Add a download single post/message option to the GUI

OF DL.Gui/ViewModels/MainWindowViewModel.cs

@@ -27,7 +27,26 @@ public partial class MainWindowViewModel(
     IStartupService startupService,
     IDownloadOrchestrationService downloadOrchestrationService) : ViewModelBase
 {
+    private enum SingleDownloadType
+    {
+        Post,
+        PaidMessage
+    }
+
+    private readonly record struct SingleDownloadRequest(
+        SingleDownloadType Type,
+        long ContentId,
+        string Username,
+        long? UserId);
+
     private const string UnknownToolVersion = "Not detected";
+    private static readonly Regex s_singlePostUrlRegex = new(
+        @"^https://onlyfans\.com/(?<postId>\d+)/(?<username>[A-Za-z0-9_.-]+)/?$",
+        RegexOptions.Compiled | RegexOptions.IgnoreCase);
+
+    private static readonly Regex s_singlePaidMessageUrlRegex = new(
+        @"^https://onlyfans\.com/my/chats/chat/(?<userId>\d+)/?\?firstId=(?<messageId>\d+)$",
+        RegexOptions.Compiled | RegexOptions.IgnoreCase);
 
     private static readonly string s_defaultDownloadPath = Path.GetFullPath(
         Path.Combine(Directory.GetCurrentDirectory(), "__user_data__", "sites", "OnlyFans"));
@@ -297,6 +316,19 @@ public partial class MainWindowViewModel(
 
     [ObservableProperty] private string _downloadProgressDescription = string.Empty;
 
+    [ObservableProperty]
+    [NotifyCanExecuteChangedFor(nameof(OpenSinglePostOrMessageModalCommand))]
+    [NotifyCanExecuteChangedFor(nameof(SubmitSinglePostOrMessageCommand))]
+    private bool _isSinglePostOrMessageModalOpen;
+
+    [ObservableProperty]
+    [NotifyCanExecuteChangedFor(nameof(SubmitSinglePostOrMessageCommand))]
+    private string _singlePostOrMessageUrl = string.Empty;
+
+    [ObservableProperty]
+    [NotifyPropertyChangedFor(nameof(HasSinglePostOrMessageUrlError))]
+    private string _singlePostOrMessageUrlError = string.Empty;
+
     public bool IsLoadingScreen => CurrentScreen == AppScreen.Loading;
 
     public bool IsConfigScreen => CurrentScreen == AppScreen.Config;
@@ -317,6 +349,8 @@ public partial class MainWindowViewModel(
 
     public bool HasMediaSourcesError => !string.IsNullOrWhiteSpace(MediaSourcesError);
 
+    public bool HasSinglePostOrMessageUrlError => !string.IsNullOrWhiteSpace(SinglePostOrMessageUrlError);
+
     public string FfmpegPathDisplay =>
         HidePrivateInfo && !string.IsNullOrWhiteSpace(FfmpegPath) ? "[Hidden for Privacy]" : FfmpegPath;
 
@@ -688,6 +722,36 @@ public partial class MainWindowViewModel(
     [RelayCommand(CanExecute = nameof(CanDownloadPurchasedTab))]
     private async Task DownloadPurchasedTabAsync() => await RunDownloadAsync(true);
 
+    [RelayCommand(CanExecute = nameof(CanOpenSinglePostOrMessageModal))]
+    private void OpenSinglePostOrMessageModal()
+    {
+        SinglePostOrMessageUrl = string.Empty;
+        SinglePostOrMessageUrlError = string.Empty;
+        IsSinglePostOrMessageModalOpen = true;
+    }
+
+    [RelayCommand(CanExecute = nameof(CanSubmitSinglePostOrMessage))]
+    private async Task SubmitSinglePostOrMessageAsync()
+    {
+        if (!TryParseSinglePostOrMessageUrl(SinglePostOrMessageUrl, out SingleDownloadRequest request,
+                out string validationError))
+        {
+            SinglePostOrMessageUrlError = validationError;
+            return;
+        }
+
+        IsSinglePostOrMessageModalOpen = false;
+        SinglePostOrMessageUrlError = string.Empty;
+        await RunSinglePostOrMessageDownloadAsync(request);
+    }
+
+    [RelayCommand]
+    private void CancelSinglePostOrMessage()
+    {
+        SinglePostOrMessageUrlError = string.Empty;
+        IsSinglePostOrMessageModalOpen = false;
+    }
+
     [RelayCommand(CanExecute = nameof(CanStopWork))]
     private void StopWork()
     {
@@ -814,6 +878,16 @@ public partial class MainWindowViewModel(
         _allUsers.Count > 0 &&
         !IsDownloading;
 
