feat: initial commit

PantherByte/ViewModels/MainWindowViewModel.cs

@@ -0,0 +1,130 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using CommunityToolkit.Mvvm.Input;
+using System.Threading.Tasks;
+using PantherByte.Services;
+using ReactiveUI;
+
+namespace PantherByte.ViewModels;
+
+public partial class MainWindowViewModel : ViewModelBase {
+    private string _link = string.Empty;
+    private string _saveLocation = string.Empty;
+    private string _format = "mp3";
+    private bool _canDownload = true;
+
+    /// <summary>
+    /// The link to the video to download. For now, only use YouTube links.
+    /// </summary>
+    public string Link { 
+        get => _link;
+        set => this.RaiseAndSetIfChanged(ref _link, value);
+    }
+
+    /// <summary>
+    /// The format to download the video in. Currently supported options are MP3, MP4, and WAV. This will become the
+    /// argument passed to the "-t" argument in <see cref="GenerateCmdStringAsync"/>.
+    /// </summary>
+    public string Format {
+        get => _format;
+        set => this.RaiseAndSetIfChanged(ref _format, value);
+    }
+    
+    /// <summary>
+    /// The folder to save the files in. This will become the argument passed to the "-P" argument in
+    /// <see cref="GenerateCmdStringAsync"/>.
+    /// </summary>
+    public string SaveLocation {
+        get => _saveLocation;
+        set => this.RaiseAndSetIfChanged(ref _saveLocation, value);
+    }
+
+    /// <summary>
+    /// Indicates if the file can be downloaded. If not, the download button is disabled.
+    /// </summary>
+    public bool CanDownload {
+        get => _canDownload;
+        set => this.RaiseAndSetIfChanged(ref _canDownload, value);
+    }
+
+    /// <summary>
+    /// Constructor. Mainly used for subscribing properties to the changes from other properties.
+    /// </summary>
+    public MainWindowViewModel() {
+        // Subscribe the CanDownload bool to the results of the Link, SaveLocation, and Format property changes.
+        this.WhenAnyValue(
+                x => x.Link,
+                x => x.SaveLocation,
+                x => x.Format,
+                (link, saveLocation, format) => !string.IsNullOrWhiteSpace(link)
+                                                && !string.IsNullOrWhiteSpace(format)
+                                                && !string.IsNullOrWhiteSpace(saveLocation)
+            )
+            .Subscribe(value => CanDownload = value);
+    }
+    
+    /// <summary>
+    /// Gets the save location for the generated file. We are only allowing users to download one file at a time for now.
+    /// </summary>
+    /// <exception cref="NullReferenceException">
+    /// Thrown when there are no available services that implement <see cref="IFileSaveService"/>, or when the
+    /// <see cref="Avalonia.Platform.Storage.IStorageFolder"/> returned from the <see cref="IFileSaveService.ChooseFolderAsync"/>
+    /// method is null.
+    /// </exception>
+    /// <exception cref="DirectoryNotFoundException">
+    /// Thrown when the selected directory path does not exist in the current filesystem.
+    /// </exception>
+    [RelayCommand]
+    private async Task GetSaveLocationAsync() {
+        try {
+            var fileService = App.Current?.Services?.GetService(typeof(IFileSaveService));
+            if (fileService is FileService service) {
+                var filePath = await service.ChooseFolderAsync();
+                if (filePath is not null) {
+                    var tempPath = filePath.Path.AbsolutePath;
+                    if (Directory.Exists(tempPath)) {
+                        SaveLocation = tempPath;
+                        Console.WriteLine("Successfully set the file path.");
+                    } else {
+                        throw new DirectoryNotFoundException($"Directory does not exist: {tempPath}");
+                    }
+                } else {
+                    throw new NullReferenceException("The resulting storage folder was null.");
+                }
+            } else {
+                throw new NullReferenceException("Missing a FileSaveService instance");
+            }
+        } catch (Exception ex) {
+            // Exceptions are caught locally for now, but will eventually require a modal error window.
+            Console.WriteLine(ex.ToString());
+        }
+    }
+    
+    /// <summary>
+    /// Generates the arguments used for the main command string.
+    /// </summary>
+    [RelayCommand]
+    private async Task<List<string>> GenerateCmdArgsAsync() {
+        // The command string format to use: yt-dlp <link> -t <mp3|mp4|wav> -P <path> --no-playlist
+        // yt-dlp requires usage of ffmpeg as well.
+        // Code will be executed when the button is clicked.
+        return await Task.Run(() => new List<string>([Link, "-t", Format, "-P", SaveLocation, "--no-playlist"]));
+    }
+
+    /// <summary>
+    /// Handles the download process of the file. Generates the command and runs it.
+    /// </summary>
+    [RelayCommand]
+    private async Task DownloadFileAsync() {
+        // Build the command and run the yt-dlp program by using the generated string.
+        // Somehow we'll need to package the program in with the application during distribution.
+        var args = await GenerateCmdArgsAsync();
+        // Run the command.
+        try {
+            System.Diagnostics.Process.Start("yt-dlp", args);
+        } catch (Exception ex) {
+            Console.WriteLine(ex.ToString());
+        }
+    }
+}