using StellaOps.Cryptography;

using StellaOps.TestKit;
namespace StellaOps.Audit.ReplayToken.Tests;

public sealed class ReplayTokenGeneratorTests
{
    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public void Generate_SameInputs_ReturnsSameValue()
    {
        var cryptoHash = DefaultCryptoHash.CreateForTests();
        var fixedNow = new DateTimeOffset(2025, 1, 1, 0, 0, 0, TimeSpan.Zero);
        var timeProvider = new FixedTimeProvider(fixedNow);

        var generator = new Sha256ReplayTokenGenerator(cryptoHash, timeProvider);

        var request = new ReplayTokenRequest
        {
            FeedManifests = new[] { "sha256:bbb", "sha256:aaa" },
            RulesVersion = "rules-v1",
            RulesHash = "sha256:rules",
            LatticePolicyVersion = "lattice-v1",
            LatticePolicyHash = "sha256:lattice",
            InputHashes = new[] { "sha256:input2", "sha256:input1" },
            ScoringConfigVersion = "score-v1",
            EvidenceHashes = new[] { "sha256:e2", "sha256:e1" },
            AdditionalContext = new Dictionary<string, string>
            {
                ["b"] = "2",
                ["a"] = "1"
            }
        };

        var token1 = generator.Generate(request);
        var token2 = generator.Generate(request);

        Assert.Equal(token1.Value, token2.Value);
        Assert.Equal(token1.Canonical, token2.Canonical);
    }

    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public void Generate_IgnoresArrayOrdering()
    {
        var cryptoHash = DefaultCryptoHash.CreateForTests();
        var timeProvider = new FixedTimeProvider(new DateTimeOffset(2025, 1, 1, 0, 0, 0, TimeSpan.Zero));

        var generator = new Sha256ReplayTokenGenerator(cryptoHash, timeProvider);

        var requestA = new ReplayTokenRequest
        {
            FeedManifests = new[] { "sha256:aaa", "sha256:bbb" },
            InputHashes = new[] { "sha256:input1", "sha256:input2" }
        };

        var requestB = new ReplayTokenRequest
        {
            FeedManifests = new[] { "sha256:bbb", "sha256:aaa" },
            InputHashes = new[] { "sha256:input2", "sha256:input1" }
        };

        var tokenA = generator.Generate(requestA);
        var tokenB = generator.Generate(requestB);

        Assert.Equal(tokenA.Value, tokenB.Value);
    }

    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public void Verify_MatchingInputs_ReturnsTrue()
    {
        var cryptoHash = DefaultCryptoHash.CreateForTests();
        var timeProvider = new FixedTimeProvider(new DateTimeOffset(2025, 1, 1, 0, 0, 0, TimeSpan.Zero));

        var generator = new Sha256ReplayTokenGenerator(cryptoHash, timeProvider);
        var request = new ReplayTokenRequest { InputHashes = new[] { "sha256:input" } };

        var token = generator.Generate(request);
        Assert.True(generator.Verify(token, request));
    }

    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public void Verify_DifferentInputs_ReturnsFalse()
    {
        var cryptoHash = DefaultCryptoHash.CreateForTests();
        var timeProvider = new FixedTimeProvider(new DateTimeOffset(2025, 1, 1, 0, 0, 0, TimeSpan.Zero));

        var generator = new Sha256ReplayTokenGenerator(cryptoHash, timeProvider);
        var request = new ReplayTokenRequest { InputHashes = new[] { "sha256:input" } };
        var different = new ReplayTokenRequest { InputHashes = new[] { "sha256:other" } };

        var token = generator.Generate(request);
        Assert.False(generator.Verify(token, different));
    }

