refactor: break up and refactor play queue components for clearer separation #676

huynhsontung · 2025-09-24T05:57:20Z

Refactored MediaListViewModel from a monolithic class into a clean MVVM architecture, separating business logic, domain models, and presentation layer for maintainability and testability.
Implemented stateless services (IPlaylistService, IPlaybackControlService, IMediaListFactory) to encapsulate playlist operations, navigation logic, and media parsing, all injected via dependency injection.

… better fit MVVM pattern

Replaced `IMediaParsingService` with `IPlaylistFactory` and `PlaylistFactory` to centralize playlist creation and parsing logic. Refactored the `Playlist` class to support cloning properties from a reference playlist and added constructors for enhanced flexibility. Introduced `PlaylistCreateResult` to encapsulate playlist creation results. Updated `PlaybackControlService`, `MediaListViewModel`, and `PlaylistService` to use `IPlaylistFactory` for playlist operations. Removed `IMediaParsingService` and its implementation. Adjusted dependency injection to register the new factory. Enabled nullable reference types in several files and performed general code cleanup. Updated `Screenbox.Core.csproj` to reflect file additions and removals.

Renamed IPlaylistFactory to IMediaListFactory and updated its methods to return NextMediaList instead of Playlist. Replaced PlaylistFactory with MediaListFactory to align with the new interface.

Copilot

Pull Request Overview

This PR refactors the media playlist components to improve code organization and maintainability by separating concerns and applying proper MVVM architecture patterns.

Renames components from "Playlist" to "PlayQueue" for clearer UI terminology
Extracts business logic from MediaListViewModel into dedicated stateless services (IPlaylistService, IPlaybackControlService, IMediaListFactory)
Introduces domain models (Playlist, PlaybackNavigationResult, NextMediaList) to separate data from presentation logic

Reviewed Changes

Copilot reviewed 22 out of 22 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
Screenbox/Screenbox.csproj	Updates project references from PlaylistView to PlayQueueControl
Screenbox/Pages/PlayerPage.xaml.cs	Updates references to use renamed PlayQueue control
Screenbox/Pages/PlayerPage.xaml	Updates XAML to use PlayQueueControl instead of PlaylistView
Screenbox/Pages/PlayQueuePage.xaml.cs	Removes unused import and updates control references
Screenbox/Pages/PlayQueuePage.xaml	Updates binding references to use PlayQueue control
Screenbox/Controls/PlayQueueControl.xaml.cs	Renames class from PlaylistView to PlayQueueControl and updates ViewModel type
Screenbox/Controls/PlayQueueControl.xaml	Updates class reference and event handler names
Screenbox.Core/ViewModels/PlayQueueViewModel.cs	Renames class from PlaylistViewModel to PlayQueueViewModel
Screenbox.Core/ViewModels/MediaListViewModel.cs	Major refactor to use injected services and domain models instead of inline business logic
Screenbox.Core/Services/PlaylistService.cs	New stateless service for playlist operations like shuffling and neighboring file management
Screenbox.Core/Services/PlaybackControlService.cs	New service handling playback navigation logic
Screenbox.Core/Services/IPlaylistService.cs	Interface for playlist operations
Screenbox.Core/Services/IPlaybackControlService.cs	Interface for playback control operations
Screenbox.Core/Screenbox.Core.csproj	Adds new service and model files to project
Screenbox.Core/Models/ShuffleBackup.cs	Extracted model for shuffle backup data
Screenbox.Core/Models/Playlist.cs	New domain model representing playlist data
Screenbox.Core/Models/PlaybackNavigationResult.cs	Model for playback navigation results
Screenbox.Core/Models/NextMediaList.cs	Model for media list parsing results
Screenbox.Core/Helpers/CollectionExtensions.cs	Minor import reordering
Screenbox.Core/Factories/MediaListFactory.cs	Extracted factory for media list creation and parsing
Screenbox.Core/Factories/IMediaListFactory.cs	Interface for media list factory
Screenbox.Core/Common/ServiceHelpers.cs	Updates service registration for renamed and new services

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Screenbox.Core/ViewModels/MediaListViewModel.cs

Copilot · 2025-09-27T11:08:35Z

Screenbox.Core/ViewModels/MediaListViewModel.cs

+                    if (_delayPlay is MediaViewModel media && Items.Contains(media))
+                    {
+                        PlaySingle(media);
+                        await TryEnqueueAndPlayPlaylistAsync(media);
+                    }
+                    else
+                    {
+                        ClearPlaylist();
+                        await EnqueueAndPlay(_delayPlay);
+                    }
+                    _delayPlay = null;


Async lambda in TryEnqueue can cause unhandled exceptions. The async operations inside the lambda should be wrapped in try-catch blocks or the lambda should be fire-and-forget with proper error handling.

