<?php

/**
 * Chill is a software for social workers
 *
 * For the full copyright and license information, please view
 * the LICENSE file that was distributed with this source code.
 */

declare(strict_types=1);

namespace Chill\BudgetBundle\Calculator;

use Chill\BudgetBundle\Entity\AbstractElement;
use OutOfBoundsException;

use function array_key_exists;
use function array_keys;
use function implode;

class CalculatorManager
{
    /**
     * @var CalculatorInterface[]
     */
    protected $calculators = [];

    protected $defaultCalculator = [];

    public function addCalculator(CalculatorInterface $calculator, bool $default)
    {
        $this->calculators[$calculator::getAlias()] = $calculator;

        if ($default) {
            $this->defaultCalculator[] = $calculator::getAlias();
        }
    }

    /**
     * @param AbstractElement[] $elements
     *
     * @return CalculatorResult[]
     */
    public function calculateDefault(array $elements)
    {
        $results = [];

        foreach ($this->defaultCalculator as $alias) {
            $calculator = $this->calculators[$alias];
            $result = $calculator->calculate($elements);

            if (null !== $result) {
                $results[$calculator::getAlias()] = $result;
            }
        }

        return $results;
    }

    /**
     * @param string $alias
     *
     * @return CalculatorInterface
     */
    public function getCalculator($alias)
    {
        if (false === array_key_exists($alias, $this->calculators)) {
            throw new OutOfBoundsException("The calculator with alias '{$alias}' does "
                . 'not exists. Possible values are ' . implode(', ', array_keys($this->calculators)));
        }

        return $this->calculators[$alias];
    }
}