<?php

/**

 * WordPress List utility class

 *

 * @package WordPress

 * @since 4.7.0

 */

/**

 * List utility.

 *

 * Utility class to handle operations on an array of objects.

 *

 * @since 4.7.0

 */

class WP_List_Util {

	/**

	 * The input array.

	 *

	 * @since 4.7.0

	 * @var array

	 */

	private $input = array();

	/**

	 * The output array.

	 *

	 * @since 4.7.0

	 * @var array

	 */

	private $output = array();

	/**

	 * Temporary arguments for sorting.

	 *

	 * @since 4.7.0

	 * @var array

	 */

	private $orderby = array();

	/**

	 * Constructor.

	 *

	 * Sets the input array.

	 *

	 * @since 4.7.0

	 *

	 * @param array $input Array to perform operations on.

	 */

	public function __construct( $input ) {

	}

	/**

	 * Returns the original input array.

	 *

	 * @since 4.7.0

	 *

	 * @return array The input array.

	 */

	public function get_input() {

		return $this->input;

	}

	/**

	 * Returns the output array.

	 *

	 * @since 4.7.0

	 *

	 * @return array The output array.

	 */

	public function get_output() {

		return $this->output;

	}

	/**

	 * Filters the list, based on a set of key => value arguments.

	 *

	 * @since 4.7.0

	 *

	 * @param array  $args     Optional. An array of key => value arguments to match

	 *                         against each object. Default empty array.

	 * @param string $operator Optional. The logical operation to perform. 'AND' means

	 *                         all elements from the array must match. 'OR' means only

	 *                         one element needs to match. 'NOT' means no elements may

	 *                         match. Default 'AND'.

	 * @return array Array of found values.

	 */

	public function filter( $args = array(), $operator = 'AND' ) {

		if ( empty( $args ) ) {

			return $this->output;

		}

		$operator = strtoupper( $operator );

		if ( ! in_array( $operator, array( 'AND', 'OR', 'NOT' ), true ) ) {

			return array();

		}

		$count    = count( $args );

		$filtered = array();

		foreach ( $this->output as $key => $obj ) {

			foreach ( $args as $m_key => $m_value ) {

				}

			}

			) {

				$filtered[ $key ] = $obj;

			}

		}

		$this->output = $filtered;

		return $this->output;

	}

	/**

	 * Plucks a certain field out of each object in the list.

	 *

	 * This has the same functionality and prototype of

	 * array_column() (PHP 5.5) but also supports objects.

	 *

	 * @since 4.7.0

	 *

	 * @param int|string $field     Field from the object to place instead of the entire object

	 * @param int|string $index_key Optional. Field from the object to use as keys for the new array.

	 *                              Default null.

	 * @return array Array of found values. If `$index_key` is set, an array of found values with keys

	 *               corresponding to `$index_key`. If `$index_key` is null, array keys from the original

	 *               `$list` will be preserved in the results.

	 */

	public function pluck( $field, $index_key = null ) {

		$newlist = array();

		if ( ! $index_key ) {

			/*

			 * This is simple. Could at some point wrap array_column()

			 * if we knew we had an array of arrays.

			 */

			foreach ( $this->output as $key => $value ) {

				if ( is_object( $value ) ) {

					$newlist[ $key ] = $value->$field;

				} else {

					$newlist[ $key ] = $value[ $field ];

				}

			}

			$this->output = $newlist;

			return $this->output;

		}

		/*

		 * When index_key is not set for a particular item, push the value

		 * to the end of the stack. This is how array_column() behaves.

		 */

		foreach ( $this->output as $value ) {

			if ( is_object( $value ) ) {

				if ( isset( $value->$index_key ) ) {

					$newlist[ $value->$index_key ] = $value->$field;

				} else {

					$newlist[] = $value->$field;

				}

			} else {

				if ( isset( $value[ $index_key ] ) ) {

					$newlist[ $value[ $index_key ] ] = $value[ $field ];

				} else {

					$newlist[] = $value[ $field ];

				}

			}

		}

		$this->output = $newlist;

		return $this->output;

	}

	/**

	 * Sorts the list, based on one or more orderby arguments.

	 *

	 * @since 4.7.0

	 *

	 * @param string|array $orderby       Optional. Either the field name to order by or an array

	 *                                    of multiple orderby fields as $orderby => $order.

	 * @param string       $order         Optional. Either 'ASC' or 'DESC'. Only used if $orderby

	 *                                    is a string.

	 * @param bool         $preserve_keys Optional. Whether to preserve keys. Default false.

	 * @return array The sorted array.

	 */

	public function sort( $orderby = array(), $order = 'ASC', $preserve_keys = false ) {

		if ( empty( $orderby ) ) {

			return $this->output;

		}

		if ( is_string( $orderby ) ) {

			$orderby = array( $orderby => $order );

		}

		foreach ( $orderby as $field => $direction ) {

			$orderby[ $field ] = 'DESC' === strtoupper( $direction ) ? 'DESC' : 'ASC';

		}

		$this->orderby = $orderby;

		if ( $preserve_keys ) {

			uasort( $this->output, array( $this, 'sort_callback' ) );

		} else {

			usort( $this->output, array( $this, 'sort_callback' ) );

		}

		$this->orderby = array();

		return $this->output;

	}

	/**

	 * Callback to sort the list by specific fields.

	 *

	 * @since 4.7.0

	 *

	 * @see WP_List_Util::sort()

	 *

	 * @param object|array $a One object to compare.

	 * @param object|array $b The other object to compare.

	 * @return int 0 if both objects equal. -1 if second object should come first, 1 otherwise.

	 */

	private function sort_callback( $a, $b ) {

		if ( empty( $this->orderby ) ) {

			return 0;

		}

		$a = (array) $a;

		$b = (array) $b;

		foreach ( $this->orderby as $field => $direction ) {

			if ( ! isset( $a[ $field ] ) || ! isset( $b[ $field ] ) ) {

				continue;

			}

			if ( $a[ $field ] == $b[ $field ] ) {

				continue;

			}

			$results = 'DESC' === $direction ? array( 1, -1 ) : array( -1, 1 );

			if ( is_numeric( $a[ $field ] ) && is_numeric( $b[ $field ] ) ) {

				return ( $a[ $field ] < $b[ $field ] ) ? $results[0] : $results[1];

			}

			return 0 > strcmp( $a[ $field ], $b[ $field ] ) ? $results[0] : $results[1];

		}

		return 0;

	}

}