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

namespace MarketAlly.AIPlugin.Analysis.Tests.Infrastructure
{
    [TestClass]
    public class ErrorHandlingTests
    {
        private ILogger? _logger;

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

        [TestMethod]
        public async Task ExecuteWithRetryAsync_SuccessfulOperation_ShouldReturnResult()
        {
            // Arrange
            var expectedResult = "success";
            var callCount = 0;

            // Act
            var result = await ErrorHandling.ExecuteWithRetryAsync(
                () =>
                {
                    callCount++;
                    return Task.FromResult(expectedResult);
                },
                maxRetries: 3,
                logger: _logger
            );

            // Assert
            Assert.AreEqual(expectedResult, result);
            Assert.AreEqual(1, callCount);
        }

        [TestMethod]
        public async Task ExecuteWithRetryAsync_TransientFailureThenSuccess_ShouldRetryAndSucceed()
        {
            // Arrange
            var expectedResult = "success";
            var callCount = 0;

            // Act
            var result = await ErrorHandling.ExecuteWithRetryAsync(
                () =>
                {
                    callCount++;
                    if (callCount < 3)
                        throw new IOException("Transient failure");
                    return Task.FromResult(expectedResult);
                },
                maxRetries: 3,
                delay: TimeSpan.FromMilliseconds(10),
                logger: _logger
            );

            // Assert
            Assert.AreEqual(expectedResult, result);
            Assert.AreEqual(3, callCount);
        }

        [TestMethod]
        [ExpectedException(typeof(AggregateException))]
        public async Task ExecuteWithRetryAsync_PersistentFailure_ShouldThrowAggregateException()
        {
            // Arrange
            var callCount = 0;

            // Act & Assert
            await ErrorHandling.ExecuteWithRetryAsync(
                () =>
                {
                    callCount++;
                    throw new IOException("Persistent failure");
                },
                maxRetries: 2,
                delay: TimeSpan.FromMilliseconds(10),
                logger: _logger
            );
        }

        [TestMethod]
        [ExpectedException(typeof(ArgumentException))]
        public async Task ExecuteWithRetryAsync_NonRetryableException_ShouldNotRetry()
        {
            // Arrange
            var callCount = 0;

            // Act & Assert
            await ErrorHandling.ExecuteWithRetryAsync(
                () =>
                {
                    callCount++;
                    throw new ArgumentException("Non-retryable failure");
                },
                maxRetries: 3,
                delay: TimeSpan.FromMilliseconds(10),
                logger: _logger
            );
        }

        [TestMethod]
        public async Task ExecuteWithRetryAsync_CancellationRequested_ShouldThrowOperationCancelledException()
        {
            // Arrange
            using var cts = new CancellationTokenSource();
            cts.Cancel();

            // Act & Assert
            await Assert.ThrowsExceptionAsync<OperationCanceledException>(async () =>
            {
                await ErrorHandling.ExecuteWithRetryAsync(
                    () => Task.FromResult("result"),
                    maxRetries: 3,
                    logger: _logger,
                    cancellationToken: cts.Token
                );
            });
        }

        [TestMethod]
        public async Task SafeExecuteAsync_SuccessfulOperation_ShouldReturnSuccessResult()
        {
            // Arrange
            var expectedValue = "success";

            // Act
            var result = await ErrorHandling.SafeExecuteAsync(
                () => Task.FromResult(expectedValue),
                logger: _logger
            );

            // Assert
            Assert.IsTrue(result.IsSuccess);
            Assert.AreEqual(expectedValue, result.Value);
            Assert.IsNull(result.Exception);
            Assert.IsNull(result.ErrorMessage);
            Assert.IsTrue(result.Duration > TimeSpan.Zero);
        }

        [TestMethod]
        public async Task SafeExecuteAsync_FailedOperation_ShouldReturnFailureResult()
        {
            // Arrange
            var expectedException = new InvalidOperationException("Test error");

            // Act
            var result = await ErrorHandling.SafeExecuteAsync<string>(
                () => throw expectedException,
                logger: _logger
            );

            // Assert
            Assert.IsFalse(result.IsSuccess);
            Assert.IsNull(result.Value);
            Assert.IsNotNull(result.Exception);
            Assert.AreEqual(expectedException, result.Exception);
            Assert.AreEqual("Test error", result.ErrorMessage);
            Assert.IsTrue(result.Duration > TimeSpan.Zero);
        }

