using System;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using GermanApp.Infrastructure.Configuration;
using GermanApp.Infrastructure.Services;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using Moq;

namespace GermanApp.Tests.Unit.Infrastructure.Services;

[TestClass]
public class VoskServiceTests
{
    private Mock<IOptions<VoskConfig>> _mockConfigOptions;
    private Mock<ILogger<VoskService>> _mockLogger;
    private VoskConfig _config;
    private VoskService _service;
    private string _tempModelPath;

    [TestInitialize]
    public void Setup()
    {
        _mockConfigOptions = new Mock<IOptions<VoskConfig>>();
        _mockLogger = new Mock<ILogger<VoskService>>();
        
        // Create a temporary model directory for testing
        _tempModelPath = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString());
        Directory.CreateDirectory(_tempModelPath);
        
        _config = new VoskConfig
        {
            PythonPath = "python3",
            ModelPath = _tempModelPath,
            SampleRate = 16000,
            TimeoutSeconds = 30,
            BeamWidth = 20
        };
        
        _mockConfigOptions.Setup(c => c.Value).Returns(_config);
        
        _service = new VoskService(_mockConfigOptions.Object, _mockLogger.Object);
    }

    [TestCleanup]
    public void Cleanup()
    {
        // Clean up temp directory
        try
        {
            if (Directory.Exists(_tempModelPath))
            {
                Directory.Delete(_tempModelPath, true);
            }
        }
        catch { }
    }

    [TestMethod]
    public void Constructor_WithValidConfig_CreatesService()
    {
        // Act & Assert
        Assert.IsNotNull(_service);
    }

    [TestMethod]
    public void Constructor_WithEmptyModelPath_ThrowsInvalidOperationException()
    {
        // Arrange
        var invalidConfig = new VoskConfig
        {
            PythonPath = "python3",
            ModelPath = "",
            SampleRate = 16000
        };
        _mockConfigOptions.Setup(c => c.Value).Returns(invalidConfig);

        // Act
        try
        {
            new VoskService(_mockConfigOptions.Object, _mockLogger.Object);
            Assert.Fail("Expected InvalidOperationException was not thrown");
        }
        catch (InvalidOperationException)
        {
            // Expected
        }
    }

    [TestMethod]
    public void Constructor_WithNonExistentModelPath_ThrowsDirectoryNotFoundException()
    {
        // Arrange
        var invalidConfig = new VoskConfig
        {
            PythonPath = "python3",
            ModelPath = "/nonexistent/path/to/model",
            SampleRate = 16000
        };
        _mockConfigOptions.Setup(c => c.Value).Returns(invalidConfig);

        // Act
        try
        {
            new VoskService(_mockConfigOptions.Object, _mockLogger.Object);
            Assert.Fail("Expected DirectoryNotFoundException was not thrown");
        }
        catch (DirectoryNotFoundException)
        {
            // Expected
        }
    }

    [TestMethod]
    public async Task RecognizeSpeechAsync_WithValidAudio_CallsPythonProcess()
    {
        // Arrange
        var audioBytes = new byte[1000];
        for (int i = 0; i < audioBytes.Length; i++)
        {
            audioBytes[i] = (byte)(i % 256);
        }
        var cancellationToken = CancellationToken.None;

        // Note: We can't easily test the actual Python execution without Vosk installed
        // This test verifies the basic validation works
        
        // Act & Assert
        // This will throw if the model is not properly configured for actual execution
        // But we're testing the validation logic
        try
        {
            var result = await _service.RecognizeSpeechAsync(audioBytes, 16000, null, cancellationToken);
            // If we get here, the validation passed
        }
        catch (Exception ex) when (ex is TimeoutException || ex is InvalidOperationException)
        {
            // Expected when Python/Vosk is not installed
            // The important thing is that basic validation passed
        }
    }

    [TestMethod]
    public async Task RecognizeSpeechAsync_WithEmptyAudio_ThrowsArgumentException()
    {
        // Arrange
        var emptyAudio = new byte[0];
        var cancellationToken = CancellationToken.None;

        // Act
        try
        {
            await _service.RecognizeSpeechAsync(emptyAudio, 16000, null, cancellationToken);
            Assert.Fail("Expected ArgumentException was not thrown");
        }
        catch (ArgumentException)
        {
            // Expected
        }
    }

    [TestMethod]
    public async Task RecognizeSpeechAsync_WithNullAudio_ThrowsArgumentException()
    {
        // Arrange
        byte[] nullAudio = null!;
        var cancellationToken = CancellationToken.None;

        // Act
        try
        {
            await _service.RecognizeSpeechAsync(nullAudio, 16000, null, cancellationToken);
            Assert.Fail("Expected ArgumentException was not thrown");
        }
        catch (ArgumentException)
        {
            // Expected
        }
    }

    [TestMethod]
    public async Task RecognizeSpeechAsync_WithDifferentSampleRate_LogsWarning()
    {
        // Arrange
        var audioBytes = new byte[1000];
        for (int i = 0; i < audioBytes.Length; i++)
        {
            audioBytes[i] = (byte)(i % 256);
        }
        var wrongSampleRate = 44100; // Different from config's 16000
        var cancellationToken = CancellationToken.None;

