// -----------------------------------------------------------------------------
// SignatureRequiredGateTests.cs
// Sprint: SPRINT_20260112_017_POLICY_signature_required_gate
// Tasks: SIG-GATE-009
// Description: Unit tests for signature required gate.
// -----------------------------------------------------------------------------

using System.Collections.Immutable;
using StellaOps.Policy.Confidence.Models;
using StellaOps.Policy.Gates;
using StellaOps.Policy.TrustLattice;
using Xunit;

namespace StellaOps.Policy.Tests.Gates;

[Trait("Category", "Unit")]
public sealed class SignatureRequiredGateTests
{
    private static MergeResult CreateMergeResult() => new()
    {
        Status = VexStatus.Affected,
        Confidence = 0.8,
        HasConflicts = false,
        AllClaims = ImmutableArray<ScoredClaim>.Empty,
        WinningClaim = new ScoredClaim
        {
            SourceId = "test",
            Status = VexStatus.Affected,
            OriginalScore = 0.8,
            AdjustedScore = 0.8,
            ScopeSpecificity = 1,
            Accepted = true,
            Reason = "test"
        },
        Conflicts = ImmutableArray<ConflictRecord>.Empty
    };

    private static PolicyGateContext CreateContext(string environment = "production") => new()
    {
        Environment = environment
    };

    [Fact]
    public async Task EvaluateAsync_Disabled_ReturnsPass()
    {
        var options = new SignatureRequiredGateOptions { Enabled = false };
        var gate = new SignatureRequiredGate(options);
        var result = await gate.EvaluateAsync(CreateMergeResult(), CreateContext());

        Assert.True(result.Passed);
        Assert.Equal("disabled", result.Reason);
    }

    [Fact]
    public async Task EvaluateAsync_MissingSignature_ReturnsFail()
    {
        var options = new SignatureRequiredGateOptions();
        var signatures = new List<SignatureInfo>(); // No signatures
        var gate = new SignatureRequiredGate(options, _ => signatures);
        var result = await gate.EvaluateAsync(CreateMergeResult(), CreateContext());

        Assert.False(result.Passed);
        Assert.Equal("signature_validation_failed", result.Reason);
    }

    [Fact]
    public async Task EvaluateAsync_AllValidSignatures_ReturnsPass()
    {
        var options = new SignatureRequiredGateOptions();
        var signatures = new List<SignatureInfo>
        {
            new() { EvidenceType = "sbom", HasSignature = true, SignatureValid = true },
            new() { EvidenceType = "vex", HasSignature = true, SignatureValid = true },
            new() { EvidenceType = "attestation", HasSignature = true, SignatureValid = true }
        };
        var gate = new SignatureRequiredGate(options, _ => signatures);
        var result = await gate.EvaluateAsync(CreateMergeResult(), CreateContext());

        Assert.True(result.Passed);
        Assert.Equal("signatures_verified", result.Reason);
    }

    [Fact]
    public async Task EvaluateAsync_InvalidSignature_ReturnsFail()
    {
        var options = new SignatureRequiredGateOptions();
        var signatures = new List<SignatureInfo>
        {
            new() { EvidenceType = "sbom", HasSignature = true, SignatureValid = false, VerificationErrors = new[] { "Invalid hash" } },
            new() { EvidenceType = "vex", HasSignature = true, SignatureValid = true },
            new() { EvidenceType = "attestation", HasSignature = true, SignatureValid = true }
        };
        var gate = new SignatureRequiredGate(options, _ => signatures);
        var result = await gate.EvaluateAsync(CreateMergeResult(), CreateContext());

        Assert.False(result.Passed);
        Assert.Contains("failures", result.Details.Keys);
    }

