feat: replace OpenSSL with native Blowfish decryption and add library rescan

- Replace OpenSSL subprocess with BouncyCastle native Blowfish CBC decryption
- Add automatic Subsonic library scan trigger after downloads (with 30s debounce)
- Improve error handling in DeezerMetadataService search methods
- Add comprehensive tests for download service, metadata service, and library service
- Increase test coverage from 13 to 32 tests

octo-fiesta.Tests/DeezerDownloadServiceTests.cs

@@ -0,0 +1,165 @@
+using octo_fiesta.Services;
+using octo_fiesta.Models;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using Moq;
+using Moq.Protected;
+using System.Net;
+using System.Text.Json;
+
+namespace octo_fiesta.Tests;
+
+public class DeezerDownloadServiceTests : IDisposable
+{
+    private readonly Mock<IHttpClientFactory> _httpClientFactoryMock;
+    private readonly Mock<HttpMessageHandler> _httpMessageHandlerMock;
+    private readonly Mock<ILocalLibraryService> _localLibraryServiceMock;
+    private readonly Mock<IMusicMetadataService> _metadataServiceMock;
+    private readonly Mock<ILogger<DeezerDownloadService>> _loggerMock;
+    private readonly IConfiguration _configuration;
+    private readonly string _testDownloadPath;
+
+    public DeezerDownloadServiceTests()
+    {
+        _testDownloadPath = Path.Combine(Path.GetTempPath(), "octo-fiesta-download-tests-" + Guid.NewGuid());
+        Directory.CreateDirectory(_testDownloadPath);
+
+        _httpMessageHandlerMock = new Mock<HttpMessageHandler>();
+        var httpClient = new HttpClient(_httpMessageHandlerMock.Object);
+        
+        _httpClientFactoryMock = new Mock<IHttpClientFactory>();
+        _httpClientFactoryMock.Setup(f => f.CreateClient(It.IsAny<string>())).Returns(httpClient);
+
+        _localLibraryServiceMock = new Mock<ILocalLibraryService>();
+        _metadataServiceMock = new Mock<IMusicMetadataService>();
+        _loggerMock = new Mock<ILogger<DeezerDownloadService>>();
+
+        _configuration = new ConfigurationBuilder()
+            .AddInMemoryCollection(new Dictionary<string, string?>
+            {
+                ["Library:DownloadPath"] = _testDownloadPath,
+                ["Deezer:Arl"] = null,
+                ["Deezer:ArlFallback"] = null
+            })
+            .Build();
+    }
+
+    public void Dispose()
+    {
+        if (Directory.Exists(_testDownloadPath))
+        {
+            Directory.Delete(_testDownloadPath, true);
+        }
+    }
+
+    private DeezerDownloadService CreateService(string? arl = null)
+    {
+        var config = new ConfigurationBuilder()
+            .AddInMemoryCollection(new Dictionary<string, string?>
+            {
+                ["Library:DownloadPath"] = _testDownloadPath,
+                ["Deezer:Arl"] = arl,
+                ["Deezer:ArlFallback"] = null
+            })
+            .Build();
+
+        return new DeezerDownloadService(
+            _httpClientFactoryMock.Object,
+            config,
+            _localLibraryServiceMock.Object,
+            _metadataServiceMock.Object,
+            _loggerMock.Object);
+    }
+
+    [Fact]
+    public async Task IsAvailableAsync_WithoutArl_ReturnsFalse()
+    {
+        // Arrange
+        var service = CreateService(arl: null);
+
+        // Act
+        var result = await service.IsAvailableAsync();
+
+        // Assert
+        Assert.False(result);
+    }
+
+    [Fact]
+    public async Task IsAvailableAsync_WithEmptyArl_ReturnsFalse()
+    {
+        // Arrange
+        var service = CreateService(arl: "");
+
+        // Act
+        var result = await service.IsAvailableAsync();
+
+        // Assert
+        Assert.False(result);
+    }
+
+    [Fact]
+    public async Task DownloadSongAsync_WithUnsupportedProvider_ThrowsNotSupportedException()
+    {
+        // Arrange
+        var service = CreateService(arl: "test-arl");
+
+        // Act & Assert
+        await Assert.ThrowsAsync<NotSupportedException>(() => 
+            service.DownloadSongAsync("spotify", "123456"));
+    }
+
+    [Fact]
+    public async Task DownloadSongAsync_WhenAlreadyDownloaded_ReturnsExistingPath()
+    {
+        // Arrange
+        var existingPath = Path.Combine(_testDownloadPath, "existing-song.mp3");
+        await File.WriteAllTextAsync(existingPath, "fake audio content");
+
+        _localLibraryServiceMock
+            .Setup(s => s.GetLocalPathForExternalSongAsync("deezer", "123456"))
+            .ReturnsAsync(existingPath);
+
+        var service = CreateService(arl: "test-arl");
+
+        // Act
+        var result = await service.DownloadSongAsync("deezer", "123456");
+
+        // Assert
+        Assert.Equal(existingPath, result);
+    }
+
+    [Fact]
+    public void GetDownloadStatus_WithUnknownSongId_ReturnsNull()
+    {
+        // Arrange
+        var service = CreateService(arl: "test-arl");
+
+        // Act
+        var result = service.GetDownloadStatus("unknown-id");
+
+        // Assert
+        Assert.Null(result);
+    }
+
+    [Fact]
+    public async Task DownloadSongAsync_WhenSongNotFound_ThrowsException()
+    {
+        // Arrange
+        _localLibraryServiceMock
+            .Setup(s => s.GetLocalPathForExternalSongAsync("deezer", "999999"))
+            .ReturnsAsync((string?)null);
+
+        _metadataServiceMock
+            .Setup(s => s.GetSongAsync("deezer", "999999"))
+            .ReturnsAsync((Song?)null);
+
+        var service = CreateService(arl: "test-arl");
+
+        // Act & Assert
+        var exception = await Assert.ThrowsAsync<Exception>(() => 
+            service.DownloadSongAsync("deezer", "999999"));
+        
+        Assert.Equal("Song not found", exception.Message);
+    }
+}