// <copyright file="ReanalysisFingerprintTests.cs" company="StellaOps">
// SPDX-License-Identifier: AGPL-3.0-or-later
// Sprint: SPRINT_20260112_004_POLICY_unknowns_determinization_greyqueue (POLICY-UNK-006)
// </copyright>

using Microsoft.Extensions.Time.Testing;
using StellaOps.Policy.Determinization.Models;
using StellaOps.TestKit;
using Xunit;

namespace StellaOps.Policy.Determinization.Tests.Models;

[Trait("Category", TestCategories.Unit)]
public class ReanalysisFingerprintTests
{
    private readonly FakeTimeProvider _timeProvider;

    public ReanalysisFingerprintTests()
    {
        _timeProvider = new FakeTimeProvider(new DateTimeOffset(2026, 1, 15, 12, 0, 0, TimeSpan.Zero));
    }

    [Fact]
    public void Build_WithAllInputs_GeneratesDeterministicFingerprint()
    {
        // Arrange
        var builder1 = new ReanalysisFingerprintBuilder(_timeProvider)
            .WithDsseBundleDigest("sha256:bundle123")
            .AddEvidenceDigest("sha256:evidence1")
            .AddEvidenceDigest("sha256:evidence2")
            .WithToolVersion("scanner", "1.0.0")
            .WithToolVersion("policy-engine", "2.0.0")
            .WithProductVersion("myapp@1.2.3")
            .WithPolicyConfigHash("sha256:config456")
            .WithSignalWeightsHash("sha256:weights789");

        var builder2 = new ReanalysisFingerprintBuilder(_timeProvider)
            .WithDsseBundleDigest("sha256:bundle123")
            .AddEvidenceDigest("sha256:evidence1")
            .AddEvidenceDigest("sha256:evidence2")
            .WithToolVersion("scanner", "1.0.0")
            .WithToolVersion("policy-engine", "2.0.0")
            .WithProductVersion("myapp@1.2.3")
            .WithPolicyConfigHash("sha256:config456")
            .WithSignalWeightsHash("sha256:weights789");

        // Act
        var fingerprint1 = builder1.Build();
        var fingerprint2 = builder2.Build();

        // Assert - same inputs produce same fingerprint ID
        Assert.Equal(fingerprint1.FingerprintId, fingerprint2.FingerprintId);
        Assert.StartsWith("sha256:", fingerprint1.FingerprintId);
    }

    [Fact]
    public void Build_WithDifferentInputs_GeneratesDifferentFingerprint()
    {
        // Arrange
        var builder1 = new ReanalysisFingerprintBuilder(_timeProvider)
            .WithDsseBundleDigest("sha256:bundle123")
            .WithProductVersion("myapp@1.2.3");

        var builder2 = new ReanalysisFingerprintBuilder(_timeProvider)
            .WithDsseBundleDigest("sha256:bundle456")  // Different
            .WithProductVersion("myapp@1.2.3");

        // Act
        var fingerprint1 = builder1.Build();
        var fingerprint2 = builder2.Build();

        // Assert - different inputs produce different fingerprint IDs
        Assert.NotEqual(fingerprint1.FingerprintId, fingerprint2.FingerprintId);
    }

    [Fact]
    public void Build_EvidenceDigests_AreSortedDeterministically()
    {
        // Arrange - add in random order
        var builder = new ReanalysisFingerprintBuilder(_timeProvider)
            .AddEvidenceDigest("sha256:zzz")
            .AddEvidenceDigest("sha256:aaa")
            .AddEvidenceDigest("sha256:mmm");

        // Act
        var fingerprint = builder.Build();

        // Assert - sorted alphabetically
        Assert.Equal(3, fingerprint.EvidenceDigests.Count);
        Assert.Equal("sha256:aaa", fingerprint.EvidenceDigests[0]);
        Assert.Equal("sha256:mmm", fingerprint.EvidenceDigests[1]);
        Assert.Equal("sha256:zzz", fingerprint.EvidenceDigests[2]);
    }

    [Fact]
    public void Build_ToolVersions_AreSortedDeterministically()
    {
        // Arrange - add in random order
        var builder = new ReanalysisFingerprintBuilder(_timeProvider)
            .WithToolVersion("zebra-tool", "1.0.0")
            .WithToolVersion("alpha-tool", "2.0.0")
            .WithToolVersion("mike-tool", "3.0.0");

        // Act
        var fingerprint = builder.Build();

        // Assert - sorted by key
        var keys = fingerprint.ToolVersions.Keys.ToList();
        Assert.Equal("alpha-tool", keys[0]);
        Assert.Equal("mike-tool", keys[1]);
        Assert.Equal("zebra-tool", keys[2]);
    }

    [Fact]
    public void Build_Triggers_AreSortedByEventTypeThenTime()
    {
        // Arrange
        var builder = new ReanalysisFingerprintBuilder(_timeProvider)
            .AddTrigger("vex.changed", 1, "excititor")
            .AddTrigger("epss.updated", 1, "signals")
            .AddTrigger("runtime.detected", 1, "zastava");

        // Act
        var fingerprint = builder.Build();

        // Assert - sorted by event type
        Assert.Equal(3, fingerprint.Triggers.Count);
        Assert.Equal("epss.updated", fingerprint.Triggers[0].EventType);
        Assert.Equal("runtime.detected", fingerprint.Triggers[1].EventType);
        Assert.Equal("vex.changed", fingerprint.Triggers[2].EventType);
    }

    [Fact]
    public void Build_DuplicateEvidenceDigests_AreDeduped()
    {
        // Arrange
        var builder = new ReanalysisFingerprintBuilder(_timeProvider)
            .AddEvidenceDigest("sha256:abc")
            .AddEvidenceDigest("sha256:abc")  // duplicate
            .AddEvidenceDigest("sha256:def");

        // Act
        var fingerprint = builder.Build();

        // Assert
        Assert.Equal(2, fingerprint.EvidenceDigests.Count);
    }

    [Fact]
    public void Build_NextActions_AreSortedAndDeduped()
    {
        // Arrange
        var builder = new ReanalysisFingerprintBuilder(_timeProvider)
            .AddNextAction("rescan")
            .AddNextAction("notify")
            .AddNextAction("rescan")  // duplicate
            .AddNextAction("adjudicate");

        // Act
        var fingerprint = builder.Build();

        // Assert
        Assert.Equal(3, fingerprint.NextActions.Count);
        Assert.Equal("adjudicate", fingerprint.NextActions[0]);
        Assert.Equal("notify", fingerprint.NextActions[1]);
        Assert.Equal("rescan", fingerprint.NextActions[2]);
    }

    [Fact]
    public void Build_SetsComputedAtFromTimeProvider()
    {
        // Arrange
        var builder = new ReanalysisFingerprintBuilder(_timeProvider);

        // Act
        var fingerprint = builder.Build();

        // Assert
        Assert.Equal(_timeProvider.GetUtcNow(), fingerprint.ComputedAt);
    }
}