Suggested change

if (_delayPlay is MediaViewModel media && Items.Contains(media))

{

PlaySingle(media);

await TryEnqueueAndPlayPlaylistAsync(media);

}

else

{

ClearPlaylist();

await EnqueueAndPlay(_delayPlay);

}

_delayPlay = null;

try

{

if (_delayPlay is MediaViewModel media && Items.Contains(media))

{

PlaySingle(media);

await TryEnqueueAndPlayPlaylistAsync(media);

}

else

{

ClearPlaylist();

await EnqueueAndPlay(_delayPlay);

}

_delayPlay = null;

}

catch (Exception ex)

{

SentrySdk.CaptureException(ex);

}

Screenbox.Core/ViewModels/MediaListViewModel.cs

Copilot · 2025-09-27T11:08:35Z

Screenbox.Core/ViewModels/MediaListViewModel.cs

+                switch (args.Button)
+                {
+                    case SystemMediaTransportControlsButton.Next:
+                        await NextAsync();
+                        break;
+                    case SystemMediaTransportControlsButton.Previous:
+                        await PreviousAsync();
+                        break;
+                }


Async lambda in TryEnqueue lacks error handling. Exceptions from NextAsync() or PreviousAsync() could become unhandled exceptions.

Screenbox.Core/Services/PlaylistService.cs

Screenbox.Core/ViewModels/MediaListViewModel.cs

Copilot

Pull Request Overview

Copilot reviewed 22 out of 22 changed files in this pull request and generated 4 comments.

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Copilot · 2025-09-29T04:03:17Z

Screenbox.Core/ViewModels/MediaListViewModel.cs

+            _mediaPlayer.PlaybackItem = vm.Item.Value;
+            _mediaPlayer.Play();


Potential null reference exception if _mediaPlayer is null. The null check at line 308 guards against this, but the assignment should be inside that check or use null-conditional operator.

Suggested change

_mediaPlayer.PlaybackItem = vm.Item.Value;

_mediaPlayer.Play();

_mediaPlayer!.PlaybackItem = vm.Item.Value;

_mediaPlayer?.Play();

Copilot · 2025-09-29T04:03:17Z

Screenbox.Core/Services/PlaylistService.cs

+
+    public Playlist RestoreFromShuffle(Playlist playlist)
+    {
+        Guard.IsNotNull(playlist.ShuffleBackup, nameof(playlist.ShuffleBackup));


Using Guard.IsNotNull with nameof(playlist.ShuffleBackup) will throw an exception with the property name rather than the parameter name. Consider using a more descriptive message or checking the condition explicitly and throwing a more meaningful exception.

Suggested change

Guard.IsNotNull(playlist.ShuffleBackup, nameof(playlist.ShuffleBackup));

if (playlist.ShuffleBackup is null)

throw new InvalidOperationException("Cannot restore from shuffle: ShuffleBackup is null. Ensure the playlist was previously shuffled.");

Screenbox.Core/Models/PlaybackNavigationResult.cs

Screenbox.Core/Models/ShuffleBackup.cs

Updated `PlaybackNavigationResult` to enforce non-nullable `NextItem`, simplifying its structure and removing unused properties and constructors. Updated `IPlaybackControlService` and `PlaybackControlService` methods to return nullable `PlaybackNavigationResult?` instead of creating instances with `null` values. Simplified logic in `MediaListViewModel` to handle nullable results consistently.

huynhsontung · 2025-09-29T04:43:38Z

@United600 Can you help me test this PR? It's a huge refactor that is needed for the persistent playlist feature in #514. I have done some testing on my end, but I just want to make sure there is no regression.

United600 · 2025-09-29T12:27:48Z

@United600 Can you help me test this PR? It's a huge refactor that is needed for the persistent playlist feature in #514. I have done some testing on my end, but I just want to make sure there is no regression.

Of course, I'd be happy to. Are there any specific actions or features I should pay special attention to?

United600 · 2025-09-29T20:43:49Z

It seems that opening files directly from the explorer doesn't work.

Gravacao.2025-09-29.192435.mp4

Reordering the play queue also leads to unexpected behavior, and possible locks (and crashes) when clicking the Previous button.

