// SPDX-License-Identifier: BUSL-1.1
// Copyright (c) 2025 StellaOps
// Sprint: SPRINT_20260112_004_BE_policy_determinization_attested_rules (DET-ATT-004)
// Task: Unit tests for VexProofGate anchor-aware mode

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

namespace StellaOps.Policy.Tests.Gates;

public class VexProofGateTests
{
    private static readonly DateTimeOffset FixedTime = new(2026, 1, 14, 12, 0, 0, TimeSpan.Zero);

    private static MergeResult CreateMergeResult(VexStatus status) =>
        new()
        {
            Status = status,
            Confidence = 0.9,
            HasConflicts = false,
            AllClaims = ImmutableArray<ScoredClaim>.Empty,
            WinningClaim = new ScoredClaim
            {
                SourceId = "test",
                Status = status,
                OriginalScore = 0.9,
                AdjustedScore = 0.9,
                ScopeSpecificity = 1,
                Accepted = true,
                Reason = "Test claim"
            },
            Conflicts = ImmutableArray<ConflictRecord>.Empty
        };

    [Fact]
    public async Task EvaluateAsync_WhenDisabled_ReturnsPass()
    {
        // Arrange
        var options = new VexProofGateOptions { Enabled = false };
        var gate = new VexProofGate(options);
        var mergeResult = CreateMergeResult(VexStatus.NotAffected);
        var context = new PolicyGateContext { Environment = "production" };

        // Act
        var result = await gate.EvaluateAsync(mergeResult, context);

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

    [Fact]
    public async Task EvaluateAsync_WhenAnchorAwareModeEnabled_RequiresAnchoring()
    {
        // Arrange
        var options = new VexProofGateOptions
        {
            Enabled = true,
            RequireProofForNotAffected = true,
            AnchorAwareMode = true,
            RequireVexAnchoring = true
        };
        var gate = new VexProofGate(options);
        var mergeResult = CreateMergeResult(VexStatus.NotAffected);
        var context = new PolicyGateContext
        {
            Environment = "production",
            Metadata = new Dictionary<string, string>
            {
                ["vex_proof_id"] = "proof-123",
                ["vex_proof_confidence_tier"] = "high",
                ["vex_proof_anchored"] = "false" // Not anchored
            }
        };

        // Act
        var result = await gate.EvaluateAsync(mergeResult, context);

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

    [Fact]
    public async Task EvaluateAsync_WhenAnchorAwareModeEnabled_PassesWithAnchoring()
    {
        // Arrange
        var options = new VexProofGateOptions
        {
            Enabled = true,
            RequireProofForNotAffected = true,
            AnchorAwareMode = true,
            RequireVexAnchoring = true,
            RequireRekorVerification = false
        };
        var gate = new VexProofGate(options);
        var mergeResult = CreateMergeResult(VexStatus.NotAffected);
        var context = new PolicyGateContext
        {
            Environment = "production",
            Metadata = new Dictionary<string, string>
            {
                ["vex_proof_id"] = "proof-123",
                ["vex_proof_confidence_tier"] = "high",
                ["vex_proof_anchored"] = "true",
                ["vex_proof_envelope_digest"] = "sha256:abc123"
            }
        };

        // Act
        var result = await gate.EvaluateAsync(mergeResult, context);

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

    [Fact]
    public async Task EvaluateAsync_WhenRekorRequired_FailsWithoutRekor()
    {
        // Arrange
        var options = new VexProofGateOptions
        {
            Enabled = true,
            RequireProofForNotAffected = true,
            AnchorAwareMode = true,
            RequireVexAnchoring = true,
            RequireRekorVerification = true
        };
        var gate = new VexProofGate(options);
        var mergeResult = CreateMergeResult(VexStatus.NotAffected);
        var context = new PolicyGateContext
        {
            Environment = "production",
            Metadata = new Dictionary<string, string>
            {
                ["vex_proof_id"] = "proof-123",
                ["vex_proof_confidence_tier"] = "high",
                ["vex_proof_anchored"] = "true",
                ["vex_proof_rekor_verified"] = "false"
            }
        };

