detect cycles in smart collection queries (#2059)

CHANGELOG.md

@@ -44,7 +44,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   - Collections synchronized from media servers are still indexed as `tag`
 - Allow searching by `smart_collection` (name)
   - Quotes are *always* required when using this feature
-  - e.g. `smart_collection:"one" NOT smart_collection:"two"`
+    - e.g. `smart_collection:"one" NOT smart_collection:"two"`
+  - Cycles will be detected and logged, and searches with cycles will not work as expected
 
 ### Changed
 - Start to make UI minimally responsive (functional on smaller screens)

ErsatzTV.Application/Maintenance/Commands/EmptyTrashHandler.cs

@@ -26,7 +26,7 @@ public class EmptyTrashHandler : IRequestHandler<EmptyTrash, Either<BaseError, U
         EmptyTrash request,
         CancellationToken cancellationToken)
     {
-        SearchResult result = await _searchIndex.Search(_client, "state:FileNotFound", 0, 10_000);
+        SearchResult result = await _searchIndex.Search(_client, "state:FileNotFound", string.Empty, 0, 10_000);
         var ids = result.Items.Map(i => i.Id).ToList();
 
         // ElasticSearch remove items may fail, so do that first

ErsatzTV.Application/MediaCollections/Commands/CreateSmartCollectionHandler.cs

@@ -1,6 +1,7 @@
 using ErsatzTV.Core;
 using ErsatzTV.Core.Domain;
 using ErsatzTV.Core.Interfaces.Search;
+using ErsatzTV.Core.Search;
 using ErsatzTV.Infrastructure.Data;
 using Microsoft.EntityFrameworkCore;
 using static ErsatzTV.Application.MediaCollections.Mapper;
@@ -12,11 +13,16 @@ public class CreateSmartCollectionHandler :
 {
     private readonly IDbContextFactory<TvContext> _dbContextFactory;
     private readonly ISearchTargets _searchTargets;
+    private readonly ISmartCollectionCache _smartCollectionCache;
 
-    public CreateSmartCollectionHandler(IDbContextFactory<TvContext> dbContextFactory, ISearchTargets searchTargets)
+    public CreateSmartCollectionHandler(
+        IDbContextFactory<TvContext> dbContextFactory,
+        ISearchTargets searchTargets,
+        ISmartCollectionCache smartCollectionCache)
     {
         _dbContextFactory = dbContextFactory;
         _searchTargets = searchTargets;
+        _smartCollectionCache = smartCollectionCache;
     }
 
     public async Task<Either<BaseError, SmartCollectionViewModel>> Handle(
@@ -35,6 +41,7 @@ public class CreateSmartCollectionHandler :
         await dbContext.SmartCollections.AddAsync(smartCollection);
         await dbContext.SaveChangesAsync();
         _searchTargets.SearchTargetsChanged();
+        await _smartCollectionCache.Refresh();
         return ProjectToViewModel(smartCollection);
     }
 

ErsatzTV.Application/MediaCollections/Commands/DeleteSmartCollectionHandler.cs

@@ -1,6 +1,7 @@
 using ErsatzTV.Core;
 using ErsatzTV.Core.Domain;
 using ErsatzTV.Core.Interfaces.Search;
+using ErsatzTV.Core.Search;
 using ErsatzTV.Infrastructure.Data;
 using ErsatzTV.Infrastructure.Extensions;
 using Microsoft.EntityFrameworkCore;
@@ -11,11 +12,16 @@ public class DeleteSmartCollectionHandler : IRequestHandler<DeleteSmartCollectio
 {
     private readonly IDbContextFactory<TvContext> _dbContextFactory;
     private readonly ISearchTargets _searchTargets;
+    private readonly ISmartCollectionCache _smartCollectionCache;
 
-    public DeleteSmartCollectionHandler(IDbContextFactory<TvContext> dbContextFactory, ISearchTargets searchTargets)
+    public DeleteSmartCollectionHandler(
+        IDbContextFactory<TvContext> dbContextFactory,
+        ISearchTargets searchTargets,
+        ISmartCollectionCache smartCollectionCache)
     {
         _dbContextFactory = dbContextFactory;
         _searchTargets = searchTargets;
+        _smartCollectionCache = smartCollectionCache;
     }
 
     public async Task<Either<BaseError, Unit>> Handle(
@@ -32,6 +38,7 @@ public class DeleteSmartCollectionHandler : IRequestHandler<DeleteSmartCollectio
         dbContext.SmartCollections.Remove(smartCollection);
         await dbContext.SaveChangesAsync();
         _searchTargets.SearchTargetsChanged();
+        await _smartCollectionCache.Refresh();
         return Unit.Default;
     }
 