Gravacao.2025-09-29.193300.mp4

Screenbox.Core/Screenbox.Core.csproj

Introduced `MediaViewModelFactory` in `MediaListViewModel` to short circut media list parsing whenever possible. Replaced `UpdateItemsFromPlaylist` with `LoadFromPlaylist` and `SaveToPlaylist` methods, separating UI syncing and playlist state management. Consolidated file handling logic into a new `ParseAndPlayAsync` method, unifying media type handling. Added `CreatePlaylistAndPlay` to reduce duplication. Enhanced shuffle handling with robust backup updates in `OnCollectionChanged`. Updated navigation methods (`NextAsync`, `PreviousAsync`, `OnEndReached`) to save playlist state before actions. Removed redundant methods (`HandleSingleFileAsync`, `HandleMultipleFilesAsync`, `EnqueueAndPlay`).

Consolidated playlist-related functionality into a single `Playlist` class by removing the redundant `PlaylistInfo` class. Updated all references to use the new `Playlist` structure. - Merged `PlaylistInfo` properties (`CurrentIndex`, `ShuffleMode`, `LastUpdated`) into `Playlist`. - Updated `MessengerExtensions` and `PlaylistRequestMessage` to use `Playlist`. - Refactored `IPlaybackControlService` and `PlaybackControlService` to handle neighboring files explicitly. - Removed `NeighboringFilesQuery` from `Playlist` and passed it as a parameter where needed. - Refactored `MediaListViewModel` and other view models to align with the new `Playlist` structure. - Updated `PlaylistService` to simplify shuffle and restore logic.

Refactored `RestoreFromShuffle` in `PlaylistService` to simplify playlist restoration using a constructor. Introduced `_deferCollectionChanged` in `MediaListViewModel` to optimize bulk collection updates and avoid excessive notifications. Updated `LoadFromPlaylist` to handle large playlists efficiently by clearing and repopulating the `Items` collection when necessary. Modified `ClearPlaylist` to defer collection change notifications during clearing. Replaced direct `_playlist` assignments with local variables and consistent use of `LoadFromPlaylist` for better clarity and reduced side effects. Added a guard clause in `OnCollectionChanged` to skip processing during deferred updates. Cleaned up `MediaViewModel` by removing unused imports and commented-out code. Commented out the `Name` assignment in `UpdateSource` for potential future adjustments.

huynhsontung · 2025-10-15T07:12:28Z

@United600 Can you help review this PR again? I have fixed the issues you mentioned. (And pretty much refactored the refactor.) The focus is on how the player queue behaves and anything that interacts with it. I have covered the following cases:

Open file(s) directly from file explorer
Drag and drop from file explorer
Toggle shuffle button
Reorder the queue manually
Have only one file in the queue and let the player get the neighboring next or previous file
Clear queue

Let me know if you spot any issues.

United600 · 2025-10-15T21:59:37Z

So far no issues 👌. I think this is a good opportunity to switch to file-scoped namespaces in the modified files.

Since you’re already working on this area, here are some additional improvements to consider:

Skipping items should not toggle between the play and pause icons.

Gravacao.2025-10-15.224631.mp4

Items should drop at the correct list position, not default to the bottom

Gravacao.2025-10-15.224919.mp4

huynhsontung · 2025-10-16T06:46:30Z

The two issues you mentioned also exist in the latest version. I have some ideas on how to fix them, but I will create separate PRs for them. If there is no regression, I will go ahead and merge this PR then, since it's already too big.

Copilot

Pull Request Overview

Copilot reviewed 31 out of 31 changed files in this pull request and generated 4 comments.

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Screenbox.Core/ViewModels/MediaViewModel.cs

Screenbox.Core/ViewModels/MediaListViewModel.cs

Screenbox.Core/Services/PlaylistService.cs

United600 · 2025-10-16T20:49:17Z

The two issues you mentioned also exist in the latest version. I have some ideas on how to fix them, but I will create separate PRs for them. If there is no regression, I will go ahead and merge this PR then, since it's already too big.

Fair enough. I only mentioned it because it stood out while I was testing the changes.

United600 · 2025-10-17T18:28:08Z

One regression slipped through 😢.

Gravacao.2025-10-17.192426.mp4

huynhsontung · 2025-10-18T07:28:38Z

One regression slipped through 😢.