        // Note: We can't easily verify the log message without more complex setup
        // This test verifies it doesn't throw with wrong sample rate
        
        // Act
        try
        {
            var result = await _service.RecognizeSpeechAsync(audioBytes, wrongSampleRate, null, cancellationToken);
            // If we get here, validation passed (though Python execution may fail)
        }
        catch (Exception ex) when (ex is TimeoutException || ex is InvalidOperationException)
        {
            // Expected when Python/Vosk is not installed
        }
    }

    [TestMethod]
    public async Task RecognizeSpeechFromFileAsync_WithNonExistentFile_ThrowsFileNotFoundException()
    {
        // Arrange
        var nonExistentFile = "/nonexistent/file.wav";
        var cancellationToken = CancellationToken.None;

        // Act
        try
        {
            await _service.RecognizeSpeechFromFileAsync(nonExistentFile, cancellationToken);
            Assert.Fail("Expected FileNotFoundException was not thrown");
        }
        catch (FileNotFoundException)
        {
            // Expected
        }
    }

    [TestMethod]
    public async Task RecognizeSpeechFromStreamAsync_WithNullStream_ThrowsArgumentException()
    {
        // Arrange
        Stream nullStream = null!;
        var cancellationToken = CancellationToken.None;

        // Act
        try
        {
            await _service.RecognizeSpeechFromStreamAsync(nullStream, 16000, cancellationToken);
            Assert.Fail("Expected ArgumentException was not thrown");
        }
        catch (ArgumentException)
        {
            // Expected
        }
    }

    [TestMethod]
    public async Task RecognizeSpeechFromStreamAsync_WithNonReadableStream_ThrowsArgumentException()
    {
        // Arrange
        var nonReadableStream = new MemoryStream();
        nonReadableStream.Close(); // Make it non-readable
        var cancellationToken = CancellationToken.None;

        // Act
        try
        {
            await _service.RecognizeSpeechFromStreamAsync(nonReadableStream, 16000, cancellationToken);
            Assert.Fail("Expected ArgumentException was not thrown");
        }
        catch (ArgumentException)
        {
            // Expected
        }
    }

    [TestMethod]
    public async Task TestModelAsync_WithValidModel_ReturnsTrue()
    {
        // Arrange
        var cancellationToken = CancellationToken.None;

        // Act
        // This will test if the model directory exists
        var result = await _service.TestModelAsync(cancellationToken);

        // Assert
        // Should return true since we created the temp directory
        // Note: Actual recognition test may fail if Vosk is not installed
        Assert.IsTrue(result);
    }

    [TestMethod]
    public async Task GetModelInfoAsync_ReturnsModelInfo()
    {
        // Act
        var result = await _service.GetModelInfoAsync();

        // Assert
        Assert.IsNotNull(result);
        Assert.IsNotNull(result.ModelName);
        Assert.IsNotNull(result.ModelPath);
        Assert.AreEqual(_tempModelPath, result.ModelPath);
    }

    [TestMethod]
    public void VoskConfig_Validate_WithValidConfig_Passes()
    {
        // Arrange
        var config = new VoskConfig
        {
            PythonPath = "python3",
            ModelPath = "/path/to/model",
            SampleRate = 16000,
            TimeoutSeconds = 30,
            BeamWidth = 20
        };

        // Act & Assert
        // Should not throw
        config.Validate();
    }

    [TestMethod]
    public void VoskConfig_Validate_WithEmptyPythonPath_Throws()
    {
        // Arrange
        var config = new VoskConfig
        {
            PythonPath = "",
            ModelPath = "/path/to/model",
            SampleRate = 16000
        };

        // Act
        try
        {
            config.Validate();
            Assert.Fail("Expected ArgumentException was not thrown");
        }
        catch (ArgumentException)
        {
            // Expected
        }
    }

    [TestMethod]
    public void VoskConfig_Validate_WithInvalidSampleRate_Throws()
    {
        // Arrange
        var config = new VoskConfig
        {
            PythonPath = "python3",
            ModelPath = "/path/to/model",
            SampleRate = 0
        };

        // Act
        try
        {
            config.Validate();
            Assert.Fail("Expected ArgumentException was not thrown");
        }
        catch (ArgumentException)
        {
            // Expected
        }
    }

    [TestMethod]
    public void VoskConfig_Validate_WithInvalidTimeout_Throws()
    {
        // Arrange
        var config = new VoskConfig
        {
            PythonPath = "python3",
            ModelPath = "/path/to/model",
            SampleRate = 16000,
            TimeoutSeconds = 0
        };

        // Act
        try
        {
            config.Validate();
            Assert.Fail("Expected ArgumentException was not thrown");
        }
        catch (ArgumentException)
        {
            // Expected
        }
    }

    [TestMethod]
    public void ParseVoskOutput_WithJsonText_ReturnsText()
    {
        // This is a private method, tested indirectly
        // We can't test it directly without reflection
    }
}