ErsatzTV.Application/MediaCollections/Commands/UpdateSmartCollectionHandler.cs

@@ -5,6 +5,7 @@ using ErsatzTV.Core.Domain;
 using ErsatzTV.Core.Interfaces.Repositories;
 using ErsatzTV.Core.Interfaces.Search;
 using ErsatzTV.Core.Scheduling;
+using ErsatzTV.Core.Search;
 using ErsatzTV.Infrastructure.Data;
 using ErsatzTV.Infrastructure.Extensions;
 using Microsoft.EntityFrameworkCore;
@@ -17,17 +18,20 @@ public class UpdateSmartCollectionHandler : IRequestHandler<UpdateSmartCollectio
     private readonly IDbContextFactory<TvContext> _dbContextFactory;
     private readonly IMediaCollectionRepository _mediaCollectionRepository;
     private readonly ISearchTargets _searchTargets;
+    private readonly ISmartCollectionCache _smartCollectionCache;
 
     public UpdateSmartCollectionHandler(
         IDbContextFactory<TvContext> dbContextFactory,
         IMediaCollectionRepository mediaCollectionRepository,
         ChannelWriter<IBackgroundServiceRequest> channel,
-        ISearchTargets searchTargets)
+        ISearchTargets searchTargets,
+        ISmartCollectionCache smartCollectionCache)
     {
         _dbContextFactory = dbContextFactory;
         _mediaCollectionRepository = mediaCollectionRepository;
         _channel = channel;
         _searchTargets = searchTargets;
+        _smartCollectionCache = smartCollectionCache;
     }
 
     public async Task<Either<BaseError, Unit>> Handle(
@@ -47,6 +51,7 @@ public class UpdateSmartCollectionHandler : IRequestHandler<UpdateSmartCollectio
         if (await dbContext.SaveChangesAsync() > 0)
         {
             _searchTargets.SearchTargetsChanged();
+            await _smartCollectionCache.Refresh();
 
             // refresh all playouts that use this smart collection
             foreach (int playoutId in await _mediaCollectionRepository.PlayoutIdsUsingSmartCollection(request.Id))

ErsatzTV.Application/Search/Queries/QuerySearchIndexAllItemsHandler.cs

@@ -30,5 +30,5 @@ public class QuerySearchIndexAllItemsHandler : IRequestHandler<QuerySearchIndexA
             await GetIds(LuceneSearchIndex.ImageType, request.Query));
 
     private async Task<List<int>> GetIds(string type, string query) =>
-        (await _searchIndex.Search(_client, $"type:{type} AND ({query})", 0, 0)).Items.Map(i => i.Id).ToList();
+        (await _searchIndex.Search(_client, $"type:{type} AND ({query})", string.Empty, 0, 0)).Items.Map(i => i.Id).ToList();
 }

ErsatzTV.Application/Search/Queries/QuerySearchIndexArtistsHandler.cs

@@ -27,6 +27,7 @@ public class QuerySearchIndexArtistsHandler : IRequestHandler<QuerySearchIndexAr
         SearchResult searchResult = await _searchIndex.Search(
             _client,
             request.Query,
+            string.Empty,
             (request.PageNumber - 1) * request.PageSize,
             request.PageSize);
 

ErsatzTV.Application/Search/Queries/QuerySearchIndexEpisodesHandler.cs

@@ -58,6 +58,7 @@ public class
         SearchResult searchResult = await _searchIndex.Search(
             _client,
             request.Query,
+            string.Empty,
             (request.PageNumber - 1) * request.PageSize,
             request.PageSize);
 

ErsatzTV.Application/Search/Queries/QuerySearchIndexImagesHandler.cs

@@ -17,6 +17,7 @@ public class QuerySearchIndexImagesHandler(IClient client, ISearchIndex searchIn
         SearchResult searchResult = await searchIndex.Search(
             client,
             request.Query,
+            string.Empty,
             (request.PageNumber - 1) * request.PageSize,
             request.PageSize);
 

