Bundles code review

gistfile1.txt

// 1. return the number of bundle that can be assembled from a list of products
// 2. Bundle is a tree of products with multiple nested levels
// 3. return the count without knowing the number of tree levels (N Stages).

int getBundleCount(List<Product> products, Product bundle) {
  Map<String, int> productsListLeaves = {};
  for (Product product in products) {
    if (productsListLeaves[product.name] == null) {
      productsListLeaves[product.name] = 1;
    } else {
      productsListLeaves[product.name] = productsListLeaves[product.name]! + 1;
    }
  }
  Map<String, int> bundleLeaves = bundle.getLeaves();

  int? count;
  for (String productType in bundleLeaves.keys) {
    int result = productsListLeaves[productType]! ~/ bundleLeaves[productType]!;
    if (count == null || result < count) {
      count = result;
    }
  }
  return count ?? 0;
}

void main() {
  Product piece1 = Product('piece1', {});
  Product piece2 = Product('piece2', {});
  Product seat = Product('Seat', {piece1: 1, piece2: 1});
  Product pedal = Product('Pedal', {});
  Product wheel = Product('Wheel', {});
  Product bike = Product('Bike', {seat: 1, pedal: 2, wheel: 2});
  Product car = Product('Car', {seat: 2, wheel: 4});
  
  // There should be one instance of each product
  // Each product holds a quantity field that determines how many units are in stock.
  // For example: instead of having multiple wheels, we should have one product named Wheel where Wheel.Quantity = 4.
  
  List<Product> products = [
    piece1,
    piece2,
    pedal,
    pedal,
    wheel,
    wheel,
    piece1,
    piece2,
    pedal,
    pedal,
    wheel,
    wheel,
    piece1,
    piece2,
    piece1,
    piece2,
  ];

  print('cars count: ${getBundleCount(products, car)}');
  print('bikes count: ${getBundleCount(products, bike)}');
}

class Product {
  String name;
  Map<Product, int> children;

  Product(this.name, this.children);

  Map<String, int> getLeaves() {
    Map<String, int> leaves = {};
    children.forEach((key, value) {
      if (key.children.isEmpty) {
        leaves[key.name] = value;
      } else {
        key.getLeaves().forEach((k, v) {
          leaves[k] = v * value;
        });
      }
    });
    return leaves;
  }

  @override
  bool operator ==(Object other) =>
      identical(this, other) ||
      other is Product &&
          runtimeType == other.runtimeType &&
          name == other.name &&
          children == other.children;

  @override
  int get hashCode => name.hashCode ^ children.hashCode;
}