<?php
/**
 * Ban the use of Yoda conditions.
 *
 * @author    Mponos George <gmponos@gmail.com>
 * @author    Mark Scherer <username@example.com>
 * @copyright 2006-2015 Squiz Pty Ltd (ABN 77 084 670 600)
 * @license   https://github.com/PHPCSStandards/PHP_CodeSniffer/blob/master/licence.txt BSD Licence
 */

namespace PHP_CodeSniffer\Standards\Generic\Sniffs\ControlStructures;

use PHP_CodeSniffer\Files\File;
use PHP_CodeSniffer\Sniffs\Sniff;
use PHP_CodeSniffer\Util\Tokens;

class DisallowYodaConditionsSniff implements Sniff
{


    /**
     * Returns an array of tokens this test wants to listen for.
     *
     * @return array<int|string>
     */
    public function register()
    {
        $tokens = Tokens::$comparisonTokens;
        unset($tokens[T_COALESCE]);

        return $tokens;

    }//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();
        $previousIndex  = $phpcsFile->findPrevious(Tokens::$emptyTokens, ($stackPtr - 1), null, true);
        $relevantTokens = [
            T_CLOSE_SHORT_ARRAY,
            T_CLOSE_PARENTHESIS,
            T_TRUE,
            T_FALSE,
            T_NULL,
            T_LNUMBER,
            T_DNUMBER,
            T_CONSTANT_ENCAPSED_STRING,
        ];

        if (in_array($tokens[$previousIndex]['code'], $relevantTokens, true) === false) {
            return;
        }

        if ($tokens[$previousIndex]['code'] === T_CLOSE_SHORT_ARRAY) {
            $previousIndex = $tokens[$previousIndex]['bracket_opener'];
            if ($this->isArrayStatic($phpcsFile, $previousIndex) === false) {
                return;
            }
        }

        $prevIndex = $phpcsFile->findPrevious(Tokens::$emptyTokens, ($previousIndex - 1), null, true);

        if (in_array($tokens[$prevIndex]['code'], Tokens::$arithmeticTokens, true) === true) {
            return;
        }

        if ($tokens[$prevIndex]['code'] === T_STRING_CONCAT) {
            return;
        }

        // Is it a parenthesis.
        if ($tokens[$previousIndex]['code'] === T_CLOSE_PARENTHESIS) {
            $beforeOpeningParenthesisIndex = $phpcsFile->findPrevious(
                Tokens::$emptyTokens,
                ($tokens[$previousIndex]['parenthesis_opener'] - 1),
                null,
                true
            );

            if ($beforeOpeningParenthesisIndex === false || $tokens[$beforeOpeningParenthesisIndex]['code'] !== T_ARRAY) {
                if ($tokens[$beforeOpeningParenthesisIndex]['code'] === T_STRING) {
                    return;
                }

                // If it is not an array, check what is inside.
                $found = $phpcsFile->findPrevious(
                    T_VARIABLE,
                    ($previousIndex - 1),
                    $tokens[$previousIndex]['parenthesis_opener']
                );

                // If a variable exists, it is not Yoda.
                if ($found !== false) {
                    return;
                }

                // If there is nothing inside the parenthesis, it is not a Yoda condition.
                $opener = $tokens[$previousIndex]['parenthesis_opener'];
                $prev   = $phpcsFile->findPrevious(Tokens::$emptyTokens, ($previousIndex - 1), ($opener + 1), true);
                if ($prev === false) {
                    return;
                }
            } else if ($tokens[$beforeOpeningParenthesisIndex]['code'] === T_ARRAY
                && $this->isArrayStatic($phpcsFile, $beforeOpeningParenthesisIndex) === false
            ) {
                return;
            }//end if
        }//end if

        $phpcsFile->addError(
            'Usage of Yoda conditions is not allowed; switch the expression order',
            $stackPtr,
            'Found'
        );

    }//end process()


    /**
     * Determines if an array is a static definition.
     *
     * @param \PHP_CodeSniffer\Files\File $phpcsFile  The file being scanned.
     * @param int                         $arrayToken The position of the array token.
     *
     * @return bool
     */
    public function isArrayStatic(File $phpcsFile, $arrayToken)
    {
        $tokens = $phpcsFile->getTokens();

        if ($tokens[$arrayToken]['code'] === T_OPEN_SHORT_ARRAY) {
            $start = $arrayToken;
            $end   = $tokens[$arrayToken]['bracket_closer'];
        } else if ($tokens[$arrayToken]['code'] === T_ARRAY) {
            $start = $tokens[$arrayToken]['parenthesis_opener'];
            $end   = $tokens[$arrayToken]['parenthesis_closer'];
        } else {
            // Shouldn't be possible but may happen if external sniffs are using this method.
            return true; // @codeCoverageIgnore
        }

        $staticTokens  = Tokens::$emptyTokens;
        $staticTokens += Tokens::$textStringTokens;
        $staticTokens += Tokens::$assignmentTokens;
        $staticTokens += Tokens::$equalityTokens;
        $staticTokens += Tokens::$comparisonTokens;
        $staticTokens += Tokens::$arithmeticTokens;
        $staticTokens += Tokens::$operators;
        $staticTokens += Tokens::$booleanOperators;
        $staticTokens += Tokens::$castTokens;
        $staticTokens += Tokens::$bracketTokens;
        $staticTokens += [
            T_DOUBLE_ARROW => T_DOUBLE_ARROW,
            T_COMMA        => T_COMMA,
            T_TRUE         => T_TRUE,
            T_FALSE        => T_FALSE,
        ];

        for ($i = ($start + 1); $i < $end; $i++) {
            if (isset($tokens[$i]['scope_closer']) === true) {
                $i = $tokens[$i]['scope_closer'];
                continue;
            }

            if (isset($staticTokens[$tokens[$i]['code']]) === false) {
                return false;
            }
        }

        return true;

    }//end isArrayStatic()


}//end class