+    private bool CanOpenSinglePostOrMessageModal() =>
+        CurrentScreen == AppScreen.UserSelection &&
+        !IsDownloading &&
+        !IsSinglePostOrMessageModalOpen;
+
+    private bool CanSubmitSinglePostOrMessage() =>
+        IsSinglePostOrMessageModalOpen &&
+        !IsDownloading &&
+        !string.IsNullOrWhiteSpace(SinglePostOrMessageUrl);
+
     private bool CanStopWork() => IsDownloading;
 
     private bool CanRefreshUsers() =>
@@ -842,6 +916,8 @@ public partial class MainWindowViewModel(
         RefreshIgnoredUsersListsCommand.NotifyCanExecuteChanged();
         LogoutCommand.NotifyCanExecuteChanged();
         EditConfigCommand.NotifyCanExecuteChanged();
+        OpenSinglePostOrMessageModalCommand.NotifyCanExecuteChanged();
+        SubmitSinglePostOrMessageCommand.NotifyCanExecuteChanged();
     }
 
     partial void OnIsDownloadingChanged(bool value)
@@ -853,6 +929,8 @@ public partial class MainWindowViewModel(
         RefreshUsersCommand.NotifyCanExecuteChanged();
         RefreshIgnoredUsersListsCommand.NotifyCanExecuteChanged();
         LogoutCommand.NotifyCanExecuteChanged();
+        OpenSinglePostOrMessageModalCommand.NotifyCanExecuteChanged();
+        SubmitSinglePostOrMessageCommand.NotifyCanExecuteChanged();
     }
 
     partial void OnIsAuthenticatedChanged(bool value)
@@ -873,6 +951,11 @@ public partial class MainWindowViewModel(
         _ = SelectUsersFromListAsync();
     }
 
+    partial void OnSinglePostOrMessageUrlChanged(string value)
+    {
+        SinglePostOrMessageUrlError = string.Empty;
+    }
+
     partial void OnFfmpegPathChanged(string value)
     {
         if (value != "[Hidden for Privacy]")
@@ -933,6 +1016,163 @@ public partial class MainWindowViewModel(
         await EnsureAuthenticationAndLoadUsersAsync();
     }
 
