using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;
using LibHac.Ncm;
using Microsoft.Extensions.Caching.Memory;
using Microsoft.Extensions.Hosting.Internal;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Moq;
using NUnit.Framework;
using TinfoilVibeServer.Models;
using TinfoilVibeServer.Services;
using TinfoilVibeServer.Utilities;

namespace TinfoilVibeServerTest.Tests
{
    [TestFixture]
    public class SnapshotServiceTests
    {
        private Mock<ILogger<SnapshotService>> _loggerMock;
        private SnapshotService _service;
        private Mock<INSPExtractor> _nspExtractorMock;
        private Mock<IArchiveHandler> _archiveHander;
        private Mock<IOptionsMonitor<SnapshotOptions>> _mockOptions;
        private SnapshotOptions _options;
        private MemoryCache _memoryCache;

        [SetUp]
        public void SetUp()
        {
            _mockOptions = new Mock<IOptionsMonitor<SnapshotOptions>>();
            _options = new SnapshotOptions()
            {
                RomExtensions = [".nsp"],
                RootDirectories = ["TestData/ROMS"],
                SnapshotFile = "TestData/snapshot.json",
                SnapshotBackupFile = "TestData/snapshot.bak"
            };
            /*// ensure ROM test directory has test files removed
            foreach (var file in Directory.GetFiles("TestData/ROMS"))
            {
                File.Delete(file);
            }*/
            _mockOptions.Setup(m => m.CurrentValue).Returns(_options);
            _loggerMock = new Mock<ILogger<SnapshotService>>();
            _archiveHander = new Mock<IArchiveHandler>();
            _nspExtractorMock = new Mock<INSPExtractor>();
            var hostEnv = new Mock<HostingEnvironment>();
            var memoryCacheOptions = Options.Create(new MemoryCacheOptions());
            _memoryCache = new MemoryCache(memoryCacheOptions); 
            

            _nspExtractorMock.Setup(extractor => extractor.ExtractHashFromStream(It.IsAny<Stream>())).Returns("HASH");
            _nspExtractorMock.Setup(extractor => extractor.ExtractFromStream(It.IsAny<Stream>())).Returns(
                new NcaMetadataWithHash(titleId: "0000000000000000","0000000000000000", version: 1, ContentMetaType.Application, "HASH"));
            //Settings.RootDirs = new List<string> { "TestData/Root1", "TestData/Root2" };
            
            _service = new SnapshotService(_memoryCache, _mockOptions.Object, _nspExtractorMock.Object, _archiveHander.Object, _loggerMock.Object, hostEnv.Object);
        }

        [TearDown]
        public void TearDown()
        {
            _service.Dispose();
            _memoryCache.Dispose();
        }
        
        [Test]
        public async Task BuildSnapshot_WhenFilesChanged_ShouldPersist()
        {
            // Arrange
            var initialHash = _service.GetSnapshot()?.Hash;
            var rebuilding = false;
            var rebuilt = false;
            CancellationTokenSource snapshotRebuilding = new();
            _service.SnapshotRebuilding += (sender, args) =>
            {
                rebuilding = true;
                snapshotRebuilding.Cancel();
            };
            CancellationTokenSource snapshotPersisting = new();
            _service.SnapshotRebuilt+= (sender, args) =>
            {
                rebuilt = true;
                snapshotPersisting.Cancel();
                // Assert
                var newHash = _service.GetSnapshot()?.Hash;
                Assert.That(newHash, Is.Not.EqualTo(initialHash));
            };
            Timer timer = new(state =>
            {
                snapshotPersisting.Cancel();
                snapshotRebuilding.Cancel();
            }, null, 20*1000, 0);
            await File.WriteAllTextAsync(_options.SnapshotFile, "[]", snapshotPersisting.Token);
            // Add a file to Root1
            var newFile = Path.Combine(_options.RootDirectories.First(), "new.nsp");
            
            // Act
            await File.WriteAllTextAsync(newFile,"TEST");

            Task.Delay(4000).Wait();
            try
            {
                while (_memoryCache.Count > 0)
                {
                    Task.Delay(200).Wait(snapshotRebuilding.Token);
                }
            }
            catch (OperationCanceledException)
            {
                Assert.That(rebuilding, Is.True);
            }

            try
            {
                while (_memoryCache.Count > 0)
                {
                    Task.Delay(200).Wait(snapshotPersisting.Token);
                }
            }
            catch (OperationCanceledException e)
            {
                Assert.That(rebuilt, Is.True);
            }
        }

        [Test]
        public async Task BuildSnapshot_NoChange_ShouldNotPersist()
        {
            // Act
            _service.BuildSnapshotAsync();

            // Act again – snapshot should be identical
            _service.BuildSnapshotAsync();

            // Assert
            _loggerMock.Verify(
                l => l.Log(
                    LogLevel.Information,
                    It.IsAny<EventId>(),
                    It.Is<It.IsAnyType>((v, t) => v.ToString().Contains("persisting new snapshot")),
                    null,
                    It.IsAny<Func<It.IsAnyType, Exception, string>>()), Times.Never);
        }
    }
}