ErsatzTV.Application/Search/Queries/QuerySearchIndexMoviesHandler.cs

@@ -34,6 +34,7 @@ public class QuerySearchIndexMoviesHandler : IRequestHandler<QuerySearchIndexMov
         SearchResult searchResult = await _searchIndex.Search(
             _client,
             request.Query,
+            string.Empty,
             (request.PageNumber - 1) * request.PageSize,
             request.PageSize);
 

ErsatzTV.Application/Search/Queries/QuerySearchIndexMusicVideosHandler.cs

@@ -45,6 +45,7 @@ public class
         SearchResult searchResult = await _searchIndex.Search(
             _client,
             request.Query,
+            string.Empty,
             (request.PageNumber - 1) * request.PageSize,
             request.PageSize);
 

ErsatzTV.Application/Search/Queries/QuerySearchIndexOtherVideosHandler.cs

@@ -32,6 +32,7 @@ public class
         SearchResult searchResult = await _searchIndex.Search(
             _client,
             request.Query,
+            string.Empty,
             (request.PageNumber - 1) * request.PageSize,
             request.PageSize);
 

ErsatzTV.Application/Search/Queries/QuerySearchIndexSeasonsHandler.cs

@@ -35,6 +35,7 @@ public class
         SearchResult searchResult = await _searchIndex.Search(
             _client,
             request.Query,
+            string.Empty,
             (request.PageNumber - 1) * request.PageSize,
             request.PageSize);
 

ErsatzTV.Application/Search/Queries/QuerySearchIndexShowsHandler.cs

@@ -35,6 +35,7 @@ public class
         SearchResult searchResult = await _searchIndex.Search(
             _client,
             request.Query,
+            string.Empty,
             (request.PageNumber - 1) * request.PageSize,
             request.PageSize);
 

ErsatzTV.Application/Search/Queries/QuerySearchIndexSongsHandler.cs

@@ -27,6 +27,7 @@ public class QuerySearchIndexSongsHandler : IRequestHandler<QuerySearchIndexSong
         SearchResult searchResult = await _searchIndex.Search(
             _client,
             request.Query,
+            string.Empty,
             (request.PageNumber - 1) * request.PageSize,
             request.PageSize);
 

ErsatzTV.Core.Tests/Fakes/FakeMediaCollectionRepository.cs

@@ -28,7 +28,7 @@ public class FakeMediaCollectionRepository : IMediaCollectionRepository
     public Task<List<MediaItem>> GetMultiCollectionItemsByName(string name) => throw new NotSupportedException();
     public Task<List<MediaItem>> GetSmartCollectionItems(int id) => _data[id].ToList().AsTask();
     public Task<List<MediaItem>> GetSmartCollectionItemsByName(string name) => throw new NotSupportedException();
-    public Task<List<MediaItem>> GetSmartCollectionItems(string query) => throw new NotSupportedException();
+    public Task<List<MediaItem>> GetSmartCollectionItems(string query, string smartCollectionName) => throw new NotSupportedException();
     public Task<List<MediaItem>> GetShowItemsByShowGuids(List<string> guids) => throw new NotSupportedException();
     public Task<List<MediaItem>> GetPlaylistItems(int id) => throw new NotSupportedException();
     public Task<List<Movie>> GetMovie(int id) => throw new NotSupportedException();

ErsatzTV.Core/Interfaces/Repositories/IMediaCollectionRepository.cs

@@ -15,7 +15,7 @@ public interface IMediaCollectionRepository
     Task<List<MediaItem>> GetMultiCollectionItemsByName(string name);
     Task<List<MediaItem>> GetSmartCollectionItems(int id);
     Task<List<MediaItem>> GetSmartCollectionItemsByName(string name);
-    Task<List<MediaItem>> GetSmartCollectionItems(string query);
+    Task<List<MediaItem>> GetSmartCollectionItems(string query, string smartCollectionName);
     Task<List<MediaItem>> GetShowItemsByShowGuids(List<string> guids);
     Task<List<MediaItem>> GetPlaylistItems(int id);
     Task<List<Movie>> GetMovie(int id);

ErsatzTV.Core/Interfaces/Search/ISearchIndex.cs

@@ -25,6 +25,6 @@ public interface ISearchIndex : IDisposable
         List<MediaItem> items);
 