+    private async Task RunSinglePostOrMessageDownloadAsync(SingleDownloadRequest request)
+    {
+        if (_allUsers.Count == 0)
+        {
+            StatusMessage = "No users are loaded. Refresh users and retry.";
+            return;
+        }
+
+        IsDownloading = true;
+        _workCancellationSource?.Dispose();
+        _workCancellationSource = new CancellationTokenSource();
+        DownloadSelectedCommand.NotifyCanExecuteChanged();
+        DownloadPurchasedTabCommand.NotifyCanExecuteChanged();
+        OpenSinglePostOrMessageModalCommand.NotifyCanExecuteChanged();
+        SubmitSinglePostOrMessageCommand.NotifyCanExecuteChanged();
+        StopWorkCommand.NotifyCanExecuteChanged();
+
+        DateTime start = DateTime.Now;
+        string label = request.Type == SingleDownloadType.Post ? "single post" : "single paid message";
+        AppendLog($"Starting {label} download from URL.");
+        StatusMessage = $"Starting {label} download...";
+
+        StartDownloadProgress($"Initializing {label} download...", 0, false);
+
+        CancellationTokenSource cancellationSource = _workCancellationSource;
+        AvaloniaDownloadEventHandler eventHandler = new(
+            AppendLog,
+            UpdateProgressStatus,
+            StartDownloadProgress,
+            IncrementDownloadProgress,
+            StopDownloadProgress,
+            () => cancellationSource.IsCancellationRequested,
+            cancellationSource.Token);
+
+        try
+        {
+            if (request.Type == SingleDownloadType.Post)
+            {
+                if (!_allUsers.TryGetValue(request.Username, out long userId))
+                {
+                    StatusMessage =
+                        $"Creator '{request.Username}' is not in loaded users. Refresh users and ensure you are subscribed.";
+                    AppendLog(StatusMessage);
+                    return;
+                }
+
+                string path = downloadOrchestrationService.ResolveDownloadPath(request.Username);
+                await downloadOrchestrationService.PrepareUserFolderAsync(request.Username, userId, path);
+
+                await downloadOrchestrationService.DownloadSinglePostAsync(
+                    request.Username,
+                    request.ContentId,
+                    path,
+                    _allUsers,
+                    _startupResult.ClientIdBlobMissing,
+                    _startupResult.DevicePrivateKeyMissing,
+                    eventHandler);
+            }
+            else
+            {
+                long userId = request.UserId ?? 0;
+                string? resolvedUsername = await downloadOrchestrationService.ResolveUsernameAsync(userId);
+                if (string.IsNullOrWhiteSpace(resolvedUsername))
+                {
+                    StatusMessage = $"Could not resolve username for user ID {userId}.";
+                    AppendLog(StatusMessage);
+                    return;
+                }
+
+                Dictionary<string, long> usersForDownload = new(_allUsers, StringComparer.Ordinal);
+                if (!usersForDownload.ContainsKey(resolvedUsername))
+                {
+                    usersForDownload[resolvedUsername] = userId;
+                }
+
+                string path = downloadOrchestrationService.ResolveDownloadPath(resolvedUsername);
+                await downloadOrchestrationService.PrepareUserFolderAsync(resolvedUsername, userId, path);
+
+                await downloadOrchestrationService.DownloadSinglePaidMessageAsync(
+                    resolvedUsername,
+                    request.ContentId,
+                    path,
+                    usersForDownload,
+                    _startupResult.ClientIdBlobMissing,
+                    _startupResult.DevicePrivateKeyMissing,
+                    eventHandler);
+            }
+
+            ThrowIfStopRequested();
+            eventHandler.OnScrapeComplete(DateTime.Now - start);
+            StatusMessage = request.Type == SingleDownloadType.Post
+                ? "Single post download completed."
+                : "Single paid message download completed.";
+        }
+        catch (OperationCanceledException)
+        {
+            StatusMessage = "Operation canceled.";
+            AppendLog("Operation canceled.");
+        }
+        catch (Exception ex)
+        {
+            AppendLog($"Single item download failed: {ex.Message}");
+            StatusMessage = "Single item download failed. Check logs.";
+        }
+        finally
+        {
+            IsDownloading = false;
+            _workCancellationSource?.Dispose();
+            _workCancellationSource = null;
+            StopDownloadProgress();
+            DownloadSelectedCommand.NotifyCanExecuteChanged();
+            DownloadPurchasedTabCommand.NotifyCanExecuteChanged();
+            OpenSinglePostOrMessageModalCommand.NotifyCanExecuteChanged();
+            SubmitSinglePostOrMessageCommand.NotifyCanExecuteChanged();
+            StopWorkCommand.NotifyCanExecuteChanged();
+        }
+    }
+
+    private static bool TryParseSinglePostOrMessageUrl(
+        string url,
+        out SingleDownloadRequest request,
+        out string validationError)
+    {
+        request = default;
+        validationError = string.Empty;
+
+        string trimmedUrl = url.Trim();
+        Match postMatch = s_singlePostUrlRegex.Match(trimmedUrl);
+        if (postMatch.Success &&
+            long.TryParse(postMatch.Groups["postId"].Value, out long postId) &&
+            !string.IsNullOrWhiteSpace(postMatch.Groups["username"].Value))
+        {
+            request = new SingleDownloadRequest(
+                SingleDownloadType.Post,
+                postId,
+                postMatch.Groups["username"].Value,
+                null);
+            return true;
+        }
+
+        Match paidMessageMatch = s_singlePaidMessageUrlRegex.Match(trimmedUrl);
+        if (paidMessageMatch.Success &&
+            long.TryParse(paidMessageMatch.Groups["messageId"].Value, out long messageId) &&
+            long.TryParse(paidMessageMatch.Groups["userId"].Value, out long userId))
+        {
+            request = new SingleDownloadRequest(
+                SingleDownloadType.PaidMessage,
+                messageId,
+                string.Empty,
+                userId);
+            return true;
+        }
+
+        validationError = "Please enter a valid post URL or paid message URL.";
+        return false;
+    }
+
     private static void ApplyThemeFromConfigFileIfAvailable()
     {
         const string configPath = "config.conf";

