using FluentAssertions;
using StellaOps.Router.Gateway.RateLimit;
using Xunit;

namespace StellaOps.Router.Gateway.Tests;

public sealed class InstanceRateLimiterTests
{
    [Fact]
    public void TryAcquire_ReportsMostConstrainedRuleWhenAllowed()
    {
        var limiter = new InstanceRateLimiter(
            [
                new RateLimitRule { PerSeconds = 300, MaxRequests = 2 },
                new RateLimitRule { PerSeconds = 30, MaxRequests = 1 },
            ]);

        var decision = limiter.TryAcquire("svc");

        decision.Allowed.Should().BeTrue();
        decision.Scope.Should().Be(RateLimitScope.Instance);
        decision.WindowSeconds.Should().Be(30);
        decision.Limit.Should().Be(1);
        decision.CurrentCount.Should().Be(1);
    }

    [Fact]
    public void TryAcquire_DeniesWhenAnyRuleIsExceeded()
    {
        var limiter = new InstanceRateLimiter(
            [
                new RateLimitRule { PerSeconds = 300, MaxRequests = 2 },
                new RateLimitRule { PerSeconds = 30, MaxRequests = 1 },
            ]);

        limiter.TryAcquire("svc").Allowed.Should().BeTrue();

        var decision = limiter.TryAcquire("svc");

        decision.Allowed.Should().BeFalse();
        decision.Scope.Should().Be(RateLimitScope.Instance);
        decision.WindowSeconds.Should().Be(30);
        decision.Limit.Should().Be(1);
        decision.RetryAfterSeconds.Should().BeGreaterThan(0);
    }
}