using MarketAlly.AIPlugin;
using MarketAlly.AIPlugin.Analysis.Infrastructure;
using Microsoft.Extensions.Logging;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;

namespace MarketAlly.AIPlugin.Analysis.Tests.Infrastructure
{
    [TestClass]
    public class PluginDiscoveryServiceTests
    {
        private PluginDiscoveryService _service = null!;
        private ILogger<PluginDiscoveryService>? _logger;

        [TestInitialize]
        public void Setup()
        {
            _logger = null; // In real tests, you might use a mock logger
            _service = new PluginDiscoveryService(_logger);
        }

        [TestMethod]
        public async Task DiscoverPluginsAsync_NonExistentDirectory_ShouldReturnEmptyList()
        {
            // Arrange
            var nonExistentDirectory = "/non/existent/directory";

            // Act
            var plugins = await _service.DiscoverPluginsAsync(nonExistentDirectory);

            // Assert
            Assert.IsNotNull(plugins);
            Assert.AreEqual(0, plugins.Count());
        }

        [TestMethod]
        public void GetBuiltInPlugins_ShouldReturnAllBuiltInPlugins()
        {
            // Act
            var plugins = _service.GetBuiltInPlugins();

            // Assert
            Assert.IsNotNull(plugins);
            var pluginList = plugins.ToList();
            Assert.IsTrue(pluginList.Count >= 6); // We expect at least 6 built-in plugins

            // Verify we have the main analysis plugins
            var pluginNames = pluginList.Select(p => p.GetType().Name).ToList();
            Assert.IsTrue(pluginNames.Contains("PerformanceAnalyzerPlugin"));
            Assert.IsTrue(pluginNames.Contains("ArchitectureValidatorPlugin"));
            Assert.IsTrue(pluginNames.Contains("TechnicalDebtPlugin"));
            Assert.IsTrue(pluginNames.Contains("ComplexityAnalyzerPlugin"));
            Assert.IsTrue(pluginNames.Contains("TestAnalysisPlugin"));
            Assert.IsTrue(pluginNames.Contains("BehaviorAnalysisPlugin"));
            Assert.IsTrue(pluginNames.Contains("SQLiteSchemaReaderPlugin"));
        }

        [TestMethod]
        public void ValidatePlugin_NullPlugin_ShouldReturnFalse()
        {
            // Act
            var isValid = _service.ValidatePlugin(null!);

            // Assert
            Assert.IsFalse(isValid);
        }

        [TestMethod]
        public void ValidatePlugin_ValidBuiltInPlugin_ShouldReturnTrue()
        {
            // Arrange
            var plugins = _service.GetBuiltInPlugins();
            var plugin = plugins.First();

            // Act
            var isValid = _service.ValidatePlugin(plugin);

            // Assert
            Assert.IsTrue(isValid);
        }

        [TestMethod]
        public void ValidatePlugin_PluginWithNullSupportedParameters_ShouldReturnFalse()
        {
            // Arrange
            var mockPlugin = new MockPluginWithNullParameters();

            // Act
            var isValid = _service.ValidatePlugin(mockPlugin);

            // Assert
            Assert.IsFalse(isValid);
        }

        [TestMethod]
        public async Task LoadPluginAsync_NonExistentAssembly_ShouldThrowFileNotFoundException()
        {
            // Arrange
            var nonExistentPath = "/non/existent/assembly.dll";
            var typeName = "SomeType";

            // Act & Assert
            await Assert.ThrowsExceptionAsync<FileNotFoundException>(async () =>
            {
                await _service.LoadPluginAsync(nonExistentPath, typeName);
            });
        }

        [TestMethod]
        public void Constructor_WithNullLogger_ShouldNotThrow()
        {
            // Act & Assert - Should not throw
            var service = new PluginDiscoveryService(null);
            Assert.IsNotNull(service);
        }

        [TestMethod]
        public void Constructor_WithLogger_ShouldNotThrow()
        {
            // Act & Assert - Should not throw
            var service = new PluginDiscoveryService(_logger);
            Assert.IsNotNull(service);
        }

        [TestMethod]
        public async Task DiscoverPluginsAsync_EmptyDirectory_ShouldReturnEmptyList()
        {
            // Arrange
            var tempDirectory = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString());
            Directory.CreateDirectory(tempDirectory);

            try
            {
                // Act
                var plugins = await _service.DiscoverPluginsAsync(tempDirectory);

                // Assert
                Assert.IsNotNull(plugins);
                Assert.AreEqual(0, plugins.Count());
            }
            finally
            {
                // Cleanup
                if (Directory.Exists(tempDirectory))
                {
                    Directory.Delete(tempDirectory, true);
                }
            }
        }
    }

    // Test helper classes
    internal class MockPluginWithNullParameters : IAIPlugin
    {
        public IReadOnlyDictionary<string, Type> SupportedParameters => null!;

        public Task<AIPluginResult> ExecuteAsync(IReadOnlyDictionary<string, object> parameters)
        {
            return Task.FromResult(new AIPluginResult("test", "test"));
        }
    }

    internal class MockValidPlugin : IAIPlugin
    {
        public IReadOnlyDictionary<string, Type> SupportedParameters => 
            new Dictionary<string, Type> { ["testParam"] = typeof(string) };

        public Task<AIPluginResult> ExecuteAsync(IReadOnlyDictionary<string, object> parameters)
        {
            return Task.FromResult(new AIPluginResult("test", "test"));
        }
    }
}