    [Fact]
    public async Task EvaluateAsync_NotRequiredType_PassesWithoutSignature()
    {
        var options = new SignatureRequiredGateOptions
        {
            EvidenceTypes = new Dictionary<string, EvidenceSignatureConfig>(StringComparer.OrdinalIgnoreCase)
            {
                ["sbom"] = new EvidenceSignatureConfig { Required = false },
                ["vex"] = new EvidenceSignatureConfig { Required = true },
                ["attestation"] = new EvidenceSignatureConfig { Required = true }
            }
        };
        var signatures = new List<SignatureInfo>
        {
            // No SBOM signature - but it's not required
            new() { EvidenceType = "vex", HasSignature = true, SignatureValid = true },
            new() { EvidenceType = "attestation", HasSignature = true, SignatureValid = true }
        };
        var gate = new SignatureRequiredGate(options, _ => signatures);
        var result = await gate.EvaluateAsync(CreateMergeResult(), CreateContext());

        Assert.True(result.Passed);
    }

    [Theory]
    [InlineData("build@company.com", new[] { "build@company.com" }, true)]
    [InlineData("release@company.com", new[] { "*@company.com" }, true)]
    [InlineData("external@other.com", new[] { "*@company.com" }, false)]
    [InlineData("build@company.com", new[] { "other@company.com" }, false)]
    public async Task EvaluateAsync_IssuerValidation_EnforcesConstraints(
        string signerIdentity,
        string[] trustedIssuers,
        bool expectedPass)
    {
        var options = new SignatureRequiredGateOptions
        {
            EvidenceTypes = new Dictionary<string, EvidenceSignatureConfig>(StringComparer.OrdinalIgnoreCase)
            {
                ["sbom"] = new EvidenceSignatureConfig
                {
                    Required = true,
                    TrustedIssuers = new HashSet<string>(trustedIssuers, StringComparer.OrdinalIgnoreCase)
                },
                ["vex"] = new EvidenceSignatureConfig { Required = false },
                ["attestation"] = new EvidenceSignatureConfig { Required = false }
            }
        };
        var signatures = new List<SignatureInfo>
        {
            new()
            {
                EvidenceType = "sbom",
                HasSignature = true,
                SignatureValid = true,
                SignerIdentity = signerIdentity
            }
        };
        var gate = new SignatureRequiredGate(options, _ => signatures);
        var result = await gate.EvaluateAsync(CreateMergeResult(), CreateContext());

        Assert.Equal(expectedPass, result.Passed);
    }

    [Theory]
    [InlineData("ES256", true)]
    [InlineData("RS256", true)]
    [InlineData("EdDSA", true)]
    [InlineData("UNKNOWN", false)]
    public async Task EvaluateAsync_AlgorithmValidation_EnforcesAccepted(string algorithm, bool expectedPass)
    {
        var options = new SignatureRequiredGateOptions
        {
            EvidenceTypes = new Dictionary<string, EvidenceSignatureConfig>(StringComparer.OrdinalIgnoreCase)
            {
                ["sbom"] = new EvidenceSignatureConfig { Required = true },
                ["vex"] = new EvidenceSignatureConfig { Required = false },
                ["attestation"] = new EvidenceSignatureConfig { Required = false }
            }
        };
        var signatures = new List<SignatureInfo>
        {
            new()
            {
                EvidenceType = "sbom",
                HasSignature = true,
                SignatureValid = true,
                Algorithm = algorithm
            }
        };
        var gate = new SignatureRequiredGate(options, _ => signatures);
        var result = await gate.EvaluateAsync(CreateMergeResult(), CreateContext());

        Assert.Equal(expectedPass, result.Passed);
    }

    [Fact]
    public async Task EvaluateAsync_KeyIdValidation_EnforcesConstraints()
    {
        var options = new SignatureRequiredGateOptions
        {
            EvidenceTypes = new Dictionary<string, EvidenceSignatureConfig>(StringComparer.OrdinalIgnoreCase)
            {
                ["sbom"] = new EvidenceSignatureConfig
                {
                    Required = true,
                    TrustedKeyIds = new HashSet<string>(StringComparer.OrdinalIgnoreCase) { "key-001", "key-002" }
                },
                ["vex"] = new EvidenceSignatureConfig { Required = false },
                ["attestation"] = new EvidenceSignatureConfig { Required = false }
            }
        };
        var signatures = new List<SignatureInfo>
        {
            new()
            {
                EvidenceType = "sbom",
                HasSignature = true,
                SignatureValid = true,
                KeyId = "key-999",
                IsKeyless = false
            }
        };
        var gate = new SignatureRequiredGate(options, _ => signatures);
        var result = await gate.EvaluateAsync(CreateMergeResult(), CreateContext());

