app-boilerplate/lib/core/logger.dart

import 'package:flutter/foundation.dart';

/// Log levels for different types of messages.
enum LogLevel {
  /// Debug messages (only in debug mode).
  debug,
  
  /// Informational messages.
  info,
  
  /// Warning messages.
  warning,
  
  /// Error messages (always shown).
  error,
}

/// Centralized logging service for the application.
/// 
/// Provides consistent logging across the app with different log levels.
/// In production, only errors are logged unless explicitly enabled.
class Logger {
  /// Whether logging is enabled (can be configured via config).
  static bool _enabled = kDebugMode;

  /// Enable or disable logging.
  static void setEnabled(bool enabled) {
    _enabled = enabled;
  }

  /// Logs a message with the specified level.
  /// 
  /// [level] - The log level (debug, info, warning, error).
  /// [message] - The message to log.
  /// [error] - Optional error object.
  /// [stackTrace] - Optional stack trace.
  static void log(
    LogLevel level,
    String message, [
    Object? error,
    StackTrace? stackTrace,
  ]) {
    // Always log errors, respect enabled flag for others
    if (!_enabled && level != LogLevel.error) {
      return;
    }

    final prefix = '[${level.name.toUpperCase()}]';
    final timestamp = DateTime.now().toIso8601String();
    
    debugPrint('$timestamp $prefix $message');
    
    if (error != null) {
      debugPrint('$timestamp $prefix Error: $error');
    }
    
    if (stackTrace != null) {
      debugPrint('$timestamp $prefix Stack trace: $stackTrace');
    }
  }

  /// Logs a debug message (only in debug mode).
  static void debug(String message) {
    log(LogLevel.debug, message);
  }

  /// Logs an informational message.
  static void info(String message) {
    log(LogLevel.info, message);
  }

  /// Logs a warning message.
  static void warning(String message, [Object? error]) {
    log(LogLevel.warning, message, error);
  }

  /// Logs an error message (always shown).
  static void error(String message, [Object? error, StackTrace? stackTrace]) {
    log(LogLevel.error, message, error, stackTrace);
  }
}