using VideoDownloader.Core.Platform;
using VideoDownloader.Server;
using VideoDownloader.Tests.Platform;

namespace VideoDownloader.Tests.Server;

/// <summary>M2 라이브러리 썸네일/해상도 — ffmpeg 서브프로세스를 Fake 러너로 검증(사이드카 캐시).</summary>
public class ThumbnailerTests
{
    private string _dir = "";

    private string NewMedia()
    {
        _dir = Path.Combine(Path.GetTempPath(), $"vd_thumb_{Guid.NewGuid():N}");
        Directory.CreateDirectory(_dir);
        var p = Path.Combine(_dir, "clip.mp4");
        File.WriteAllBytes(p, new byte[100]);
        return p;
    }

    private static Task<ProcessResult> FakeFfmpegCreatesJpg(ProcessSpec spec, Action<string, string>? _, CancellationToken __)
    {
        // 출력 경로(마지막 인자)에 가짜 JPEG 생성
        var outPath = spec.Args[^1];
        File.WriteAllBytes(outPath, new byte[] { 0xFF, 0xD8, 0xFF, 0xE0 }); // JPEG SOI/APP0
        return Task.FromResult(new ProcessResult(0, "", ""));
    }

    private static Task<ProcessResult> FakeFfmpegReportsResolution(ProcessSpec spec, Action<string, string>? onLine, CancellationToken _)
    {
        var line = "    Stream #0:0[0x1](und): Video: h264 (High), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 5000 kb/s";
        onLine?.Invoke("err", line);
        return Task.FromResult(new ProcessResult(0, "", line));
    }

    [Fact]
    public async Task 썸네일_생성후_사이드카_캐시로_재실행_없음()
    {
        var media = NewMedia();
        var runner = new FakeProcessRunner { Behavior = FakeFfmpegCreatesJpg };
        var t = new Thumbnailer(runner);

        var bytes1 = await t.GetThumbnailAsync("ffmpeg", media);
        Assert.NotNull(bytes1);
        Assert.True(bytes1!.Length == 4);

        runner.Behavior = (_, _, _) => throw new Xunit.Sdk.XunitException("캐시 히트 시 ffmpeg 재실행 없음");
        var bytes2 = await t.GetThumbnailAsync("ffmpeg", media); // 캐시
        Assert.Equal(bytes1, bytes2);
        Directory.Delete(_dir, true);
    }

    [Fact]
    public async Task ffmpeg_실패_시_null()
    {
        var media = NewMedia();
        var runner = new FakeProcessRunner { Behavior = (_, _, _) => Task.FromResult(new ProcessResult(1, "", "boom")) };
        Assert.Null(await new Thumbnailer(runner).GetThumbnailAsync("ffmpeg", media));
        Directory.Delete(_dir, true);
    }

    [Fact]
    public async Task 해상도_추출후_사이드카_캐시()
    {
        var media = NewMedia();
        var runner = new FakeProcessRunner { Behavior = FakeFfmpegReportsResolution };
        var t = new Thumbnailer(runner);

        Assert.Equal("1920x1080", await t.GetResolutionAsync("ffmpeg", media));

        runner.Behavior = (_, _, _) => throw new Xunit.Sdk.XunitException("캐시 히트 시 재실행 없음");
        Assert.Equal("1920x1080", await t.GetResolutionAsync("ffmpeg", media));
        Directory.Delete(_dir, true);
    }

    [Fact]
    public async Task 해상기_추출_불가_시_null()
    {
        var media = NewMedia();
        var runner = new FakeProcessRunner { Behavior = (_, _, _) => Task.FromResult(new ProcessResult(0, "", "no streams")) };
        Assert.Null(await new Thumbnailer(runner).GetResolutionAsync("ffmpeg", media));
        Directory.Delete(_dir, true);
    }
}