using Explorer.Application;
using Explorer.Domain;
using Explorer.Domain.Abstractions;
using Explorer.Storage.Sqlite;
using Microsoft.Extensions.Logging.Abstractions;

namespace Explorer.Application.Tests;

public class EntryClassificationServiceTests
{
    [Fact]
    public async Task Archive_children_override_zip_as_photos()
    {
        await using var store = await OpenStore();
        var source = await AddSource(store, @"C:\media");
        var zip = await Upsert(store, new IndexEntry
        {
            SourceId = source.Id,
            Name = "photos.zip",
            NameNorm = "photos.zip",
            Extension = "zip",
            PathRel = "photos.zip",
            LastSeenUtc = DateTimeOffset.UtcNow
        });
        await Upsert(store, Child(source.Id, zip.Id, "a.jpg", "jpg"));
        await Upsert(store, Child(source.Id, zip.Id, "b.jpg", "jpg"));
        await Upsert(store, Child(source.Id, zip.Id, "c.jpg", "jpg"));

        var service = Create(store, new MemoryEnumerator());
        service.Resume();
        Assert.True(await service.ProcessPendingAsync());
        var loaded = await store.Entries.GetAsync(zip.Id);
        Assert.Equal(FileCategory.Photos, loaded!.Category);
        Assert.Equal(CategorySources.ArchiveContents, loaded.CategorySource);
        Assert.False(await service.ProcessPendingAsync());
    }

    [Fact]
    public async Task Signature_classifies_jpeg_without_extension()
    {
        var root = Path.Combine(Path.GetTempPath(), "ew-classify", Guid.NewGuid().ToString("N"));
        Directory.CreateDirectory(root);
        var file = Path.Combine(root, "pic.bin");
        File.WriteAllBytes(file, [0xFF, 0xD8, 0xFF, 0xE0, 0x00, 0x10, 0x4A, 0x46, 0x49, 0x46, 0x00, 0x01]);
        await using var store = await OpenStore();
        var source = await AddSource(store, root);
        var entry = await Upsert(store, new IndexEntry
        {
            SourceId = source.Id,
            Name = "pic.bin",
            NameNorm = "pic.bin",
            Extension = "bin",
            PathRel = "pic.bin",
            LastSeenUtc = DateTimeOffset.UtcNow
        });
        Assert.Equal(FileCategory.Unknown, entry.Category);

        var enumerator = new MemoryEnumerator();
        enumerator.Add(new FileSystemItem { FullPath = file, Name = "pic.bin" });
        var service = Create(store, enumerator);
        service.Resume();
        Assert.True(await service.ProcessPendingAsync());
        var loaded = await store.Entries.GetAsync(entry.Id);
        Assert.Equal(FileCategory.Photos, loaded!.Category);
        Assert.Equal(CategorySources.Mime, loaded.CategorySource);
    }

    [Fact]
    public async Task Pause_skips_work()
    {
        await using var store = await OpenStore();
        var source = await AddSource(store, @"C:\media");
        var zip = await Upsert(store, new IndexEntry
        {
            SourceId = source.Id,
            Name = "photos.zip",
            NameNorm = "photos.zip",
            Extension = "zip",
            PathRel = "photos.zip",
            LastSeenUtc = DateTimeOffset.UtcNow
        });
        await Upsert(store, Child(source.Id, zip.Id, "a.jpg", "jpg"));
        var service = Create(store, new MemoryEnumerator());
        Assert.True(service.IsPaused);
        Assert.False(await service.ProcessPendingAsync());
        var loaded = await store.Entries.GetAsync(zip.Id);
        Assert.Equal(FileCategory.Archive, loaded!.Category);
    }

    private static EntryClassificationService Create(IIndexStore store, IFileSystemEnumerator enumerator)
        => new(
            store,
            enumerator,
            new NeverHydrate(),
            NullLogger<EntryClassificationService>.Instance);

    private static async Task<SqliteIndexStore> OpenStore()
    {
        var db = Path.Combine(Path.GetTempPath(), "ew-classify", Guid.NewGuid().ToString("N"), "index.db");
        var store = new SqliteIndexStore(db, NullLogger<SqliteIndexStore>.Instance);
        await store.OpenAsync();
        return store;
    }

    private static async Task<Source> AddSource(IIndexStore store, string root)
    {
        var source = new Source
        {
            StableKey = Guid.NewGuid().ToString("N"),
            Kind = SourceKind.NtfsLocal,
            DisplayName = "Test",
            LastRootPath = root,
            Status = SourceStatus.Online
        };
        source.Id = await store.Sources.UpsertAsync(source);
        return source;
    }

    private static async Task<IndexEntry> Upsert(IIndexStore store, IndexEntry entry)
    {
        entry.Id = await store.Entries.UpsertAsync(entry);
        return (await store.Entries.GetAsync(entry.Id))!;
    }

    private static IndexEntry Child(long sourceId, long parentId, string name, string ext)
        => new()
        {
            SourceId = sourceId,
            ParentId = parentId,
            Name = name,
            NameNorm = name,
            Extension = ext,
            PathRel = name,
            LastSeenUtc = DateTimeOffset.UtcNow
        };

    private sealed class NeverHydrate : IHydrationGuard
    {
        public bool WouldHydrateOnRead(FileSystemItem item) => false;
        public bool WouldHydrateOnRead(int attributes, CloudAvailability? availability) => false;
        public Task<bool> WouldHydrateOnReadAsync(string path, CancellationToken cancellationToken = default)
            => Task.FromResult(false);
    }

    private sealed class MemoryEnumerator : IFileSystemEnumerator
    {
        private readonly Dictionary<string, FileSystemItem> _items = new(StringComparer.OrdinalIgnoreCase);

        public void Add(FileSystemItem item) => _items[item.FullPath] = item;

        public IEnumerable<FileSystemItem> EnumerateChildren(string directoryPath) => [];
        public FileSystemItem? GetItem(string path)
            => _items.TryGetValue(path, out var item) ? item : null;
        public IReadOnlyList<FileSystemItem> EnumerateChildrenSafe(string directoryPath, out string? error)
        {
            error = null;
            return [];
        }
    }
}