Initial Commit after switching from SVN to git

Fuchs/Logging/FuchsLoggerProvider.cs

@@ -0,0 +1,117 @@
+using Microsoft.Extensions.Logging;
+using System.Diagnostics;
+
+namespace Fuchs.Logging;
+
+/// <summary>
+/// Writes log entries to Debug output and a rolling file.
+/// Database logging is wired up but disabled — set <see cref="DatabaseLoggingEnabled"/> to true to activate.
+/// </summary>
+public sealed class FuchsLoggerProvider : ILoggerProvider
+{
+    private readonly string _logDirectory;
+
+    /// <summary>Set to true to activate database logging via the Fuchs admin log procedure.</summary>
+    public static bool DatabaseLoggingEnabled { get; set; } = false;
+
+    public FuchsLoggerProvider(string? logDirectory = null)
+    {
+        _logDirectory = logDirectory
+            ?? Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "logs");
+        Directory.CreateDirectory(_logDirectory);
+    }
+
+    public ILogger CreateLogger(string categoryName) =>
+        new FuchsLogger(categoryName, _logDirectory);
+
+    public void Dispose() { }
+}
+
+internal sealed class FuchsLogger : ILogger
+{
+    private readonly string _categoryName;
+    private readonly string _logDirectory;
+    private static readonly Lock _fileLock = new();
+
+    internal FuchsLogger(string categoryName, string logDirectory)
+    {
+        _categoryName = categoryName;
+        _logDirectory = logDirectory;
+    }
+
+    public IDisposable? BeginScope<TState>(TState state) where TState : notnull => null;
+
+    public bool IsEnabled(LogLevel logLevel) => logLevel != LogLevel.None;
+
+    public void Log<TState>(LogLevel logLevel, EventId eventId, TState state,
+        Exception? exception, Func<TState, Exception?, string> formatter)
+    {
+        if (!IsEnabled(logLevel)) return;
+
+        string message = formatter(state, exception);
+        string timestamp = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");
+        string levelTag = logLevel switch
+        {
+            LogLevel.Trace       => "TRC",
+            LogLevel.Debug       => "DBG",
+            LogLevel.Information => "INF",
+            LogLevel.Warning     => "WRN",
+            LogLevel.Error       => "ERR",
+            LogLevel.Critical    => "CRT",
+            _                    => "???"
+        };
+
+        string line = $"{timestamp} [{levelTag}] {_categoryName}: {message}";
+        if (exception != null)
+            line += $"\r\n  Exception: {exception.Message}\r\n  Stack: {exception.StackTrace}";
+
+        // Always emit to Debug output
+        Debug.WriteLine(line);
+
+        // Write to file
+        string filename = logLevel >= LogLevel.Error ? "ErrorLog.txt" : "AppLog.txt";
+        AppendToFile(filename, line);
+
+        // Database logging — prepared, not activated
+        if (FuchsLoggerProvider.DatabaseLoggingEnabled)
+            WriteToDatabase(_categoryName, message, exception);
+    }
+
+    private void AppendToFile(string filename, string line)
+    {
+        try
+        {
+            lock (_fileLock)
+                File.AppendAllText(Path.Combine(_logDirectory, filename), line + "\r\n");
+        }
+        catch { /* never throw from logger */ }
+    }
+
+    /// <summary>
+    /// Prepared DB logging for the Fuchs web project.
+    /// Enable by setting <see cref="FuchsLoggerProvider.DatabaseLoggingEnabled"/> = true in Program.cs or appsettings.
+    /// </summary>
+    private static void WriteToDatabase(string codeReference, string message, Exception? exception)
+    {
+        // Activate by setting FuchsLoggerProvider.DatabaseLoggingEnabled = true.
+        //
+        // using var con = new Microsoft.Data.SqlClient.SqlConnection(/* Fuchs connection string */);
+        // using var cmd = new Microsoft.Data.SqlClient.SqlCommand(
+        //     "EXECUTE [dbo].[fuchs__admin_logdebug] @CodeReference, @ExceptionMessage, @StackTrace, @Data;", con);
+        // cmd.Parameters.AddWithValue("@CodeReference", codeReference);
+        // cmd.Parameters.AddWithValue("@ExceptionMessage", (object?)exception?.Message ?? DBNull.Value);
+        // cmd.Parameters.AddWithValue("@StackTrace",       (object?)exception?.StackTrace ?? DBNull.Value);
+        // cmd.Parameters.AddWithValue("@Data",             message);
+        // con.Open();
+        // cmd.ExecuteNonQuery();
+    }
+}
+
+public static class FuchsLoggingExtensions
+{
+    public static ILoggingBuilder AddFuchsLogging(this ILoggingBuilder builder, string? logDirectory = null)
+    {
+        builder.AddProvider(new FuchsLoggerProvider(logDirectory));
+        return builder;
+    }
+}