<?php

/**
 * Detects variable assignments being made within conditions.
 *
 * This is a typical code smell and more often than not a comparison was intended.
 *
 * Note: this sniff does not detect variable assignments in the conditional part of ternaries!
 *
 * @author    Juliette Reinders Folmer <phpcs_nospam@adviesenzo.nl>
 * @copyright 2017 Juliette Reinders Folmer. All rights reserved.
 * @license   https://github.com/PHPCSStandards/PHP_CodeSniffer/blob/master/licence.txt BSD Licence
 */
namespace PHP_CodeSniffer\Standards\Generic\Sniffs\CodeAnalysis;

use PHP_CodeSniffer\Files\File;
use PHP_CodeSniffer\Sniffs\Sniff;
use PHP_CodeSniffer\Util\Tokens;
class AssignmentInConditionSniff implements Sniff
{
    /**
     * Assignment tokens to trigger on.
     *
     * Set in the register() method.
     *
     * @var array
     */
    protected $assignmentTokens = [];
    /**
     * The tokens that indicate the start of a condition.
     *
     * @var array
     */
    protected $conditionStartTokens = [];
    /**
     * Registers the tokens that this sniff wants to listen for.
     *
     * @return array<int|string>
     */
    public function register()
    {
        $this->assignmentTokens = Tokens::$assignmentTokens;
        unset($this->assignmentTokens[\T_DOUBLE_ARROW]);
        $starters = Tokens::$booleanOperators;
        $starters[\T_SEMICOLON] = \T_SEMICOLON;
        $starters[\T_OPEN_PARENTHESIS] = \T_OPEN_PARENTHESIS;
        $this->conditionStartTokens = $starters;
        return [\T_IF, \T_ELSEIF, \T_FOR, \T_SWITCH, \T_CASE, \T_WHILE, \T_MATCH];
    }
    //end register()
    /**
     * Processes this test, when one of its tokens is encountered.
     *
     * @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)
    {
        $tokens = $phpcsFile->getTokens();
        $token = $tokens[$stackPtr];
        // Find the condition opener/closer.
        if ($token['code'] === \T_FOR) {
            if (isset($token['parenthesis_opener'], $token['parenthesis_closer']) === \false) {
                return;
            }
            $semicolon = $phpcsFile->findNext(\T_SEMICOLON, $token['parenthesis_opener'] + 1, $token['parenthesis_closer']);
            if ($semicolon === \false) {
                return;
            }
            $opener = $semicolon;
            $semicolon = $phpcsFile->findNext(\T_SEMICOLON, $opener + 1, $token['parenthesis_closer']);
            if ($semicolon === \false) {
                return;
            }
            $closer = $semicolon;
            unset($semicolon);
        } else {
            if ($token['code'] === \T_CASE) {
                if (isset($token['scope_opener']) === \false) {
                    return;
                }
                $opener = $stackPtr;
                $closer = $token['scope_opener'];
            } else {
                if (isset($token['parenthesis_opener'], $token['parenthesis_closer']) === \false) {
                    return;
                }
                $opener = $token['parenthesis_opener'];
                $closer = $token['parenthesis_closer'];
            }
        }
        //end if
        $startPos = $opener;
        do {
            $hasAssignment = $phpcsFile->findNext($this->assignmentTokens, $startPos + 1, $closer);
            if ($hasAssignment === \false) {
                return;
            }
            // Examine whether the left side is a variable.
            $hasVariable = \false;
            $conditionStart = $startPos;
            $altConditionStart = $phpcsFile->findPrevious($this->conditionStartTokens, $hasAssignment - 1, $startPos);
            if ($altConditionStart !== \false) {
                $conditionStart = $altConditionStart;
            }
            for ($i = $hasAssignment; $i > $conditionStart; $i--) {
                if (isset(Tokens::$emptyTokens[$tokens[$i]['code']]) === \true) {
                    continue;
                }
                // If this is a variable or array, we've seen all we need to see.
                if ($tokens[$i]['code'] === \T_VARIABLE || $tokens[$i]['code'] === \T_CLOSE_SQUARE_BRACKET) {
                    $hasVariable = \true;
                    break;
                }
                // If this is a function call or something, we are OK.
                if ($tokens[$i]['code'] === \T_CLOSE_PARENTHESIS) {
                    break;
                }
            }
            if ($hasVariable === \true) {
                $errorCode = 'Found';
                if ($token['code'] === \T_WHILE) {
                    $errorCode = 'FoundInWhileCondition';
                }
                $phpcsFile->addWarning('Variable assignment found within a condition. Did you mean to do a comparison ?', $hasAssignment, $errorCode);
            }
            $startPos = $hasAssignment;
        } while ($startPos < $closer);
    }
    //end process()
}
//end class
