BE_HR_q1.php

<?php

class Order
{
  /** @var int */
  private $id;

  /** @var OrderItem[] */
  private $orderedItems = [];

  /** @var int */
  private $itemCount = 0;

  /** @var float */
  private $totalAmount = 0;

  public function __construct($orderItems)
  {
    $this->id = $this->generateId();
    $this->addOrderItem($orderItems);
    $this->calculateTotals();
  }

  /**
   * @return OrderItem[]
   */
  public function getOrderedItems(): array
  {
    return $this->orderedItems;
  }

  /**
   * Supply an OrderItem or Array of OrderItems
   * to be added to the orderItems list
   * @param OrderItem|OrderItem[] $orderItems
   */
  public function addOrderItem($orderItems): void
  {
    $orderItems = is_array($orderItems) ? $orderItems : [$orderItems];
    $this->orderedItems = array_merge($this->orderedItems, array_map(function ($orderedItem) {
      if ($orderedItem instanceof OrderItem) {
        return $orderedItem;
      }
    }, $orderItems));
    $this->calculateTotals();
  }

  /**
   * Supply an OrderItem [id] or Array of OrderItem [id]s
   * to be removed from the orderItems list
   * @param Int|Int[] $removable
   */
  public function removeOrderItem($removable): void
  {
    $removables = is_array($removable) ? $removable : [$removable];
    $this->orderedItems = array_filter($this->orderedItems, function ($orderedItem) use ($removables) {
      return in_array($orderedItem->id, $removables);
    });
    $this->calculateTotals();
  }

  /**
   * @return int
   */
  public function getItemCount(): int
  {
    return $this->itemCount;
  }

  /**
   * @return float
   */
  public function getTotalAmount(): int
  {
    return $this->totalAmount;
  }

  private function calculateTotals(): void
  {
    $this->itemCount = count($this->orderedItems);
    $this->totalAmount = 0;
    foreach ($this->orderedItems as $orderedItem) {
      $this->totalAmount += $orderedItem->amount;
    }
  }

  private function generateId(): int
  {
    return random_int(1, 99999);
  }
}


class OrderItem
{
  /** @var int */
  private $id;

  /** @var Item */
  private $orderItem;

  /** @var float */
  private $quantity;

  /** @var int */
  public $amount;

  public function __construct(Item $orderItem, Float $quantity)
  {
    $this->id = $this->generateId();
    $this->orderItem = $orderItem;
    $this->quantity = $quantity;
    $this->calculateAmount();
  }

  public function setOrderItem(OrderItem $orderItem)
  {
    $this->orderItem = $orderItem;
    $this->calculateAmount();
  }

  public function setQuantity(Float $quantity)
  {
    $this->quantity = $quantity;
    $this->calculateAmount();
  }

  private function calculateAmount(): void
  {
    $this->amount = $this->quantity * $this->orderItem->price;
  }

  private function generateId(): int
  {
    return random_int(1, 9999);
  }
}


/**
 * Creates a new Order Item
 * @param String $name
 * @param Float $price
 */
class Item
{
  /** @var int */
  private $id;

  /** @var int */
  private $price;

  public function __construct(String $name, Float $price)
  {
    $this->id = $this->generateId();
    $this->name = $name;
    $this->price = $price;
  }

  private function generateId(): int
  {
    return random_int(1, 999);
  }
}