        Assert.False(result.Passed);
    }

    [Fact]
    public async Task EvaluateAsync_KeylessSignature_ValidWithTransparencyLog()
    {
        var options = new SignatureRequiredGateOptions
        {
            EnableKeylessVerification = true,
            RequireTransparencyLogInclusion = true,
            EvidenceTypes = new Dictionary<string, EvidenceSignatureConfig>(StringComparer.OrdinalIgnoreCase)
            {
                ["sbom"] = new EvidenceSignatureConfig { Required = true },
                ["vex"] = new EvidenceSignatureConfig { Required = false },
                ["attestation"] = new EvidenceSignatureConfig { Required = false }
            }
        };
        var signatures = new List<SignatureInfo>
        {
            new()
            {
                EvidenceType = "sbom",
                HasSignature = true,
                SignatureValid = true,
                IsKeyless = true,
                HasTransparencyLogInclusion = true,
                CertificateChainValid = true
            }
        };
        var gate = new SignatureRequiredGate(options, _ => signatures);
        var result = await gate.EvaluateAsync(CreateMergeResult(), CreateContext());

        Assert.True(result.Passed);
    }

    [Fact]
    public async Task EvaluateAsync_KeylessSignature_FailsWithoutTransparencyLog()
    {
        var options = new SignatureRequiredGateOptions
        {
            EnableKeylessVerification = true,
            RequireTransparencyLogInclusion = true,
            EvidenceTypes = new Dictionary<string, EvidenceSignatureConfig>(StringComparer.OrdinalIgnoreCase)
            {
                ["sbom"] = new EvidenceSignatureConfig { Required = true },
                ["vex"] = new EvidenceSignatureConfig { Required = false },
                ["attestation"] = new EvidenceSignatureConfig { Required = false }
            }
        };
        var signatures = new List<SignatureInfo>
        {
            new()
            {
                EvidenceType = "sbom",
                HasSignature = true,
                SignatureValid = true,
                IsKeyless = true,
                HasTransparencyLogInclusion = false
            }
        };
        var gate = new SignatureRequiredGate(options, _ => signatures);
        var result = await gate.EvaluateAsync(CreateMergeResult(), CreateContext());

        Assert.False(result.Passed);
    }

    [Fact]
    public async Task EvaluateAsync_KeylessDisabled_FailsKeylessSignature()
    {
        var options = new SignatureRequiredGateOptions
        {
            EnableKeylessVerification = false,
            EvidenceTypes = new Dictionary<string, EvidenceSignatureConfig>(StringComparer.OrdinalIgnoreCase)
            {
                ["sbom"] = new EvidenceSignatureConfig { Required = true },
                ["vex"] = new EvidenceSignatureConfig { Required = false },
                ["attestation"] = new EvidenceSignatureConfig { Required = false }
            }
        };
        var signatures = new List<SignatureInfo>
        {
            new()
            {
                EvidenceType = "sbom",
                HasSignature = true,
                SignatureValid = true,
                IsKeyless = true
            }
        };
        var gate = new SignatureRequiredGate(options, _ => signatures);
        var result = await gate.EvaluateAsync(CreateMergeResult(), CreateContext());

        Assert.False(result.Passed);
    }

    [Fact]
    public async Task EvaluateAsync_EnvironmentOverride_SkipsTypes()
    {
        var options = new SignatureRequiredGateOptions
        {
            EvidenceTypes = new Dictionary<string, EvidenceSignatureConfig>(StringComparer.OrdinalIgnoreCase)
            {
                ["sbom"] = new EvidenceSignatureConfig { Required = true },
                ["vex"] = new EvidenceSignatureConfig { Required = true },
                ["attestation"] = new EvidenceSignatureConfig { Required = true }
            },
            Environments = new Dictionary<string, EnvironmentSignatureConfig>(StringComparer.OrdinalIgnoreCase)
            {
                ["development"] = new EnvironmentSignatureConfig
                {
                    SkipEvidenceTypes = new HashSet<string>(StringComparer.OrdinalIgnoreCase) { "sbom", "vex" }
                }
            }
        };
        var signatures = new List<SignatureInfo>
        {
            // Only attestation signature in development
            new() { EvidenceType = "attestation", HasSignature = true, SignatureValid = true }
        };
        var gate = new SignatureRequiredGate(options, _ => signatures);
        var result = await gate.EvaluateAsync(CreateMergeResult(), CreateContext(environment: "development"));

