<?php
namespace JVBase\managers\queue\mergers;

use JVBase\managers\queue\Mergeable;
use JVBase\managers\queue\Operation;

/**
 * Default merger, uses the chunkKey as the mergeable array
 */
final class DefaultMerger implements Mergeable
{
	public function __construct(
		private string|array $chunkKey
	) {}

	public function canMerge(Operation $existing, Operation $incoming): bool
	{
		foreach ((array) $this->chunkKey as $key) {
			if (!isset($incoming->requestData[$key])) {
				return false;
			}
		}
		return true;
	}

	public function merge(Operation $existing, Operation $incoming): Operation
	{
		foreach ((array) $this->chunkKey as $key) {
			$existing->requestData[$key] = array_merge(
				$existing->requestData[$key] ?? [],
				$incoming->requestData[$key] ?? []
			);
		}

		$existing->totalItems += $incoming->totalItems;
		return $existing;
	}
}