     Task<bool> RemoveItems(IEnumerable<int> ids);
-    Task<SearchResult> Search(IClient client, string query, int skip, int limit);
+    Task<SearchResult> Search(IClient client, string query, string smartCollectionName, int skip, int limit);
     void Commit();
 }

ErsatzTV.Core/Scheduling/YamlScheduling/EnumeratorCache.cs

@@ -64,7 +64,7 @@ public class EnumeratorCache(IMediaCollectionRepository mediaCollectionRepositor
         switch (content)
         {
             case YamlPlayoutContentSearchItem search:
-                items = await mediaCollectionRepository.GetSmartCollectionItems(search.Query);
+                items = await mediaCollectionRepository.GetSmartCollectionItems(search.Query, string.Empty);
                 break;
             case YamlPlayoutContentShowItem show:
                 items = await mediaCollectionRepository.GetShowItemsByShowGuids(

ErsatzTV.Core/Scheduling/YamlScheduling/YamlPlayoutMarathonHelper.cs

@@ -29,7 +29,7 @@ public class YamlPlayoutMarathonHelper(IMediaCollectionRepository mediaCollectio
         // grab items from each search
         foreach (string query in marathon.Searches)
         {
-            allMediaItems.AddRange(await mediaCollectionRepository.GetSmartCollectionItems(query));
+            allMediaItems.AddRange(await mediaCollectionRepository.GetSmartCollectionItems(query, string.Empty));
         }
 
         List<IGrouping<GroupKey, MediaItem>> groups = [];

ErsatzTV.Core/Search/ISmartCollectionCache.cs

@@ -0,0 +1,10 @@
+namespace ErsatzTV.Core.Search;
+
+public interface ISmartCollectionCache
+{
+    Task Refresh();
+
+    Task<bool> HasCycle(string name);
+
+    Task<Option<string>> GetQuery(string name);
+}

ErsatzTV.Infrastructure.Tests/Search/SearchQueryParserTests.cs

@@ -1,6 +1,8 @@
+using ErsatzTV.Core.Search;
 using ErsatzTV.Infrastructure.Search;
 using Shouldly;
 using Lucene.Net.Search;
+using NSubstitute;
 using NUnit.Framework;
 
 namespace ErsatzTV.Infrastructure.Tests.Search;
@@ -16,9 +18,10 @@ public class SearchQueryParserTests
         [TestCase("content_rating:\"TV-14\"", "content_rating:TV-14")]
         public async Task Test(string input, string expected)
         {
-            var parser = new SearchQueryParser(null);
+            ISmartCollectionCache smartCollectionCache = Substitute.For<ISmartCollectionCache>();
+            var parser = new SearchQueryParser(smartCollectionCache);
 
-            Query result = await parser.ParseQuery(input);
+            Query result = await parser.ParseQuery(input, null);
             result.ToString().ShouldBe(expected);
         }
     }

ErsatzTV.Infrastructure/Data/Repositories/MediaCollectionRepository.cs

@@ -398,7 +398,7 @@ public class MediaCollectionRepository : IMediaCollectionRepository
 
         foreach (SmartCollection collection in maybeCollection)
         {
-            return await GetSmartCollectionItems(collection.Query);
+            return await GetSmartCollectionItems(collection.Query, collection.Name);
         }
 
         return [];
@@ -415,20 +415,20 @@ public class MediaCollectionRepository : IMediaCollectionRepository
 
         foreach (SmartCollection collection in maybeCollection)
         {
-            return await GetSmartCollectionItems(collection.Query);
+            return await GetSmartCollectionItems(collection.Query, collection.Name);
         }
 
         return [];
     }
 
-    public async Task<List<MediaItem>> GetSmartCollectionItems(string query)
+    public async Task<List<MediaItem>> GetSmartCollectionItems(string query, string smartCollectionName)
     {
         await using TvContext dbContext = await _dbContextFactory.CreateDbContextAsync();
 
         var result = new List<MediaItem>();
 
         // elasticsearch doesn't like when we ask for a limit of zero, so use 10,000
-        SearchResult searchResults = await _searchIndex.Search(_client, query, 0, 10_000);
+        SearchResult searchResults = await _searchIndex.Search(_client, query, smartCollectionName, 0, 10_000);
 
         var movieIds = searchResults.Items
             .Filter(i => i.Type == LuceneSearchIndex.MovieType)

