Corrected issue with channel delete (#1247)

* Channel delete now updates the guide cache.

* update changelog

---------

Co-authored-by: Jason Dove <jason@jasondove.me>

CHANGELOG.md

@@ -15,6 +15,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   - This fixes potential UI hangs and database concurrency bugs
 - Maintain watermark alpha channel (built-in transparency) using QSV acceleration
 - Properly extract and burn in embedded text subtitles using Jellyfin, Emby and Plex libraries
+- Fix bug where deleting a channel would not remove its data from XMLTV
 
 ### Changed
 - Remove duplicate items from smart collections before scheduling

ErsatzTV.Application/Channels/Commands/DeleteChannelHandler.cs

@@ -1,5 +1,8 @@
-using ErsatzTV.Core;
+using System.Threading;
+using System.Threading.Channels;
+using ErsatzTV.Core;
 using ErsatzTV.Core.Domain;
+using ErsatzTV.Core.Interfaces.Metadata;
 using ErsatzTV.Infrastructure.Data;
 using ErsatzTV.Infrastructure.Extensions;
 using Microsoft.EntityFrameworkCore;
@@ -8,31 +11,49 @@ namespace ErsatzTV.Application.Channels;
 
 public class DeleteChannelHandler : IRequestHandler<DeleteChannel, Either<BaseError, Unit>>
 {
+    private readonly ChannelWriter<IBackgroundServiceRequest> _workerChannel;
     private readonly IDbContextFactory<TvContext> _dbContextFactory;
+    private readonly ILocalFileSystem _localFileSystem;
 
-    public DeleteChannelHandler(IDbContextFactory<TvContext> dbContextFactory)
+    public DeleteChannelHandler(
+        ChannelWriter<IBackgroundServiceRequest> workerChannel,
+        IDbContextFactory<TvContext> dbContextFactory,
+        ILocalFileSystem localFileSystem)
     {
+        _workerChannel = workerChannel;
         _dbContextFactory = dbContextFactory;
+        _localFileSystem = localFileSystem;
     }
 
     public async Task<Either<BaseError, Unit>> Handle(DeleteChannel request, CancellationToken cancellationToken)
     {
         await using TvContext dbContext = await _dbContextFactory.CreateDbContextAsync(cancellationToken);
-        Validation<BaseError, Channel> validation = await ChannelMustExist(dbContext, request);
-        return await validation.Apply(c => DoDeletion(dbContext, c));
+        Validation<BaseError, Core.Domain.Channel> validation = await ChannelMustExist(dbContext, request);
+
+        return await validation.Apply(c => DoDeletion(dbContext, c, cancellationToken));
     }
 
-    private static async Task<Unit> DoDeletion(TvContext dbContext, Channel channel)
+    private async Task<Unit> DoDeletion(TvContext dbContext, Core.Domain.Channel channel, CancellationToken cancellationToken)
     {
         dbContext.Channels.Remove(channel);
         await dbContext.SaveChangesAsync();
-        
+
+        // delete channel data from channel guide cache
+        string cacheFile = Path.Combine(FileSystemLayout.ChannelGuideCacheFolder, $"{channel.Number}.xml");
+        if (_localFileSystem.FileExists(cacheFile))
+        {
+            File.Delete(cacheFile);
+        }
+
+        // refresh channel list to remove channel that has no playout
+        await _workerChannel.WriteAsync(new RefreshChannelList(), cancellationToken);
+
         return Unit.Default;
     }
 
-    private static async Task<Validation<BaseError, Channel>> ChannelMustExist(TvContext dbContext, DeleteChannel deleteChannel)
+    private static async Task<Validation<BaseError, Core.Domain.Channel>> ChannelMustExist(TvContext dbContext, DeleteChannel deleteChannel)
     {
-        Option<Channel> maybeChannel = await dbContext.Channels
+        Option<Core.Domain.Channel> maybeChannel = await dbContext.Channels
             .SelectOneAsync(c => c.Id, c => c.Id == deleteChannel.ChannelId);
         return maybeChannel.ToValidation<BaseError>($"Channel {deleteChannel.ChannelId} does not exist.");
     }