refactor: Delay file logging until IAppPaths initialized

The logger, which also writes to a file in addition to console,
requires `IAppPaths` in order to find the directory to place the log
files. However, this cannot be obtained until the system calculates
the app data directory OR the user specifies it with the `--app-data`
option.

A custom sink has been added that will allow the logger to write to
console without file logs until that initialization is performed and
the log directory is available.

src/Recyclarr.Tests/Logging/DelayedFileSinkTest.cs

@@ -0,0 +1,29 @@
+using System.IO.Abstractions;
+using AutoFixture.NUnit3;
+using NSubstitute;
+using NUnit.Framework;
+using Recyclarr.Logging;
+using Serilog.Events;
+using TestLibrary.AutoFixture;
+using TrashLib;
+
+namespace Recyclarr.Tests.Logging;
+
+[TestFixture]
+[Parallelizable(ParallelScope.All)]
+public class DelayedFileSinkTest
+{
+    [Test, AutoMockData]
+    public void Should_not_open_file_if_app_data_invalid(
+        [Frozen] IAppPaths paths,
+        [Frozen] IFileSystem fs,
+        LogEvent logEvent,
+        DelayedFileSink sut)
+    {
+        paths.IsAppDataPathValid.Returns(false);
+
+        sut.Emit(logEvent);
+
+        fs.File.DidNotReceiveWithAnyArgs().OpenWrite(default!);
+    }
+}

src/Recyclarr/AppPaths.cs

@@ -16,6 +16,7 @@ public class AppPaths : IAppPaths
 
     public string DefaultConfigFilename => "recyclarr.yml";
 
+    public bool IsAppDataPathValid => _appDataPath is not null;
     public void SetAppDataPath(string path) => _appDataPath = path;
 
     [SuppressMessage("Design", "CA1024:Use properties where appropriate")]

src/Recyclarr/CompositionRoot.cs

@@ -32,6 +32,7 @@ public static class CompositionRoot
     private static void SetupLogging(ContainerBuilder builder)
     {
         builder.RegisterType<LogJanitor>().As<ILogJanitor>();
+        builder.RegisterType<DelayedFileSink>().As<IDelayedFileSink>();
         builder.RegisterType<LoggingLevelSwitch>().SingleInstance();
         builder.RegisterType<LoggerFactory>();
         builder.Register(c => c.Resolve<LoggerFactory>().Create())

src/Recyclarr/Logging/DelayedFileSink.cs

@@ -0,0 +1,39 @@
+using System.IO.Abstractions;
+using Serilog.Events;
+using TrashLib;
+
+namespace Recyclarr.Logging;
+
+public class DelayedFileSink : IDelayedFileSink
+{
+    private readonly IAppPaths _paths;
+    private readonly Lazy<StreamWriter> _stream;
+
+    public DelayedFileSink(IAppPaths paths, IFileSystem fs)
+    {
+        _paths = paths;
+        _stream = new Lazy<StreamWriter>(() =>
+        {
+            var logPath = fs.Path.Combine(_paths.LogDirectory, $"trash_{DateTime.Now:yyyy-MM-dd_HH-mm-ss}.log");
+            return fs.File.CreateText(logPath);
+        });
+    }
+
+    public void Emit(LogEvent logEvent)
+    {
+        if (!_paths.IsAppDataPathValid)
+        {
+            return;
+        }
+
+        _stream.Value.WriteLine(logEvent.RenderMessage());
+    }
+
+    public void Dispose()
+    {
+        if (_stream.IsValueCreated)
+        {
+            _stream.Value.Close();
+        }
+    }
+}

src/Recyclarr/Logging/IDelayedFileSink.cs

@@ -0,0 +1,7 @@
+using Serilog.Core;
+
+namespace Recyclarr.Logging;
+
+public interface IDelayedFileSink : ILogEventSink, IDisposable
+{
+}

src/Recyclarr/Logging/LoggerFactory.cs

@@ -1,33 +1,27 @@
-using System.IO.Abstractions;
 using Serilog;
 using Serilog.Core;
-using TrashLib;
 
 namespace Recyclarr.Logging;
 
 public class LoggerFactory
 {
-    private readonly IFileSystem _fs;
-    private readonly IAppPaths _paths;
     private readonly LoggingLevelSwitch _logLevel;
+    private readonly IDelayedFileSink _fileSink;
 
-    public LoggerFactory(IFileSystem fs, IAppPaths paths, LoggingLevelSwitch logLevel)
+    public LoggerFactory(LoggingLevelSwitch logLevel, IDelayedFileSink fileSink)
     {
-        _fs = fs;
-        _paths = paths;
         _logLevel = logLevel;
+        _fileSink = fileSink;
     }
 
     public ILogger Create()
     {
-        var logPath = _fs.Path.Combine(_paths.LogDirectory, $"trash_{DateTime.Now:yyyy-MM-dd_HH-mm-ss}.log");
-
         const string consoleTemplate = "[{Level:u3}] {Message:lj}{NewLine}{Exception}";
 
         return new LoggerConfiguration()
             .MinimumLevel.Debug()
             .WriteTo.Console(outputTemplate: consoleTemplate, levelSwitch: _logLevel)
-            .WriteTo.File(logPath)
+            .WriteTo.Sink(_fileSink)
             .CreateLogger();
     }
 }

src/TrashLib/IAppPaths.cs

@@ -10,4 +10,5 @@ public interface IAppPaths
     string RepoDirectory { get; }
     string CacheDirectory { get; }
     string DefaultConfigFilename { get; }
+    bool IsAppDataPathValid { get; }
 }