using System.Text;
using DeepDrftAPI.Controllers;
using DeepDrftContent.Constants;
using DeepDrftContent.FileDatabase.Models;
using DeepDrftContent.Processors;
using DeepDrftContent.Processors.Opus;
using DeepDrftModels.Enums;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using ContentTrackService = DeepDrftContent.TrackContentService;
using FileDb = DeepDrftContent.FileDatabase.Services.FileDatabase;

namespace DeepDrftTests;

/// <summary>
/// Delivery-layer tests for the Phase 18.3 <c>?format=</c> stream selector and the Opus seek/setup sidecar
/// endpoint on <see cref="TrackController"/>. These exercise the real <see cref="FileDb"/>, the real
/// <see cref="TrackContentService"/>, and the real <see cref="TrackFormatResolver"/> over temp-directory
/// vaults — the same integration posture as <see cref="TrackReplaceAudioTests"/>.
///
/// The SQL-only collaborators (<c>UnifiedTrackService</c>, <c>ITrackService</c>) are passed as null: the
/// actions under test (<see cref="TrackController.GetTrack"/>, <see cref="TrackController.GetOpusSeekData"/>)
/// only touch the FileDatabase + resolver path, never the SQL services, so standing up a database is not
/// required to assert the delivery contract.
///
/// The Range→206 contract is asserted at the load-bearing seam: ASP.NET performs the actual byte-slicing
/// for any <see cref="FileResult"/> whose <see cref="FileResult"/>.EnableRangeProcessing is true. The lossless
/// path proves this via the disk-stream <see cref="FileStreamResult"/>; the resolved Opus path via the
/// in-memory <see cref="FileContentResult"/> — both must report range processing enabled, the explicit fix
/// the 18.2 reviewer flagged for the byte[] path.
/// </summary>
[TestFixture]
public class TrackFormatDeliveryTests
{
    private string _testDir = string.Empty;

    [SetUp]
    public void SetUp()
    {
        _testDir = Path.Combine(Path.GetTempPath(), "TrackFormatDeliveryTests", Guid.NewGuid().ToString());
        Directory.CreateDirectory(_testDir);
    }

    [TearDown]
    public void TearDown()
    {
        try { Directory.Delete(_testDir, recursive: true); }
        catch { /* Best-effort cleanup — ignore failures */ }
    }

    // --- Format resolution at the endpoint ---

    [Test]
    public async Task GetTrack_FormatOpus_WhenOpusArtifactPresent_ServesOpusBytesAndOggContentType()
    {
        var (controller, entryKey) = await SeedAsync(withOpus: true, withSidecar: false);

        var result = await controller.GetTrack(entryKey, format: "opus");

        var file = result as FileContentResult;
        Assert.That(file, Is.Not.Null, "Opus delivery serves an in-memory byte[] (FileContentResult)");
        Assert.Multiple(() =>
        {
            Assert.That(file!.ContentType, Is.EqualTo("audio/ogg"), "Opus bytes must carry the audio/ogg content-type");
            Assert.That(file.FileContents, Is.EqualTo(OpusBytes), "The served bytes must be the Opus artifact, not the source");
            Assert.That(file.EnableRangeProcessing, Is.True, "Range processing must be enabled on the resolved Opus byte[] path");
        });
    }

    // --- The C2 fallback ---

    [Test]
    public async Task GetTrack_FormatOpus_WhenNoOpusArtifact_FallsBackToLosslessBytesAndContentType()
    {
        // No Opus artifact stored — the resolver degrades to lossless (C2): the listener still gets audio,
        // never a 404 or silence, and the content-type reports the lossless format actually served.
        var (controller, entryKey) = await SeedAsync(withOpus: false, withSidecar: false);

        var result = await controller.GetTrack(entryKey, format: "opus");

        var file = result as FileContentResult;
        Assert.That(file, Is.Not.Null, "The fallback still serves resolved bytes via the byte[] path");
        Assert.Multiple(() =>
        {
            Assert.That(file!.ContentType, Is.EqualTo("audio/wav"), "Fallback content-type must be the lossless source's MIME");
            Assert.That(file.FileContents, Is.EqualTo(_sourceWav), "Fallback must serve the lossless source bytes");
            Assert.That(file.EnableRangeProcessing, Is.True, "Range processing stays enabled on the fallback path too");
        });
    }

