using System;
using System.IO;
using FluentAssertions;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Time.Testing;
using StellaOps.Signals.Hosting;
using StellaOps.Signals.Options;
using Xunit;

namespace StellaOps.Signals.Reachability.Tests;

public sealed class SignalsSealedModeMonitorTests : IDisposable
{
    private readonly string tempDir = Path.Combine(Path.GetTempPath(), $"signals-sealed-tests-{Guid.NewGuid():N}");

    [Fact]
    public void IsCompliant_WhenEnforcementDisabled_ReturnsTrue()
    {
        var options = new SignalsOptions();
        options.AirGap.SealedMode.EnforcementEnabled = false;

        var monitor = CreateMonitor(options);

        monitor.IsCompliant(out _).Should().BeTrue();
    }

    [Fact]
    public void IsCompliant_WhenEvidenceMissing_ReturnsFalse()
    {
        var options = CreateEnforcedOptions();
        options.AirGap.SealedMode.EvidencePath = Path.Combine(tempDir, "missing.json");

        var monitor = CreateMonitor(options);

        monitor.IsCompliant(out var reason).Should().BeFalse();
        reason.Should().Contain("not found");
    }

    [Fact]
    public void IsCompliant_WhenEvidenceFresh_ReturnsTrue()
    {
        var evidencePath = CreateEvidenceFile(TimeSpan.Zero);
        var options = CreateEnforcedOptions();
        options.AirGap.SealedMode.EvidencePath = evidencePath;

        var monitor = CreateMonitor(options);

        monitor.IsCompliant(out _).Should().BeTrue();
    }

    [Fact]
    public void IsCompliant_WhenEvidenceStale_ReturnsFalse()
    {
        var evidencePath = CreateEvidenceFile(TimeSpan.FromHours(7));
        var options = CreateEnforcedOptions();
        options.AirGap.SealedMode.EvidencePath = evidencePath;

        var monitor = CreateMonitor(options);

        monitor.IsCompliant(out _).Should().BeFalse();
    }

    private SignalsOptions CreateEnforcedOptions()
    {
        var options = new SignalsOptions();
        options.AirGap.SealedMode.EnforcementEnabled = true;
        options.AirGap.SealedMode.MaxEvidenceAge = TimeSpan.FromHours(6);
        options.AirGap.SealedMode.CacheLifetime = TimeSpan.FromSeconds(1);
        return options;
    }

    private string CreateEvidenceFile(TimeSpan age)
    {
        Directory.CreateDirectory(tempDir);
        var path = Path.Combine(tempDir, $"{Guid.NewGuid():N}.json");
        File.WriteAllText(path, "{}");
        if (age > TimeSpan.Zero)
        {
            File.SetLastWriteTimeUtc(path, DateTime.UtcNow - age);
        }

        return path;
    }

    private SignalsSealedModeMonitor CreateMonitor(SignalsOptions options)
    {
        return new SignalsSealedModeMonitor(
            options,
            new FakeTimeProvider(DateTimeOffset.UtcNow),
            NullLogger<SignalsSealedModeMonitor>.Instance);
    }

    public void Dispose()
    {
        if (Directory.Exists(tempDir))
        {
            Directory.Delete(tempDir, recursive: true);
        }
    }
}