ErsatzTV.Infrastructure/Search/AdjGraph.cs

@@ -0,0 +1,51 @@
+namespace ErsatzTV.Infrastructure.Search;
+
+public class AdjGraph
+{
+    private readonly List<Edge> _edges = [];
+
+    public void Clear()
+    {
+        _edges.Clear();
+    }
+
+    public void AddEdge(string from, string to)
+    {
+        _edges.Add(new Edge(from.ToLowerInvariant(), to.ToLowerInvariant()));
+    }
+
+    public bool HasCycle(string from)
+    {
+        var visited = new System.Collections.Generic.HashSet<string>();
+        var stack = new System.Collections.Generic.HashSet<string>();
+        return HasCycleImpl(from.ToLowerInvariant(), visited, stack);
+    }
+
+    private bool HasCycleImpl(string node, ISet<string> visited, ISet<string> stack)
+    {
+        if (stack.Contains(node))
+        {
+            return true;
+        }
+
+        if (!visited.Add(node))
+        {
+            return false;
+        }
+
+        stack.Add(node);
+
+        foreach (Edge edge in _edges.Where(e => e.From == node))
+        {
+            if (HasCycleImpl(edge.To, visited, stack))
+            {
+                return true;
+            }
+        }
+
+        stack.Remove(node);
+        return false;
+    }
+
+    private record Edge(string From, string To);
+}

ErsatzTV.Infrastructure/Search/ElasticSearchIndex.cs

@@ -163,12 +163,12 @@ public class ElasticSearchIndex : ISearchIndex
         return deleteResponse.IsValidResponse;
     }
 
-    public async Task<SearchResult> Search(IClient client, string query, int skip, int limit)
+    public async Task<SearchResult> Search(IClient client, string query, string smartCollectionName, int skip, int limit)
     {
         var items = new List<MinimalElasticSearchItem>();
         var totalCount = 0;
 
-        Query parsedQuery = await _searchQueryParser.ParseQuery(query);
+        Query parsedQuery = await _searchQueryParser.ParseQuery(query, smartCollectionName);
 
         SearchResponse<MinimalElasticSearchItem> response = await _client.SearchAsync<MinimalElasticSearchItem>(
             s => s.Indices(IndexName)

ErsatzTV.Infrastructure/Search/LuceneSearchIndex.cs

@@ -200,7 +200,7 @@ public sealed class LuceneSearchIndex : ISearchIndex
         return Task.FromResult(true);
     }
 
-    public async Task<SearchResult> Search(IClient client, string query, int skip, int limit)
+    public async Task<SearchResult> Search(IClient client, string query, string smartCollectionName, int skip, int limit)
     {
         var metadata = new Dictionary<string, string>
         {
@@ -220,7 +220,7 @@ public sealed class LuceneSearchIndex : ISearchIndex
         using DirectoryReader reader = _writer.GetReader(true);
         var searcher = new IndexSearcher(reader);
         int hitsLimit = limit == 0 ? searcher.IndexReader.MaxDoc : skip + limit;
-        Query parsedQuery = await _searchQueryParser.ParseQuery(query);
+        Query parsedQuery = await _searchQueryParser.ParseQuery(query, smartCollectionName);
         // TODO: figure out if this is actually needed
         // var filter = new DuplicateFilter(TitleAndYearField);
         var sort = new Sort(new SortField(SortTitleField, SortFieldType.STRING));

ErsatzTV.Infrastructure/Search/SearchQueryParser.cs

@@ -1,18 +1,17 @@
 using System.Text.RegularExpressions;
-using ErsatzTV.Infrastructure.Data;
+using ErsatzTV.Core.Search;
 using Lucene.Net.Analysis;
 using Lucene.Net.Analysis.Core;
 using Lucene.Net.Analysis.Miscellaneous;
 using Lucene.Net.Analysis.Standard;
 using Lucene.Net.QueryParsers.Classic;
 using Lucene.Net.Search;
-using Microsoft.EntityFrameworkCore;
 using Serilog;
 using Query = Lucene.Net.Search.Query;
 
 namespace ErsatzTV.Infrastructure.Search;
 
-public partial class SearchQueryParser(IDbContextFactory<TvContext> dbContextFactory)
+public partial class SearchQueryParser(ISmartCollectionCache smartCollectionCache)
 {
     static SearchQueryParser() => BooleanQuery.MaxClauseCount = 1024 * 4;
 