    [Test]
    public async Task GetTrack_NoFormatParam_ServesLosslessDiskStream_ByteIdenticalToPrePhase18()
    {
        // The no-format path must be byte-identical to today: the zero-copy disk-stream FileStreamResult,
        // NOT the resolver's in-memory byte[] path (which would force the whole source into memory).
        var (controller, entryKey) = await SeedAsync(withOpus: true, withSidecar: false);

        var result = await controller.GetTrack(entryKey, format: null);

        var file = result as FileStreamResult;
        Assert.That(file, Is.Not.Null, "Lossless delivery streams from disk (FileStreamResult), not a byte[]");
        Assert.Multiple(() =>
        {
            Assert.That(file!.ContentType, Is.EqualTo("audio/wav"));
            Assert.That(file.EnableRangeProcessing, Is.True, "Range→206 must work on the lossless disk-stream path");
        });
    }

    [Test]
    public async Task GetTrack_FormatLossless_TakesTheLosslessDiskStreamPath()
    {
        // An explicit format=lossless must behave exactly like no param — the disk-stream path, never Opus.
        var (controller, entryKey) = await SeedAsync(withOpus: true, withSidecar: false);

        var result = await controller.GetTrack(entryKey, format: "lossless");

        Assert.That(result, Is.InstanceOf<FileStreamResult>(),
            "format=lossless must take the disk-stream path even when an Opus artifact exists");
    }

    [Test]
    public async Task GetTrack_FormatOpus_WhenTrackDoesNotExist_Returns404()
    {
        var controller = BuildController(await FreshDbAsync());

        var result = await controller.GetTrack("no-such-track", format: "opus");

        Assert.That(result, Is.InstanceOf<NotFoundResult>(),
            "When even the lossless source is missing, the Opus request 404s (no audio at all)");
    }

    // --- Sidecar 200 / 404 ---

    [Test]
    public async Task GetOpusSeekData_WhenSidecarPresent_Returns200WithRawBytes()
    {
        var (controller, entryKey) = await SeedAsync(withOpus: true, withSidecar: true);

        var result = await controller.GetOpusSeekData(entryKey);

        var file = result as FileContentResult;
        Assert.That(file, Is.Not.Null, "A stored sidecar is served as raw bytes");
        Assert.Multiple(() =>
        {
            Assert.That(file!.ContentType, Is.EqualTo("application/octet-stream"));
            Assert.That(file.FileContents, Is.EqualTo(SidecarBytes), "The served bytes must be the stored sidecar blob");
        });
    }

    [Test]
    public async Task GetOpusSeekData_WhenNoSidecar_Returns404()
    {
        var (controller, entryKey) = await SeedAsync(withOpus: true, withSidecar: false);

        var result = await controller.GetOpusSeekData(entryKey);

        Assert.That(result, Is.InstanceOf<NotFoundResult>(),
            "No sidecar → 404, so the client degrades to lossless rather than treating it as an error");
    }

    // --- Fixtures + helpers ---

    private static readonly byte[] OpusBytes = Encoding.ASCII.GetBytes("OggS-fake-opus-payload-for-delivery-test");
    private static readonly byte[] SidecarBytes = Encoding.ASCII.GetBytes("setup-header+seek-index-sidecar-blob");

    private byte[] _sourceWav = [];

    private async Task<FileDb> FreshDbAsync()
    {
        var db = await FileDb.FromAsync(_testDir);
        Assert.That(db, Is.Not.Null);
        return db!;
    }

    // Seeds a track's lossless source in the tracks vault and, optionally, its Opus artifact and sidecar in
    // the track-opus vault, then returns a controller wired over those real vaults plus the entry key.
    private async Task<(TrackController Controller, string EntryKey)> SeedAsync(bool withOpus, bool withSidecar)
    {
        var db = await FreshDbAsync();
        var content = new ContentTrackService(db, new AudioProcessorRouter(
            new AudioProcessor(), new Mp3AudioProcessor(), new FlacAudioProcessor()));

        var wavPath = Path.Combine(_testDir, Guid.NewGuid().ToString("N") + ".wav");
        _sourceWav = BuildMinimalPcmWav(2.0);
        await File.WriteAllBytesAsync(wavPath, _sourceWav);

        var seeded = await content.AddTrackAsync(wavPath, "Track", "Artist");
        Assert.That(seeded, Is.Not.Null);
        var entryKey = seeded!.EntryKey;

