using System.Runtime.CompilerServices;

namespace IBKRTrader.Core.Logging;

/// <summary>
/// Thread-sicherer Logging-Service.
/// – Schreibt farbig in die RichTextBox (UI-Thread-safe via BeginInvoke)
/// – Schreibt in Logs\{Module}\{Level}-dd-MM-yy.txt
/// </summary>
public class LoggingService
{
    private RichTextBox? _rtb;
    private AppLogLevel  _minLevel = AppLogLevel.Info;
    private readonly object _fileLock = new();

    private static readonly string LogBaseDir =
        Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Logs");

    // ─── Konfiguration ────────────────────────────────────────────────────────

    public void AttachRichTextBox(RichTextBox rtb) => _rtb = rtb;

    public void SetMinLevel(AppLogLevel level) => _minLevel = level;

    // ─── Öffentliche API ─────────────────────────────────────────────────────

    public void Info (string module, string message, Exception? ex = null)
        => Write(AppLogLevel.Info,  module, message, ex);

    public void Warn (string module, string message, Exception? ex = null)
        => Write(AppLogLevel.Warn,  module, message, ex);

    public void Error(string module, string message, Exception? ex = null)
        => Write(AppLogLevel.Error, module, message, ex);

    public void Write(AppLogLevel level, string module, string message, Exception? ex = null)
    {
        if (level < _minLevel) return;
        var entry = new LogEntry(DateTime.Now, level, module, message, ex);
        WriteToFile(entry);
        WriteToRtb(entry);
    }

    // ─── Datei ────────────────────────────────────────────────────────────────

    private void WriteToFile(LogEntry e)
    {
        try
        {
            var dir = Path.Combine(LogBaseDir, e.Module);
            Directory.CreateDirectory(dir);

            var file = Path.Combine(dir, $"{e.Level}-{e.Timestamp:dd-MM-yy}.txt");
            var line = $"[{e.Timestamp:HH:mm:ss}] {e.Message}";
            if (e.Exception != null)
                line += $"\r\n  {e.Exception}";

            lock (_fileLock)
                File.AppendAllText(file, line + "\r\n");
        }
        catch { /* Logging darf niemals abstürzen */ }
    }

    // ─── RichTextBox ──────────────────────────────────────────────────────────

    private static readonly Color ColorInfo  = Color.FromArgb(150, 210, 150);
    private static readonly Color ColorWarn  = Color.FromArgb(255, 190,  60);
    private static readonly Color ColorError = Color.FromArgb(255,  80,  80);

    private void WriteToRtb(LogEntry e)
    {
        if (_rtb == null) return;
        try
        {
            var color = e.Level switch
            {
                AppLogLevel.Warn  => ColorWarn,
                AppLogLevel.Error => ColorError,
                _                 => ColorInfo
            };
            var text = $"[{e.Timestamp:HH:mm:ss}] [{e.Level.ToString().ToUpper(),-5}] [{e.Module}] {e.Message}";
            if (e.Exception != null)
                text += $"\r\n  {e.Exception.Message}";
            text += "\r\n";

            if (_rtb.InvokeRequired)
                _rtb.BeginInvoke(() => AppendColored(text, color));
            else
                AppendColored(text, color);
        }
        catch { }
    }

    private void AppendColored(string text, Color color)
    {
        if (_rtb == null) return;
        _rtb.SelectionStart  = _rtb.TextLength;
        _rtb.SelectionLength = 0;
        _rtb.SelectionColor  = color;
        _rtb.AppendText(text);
        _rtb.SelectionColor  = _rtb.ForeColor;
        if (_rtb.TextLength > 0)
            _rtb.ScrollToCaret();
    }
}