OF DL.Gui/Views/MainWindow.axaml

@@ -1008,6 +1008,9 @@
                                 <Button Content="Download Purchased Tab"
                                         Classes="secondary"
                                         Command="{Binding DownloadPurchasedTabCommand}" />
+                                <Button Content="Download Single Post/Message"
+                                        Classes="secondary"
+                                        Command="{Binding OpenSinglePostOrMessageModalCommand}" />
                             </StackPanel>
                             <Button Grid.Column="1"
                                     IsVisible="{Binding IsDownloading}"
@@ -1349,5 +1352,95 @@
                 </ScrollViewer>
             </Border>
         </Grid>
+
+        <Grid Grid.Row="0" Grid.RowSpan="3"
+              IsVisible="{Binding IsSinglePostOrMessageModalOpen}"
+              Background="{DynamicResource OverlayBackgroundBrush}"
+              ZIndex="1001"
+              PointerPressed="OnModalOverlayClicked">
+            <Border Background="{DynamicResource ModalBackgroundBrush}"
+                    BorderBrush="{DynamicResource ModalBorderBrush}"
+                    BorderThickness="1"
+                    CornerRadius="16"
+                    Padding="32"
+                    Width="760"
+                    MaxHeight="700"
+                    HorizontalAlignment="Center"
+                    VerticalAlignment="Center"
+                    BoxShadow="0 20 25 -5 #19000000, 0 10 10 -5 #0F000000"
+                    PointerPressed="OnModalContentClicked">
+                <ScrollViewer>
+                    <StackPanel Spacing="18" Margin="8,4,8,4">
+                        <TextBlock FontSize="20"
+                                   FontWeight="Bold"
+                                   Foreground="{DynamicResource TextPrimaryBrush}"
+                                   Text="Download Single Post/Message" />
+
+                        <TextBlock Foreground="{DynamicResource TextSecondaryBrush}"
+                                   TextWrapping="Wrap"
+                                   Text="Enter a post URL or paid message URL to download only that item." />
+
+                        <Border Padding="16"
+                                CornerRadius="10"
+                                Background="{DynamicResource PreviewBackgroundBrush}"
+                                BorderBrush="{DynamicResource PreviewBorderBrush}"
+                                BorderThickness="1">
+                            <StackPanel Spacing="14">
+                                <TextBlock FontSize="15"
+                                           FontWeight="Bold"
+                                           Foreground="{DynamicResource TextPrimaryBrush}"
+                                           Text="How to find a URL" />
+
+                                <!-- Post Instructions -->
+                                <StackPanel Spacing="6">
+                                    <TextBlock FontWeight="SemiBold"
+                                               Foreground="{DynamicResource TextPrimaryBrush}"
+                                               Text="Posts" />
+                                    <TextBlock Foreground="{DynamicResource TextSecondaryBrush}"
+                                               TextWrapping="Wrap"
+                                               Text="Click the ... menu on any post → 'Copy link to post'" />
+                                </StackPanel>
+
+                                <!-- Message Instructions -->
+                                <StackPanel Spacing="6">
+                                    <TextBlock FontWeight="SemiBold"
+                                               Foreground="{DynamicResource TextPrimaryBrush}"
+                                               Text="Messages (Paid Only)" />
+                                    <TextBlock Foreground="{DynamicResource TextSecondaryBrush}"
+                                               TextWrapping="Wrap"
+                                               Text="Go to main timeline → Purchased tab → Find message → Click ... menu → 'Copy link to message'" />
+                                    <TextBlock Foreground="{DynamicResource TextSecondaryBrush}"
+                                               FontStyle="Italic"
+                                               FontSize="12"
+                                               TextWrapping="Wrap"
+                                               Text="Note: Only unlocked PPV messages can be downloaded individually. For other messages, download all messages from the creator." />
+                                </StackPanel>
+                            </StackPanel>
+                        </Border>
+
+                        <StackPanel Spacing="6">
+                            <TextBlock FontWeight="SemiBold"
+                                       Foreground="{DynamicResource TextPrimaryBrush}"
+                                       Text="Post or Message URL" />
+                            <TextBox Text="{Binding SinglePostOrMessageUrl}"
+                                     Watermark="https://onlyfans.com/... or https://onlyfans.com/my/chats/chat/.../?firstId=..." />
+                            <TextBlock IsVisible="{Binding HasSinglePostOrMessageUrlError}"
+                                       Foreground="{DynamicResource ErrorTextBrush}"
+                                       Text="{Binding SinglePostOrMessageUrlError}"
+                                       TextWrapping="Wrap" />
+                        </StackPanel>
+
+                        <StackPanel Orientation="Horizontal" Spacing="10" HorizontalAlignment="Right">
+                            <Button Content="Cancel"
+                                    Classes="secondary"
+                                    Command="{Binding CancelSinglePostOrMessageCommand}" />
+                            <Button Content="Download"
+                                    Classes="primary"
+                                    Command="{Binding SubmitSinglePostOrMessageCommand}" />
+                        </StackPanel>
+                    </StackPanel>
+                </ScrollViewer>
+            </Border>
+        </Grid>
     </Grid>
 </Window>