        [TestMethod]
        public async Task WithTimeoutAsync_OperationCompletesInTime_ShouldReturnResult()
        {
            // Arrange
            var expectedResult = "success";

            // Act
            var result = await ErrorHandling.WithTimeoutAsync(
                async token =>
                {
                    await Task.Delay(50, token);
                    return expectedResult;
                },
                timeout: TimeSpan.FromSeconds(1),
                logger: _logger
            );

            // Assert
            Assert.AreEqual(expectedResult, result);
        }

        [TestMethod]
        [ExpectedException(typeof(TimeoutException))]
        public async Task WithTimeoutAsync_OperationTimesOut_ShouldThrowTimeoutException()
        {
            // Act & Assert
            await ErrorHandling.WithTimeoutAsync(
                async token =>
                {
                    await Task.Delay(1000, token);
                    return "result";
                },
                timeout: TimeSpan.FromMilliseconds(100),
                logger: _logger
            );
        }

        [TestMethod]
        public void HandlePluginException_ShouldReturnPluginErrorInfo()
        {
            // Arrange
            var exception = new InvalidOperationException("Plugin error");
            var pluginName = "TestPlugin";
            var operationName = "ExecuteAsync";

            // Act
            var errorInfo = ErrorHandling.HandlePluginException(
                exception,
                pluginName,
                operationName,
                _logger
            );

            // Assert
            Assert.IsNotNull(errorInfo);
            Assert.AreEqual(pluginName, errorInfo.PluginName);
            Assert.AreEqual(operationName, errorInfo.OperationName);
            Assert.AreEqual(exception, errorInfo.Exception);
            Assert.AreEqual("General", errorInfo.ErrorType);
            Assert.AreEqual(ErrorSeverity.Medium, errorInfo.Severity);
            Assert.IsTrue(errorInfo.Recoverable);
            Assert.IsTrue(errorInfo.Timestamp <= DateTime.UtcNow);
        }

        [TestMethod]
        public void HandlePluginException_IOError_ShouldClassifyCorrectly()
        {
            // Arrange
            var exception = new IOException("File not accessible");
            var pluginName = "TestPlugin";
            var operationName = "ReadFile";

            // Act
            var errorInfo = ErrorHandling.HandlePluginException(
                exception,
                pluginName,
                operationName,
                _logger
            );

            // Assert
            Assert.AreEqual("IO", errorInfo.ErrorType);
            Assert.AreEqual(ErrorSeverity.Medium, errorInfo.Severity);
            Assert.IsTrue(errorInfo.Recoverable);
        }

        [TestMethod]
        public void HandlePluginException_OutOfMemoryError_ShouldClassifyAsCritical()
        {
            // Arrange
            var exception = new OutOfMemoryException("Out of memory");
            var pluginName = "TestPlugin";
            var operationName = "ProcessLargeFile";

            // Act
            var errorInfo = ErrorHandling.HandlePluginException(
                exception,
                pluginName,
                operationName,
                _logger
            );

            // Assert
            Assert.AreEqual("Memory", errorInfo.ErrorType);
            Assert.AreEqual(ErrorSeverity.Critical, errorInfo.Severity);
            Assert.IsFalse(errorInfo.Recoverable);
        }

        [TestMethod]
        public void HandlePluginException_UnauthorizedAccessError_ShouldClassifyAsHighSeverity()
        {
            // Arrange
            var exception = new UnauthorizedAccessException("Access denied");
            var pluginName = "TestPlugin";
            var operationName = "AccessSecureResource";

            // Act
            var errorInfo = ErrorHandling.HandlePluginException(
                exception,
                pluginName,
                operationName,
                _logger
            );

            // Assert
            Assert.AreEqual("Security", errorInfo.ErrorType);
            Assert.AreEqual(ErrorSeverity.High, errorInfo.Severity);
            Assert.IsFalse(errorInfo.Recoverable);
        }

        [TestMethod]
        public async Task ExecuteWithRetryAsync_NonGeneric_ShouldWork()
        {
            // Arrange
            var callCount = 0;

            // Act
            await ErrorHandling.ExecuteWithRetryAsync(
                () =>
                {
                    callCount++;
                    return Task.CompletedTask;
                },
                maxRetries: 3,
                logger: _logger
            );

            // Assert
            Assert.AreEqual(1, callCount);
        }
    }
}