<?php declare(strict_types=1);
/**
 * This file is part of the Phootwork package.
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 *
 * @license MIT License
 * @copyright Thomas Gossmann
 */
namespace phootwork\collection;

use Iterator;
use stdClass;

/**
 * CollectionUtils help to transform data recursively into collections.
 *
 * It must be mentioned the API is experimental and may change. Please
 * report to the issue tracker.
 */
class CollectionUtils {
	/**
	 * Returns a proper collection for the given array (also transforms nested collections)
	 * (experimental API)
	 *
	 * @param array|Iterator $collection
	 *
	 * @return Map|ArrayList the collection
	 *
	 * @psalm-suppress MixedReturnStatement `self::toCollection()` returns a collection if the input
	 *                                      is an array or Iterator
	 * @psalm-suppress MixedInferredReturnType
	 */
	public static function fromCollection(array|Iterator $collection): Map|ArrayList {
		return self::toCollection($collection);
	}

	/**
	 * @param mixed $data
	 *
	 * @return mixed
	 */
	private static function toCollection(mixed $data): mixed {
		// prepare normal array
		if (!($data instanceof Iterator)) {
			/** @var mixed $data */
			$data = json_decode(json_encode($data));
		}

		// check if we can transform it into a collection or just return as is
		if (!(is_array($data) || $data instanceof Iterator || $data instanceof stdClass)) {
			return $data;
		}

		// check we have a list
		if (is_array($data) || $data instanceof AbstractList) {
			return self::toList($data);
		}

		// everything else must be a map
		return self::toMap($data);
	}

	/**
	 * Recursively transforms data into a map (on the first level, deeper levels
	 * transformed to an appropriate collection) (experimental API)
	 *
	 * @param array|Iterator|stdClass $collection
	 *
	 * @return Map
	 */
	public static function toMap(Iterator|array|stdClass $collection): Map {
		if ($collection instanceof stdClass) {
			/** @var array $collection */
			$collection = json_decode(json_encode($collection), true);
		}

		$map = new Map();
		/**
		 * @var string $k
		 * @var string $v
		 */
		foreach ($collection as $k => $v) {
			$map->set($k, self::toCollection($v));
		}

		return $map;
	}

	/**
	 * Recursively transforms data into a list (on the first level, deeper levels
	 * transformed to an appropriate collection) (experimental API)
	 *
	 * @param array|Iterator $collection
	 *
	 * @return ArrayList
	 */
	public static function toList(Iterator|array $collection): ArrayList {
		$list = new ArrayList();
		/** @var mixed $v */
		foreach ($collection as $v) {
			$list->add(self::toCollection($v));
		}

		return $list;
	}

	/**
	 * Recursively exports a collection to an array
	 *
	 * @param mixed $collection
	 *
	 * @return array
	 *
	 * @psalm-suppress MixedAssignment
	 */
	public static function toArrayRecursive(mixed $collection): array {
		$arr = $collection;
		if (is_object($collection) && method_exists($collection, 'toArray')) {
			$arr = $collection->toArray();
		}

		/** @var array $arr */
		return array_map(
			function (mixed $v): mixed {
				if (is_object($v) && method_exists($v, 'toArray')) {
					return static::toArrayRecursive($v);
				}

				return $v;
			},
			$arr
		);
	}
}