apskel-pos-flutter-v2/lib/domain/product/entities/product_quantity_entity.dart

part of '../product.dart';

/// Satu baris keranjang.
///
/// Untuk produk timbangan, **satu penimbangan = satu baris**: dua kali menimbang
/// Ikan Tude menghasilkan dua baris terpisah dengan [quantity] 1 dan [weight]
/// masing-masing. Karena itu baris dibedakan lewat [lineId], bukan lewat
/// kombinasi produk + varian.
@freezed
class ProductQuantity with _$ProductQuantity {
  const ProductQuantity._();

  const factory ProductQuantity({
    required Product product,
    ProductVariant? variant,
    required int quantity,
    required String notes,
    @Default('') String lineId,

    /// Angka timbangan dalam satuan produk. `null` untuk produk cacah.
    double? weight,
  }) = _ProductQuantity;

  factory ProductQuantity.empty() =>
      ProductQuantity(product: Product.empty(), quantity: 0, notes: '');

  bool get isWeighted => weight != null;

  double get unitPrice => product.price + (variant?.priceModifier ?? 0);

  /// Harga baris: `weight × unit_price` untuk timbangan, `quantity × unit_price`
  /// untuk produk cacah.
  double get lineTotal =>
      isWeighted ? unitPrice * weight! : unitPrice * quantity;

  /// `4,2 ons` atau `2` — dipakai di kolom Qty keranjang.
  String get quantityLabel {
    if (!isWeighted) return quantity.toString();
    final label = product.unitLabel;
    final value = weight!.weightFormat;
    return label.isEmpty ? value : '$value $label';
  }
}

extension ProductQuantityListExt on List<ProductQuantity> {
  /// Total keranjang: baris berbobot pakai `weight × harga`, baris cacah pakai
  /// `quantity × harga`.
  double get cartTotal => fold<double>(0, (sum, item) => sum + item.lineTotal);

  /// Baris berbobot dihitung satu — satu penimbangan, satu barang.
  int get cartItemCount =>
      fold<int>(0, (sum, item) => sum + (item.isWeighted ? 1 : item.quantity));
}