@@ -47,22 +46,41 @@ public partial class SearchQueryParser(IDbContextFactory<TvContext> dbContextFac
         return new PerFieldAnalyzerWrapper(defaultAnalyzer, customAnalyzers);
     }
 
-    public async Task<Query> ParseQuery(string query)
+    public async Task<Query> ParseQuery(string query, string smartCollectionName)
     {
         string parsedQuery = query;
 
-        var replaceCount = 0;
-        while (parsedQuery.Contains("smart_collection"))
+        if (!string.IsNullOrWhiteSpace(smartCollectionName) && await smartCollectionCache.HasCycle(smartCollectionName))
         {
-            if (replaceCount > 10)
+            Log.Logger.Error("Smart collection {Name} contains a cycle; will not evaluate", smartCollectionName);
+        }
+        else
+        {
+            var replaceCount = 0;
+            while (parsedQuery.Contains("smart_collection"))
             {
-                Log.Logger.Warning("smart_collection query is nested too deep; giving up");
-                break;
+                if (replaceCount > 100)
+                {
+                    Log.Logger.Warning("smart_collection query is nested too deep; giving up");
+                    break;
+                }
+
+                ReplaceResult replaceResult = await ReplaceSmartCollections(parsedQuery);
+                if (replaceResult.Fatal)
+                {
+                    break;
+                }
+
+                if (parsedQuery == replaceResult.Query)
+                {
+                    Log.Logger.Warning("Failed to replace smart_collection in query; is the syntax correct? Quotes are required. Giving up...");
+                    break;
+                }
+
+                parsedQuery = replaceResult.Query;
+
+                replaceCount++;
             }
-
-            parsedQuery = await ReplaceSmartCollections(parsedQuery);
-
-            replaceCount++;
         }
 
         using Analyzer analyzerWrapper = AnalyzerWrapper();
@@ -81,26 +99,34 @@ public partial class SearchQueryParser(IDbContextFactory<TvContext> dbContextFac
         return result;
     }
 
-    private async Task<string> ReplaceSmartCollections(string query)
+    private async Task<ReplaceResult> ReplaceSmartCollections(string query)
     {
         try
         {
-            Regex regex = SmartCollectionRegex();
-            await using TvContext dbContext = await dbContextFactory.CreateDbContextAsync();
-            Dictionary<string, string> smartCollectionMap = await dbContext.SmartCollections
-                .ToDictionaryAsync(x => x.Name, x => x.Query, StringComparer.OrdinalIgnoreCase);
-            return regex.Replace(query, match =>
+            string result = query;
+
+            foreach (Match match in SmartCollectionRegex().Matches(query))
             {
                 string smartCollectionName = match.Groups[1].Value;
-                return smartCollectionMap.TryGetValue(smartCollectionName, out string smartCollectionQuery)
-                    ? $"({smartCollectionQuery})"
-                    : match.Value;
-            });
+                if (await smartCollectionCache.HasCycle(smartCollectionName))
+                {
+                    Log.Logger.Error("Smart collection {Name} contains a cycle; will not evaluate", smartCollectionName);
+                    return new ReplaceResult(query, true);
+                }
+
+                Option<string> maybeQuery = await smartCollectionCache.GetQuery(smartCollectionName);
+                foreach (string smartCollectionQuery in maybeQuery)
+                {
+                    result = result.Replace(match.Value, $"({smartCollectionQuery})");
+                }
+            }
+
+            return new ReplaceResult(result, false);
         }
         catch (Exception ex)
         {
-            Console.WriteLine(ex);
-            return query;
+            Log.Logger.Warning(ex, "Unexpected exception replacing smart collections in search query");
+            return new ReplaceResult(query, true);
         }
     }
 
@@ -122,5 +148,7 @@ public partial class SearchQueryParser(IDbContextFactory<TvContext> dbContextFac
     [GeneratedRegex("""
                     smart_collection:"([^"]+)"
                     """)]
-    private static partial Regex SmartCollectionRegex();
+    internal static partial Regex SmartCollectionRegex();
+
+    private record ReplaceResult(string Query, bool Fatal);
 }