    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public void Generate_IgnoresAdditionalContextOrdering()
    {
        var cryptoHash = DefaultCryptoHash.CreateForTests();
        var timeProvider = new FixedTimeProvider(new DateTimeOffset(2025, 1, 1, 0, 0, 0, TimeSpan.Zero));

        var generator = new Sha256ReplayTokenGenerator(cryptoHash, timeProvider);

        var requestA = new ReplayTokenRequest
        {
            InputHashes = new[] { "sha256:input" },
            AdditionalContext = new Dictionary<string, string>
            {
                ["a"] = "1",
                ["b"] = "2"
            }
        };

        var requestB = new ReplayTokenRequest
        {
            InputHashes = new[] { "sha256:input" },
            AdditionalContext = new Dictionary<string, string>
            {
                ["b"] = "2",
                ["a"] = "1"
            }
        };

        var tokenA = generator.Generate(requestA);
        var tokenB = generator.Generate(requestB);

        Assert.Equal(tokenA.Value, tokenB.Value);
    }

    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public void Generate_DuplicateAdditionalContextKeys_Throws()
    {
        var cryptoHash = DefaultCryptoHash.CreateForTests();
        var timeProvider = new FixedTimeProvider(new DateTimeOffset(2025, 1, 1, 0, 0, 0, TimeSpan.Zero));

        var generator = new Sha256ReplayTokenGenerator(cryptoHash, timeProvider);

        var request = new ReplayTokenRequest
        {
            InputHashes = new[] { "sha256:input" },
            AdditionalContext = new Dictionary<string, string>
            {
                ["key"] = "1",
                [" key "] = "2"
            }
        };

        Assert.Throws<ArgumentException>(() => generator.Generate(request));
    }

    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public void GenerateWithExpiration_UsesDistinctCanonicalVersion()
    {
        var cryptoHash = DefaultCryptoHash.CreateForTests();
        var timeProvider = new FixedTimeProvider(new DateTimeOffset(2025, 1, 1, 0, 0, 0, TimeSpan.Zero));

        var generator = new Sha256ReplayTokenGenerator(cryptoHash, timeProvider);
        var request = new ReplayTokenRequest { InputHashes = new[] { "sha256:input" } };

        var v1Token = generator.Generate(request);
        var v2Token = generator.GenerateWithExpiration(request, TimeSpan.FromMinutes(5));

        Assert.NotEqual(v1Token.Value, v2Token.Value);
    }

    [Trait("Category", TestCategories.Unit)]
        [Theory]
    [InlineData(0)]
    [InlineData(-1)]
    public void GenerateWithExpiration_NonPositiveExpiration_Throws(int seconds)
    {
        var cryptoHash = DefaultCryptoHash.CreateForTests();
        var timeProvider = new FixedTimeProvider(new DateTimeOffset(2025, 1, 1, 0, 0, 0, TimeSpan.Zero));

        var generator = new Sha256ReplayTokenGenerator(cryptoHash, timeProvider);
        var request = new ReplayTokenRequest { InputHashes = new[] { "sha256:input" } };

        var expiration = TimeSpan.FromSeconds(seconds);

        Assert.Throws<ArgumentOutOfRangeException>(() => generator.GenerateWithExpiration(request, expiration));
    }

    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public void ReplayToken_Parse_RoundTripsCanonical()
    {
        var token = new ReplayToken("0123456789abcdef", DateTimeOffset.UnixEpoch);
        var parsed = ReplayToken.Parse(token.Canonical);

        Assert.Equal(token.Value, parsed.Value);
        Assert.Equal(token.Algorithm, parsed.Algorithm);
        Assert.Equal(token.Version, parsed.Version);
    }

    [Trait("Category", TestCategories.Unit)]
        [Theory]
    [InlineData("")]
    [InlineData("replay")]
    [InlineData("replay:v1.0:SHA-256")]
    [InlineData("other:v1.0:SHA-256:abc")]
    public void ReplayToken_Parse_Invalid_Throws(string canonical)
    {
        Assert.ThrowsAny<Exception>(() => ReplayToken.Parse(canonical));
    }

    private sealed class FixedTimeProvider(DateTimeOffset now) : TimeProvider
    {
        public override DateTimeOffset GetUtcNow() => now;
    }
}