        Assert.True(result.Passed);
    }

    [Fact]
    public async Task EvaluateAsync_EnvironmentOverride_AddsIssuers()
    {
        var options = new SignatureRequiredGateOptions
        {
            EvidenceTypes = new Dictionary<string, EvidenceSignatureConfig>(StringComparer.OrdinalIgnoreCase)
            {
                ["sbom"] = new EvidenceSignatureConfig
                {
                    Required = true,
                    TrustedIssuers = new HashSet<string>(StringComparer.OrdinalIgnoreCase) { "prod@company.com" }
                },
                ["vex"] = new EvidenceSignatureConfig { Required = false },
                ["attestation"] = new EvidenceSignatureConfig { Required = false }
            },
            Environments = new Dictionary<string, EnvironmentSignatureConfig>(StringComparer.OrdinalIgnoreCase)
            {
                ["staging"] = new EnvironmentSignatureConfig
                {
                    AdditionalIssuers = new HashSet<string>(StringComparer.OrdinalIgnoreCase) { "staging@company.com" }
                }
            }
        };
        var signatures = new List<SignatureInfo>
        {
            new()
            {
                EvidenceType = "sbom",
                HasSignature = true,
                SignatureValid = true,
                SignerIdentity = "staging@company.com"
            }
        };
        var gate = new SignatureRequiredGate(options, _ => signatures);
        var result = await gate.EvaluateAsync(CreateMergeResult(), CreateContext(environment: "staging"));

        Assert.True(result.Passed);
    }

    [Fact]
    public async Task EvaluateAsync_InvalidCertificateChain_Fails()
    {
        var options = new SignatureRequiredGateOptions
        {
            EvidenceTypes = new Dictionary<string, EvidenceSignatureConfig>(StringComparer.OrdinalIgnoreCase)
            {
                ["sbom"] = new EvidenceSignatureConfig { Required = true },
                ["vex"] = new EvidenceSignatureConfig { Required = false },
                ["attestation"] = new EvidenceSignatureConfig { Required = false }
            }
        };
        var signatures = new List<SignatureInfo>
        {
            new()
            {
                EvidenceType = "sbom",
                HasSignature = true,
                SignatureValid = true,
                IsKeyless = true,
                HasTransparencyLogInclusion = true,
                CertificateChainValid = false
            }
        };
        var gate = new SignatureRequiredGate(options, _ => signatures);
        var result = await gate.EvaluateAsync(CreateMergeResult(), CreateContext());

        Assert.False(result.Passed);
    }

    [Fact]
    public async Task EvaluateAsync_WildcardIssuerMatch_MatchesSubdomains()
    {
        var options = new SignatureRequiredGateOptions
        {
            EvidenceTypes = new Dictionary<string, EvidenceSignatureConfig>(StringComparer.OrdinalIgnoreCase)
            {
                ["sbom"] = new EvidenceSignatureConfig
                {
                    Required = true,
                    TrustedIssuers = new HashSet<string>(StringComparer.OrdinalIgnoreCase) { "*@*.company.com" }
                },
                ["vex"] = new EvidenceSignatureConfig { Required = false },
                ["attestation"] = new EvidenceSignatureConfig { Required = false }
            }
        };
        var signatures = new List<SignatureInfo>
        {
            new()
            {
                EvidenceType = "sbom",
                HasSignature = true,
                SignatureValid = true,
                SignerIdentity = "build@ci.company.com"
            }
        };
        var gate = new SignatureRequiredGate(options, _ => signatures);
        var result = await gate.EvaluateAsync(CreateMergeResult(), CreateContext());

        Assert.True(result.Passed);
    }
}