using Xunit;
using System.Collections.Immutable;
using StellaOps.Policy.Engine.Domain;
using StellaOps.Policy.Engine.Services;

using StellaOps.TestKit;
namespace StellaOps.Policy.Engine.Tests;

public sealed class PolicyRuntimeEvaluatorTests
{
    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public async Task EvaluateAsync_ReturnsDeterministicDecisionAndCaches()
    {
        var repo = new InMemoryPolicyPackRepository(TimeProvider.System);
        await repo.StoreBundleAsync(
            "pack-1",
            1,
            new PolicyBundleRecord(
                Digest: "sha256:abc",
                Signature: "sig:sha256:abc",
                Size: 4,
                CreatedAt: DateTimeOffset.UnixEpoch,
                Payload: new byte[] { 1, 2, 3, 4 }.ToImmutableArray()),
            TestContext.Current.CancellationToken);

        var evaluator = new PolicyRuntimeEvaluator(repo);
        var request = new PolicyEvaluationRequest("pack-1", 1, "subject-a");

        var first = await evaluator.EvaluateAsync(request, TestContext.Current.CancellationToken);
        var second = await evaluator.EvaluateAsync(request, TestContext.Current.CancellationToken);

        Assert.Equal(first.Decision, second.Decision);
        Assert.False(first.Cached);
        Assert.True(second.Cached);
        Assert.Equal("pack-1", first.PackId);
        Assert.Equal(1, first.Version);
    }

    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public async Task EvaluateAsync_ThrowsWhenBundleMissing()
    {
        var evaluator = new PolicyRuntimeEvaluator(new InMemoryPolicyPackRepository(TimeProvider.System));
        var request = new PolicyEvaluationRequest("pack-x", 1, "subject-a");

        await Assert.ThrowsAsync<InvalidOperationException>(() => evaluator.EvaluateAsync(request, TestContext.Current.CancellationToken));
    }
}