using System;
using System.IO;
using Paca.Mobile.Core;
using Xunit;

namespace Paca.Tests.Core;

public class MediaIntegrityVerifierGateTests
{
    [Fact]
    public void Gate273_MediaIntegrityVerifier_IdentifiesValidMp4()
    {
        // MP4 signature: 00 00 00 18 66 74 79 70 (ftyp) 69 73 6F 6D (isom)
        var mp4Bytes = new byte[] {
            0x00, 0x00, 0x00, 0x18, 0x66, 0x74, 0x79, 0x70,
            0x69, 0x73, 0x6F, 0x6D, 0x00, 0x00, 0x02, 0x00,
            0x69, 0x73, 0x6F, 0x6D, 0x69, 0x73, 0x6F, 0x32,
            0x00, 0x00, 0x00, 0x08, 0x6D, 0x6F, 0x6F, 0x76 // moov
        };

        var result = MediaIntegrityVerifier.Verify(mp4Bytes);

        Assert.Equal(MediaIntegrityStatus.Healthy, result.Status);
        Assert.Equal("mp4", result.DetectedFormat);
    }

    [Fact]
    public void Gate274_MediaIntegrityVerifier_IdentifiesValidWebmAndMp3()
    {
        // EBML (WebM/MKV): 1A 45 DF A3
        var webmBytes = new byte[] { 0x1A, 0x45, 0xDF, 0xA3, 0x9F, 0x42, 0x86, 0x81 };
        var webmResult = MediaIntegrityVerifier.Verify(webmBytes);
        Assert.Equal(MediaIntegrityStatus.Healthy, webmResult.Status);
        Assert.Equal("webm", webmResult.DetectedFormat);

        // MP3 ID3: 49 44 33 (ID3)
        var mp3Bytes = new byte[] { 0x49, 0x44, 0x33, 0x03, 0x00, 0x00, 0x00, 0x00 };
        var mp3Result = MediaIntegrityVerifier.Verify(mp3Bytes);
        Assert.Equal(MediaIntegrityStatus.Healthy, mp3Result.Status);
        Assert.Equal("mp3", mp3Result.DetectedFormat);
    }

    [Fact]
    public void Gate275_MediaIntegrityVerifier_DetectsZeroByteAndTruncatedFiles()
    {
        var zeroResult = MediaIntegrityVerifier.Verify(Array.Empty<byte>());
        Assert.Equal(MediaIntegrityStatus.FatalCorruption, zeroResult.Status);
        Assert.Equal(CorruptionReason.ZeroByteFile, zeroResult.Reason);

        var truncated = new byte[] { 0x00, 0x00, 0x00 };
        var truncResult = MediaIntegrityVerifier.Verify(truncated);
        Assert.Equal(MediaIntegrityStatus.FatalCorruption, truncResult.Status);
        Assert.Equal(CorruptionReason.TruncatedHeader, truncResult.Reason);
    }

    [Fact]
    public void Gate276_MediaIntegrityVerifier_SuggestsRemuxRecovery_ForMissingMoovAtom()
    {
        // MP4 with ftyp and mdat but no moov atom (interrupted recording/mux)
        var brokenMp4 = new byte[] {
            0x00, 0x00, 0x00, 0x18, 0x66, 0x74, 0x79, 0x70,
            0x69, 0x73, 0x6F, 0x6D, 0x00, 0x00, 0x02, 0x00,
            0x00, 0x00, 0x00, 0x08, 0x6D, 0x64, 0x61, 0x74 // mdat (no moov)
        };

        var result = MediaIntegrityVerifier.Verify(brokenMp4);
        Assert.Equal(MediaIntegrityStatus.RecoverableByRemux, result.Status);
        Assert.Equal(CorruptionReason.MissingMoovAtom, result.Reason);
    }
}