using AvParser.Core.Collecting;
using AvParser.Infrastructure.Storage;
using AvParser.UI.Media;
using Microsoft.Extensions.Logging.Abstractions;

namespace AvParser.UI.Tests;

/// <summary>
/// The cache's refusals.
/// </summary>
/// <remarks>
/// Only the paths that answer before touching a decoder are covered here: decoding needs an
/// Avalonia rendering platform, which this project deliberately does not start. The decode itself
/// is one framework call; what is worth pinning is that the cache never reaches it for content it
/// cannot handle, because doing so would mean an exception per tile.
/// </remarks>
public sealed class ThumbnailCacheTests : IDisposable
{
    private readonly string _root = Path.Combine(Path.GetTempPath(), "AvParserTests", Guid.NewGuid().ToString("N"));
    private readonly ThumbnailCache _cache;

    public ThumbnailCacheTests()
    {
        var paths = new AppPaths(_root);
        paths.EnsureCreated();

        _cache = new ThumbnailCache(paths, NullLogger<ThumbnailCache>.Instance);
    }

    public void Dispose()
    {
        _cache.Dispose();

        if (Directory.Exists(_root))
        {
            Directory.Delete(_root, recursive: true);
        }
    }

    [Theory]
    [InlineData(MediaKind.Mp4)]
    [InlineData(MediaKind.WebM)]
    public async Task A_video_is_refused_without_looking_at_the_disk(MediaKind kind)
    {
        var result = await _cache.GetAsync(
            new string('a', 64),
            ".mp4",
            kind,
            220,
            TestContext.Current.CancellationToken
        );

        result.ShouldBeNull();
    }

    [Fact]
    public async Task A_missing_blob_is_a_blank_tile_rather_than_a_throw()
    {
        var result = await _cache.GetAsync(
            new string('b', 64),
            ".png",
            MediaKind.Png,
            220,
            TestContext.Current.CancellationToken
        );

        result.ShouldBeNull();
    }

    [Fact]
    public void Clearing_an_empty_cache_is_harmless() => _cache.Clear();

    [Fact]
    public void The_capacity_leaves_room_for_more_than_one_screenful()
    {
        // The cache disposes what it evicts, so a capacity near the page size would dispose
        // bitmaps that are still on screen.
        ThumbnailCache.Capacity.ShouldBeGreaterThan(120 * 2);
    }
}