<?php
/**
 * PHPCompatibility, an external standard for PHP_CodeSniffer.
 *
 * @package   PHPCompatibility
 * @copyright 2012-2020 PHPCompatibility Contributors
 * @license   https://opensource.org/licenses/LGPL-3.0 LGPL3
 * @link      https://github.com/PHPCompatibility/PHPCompatibility
 */

namespace PHPCompatibility\Sniffs\ControlStructures;

use PHPCompatibility\Helpers\ScannedCode;
use PHPCompatibility\Sniff;
use PHPCompatibility\Helpers\TokenGroup;
use PHP_CodeSniffer\Files\File;

/**
 * Detect `foreach` expression referencing.
 *
 * Before PHP 5.5.0, referencing `$value` in a `foreach` was only possible
 * if the iterated array could be referenced (i.e. if it is a variable).
 *
 * PHP version 5.5
 *
 * @link https://www.php.net/manual/en/control-structures.foreach.php
 *
 * @since 9.0.0
 * @since 10.0.0 This class is now `final`.
 */
final class NewForeachExpressionReferencingSniff extends Sniff
{

    /**
     * Returns an array of tokens this test wants to listen for.
     *
     * @since 9.0.0
     *
     * @return array<int|string>
     */
    public function register()
    {
        return [\T_FOREACH];
    }

    /**
     * Processes this test, when one of its tokens is encountered.
     *
     * @since 9.0.0
     *
     * @param \PHP_CodeSniffer\Files\File $phpcsFile The file being scanned.
     * @param int                         $stackPtr  The position of the current token in the
     *                                               stack passed in $tokens.
     *
     * @return void
     */
    public function process(File $phpcsFile, $stackPtr)
    {
        if (ScannedCode::shouldRunOnOrBelow('5.4') === false) {
            return;
        }

        $tokens = $phpcsFile->getTokens();

        if (isset($tokens[$stackPtr]['parenthesis_opener'], $tokens[$stackPtr]['parenthesis_closer']) === false) {
            return;
        }

        $opener = $tokens[$stackPtr]['parenthesis_opener'];
        $closer = $tokens[$stackPtr]['parenthesis_closer'];

        $asToken = $phpcsFile->findNext(\T_AS, ($opener + 1), $closer);
        if ($asToken === false) {
            return;
        }

        /*
         * Note: referencing $key is not allowed in any version, so this should only find referenced $values.
         * If it does find a referenced key, it would be a parse error anyway.
         */
        $hasReference = $phpcsFile->findNext(\T_BITWISE_AND, ($asToken + 1), $closer);
        if ($hasReference === false) {
            return;
        }

        $nestingLevel = 0;
        if ($asToken !== ($opener + 1) && isset($tokens[$opener + 1]['nested_parenthesis'])) {
            $nestingLevel = \count($tokens[$opener + 1]['nested_parenthesis']);
        }

        if (TokenGroup::isVariable($phpcsFile, ($opener + 1), $asToken, $nestingLevel) === true) {
            return;
        }

        // Non-variable detected before the `as` keyword.
        $phpcsFile->addError(
            'Referencing $value is only possible if the iterated array is a variable in PHP 5.4 or earlier.',
            $hasReference,
            'Found'
        );
    }
}