export type ClientCartItem = {
  productId: string;
  productName: string;
  sku: string;
  isCustomizable: boolean;
  quantity: number;
  parameters: {
    width: number;
    thickness: number;
    color: string;
  };
};

function normalizeQuantity(value: number) {
  if (!Number.isFinite(value) || value < 1) {
    return 1;
  }

  return Math.floor(value);
}

export function useClientCart() {
  const items = useState<ClientCartItem[]>('client-cart-items', () => []);

  const totalPositions = computed(() => items.value.length);
  const totalItems = computed(() => items.value.reduce((sum, item) => sum + item.quantity, 0));
  const totalVolume = computed(() =>
    items.value.reduce((sum, item) => sum + item.quantity * item.parameters.width * item.parameters.thickness, 0),
  );

  function getQuantity(productId: string) {
    return items.value.find((item) => item.productId === productId)?.quantity ?? 0;
  }

  function addProduct(product: {
    id: string;
    name: string;
    sku: string;
    isCustomizable: boolean;
  }) {
    const existing = items.value.find((item) => item.productId === product.id);
    if (existing) {
      existing.quantity += 1;
      return;
    }

    items.value.push({
      productId: product.id,
      productName: product.name,
      sku: product.sku,
      isCustomizable: product.isCustomizable,
      quantity: 1,
      parameters: {
        width: 100,
        thickness: 50,
        color: 'прозрачный',
      },
    });
  }

  function setQuantity(productId: string, quantity: number) {
    const existing = items.value.find((item) => item.productId === productId);
    if (!existing) {
      return;
    }

    existing.quantity = normalizeQuantity(quantity);
  }

  function incrementQuantity(productId: string) {
    const existing = items.value.find((item) => item.productId === productId);
    if (!existing) {
      return;
    }

    existing.quantity += 1;
  }

  function decrementQuantity(productId: string) {
    const existing = items.value.find((item) => item.productId === productId);
    if (!existing) {
      return;
    }

    existing.quantity = normalizeQuantity(existing.quantity - 1);
  }

  function removeProduct(productId: string) {
    items.value = items.value.filter((item) => item.productId !== productId);
  }

  function clearCart() {
    items.value = [];
  }

  return {
    items,
    totalPositions,
    totalItems,
    totalVolume,
    addProduct,
    setQuantity,
    incrementQuantity,
    decrementQuantity,
    removeProduct,
    clearCart,
    getQuantity,
  };
}