ErsatzTV.Infrastructure/Search/SmartCollectionCache.cs

@@ -0,0 +1,91 @@
+using System.Text.RegularExpressions;
+using ErsatzTV.Core.Domain;
+using ErsatzTV.Core.Search;
+using ErsatzTV.Infrastructure.Data;
+using Microsoft.EntityFrameworkCore;
+
+namespace ErsatzTV.Infrastructure.Search;
+
+public sealed class SmartCollectionCache(IDbContextFactory<TvContext> dbContextFactory)
+    : ISmartCollectionCache, IDisposable
+{
+    private readonly Dictionary<string, SmartCollectionData> _data = new(StringComparer.OrdinalIgnoreCase);
+    private readonly SemaphoreSlim _semaphoreSlim = new(1, 1);
+    private readonly AdjGraph _graph = new();
+
+    public async Task Refresh()
+    {
+        await _semaphoreSlim.WaitAsync();
+
+        try
+        {
+            await using TvContext dbContext = await dbContextFactory.CreateDbContextAsync();
+            List<SmartCollection> smartCollections = await dbContext.SmartCollections
+                .AsNoTracking()
+                .ToListAsync();
+
+            _data.Clear();
+            _graph.Clear();
+
+            foreach (SmartCollection smartCollection in smartCollections)
+            {
+                var data = new SmartCollectionData(smartCollection.Query);
+                _data.Add(smartCollection.Name, data);
+
+                foreach (Match match in SearchQueryParser.SmartCollectionRegex().Matches(smartCollection.Query))
+                {
+                    string otherCollectionName = match.Groups[1].Value;
+                    _graph.AddEdge(smartCollection.Name, otherCollectionName);
+                }
+            }
+
+            foreach (SmartCollection smartCollection in smartCollections)
+            {
+                SmartCollectionData data = _data[smartCollection.Name];
+                data.HasCycle = _graph.HasCycle(smartCollection.Name);
+            }
+        }
+        finally
+        {
+            _semaphoreSlim.Release();
+        }
+    }
+
+    public async Task<bool> HasCycle(string name)
+    {
+        await _semaphoreSlim.WaitAsync();
+
+        try
+        {
+            return _data.TryGetValue(name, out SmartCollectionData data) && data.HasCycle;
+        }
+        finally
+        {
+            _semaphoreSlim.Release();
+        }
+    }
+
+    public async Task<Option<string>> GetQuery(string name)
+    {
+        await _semaphoreSlim.WaitAsync();
+
+        try
+        {
+            return _data.TryGetValue(name, out SmartCollectionData data) ? data.Query : Option<string>.None;
+        }
+        finally
+        {
+            _semaphoreSlim.Release();
+        }
+    }
+
+    public void Dispose()
+    {
+        _semaphoreSlim.Dispose();
+    }
+
+    private record SmartCollectionData(string Query)
+    {
+        public bool HasCycle { get; set; }
+    }
+}

ErsatzTV/Pages/Search.razor

@@ -830,29 +830,37 @@
     private async Task SaveAsSmartCollection(MouseEventArgs _)
     {
         var options = new DialogOptions { CloseButton = true, MaxWidth = MaxWidth.ExtraSmall };
-
-        IDialogReference dialog = await Dialog.ShowAsync<SaveAsSmartCollectionDialog>("Save As Smart Collection", options);
-        DialogResult result = await dialog.Result;
-        if (!result.Canceled && result.Data is SmartCollectionViewModel collection)
+        var parameters = new DialogParameters<SaveAsSmartCollectionDialog>
         {
-            var request = new UpdateSmartCollection(
-                collection.Id,
-                _query);
+            { x => x.Query, _query }
+        };
 
