyne.Do(func() {
+		progressMessage.Text = lang.L("completedQueue")
+		progressMessage.Refresh()
+	})
+
+	return 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 unZip(fileZip string, directory string, progressBar *widget.ProgressBar) error {
+	progressBar.Value = 0
+	progressBar.Max = 100
+
+	fyne.Do(func() {
+		progressBar.Refresh()
+	})
+
+	archive, err := zip.OpenReader(fileZip)
+	if err != nil {
+		return err
+	}
+	defer archive.Close()
+
+	totalBytes := int64(0)
+	for _, f := range archive.File {
+		totalBytes += int64(f.UncompressedSize64)
+	}
+
+	unpackedBytes := int64(0)
+
+	for _, f := range archive.File {
+		filePath := filepath.Join(directory, f.Name)
+
+		if !strings.HasPrefix(filePath, filepath.Clean(directory)+string(os.PathSeparator)) {
+			return errors.New("invalid file path")
+		}
+		if f.FileInfo().IsDir() {
+			os.MkdirAll(filePath, os.ModePerm)
+			continue
+		}
+
+		if err := os.MkdirAll(filepath.Dir(filePath), os.ModePerm); err != nil {
+			return err
+		}
+
+		dstFile, err := os.OpenFile(filePath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, f.Mode())
+		if err != nil {
+			return err
+		}
+
+		fileInArchive, err := f.Open()
+		if err != nil {
+			return err
+		}
+
+		bytesRead, err := io.Copy(dstFile, fileInArchive)
+		if err != nil {
+			return err
+		}
+
+		unpackedBytes += bytesRead
+		progressBar.Value = float64(unpackedBytes) / float64(totalBytes) * 100
+		fyne.Do(func() {
+			progressBar.Refresh()
+		})
+
+		dstFile.Close()
+		fileInArchive.Close()
+	}
+
+	return nil
+}