<?php
/**
 * @license GPL-2.0-or-later
 * @file
 * @ingroup Parser
 */

namespace MediaWiki\Parser;

use RuntimeException;

/**
 * Stack class to help Preprocessor::preprocessToObj()
 * @ingroup Parser
 */
// phpcs:ignore Squiz.Classes.ValidClassName.NotCamelCaps
class PPDStack_Hash {
	/** @var PPDStackElement_Hash[] */
	public $stack;
	/** @var string[] */
	public $rootAccum;
	/** @var string[] */
	public $accum;

	/**
	 * @var PPDStackElement_Hash|false
	 */
	public $top;
	/** @var string|null */
	public $out;
	/** @var class-string<PPDStackElement_Hash> */
	public $elementClass = PPDStackElement_Hash::class;

	public function __construct() {
		$this->stack = [];
		$this->top = false;
		$this->rootAccum = [];
		$this->accum =& $this->rootAccum;
	}

	/**
	 * @return int
	 */
	public function count() {
		return count( $this->stack );
	}

	/** @inheritDoc */
	public function &getAccum() {
		return $this->accum;
	}

	/**
	 * @return false|PPDPart_Hash
	 */
	public function getCurrentPart() {
		if ( $this->top === false ) {
			return false;
		} else {
			return $this->top->getCurrentPart();
		}
	}

	/** @inheritDoc */
	public function push( $data ) {
		if ( $data instanceof $this->elementClass ) {
			$this->stack[] = $data;
		} else {
			$class = $this->elementClass;
			$this->stack[] = new $class( $data );
		}
		$this->top = $this->stack[count( $this->stack ) - 1];
		$this->accum =& $this->top->getAccum();
	}

	/** @inheritDoc */
	public function pop() {
		if ( $this->stack === [] ) {
			throw new RuntimeException( __METHOD__ . ': no elements remaining' );
		}
		$temp = array_pop( $this->stack );

		if ( count( $this->stack ) ) {
			$this->top = $this->stack[count( $this->stack ) - 1];
			$this->accum =& $this->top->getAccum();
		} else {
			$this->top = false;
			$this->accum =& $this->rootAccum;
		}
		return $temp;
	}

	/** @inheritDoc */
	public function addPart( $s = '' ) {
		$this->top->addPart( $s );
		$this->accum =& $this->top->getAccum();
	}

	/**
	 * @return array
	 */
	public function getFlags() {
		if ( $this->stack === [] ) {
			return [
				'findEquals' => false,
				'findPipe' => false,
				'inHeading' => false,
			];
		} else {
			return $this->top->getFlags();
		}
	}
}

/** @deprecated class alias since 1.43 */
class_alias( PPDStack_Hash::class, 'PPDStack_Hash' );