-            Either<BaseError, Unit> updateResult = await Mediator.Send(request, CancellationToken);
-            updateResult.Match(
-                Left: error =>
-                {
-                    Snackbar.Add($"Unexpected error saving smart collection: {error.Value}");
-                    Logger.LogError("Unexpected error saving smart collection: {Error}", error.Value);
-                },
-                Right: _ =>
-                {
-                    Snackbar.Add(
-                        $"Saved smart collection {collection.Name}",
-                        Severity.Success);
-                    ClearSelection();
-                });
+        IDialogReference dialog = await Dialog.ShowAsync<SaveAsSmartCollectionDialog>("Save As Smart Collection", parameters, options);
+        DialogResult result = await dialog.Result;
+        if (result is { Canceled: false, Data: Tuple<SmartCollectionViewModel, bool> collectionResult })
+        {
+            // Item2 => update is needed
+            if (collectionResult.Item2)
+            {
+                var request = new UpdateSmartCollection(
+                    collectionResult.Item1.Id,
+                    _query);
+
+                Either<BaseError, Unit> updateResult = await Mediator.Send(request, CancellationToken);
+                updateResult.Match(
+                    Left: error =>
+                    {
+                        Snackbar.Add($"Unexpected error saving smart collection: {error.Value}");
+                        Logger.LogError("Unexpected error saving smart collection: {Error}", error.Value);
+                    },
+                    Right: _ =>
+                    {
+                        Snackbar.Add(
+                            $"Saved smart collection {collectionResult.Item1.Name}",
+                            Severity.Success);
+                        ClearSelection();
+                    });
+            }
         }
     }
 

ErsatzTV/Services/RunOnce/RebuildSearchIndexService.cs

@@ -1,5 +1,6 @@
 using ErsatzTV.Application.Search;
 using ErsatzTV.Core;
+using ErsatzTV.Core.Search;
 using MediatR;
 
 namespace ErsatzTV.Services.RunOnce;
@@ -34,5 +35,8 @@ public class RebuildSearchIndexService : BackgroundService
         using IServiceScope scope = _serviceScopeFactory.CreateScope();
         IMediator mediator = scope.ServiceProvider.GetRequiredService<IMediator>();
         await mediator.Send(new RebuildSearchIndex(), stoppingToken);
+
+        ISmartCollectionCache cache = scope.ServiceProvider.GetRequiredService<ISmartCollectionCache>();
+        await cache.Refresh();
     }
 }

ErsatzTV/Shared/SaveAsSmartCollectionDialog.razor

@@ -43,6 +43,9 @@
     [CascadingParameter]
     IMudDialogInstance MudDialog { get; set; }
 
+    [Parameter]
+    public string Query { get; set; }
+
     private readonly SmartCollectionViewModel _newCollection = new(-1, "(New Collection)", string.Empty);
     private string _newCollectionName;
 
@@ -88,13 +91,13 @@
         if (_selectedCollection == _newCollection)
         {
             Either<BaseError, SmartCollectionViewModel> maybeResult =
-                await Mediator.Send(new CreateSmartCollection(string.Empty, _newCollectionName), _cts.Token);
+                await Mediator.Send(new CreateSmartCollection(Query, _newCollectionName), _cts.Token);
 
             maybeResult.Match(
                 collection =>
                 {
                     MemoryCache.Set("SaveAsSmartCollectionDialog.SelectedCollectionId", collection.Id);
-                    MudDialog.Close(DialogResult.Ok(collection));
+                    MudDialog.Close(DialogResult.Ok(new Tuple<SmartCollectionViewModel, bool>(collection, false)));
                 },
                 error =>
                 {
@@ -106,7 +109,7 @@
         else
         {
             MemoryCache.Set("SaveAsSmartCollectionDialog.SelectedCollectionId", _selectedCollection.Id);
-            MudDialog.Close(DialogResult.Ok(_selectedCollection));
+            MudDialog.Close(DialogResult.Ok(new Tuple<SmartCollectionViewModel, bool>(_selectedCollection, true)));
         }
     }
 

ErsatzTV/Startup.cs

@@ -38,6 +38,7 @@ using ErsatzTV.Core.Plex;
 using ErsatzTV.Core.Scheduling;
 using ErsatzTV.Core.Scheduling.BlockScheduling;
 using ErsatzTV.Core.Scheduling.YamlScheduling;
+using ErsatzTV.Core.Search;
 using ErsatzTV.Core.Trakt;
 using ErsatzTV.FFmpeg.Capabilities;
 using ErsatzTV.FFmpeg.Pipeline;
@@ -609,6 +610,7 @@ public class Startup
         services.AddSingleton<ITraktApiClient, TraktApiClient>();
         services.AddSingleton<IEntityLocker, EntityLocker>();
         services.AddSingleton<ISearchTargets, SearchTargets>();
+        services.AddSingleton<ISmartCollectionCache, SmartCollectionCache>();
         services.AddSingleton<SearchQueryParser>();
 
         if (SearchHelper.IsElasticSearchEnabled)