OF DL.Gui/Views/MainWindow.axaml.cs

@@ -183,8 +183,9 @@ public partial class MainWindow : Window
             return;
         }
 
-        // Execute cancel command on the modal
+        // Execute cancel command on any open modal
         vm.CreatorConfigEditor.ModalViewModel?.CancelCommand?.Execute(null);
+        vm.CancelSinglePostOrMessageCommand.Execute(null);
     }
 
     private void OnModalContentClicked(object? sender, PointerPressedEventArgs e) =>

docs/running-the-program.md

@@ -20,6 +20,19 @@ In GUI mode, the **Help** menu includes:
 - **Documentation** (opens https://docs.ofdl.tools/)
 - **About** (shows version details and project/license links)
 
+In GUI mode, the main download screen includes:
+
+- **Download Selected** (downloads configured content for selected creators)
+- **Download Purchased Tab** (downloads purchased tab content)
+- **Download Single Post/Message** (opens a modal to download one post or one paid message by URL)
+
+For **Download Single Post/Message** in GUI:
+
+- Post URL: click `...` on a post and choose **Copy link to post**.
+- Message URL: only unlocked PPV paid messages are supported by URL. From the main timeline, open **Purchased**,
+  find the message, click `...`, and choose **Copy link to message**.
+- Other message types cannot be downloaded individually by URL; scrape all messages for that creator instead.
+
 If you're logged in successfully then you will be greeted with a selection prompt. To navigate the menu the can use the ↑ & ↓ arrows and press `enter` to choose that option.
 
 ![CLI main menu](/img/cli_menu.png)