Gravacao.2025-10-17.192426.mp4

#697 should fix this

* Initial plan * feat: pass NeighboringFilesQuery through PlaylistCurrentItemChangedMessage to fix subtitle auto-loading Co-authored-by: huynhsontung <31434093+huynhsontung@users.noreply.github.com> * refactor: use ToArray() instead of ToList() for better performance Co-authored-by: huynhsontung <31434093+huynhsontung@users.noreply.github.com> * neighborhood query should be set before active media is changed * better subtitle file name matching logic --------- Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: huynhsontung <31434093+huynhsontung@users.noreply.github.com> Co-authored-by: Tung Huynh <tung75605@gmail.com>

huynhsontung added 2 commits September 23, 2025 22:55

rename PlaylistView -> PlayQueueControl

05cd237

break up and refactor MediaListViewModel into smaller components that…

0f19d7f

… better fit MVVM pattern

huynhsontung changed the title ~~refactor: rename play queue components to disambiguate "playlist" and "play queue"~~ refactor: rename play queue components Sep 24, 2025

huynhsontung changed the title ~~refactor: rename play queue components~~ refactor: break up and rename play queue components for clearer separation Sep 24, 2025

huynhsontung added 5 commits September 24, 2025 01:14

handle repeat mode in when going next or previous

45a5287

handle repeat modes inside the service

b1684d0

Refactor playlist handling to use NextMediaList

501865e

Renamed IPlaylistFactory to IMediaListFactory and updated its methods to return NextMediaList instead of Playlist. Replaced PlaylistFactory with MediaListFactory to align with the new interface.

move PlaybackNavigationResult into its own file and minor refactor

7ee93ae

huynhsontung marked this pull request as ready for review September 27, 2025 11:06

dosubot bot added the size:XXL This PR changes 1000+ lines, ignoring generated files. label Sep 27, 2025

huynhsontung requested a review from Copilot September 27, 2025 11:06

Copilot AI reviewed Sep 27, 2025

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huynhsontung added 2 commits September 28, 2025 20:04

vibe code bug fixes

9c64886

remove empty exception catches

4d80779

huynhsontung requested a review from United600 September 29, 2025 03:33

clean up

c3ff877

huynhsontung requested a review from Copilot September 29, 2025 04:02

Copilot AI reviewed Sep 29, 2025

View reviewed changes

United600 reviewed Sep 29, 2025

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Screenbox.Core/Screenbox.Core.csproj Outdated Show resolved Hide resolved

huynhsontung added 6 commits October 3, 2025 00:39

notify NextCommand and PreviousCommand state change on playlist load

a737d56

ensure setting position from UI thread in MediaListViewModel

8989075

fix neighboring queue not working

699081a

United600 mentioned this pull request Oct 15, 2025

Feature: Enqueue in recent played #692

Open

use file-scoped namespace on changed files

bebfd62

huynhsontung requested a review from Copilot October 16, 2025 06:56

Copilot AI reviewed Oct 16, 2025

View reviewed changes

resolve minor issues

d028f1e

huynhsontung changed the title ~~refactor: break up and rename play queue components for clearer separation~~ refactor: break up and refactor play queue components for clearer separation Oct 16, 2025

huynhsontung enabled auto-merge (squash) October 16, 2025 07:13

huynhsontung disabled auto-merge October 16, 2025 07:16

move can next and can previous checks into playback control service

d4e229a

huynhsontung enabled auto-merge (squash) October 16, 2025 07:25

huynhsontung merged commit 86560e9 into main Oct 16, 2025
4 checks passed

huynhsontung deleted the fix-play-queue-names branch October 16, 2025 15:01

huynhsontung mentioned this pull request Oct 18, 2025

fix: rapid current item changing that break UI transitions #697

Merged

huynhsontung mentioned this pull request Dec 3, 2025

cannot load subtitles automatically #736

Closed

Copilot AI mentioned this pull request Dec 3, 2025

fix: subtitle auto-loading regression from PR #676 #746

Merged

		_mediaPlayer.PlaybackItem = vm.Item.Value;
		_mediaPlayer.Play();

	Guard.IsNotNull(playlist.ShuffleBackup, nameof(playlist.ShuffleBackup));
	if (playlist.ShuffleBackup is null)
	throw new InvalidOperationException("Cannot restore from shuffle: ShuffleBackup is null. Ensure the playlist was previously shuffled.");

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refactor: break up and refactor play queue components for clearer separation #676

refactor: break up and refactor play queue components for clearer separation #676

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huynhsontung commented Sep 24, 2025 •

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