<?php
/**
 * Ensures there is only one assignment on a line, and that it is the first thing on the line.
 *
 * @author    Greg Sherwood <gsherwood@squiz.net>
 * @copyright 2006-2015 Squiz Pty Ltd (ABN 77 084 670 600)
 * @license   https://github.com/squizlabs/PHP_CodeSniffer/blob/master/licence.txt BSD Licence
 */

namespace PHP_CodeSniffer\Standards\Squiz\Sniffs\PHP;

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

class DisallowMultipleAssignmentsSniff implements Sniff
{


    /**
     * Returns an array of tokens this test wants to listen for.
     *
     * @return array
     */
    public function register()
    {
        return [T_EQUAL];

    }//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();

        // Ignore default value assignments in function definitions.
        $function = $phpcsFile->findPrevious([T_FUNCTION, T_CLOSURE], ($stackPtr - 1), null, false, null, true);
        if ($function !== false) {
            $opener = $tokens[$function]['parenthesis_opener'];
            $closer = $tokens[$function]['parenthesis_closer'];
            if ($opener < $stackPtr && $closer > $stackPtr) {
                return;
            }
        }

        // Ignore assignments in WHILE loop conditions.
        if (isset($tokens[$stackPtr]['nested_parenthesis']) === true) {
            $nested = $tokens[$stackPtr]['nested_parenthesis'];
            foreach ($nested as $opener => $closer) {
                if (isset($tokens[$opener]['parenthesis_owner']) === true
                    && $tokens[$tokens[$opener]['parenthesis_owner']]['code'] === T_WHILE
                ) {
                    return;
                }
            }
        }

        /*
            The general rule is:
            Find an equal sign and go backwards along the line. If you hit an
            end bracket, skip to the opening bracket. When you find a variable,
            stop. That variable must be the first non-empty token on the line
            or in the statement. If not, throw an error.
        */

        for ($varToken = ($stackPtr - 1); $varToken >= 0; $varToken--) {
            // Skip brackets.
            if (isset($tokens[$varToken]['parenthesis_opener']) === true && $tokens[$varToken]['parenthesis_opener'] < $varToken) {
                $varToken = $tokens[$varToken]['parenthesis_opener'];
                continue;
            }

            if (isset($tokens[$varToken]['bracket_opener']) === true) {
                $varToken = $tokens[$varToken]['bracket_opener'];
                continue;
            }

            if ($tokens[$varToken]['code'] === T_SEMICOLON) {
                // We've reached the next statement, so we
                // didn't find a variable.
                return;
            }

            if ($tokens[$varToken]['code'] === T_VARIABLE) {
                // We found our variable.
                break;
            }
        }//end for

        if ($varToken <= 0) {
            // Didn't find a variable.
            return;
        }

        $start = $phpcsFile->findStartOfStatement($varToken);

        $allowed = Tokens::$emptyTokens;

        $allowed[T_STRING]          = T_STRING;
        $allowed[T_NS_SEPARATOR]    = T_NS_SEPARATOR;
        $allowed[T_DOUBLE_COLON]    = T_DOUBLE_COLON;
        $allowed[T_OBJECT_OPERATOR] = T_OBJECT_OPERATOR;
        $allowed[T_ASPERAND]        = T_ASPERAND;
        $allowed[T_DOLLAR]          = T_DOLLAR;
        $allowed[T_SELF]            = T_SELF;
        $allowed[T_PARENT]          = T_PARENT;
        $allowed[T_STATIC]          = T_STATIC;

        $varToken = $phpcsFile->findPrevious($allowed, ($varToken - 1), null, true);

        if ($varToken < $start
            && $tokens[$varToken]['code'] !== T_OPEN_PARENTHESIS
            && $tokens[$varToken]['code'] !== T_OPEN_SQUARE_BRACKET
        ) {
            $varToken = $start;
        }

        // Ignore member var definitions.
        if (isset(Tokens::$scopeModifiers[$tokens[$varToken]['code']]) === true
            || $tokens[$varToken]['code'] === T_VAR
            || $tokens[$varToken]['code'] === T_STATIC
        ) {
            return;
        }

        // Ignore the first part of FOR loops as we are allowed to
        // assign variables there even though the variable is not the
        // first thing on the line.
        if ($tokens[$varToken]['code'] === T_OPEN_PARENTHESIS && isset($tokens[$varToken]['parenthesis_owner']) === true) {
            $owner = $tokens[$varToken]['parenthesis_owner'];
            if ($tokens[$owner]['code'] === T_FOR) {
                return;
            }
        }

        if ($tokens[$varToken]['code'] === T_VARIABLE
            || $tokens[$varToken]['code'] === T_OPEN_TAG
            || $tokens[$varToken]['code'] === T_INLINE_THEN
            || $tokens[$varToken]['code'] === T_INLINE_ELSE
            || $tokens[$varToken]['code'] === T_SEMICOLON
            || $tokens[$varToken]['code'] === T_CLOSE_PARENTHESIS
            || isset($allowed[$tokens[$varToken]['code']]) === true
        ) {
            return;
        }

        $error = 'Assignments must be the first block of code on a line';
        $phpcsFile->addError($error, $stackPtr, 'Found');

    }//end process()


}//end class