        // GetAudioBinaryAsync re-reads what AddTrackAsync stored, so the bytes we assert the fallback against
        // are the exact stored source bytes (the processor may normalize the input WAV before storing).
        var storedSource = await content.GetAudioBinaryAsync(entryKey);
        Assert.That(storedSource, Is.Not.Null);
        _sourceWav = storedSource!.Buffer;

        await db.CreateVaultAsync(VaultConstants.TrackOpus, MediaVaultType.Audio);

        if (withOpus)
        {
            var opus = new AudioBinary(new AudioBinaryParams(OpusBytes, OpusBytes.Length, ".opus", 2.0, 320));
            Assert.That(
                await db.RegisterResourceAsync(VaultConstants.TrackOpus, OpusTranscodeService.OpusAudioKey(entryKey), opus),
                Is.True);
        }

        if (withSidecar)
        {
            var sidecar = new MediaBinary(new MediaBinaryParams(SidecarBytes, SidecarBytes.Length, ".opusidx"));
            Assert.That(
                await db.RegisterResourceAsync(VaultConstants.TrackOpus, OpusTranscodeService.OpusSidecarKey(entryKey), sidecar),
                Is.True);
        }

        return (BuildController(db, content), entryKey);
    }

    private static TrackController BuildController(FileDb db, ContentTrackService? content = null)
    {
        content ??= new ContentTrackService(db, new AudioProcessorRouter(
            new AudioProcessor(), new Mp3AudioProcessor(), new FlacAudioProcessor()));

        var waveforms = new WaveformProfileService(
            db, new AudioProcessor(), new RmsLoudnessAlgorithm(),
            Options.Create(new WaveformProfileOptions()), NullLogger<WaveformProfileService>.Instance);

        var resolver = new TrackFormatResolver(db, content, NullLogger<TrackFormatResolver>.Instance);

        // SQL-only collaborators are null: the delivery actions under test never touch them.
        var controller = new TrackController(
            content,
            db,
            unifiedService: null!,
            sqlTrackService: null!,
            waveforms,
            resolver,
            stagingDirectory: null!,
            NullLogger<TrackController>.Instance)
        {
            ControllerContext = new ControllerContext { HttpContext = new DefaultHttpContext() }
        };

        return controller;
    }

    // Standard-PCM mono 16-bit 44.1 kHz WAV, full-scale square wave. Same layout as the other suites.
    private static byte[] BuildMinimalPcmWav(double durationSeconds)
    {
        const int sampleRate = 44100;
        const ushort channels = 1;
        const ushort bitsPerSample = 16;
        const ushort blockAlign = channels * (bitsPerSample / 8);
        const uint byteRate = sampleRate * blockAlign;

        var frames = (int)(sampleRate * durationSeconds);
        var data = new byte[frames * blockAlign];
        for (var i = 0; i < frames; i++)
        {
            var sample = (i % 2 == 0) ? short.MaxValue : short.MinValue;
            data[i * 2] = (byte)(sample & 0xFF);
            data[i * 2 + 1] = (byte)((sample >> 8) & 0xFF);
        }

        using var ms = new MemoryStream();
        using var w = new BinaryWriter(ms, Encoding.ASCII, leaveOpen: true);

        w.Write(Encoding.ASCII.GetBytes("RIFF"));
        w.Write((uint)(36 + data.Length));
        w.Write(Encoding.ASCII.GetBytes("WAVE"));

        w.Write(Encoding.ASCII.GetBytes("fmt "));
        w.Write(16u);
        w.Write((ushort)1); // PCM
        w.Write(channels);
        w.Write((uint)sampleRate);
        w.Write(byteRate);
        w.Write(blockAlign);
        w.Write(bitsPerSample);

        w.Write(Encoding.ASCII.GetBytes("data"));
        w.Write((uint)data.Length);
        w.Write(data);

        w.Flush();
        return ms.ToArray();
    }
}