extension StringExtension on String {
  /// Capitalize first letter
  String capitalize() {
    if (isEmpty) return this;
    return '${this[0].toUpperCase()}${substring(1)}';
  }

  /// Check if string is a valid number
  bool isNumeric() {
    return double.tryParse(this) != null;
  }

  /// Truncate string with ellipsis
  String truncate(int maxLength, {String suffix = '...'}) {
    if (length <= maxLength) return this;
    return '${substring(0, maxLength)}$suffix';
  }
}

extension DateTimeExtension on DateTime {
  /// Check if date is today
  bool isToday() {
    final now = DateTime.now();
    return year == now.year && month == now.month && day == now.day;
  }

  /// Check if date is yesterday
  bool isYesterday() {
    final yesterday = DateTime.now().subtract(const Duration(days: 1));
    return year == yesterday.year && 
           month == yesterday.month && 
           day == yesterday.day;
  }

  /// Get relative time string (e.g., "2 hours ago")
  String getRelativeTime() {
    final now = DateTime.now();
    final difference = now.difference(this);

    if (difference.inSeconds < 60) {
      return 'Just now';
    } else if (difference.inMinutes < 60) {
      return '${difference.inMinutes}m ago';
    } else if (difference.inHours < 24) {
      return '${difference.inHours}h ago';
    } else if (difference.inDays < 7) {
      return '${difference.inDays}d ago';
    } else {
      return '${(difference.inDays / 7).floor()}w ago';
    }
  }
}

extension DoubleExtension on double {
  /// Round to specific decimal places
  double roundToDecimals(int decimals) {
    final mod = 10.0 * decimals;
    return (this * mod).round() / mod;
  }

  /// Format as currency
  String toCurrency({String symbol = '\$'}) {
    return '$symbol${toStringAsFixed(2)}';
  }
}

extension ListExtension<T> on List<T> {
  /// Check if list is not null and not empty
  bool get isNotEmpty => this.isNotEmpty;

  /// Get first element or null
  T? get firstOrNull => isEmpty ? null : first;

  /// Get last element or null
  T? get lastOrNull => isEmpty ? null : last;
}