/// Domain Entity: Cart
///
/// Represents a shopping cart for a user.
library;

/// Cart Entity
///
/// Contains cart-level information:
/// - User ID
/// - Total amount
/// - Sync status
/// - Timestamps
class Cart {
  /// Unique cart identifier
  final String cartId;

  /// User ID who owns this cart
  final String userId;

  /// Total cart amount
  final double totalAmount;

  /// Whether cart is synced with backend
  final bool isSynced;

  /// Last modification timestamp
  final DateTime lastModified;

  /// Cart creation timestamp
  final DateTime createdAt;

  const Cart({
    required this.cartId,
    required this.userId,
    required this.totalAmount,
    required this.isSynced,
    required this.lastModified,
    required this.createdAt,
  });

  /// Check if cart is empty
  bool get isEmpty => totalAmount == 0;

  /// Check if cart needs sync
  bool get needsSync => !isSynced;

  /// Copy with method for immutability
  Cart copyWith({
    String? cartId,
    String? userId,
    double? totalAmount,
    bool? isSynced,
    DateTime? lastModified,
    DateTime? createdAt,
  }) {
    return Cart(
      cartId: cartId ?? this.cartId,
      userId: userId ?? this.userId,
      totalAmount: totalAmount ?? this.totalAmount,
      isSynced: isSynced ?? this.isSynced,
      lastModified: lastModified ?? this.lastModified,
      createdAt: createdAt ?? this.createdAt,
    );
  }

  @override
  bool operator ==(Object other) {
    if (identical(this, other)) return true;

    return other is Cart &&
        other.cartId == cartId &&
        other.userId == userId &&
        other.totalAmount == totalAmount &&
        other.isSynced == isSynced;
  }

  @override
  int get hashCode {
    return Object.hash(cartId, userId, totalAmount, isSynced);
  }

  @override
  String toString() {
    return 'Cart(cartId: $cartId, userId: $userId, totalAmount: $totalAmount, '
        'isSynced: $isSynced, lastModified: $lastModified)';
  }
}