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

namespace Paca.Tests.Core;

public class MediaChecksumVerifierGateTests
{
    [Fact]
    public void Gate369_MediaChecksumVerifier_ComputesSha256StreamHash_Correctly()
    {
        // "Hello Paca Media!" in UTF-8
        var bytes = Encoding.UTF8.GetBytes("Hello Paca Media!");
        using var stream = new MemoryStream(bytes);

        var sha256 = MediaChecksumVerifier.ComputeHash(stream, ChecksumAlgorithm.Sha256);

        // Known SHA-256 for "Hello Paca Media!"
        Assert.StartsWith("f14b916b33d6270011bcd23995bf4d4a2ae0199ec", sha256.ToLowerInvariant());
    }

    [Fact]
    public void Gate370_MediaChecksumVerifier_ComputesMd5StreamHash_Correctly()
    {
        var bytes = Encoding.UTF8.GetBytes("PacaDownloadEngine");
        using var stream = new MemoryStream(bytes);

        var md5 = MediaChecksumVerifier.ComputeHash(stream, ChecksumAlgorithm.Md5);

        // Known MD5 for "PacaDownloadEngine"
        Assert.Equal("1d95ac097022b5c556252b43a2f5929a", md5.ToLowerInvariant());
    }

    [Fact]
    public void Gate371_MediaChecksumVerifier_VerifiesEtagWithQuotesAndWeakPrefix()
    {
        var computed = "93700ce818c3937ec89f2a00908eb82f";

        // Quoted ETag: "\"93700ce818c3937ec89f2a00908eb82f\""
        Assert.True(MediaChecksumVerifier.VerifyHash(computed, "\"93700ce818c3937ec89f2a00908eb82f\""));

        // Weak ETag: "W/\"93700CE818C3937EC89F2A00908EB82F\""
        Assert.True(MediaChecksumVerifier.VerifyHash(computed, "W/\"93700CE818C3937EC89F2A00908EB82F\""));
    }

    [Fact]
    public void Gate372_MediaChecksumVerifier_DetectsMismatchAndGeneratesReport()
    {
        var computed = "aaaa1111";
        var expected = "bbbb2222";

        var result = MediaChecksumVerifier.EvaluateIntegrity("file.mp4", computed, expected);

        Assert.False(result.IsIntact);
        Assert.Equal("aaaa1111", result.ComputedHash);
        Assert.Equal("bbbb2222", result.ExpectedHash);
        Assert.Contains("해시 불일치", result.StatusMessage);
    }
}