import 'package:flutter/foundation.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';
import 'dart:io';

class LogEntry {
  final String level; // DEBUG, INFO, WARNING, ERROR
  final String message;
  final String? stackTrace;
  final DateTime timestamp;
  final String? userAgent;
  final String? deviceModel;

  LogEntry({
    required this.level,
    required this.message,
    this.stackTrace,
    DateTime? timestamp,
    this.userAgent,
    this.deviceModel,
  }) : timestamp = timestamp ?? DateTime.now();

  Map<String, dynamic> toJson() => {
    'level': level,
    'message': message,
    'stackTrace': stackTrace,
    'timestamp': timestamp.toIso8601String(),
    'userAgent': userAgent,
    'deviceModel': deviceModel,
  };
}

/// Centralized Logging Service mit Auto-Upload zu Server
class LoggerService extends ChangeNotifier {
  static const String _logServerUrl = 'https://logs.baka-net.de/api/logs';
  static const int _batchSize = 5;

  final List<LogEntry> _logs = [];
  late final String _deviceModel;
  bool _initialized = false;

  Future<void> init() async {
    if (_initialized) return;
    // Datenschutz: nur grobe Plattform senden statt Hersteller+Modell
    // (das war ein Geräte-Fingerprint). Reicht für Bug-Triage.
    _deviceModel = Platform.isAndroid
        ? 'android'
        : (Platform.isIOS ? 'ios' : Platform.operatingSystem);
    _initialized = true;
    debugPrint('✅ LoggerService initialized for $_deviceModel');
  }

  // ─── Datenschutz: Bereinigung vor dem Server-Upload ───

  static const int _maxFrames = 8;

  /// Maskiert sensible Fragmente in Log-Freitext (message/stackTrace), bevor
  /// er an den Server geht: sensible `key=value`-Fragmente, Datei-Pfade,
  /// nackte URLs, Bearer-Token, JWTs und lange Hex-IDs.
  @visibleForTesting
  static String scrubText(String? roh) {
    if (roh == null || roh.isEmpty) return roh ?? '';
    var s = roh.replaceAllMapped(
      RegExp(r'\b(user|username|benutzer|pw|pass|passwort|password|token|secret|url|serverurl)=([^\s&]+)',
          caseSensitive: false),
      (m) => '${m.group(1)}=<redacted>',
    );
    s = s
        .replaceAll(RegExp(r'/(storage|data|home|Users|var)/\S+'), '<path>')
        .replaceAll(RegExp(r'https?://\S+'), '<url>')
        .replaceAll(RegExp(r'Bearer\s+[A-Za-z0-9._-]+'), 'Bearer <token>')
        .replaceAll(RegExp(r'eyJ[A-Za-z0-9._-]{10,}'), '<jwt>')
        .replaceAll(RegExp(r'\b[A-Fa-f0-9]{16,}\b'), '<hex>');
    return s;
  }

  /// Kürzt einen (bereits gescrubbten) Stack-Trace auf wenige Zeilen.
  @visibleForTesting
  static String capFrames(String s) {
    final zeilen = s.split('\n');
    if (zeilen.length <= _maxFrames) return s;
    final rest = zeilen.length - _maxFrames;
    return '${zeilen.take(_maxFrames).join('\n')}\n… ($rest weitere Zeilen entfernt)';
  }

  /// Bereinigter Upload-Payload eines Eintrags. Der lokale Puffer/debugPrint
  /// bleibt unberührt — die Maskierung greift nur auf dem Versand-Pfad.
  @visibleForTesting
  static Map<String, dynamic> sanitizedJson(LogEntry l) => {
        'level': l.level,
        'message': scrubText(l.message),
        'stackTrace':
            l.stackTrace == null ? null : capFrames(scrubText(l.stackTrace)),
        'timestamp': l.timestamp.toIso8601String(),
        'userAgent': l.userAgent,
        'deviceModel': l.deviceModel,
      };

  /// Logge einen Fehler (wird sofort zum Server geschickt)
  Future<void> error(String message, [Object? error, StackTrace? stackTrace]) async {
    final entry = LogEntry(
      level: 'ERROR',
      message: message,
      stackTrace: '$error\n$stackTrace',
      deviceModel: _deviceModel,
    );
    _logs.add(entry);
    debugPrint('❌ ERROR: $message');
    await _uploadIfError(entry);
  }

  /// Logge eine Warnung
  void warning(String message) {
    final entry = LogEntry(
      level: 'WARNING',
      message: message,
      deviceModel: _deviceModel,
    );
    _logs.add(entry);
    debugPrint('⚠️ WARNING: $message');
    _checkAndFlush();
  }

  /// Logge Info-Event
  void info(String message) {
    final entry = LogEntry(
      level: 'INFO',
      message: message,
      deviceModel: _deviceModel,
    );
    _logs.add(entry);
    debugPrint('ℹ️ INFO: $message');
    _checkAndFlush();
  }

  void _checkAndFlush() {
    if (_logs.length >= _batchSize) {
      _uploadLogs();
    }
  }

  Future<void> _uploadIfError(LogEntry entry) async {
    debugPrint('📤 Uploading ERROR immediately: ${entry.message}');
    await _uploadLogs();
  }

  /// Hochladen der Logs zum Server
  Future<void> _uploadLogs() async {
    if (_logs.isEmpty) return;
    try {
      final logsToUpload = List<LogEntry>.from(_logs);
      await http.post(
        Uri.parse(_logServerUrl),
        headers: {'Content-Type': 'application/json'},
        body: jsonEncode({
          'logs': logsToUpload.map(sanitizedJson).toList(),
          'timestamp': DateTime.now().toIso8601String(),
        }),
      ).timeout(const Duration(seconds: 10));
      _logs.clear();
      debugPrint('✅ Logs uploaded successfully (${logsToUpload.length} entries)');
    } catch (e) {
      debugPrint('⚠️ Failed to upload logs: $e');
    }
  }

  /// Manuelles Flushen (z.B. vor App-Exit)
  Future<void> flush() async {
    await _uploadLogs();
  }

  int get logCount => _logs.length;
}

/// Global Logger Instance
final logger = LoggerService();