        // Act
        var result = await gate.EvaluateAsync(mergeResult, context);

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

    [Fact]
    public async Task EvaluateAsync_WhenRekorRequired_PassesWithRekor()
    {
        // Arrange
        var options = new VexProofGateOptions
        {
            Enabled = true,
            RequireProofForNotAffected = true,
            AnchorAwareMode = true,
            RequireVexAnchoring = true,
            RequireRekorVerification = true
        };
        var gate = new VexProofGate(options);
        var mergeResult = CreateMergeResult(VexStatus.NotAffected);
        var context = new PolicyGateContext
        {
            Environment = "production",
            Metadata = new Dictionary<string, string>
            {
                ["vex_proof_id"] = "proof-123",
                ["vex_proof_confidence_tier"] = "high",
                ["vex_proof_anchored"] = "true",
                ["vex_proof_envelope_digest"] = "sha256:abc123",
                ["vex_proof_rekor_verified"] = "true",
                ["vex_proof_rekor_log_index"] = "12345678"
            }
        };

        // Act
        var result = await gate.EvaluateAsync(mergeResult, context);

        // Assert
        Assert.True(result.Passed);
        Assert.Equal("proof_valid", result.Reason);
        Assert.True(result.Details.ContainsKey("rekorLogIndex"));
    }

    [Fact]
    public async Task EvaluateAsync_StrictAnchorAware_EnforcesAllRequirements()
    {
        // Arrange
        var options = VexProofGateOptions.StrictAnchorAware;
        var gate = new VexProofGate(options);
        var mergeResult = CreateMergeResult(VexStatus.NotAffected);
        var context = new PolicyGateContext
        {
            Environment = "production",
            Metadata = new Dictionary<string, string>
            {
                ["vex_proof_id"] = "proof-123",
                ["vex_proof_confidence_tier"] = "high",
                ["vex_proof_all_signed"] = "true",
                ["vex_proof_anchored"] = "true",
                ["vex_proof_envelope_digest"] = "sha256:abc123",
                ["vex_proof_rekor_verified"] = "true",
                ["vex_proof_rekor_log_index"] = "12345678"
            }
        };

        // Act
        var result = await gate.EvaluateAsync(mergeResult, context);

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

    [Fact]
    public async Task EvaluateAsync_StrictAnchorAware_FailsWithoutSignedStatements()
    {
        // Arrange
        var options = VexProofGateOptions.StrictAnchorAware;
        var gate = new VexProofGate(options);
        var mergeResult = CreateMergeResult(VexStatus.NotAffected);
        var context = new PolicyGateContext
        {
            Environment = "production",
            Metadata = new Dictionary<string, string>
            {
                ["vex_proof_id"] = "proof-123",
                ["vex_proof_confidence_tier"] = "high",
                ["vex_proof_all_signed"] = "false", // Not signed
                ["vex_proof_anchored"] = "true",
                ["vex_proof_rekor_verified"] = "true"
            }
        };

        // Act
        var result = await gate.EvaluateAsync(mergeResult, context);

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

    [Fact]
    public void StrictAnchorAware_HasExpectedDefaults()
    {
        // Act
        var options = VexProofGateOptions.StrictAnchorAware;

        // Assert
        Assert.True(options.Enabled);
        Assert.Equal("high", options.MinimumConfidenceTier);
        Assert.True(options.RequireProofForNotAffected);
        Assert.True(options.RequireProofForFixed);
        Assert.True(options.RequireSignedStatements);
        Assert.True(options.AnchorAwareMode);
        Assert.True(options.RequireVexAnchoring);
        Assert.True(options.RequireRekorVerification);
        Assert.Equal(0, options.MaxAllowedConflicts);
        Assert.Equal(72, options.MaxProofAgeHours);
    }
}