<?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\Helpers;

use PHP_CodeSniffer\Files\File;
use PHP_CodeSniffer\Util\Tokens;
use PHPCSUtils\Tokens\Collections;
use PHPCSUtils\Utils\Scopes;

/**
 * Miscellaneous helper functions
 *
 * ---------------------------------------------------------------------------------------------
 * This class is only intended for internal use by PHPCompatibility and is not part of the public API.
 * This also means that it has no promise of backward compatibility. Use at your own risk.
 * ---------------------------------------------------------------------------------------------
 *
 * {@internal The functionality in this class will likely be replaced at some point in
 * the future by functions from PHPCSUtils.}
 *
 * @since 10.0.0 These functions were moved from the generic `Sniff` class to this class.
 */
final class MiscHelper
{

    /**
     * Determine whether an arbitrary T_STRING token is the use of a global constant.
     *
     * @since 8.1.0
     * @since 10.0.0 This method is now static.
     *
     * @param \PHP_CodeSniffer\Files\File $phpcsFile The file being scanned.
     * @param int                         $stackPtr  The position of the T_STRING token.
     *
     * @return bool
     */
    public static function isUseOfGlobalConstant(File $phpcsFile, $stackPtr)
    {
        $tokens = $phpcsFile->getTokens();

        // Check for the existence of the token.
        if (isset($tokens[$stackPtr]) === false) {
            return false;
        }

        // Is this one of the tokens this function handles ?
        if ($tokens[$stackPtr]['code'] !== \T_STRING) {
            return false;
        }

        $next = $phpcsFile->findNext(Tokens::$emptyTokens, ($stackPtr + 1), null, true);
        if ($next !== false
            && ($tokens[$next]['code'] === \T_OPEN_PARENTHESIS
                || $tokens[$next]['code'] === \T_DOUBLE_COLON)
        ) {
            // Function call or declaration.
            return false;
        }

        // Array of tokens which if found preceding the $stackPtr indicate that a T_STRING is not a global constant.
        $tokensToIgnore  = [
            \T_NAMESPACE  => true,
            \T_USE        => true,
            \T_EXTENDS    => true,
            \T_IMPLEMENTS => true,
            \T_NEW        => true,
            \T_FUNCTION   => true,
            \T_INSTANCEOF => true,
            \T_INSTEADOF  => true,
            \T_GOTO       => true,
            \T_AS         => true,
        ];
        $tokensToIgnore += Tokens::$ooScopeTokens;
        $tokensToIgnore += Collections::objectOperators();
        $tokensToIgnore += Tokens::$scopeModifiers;

        $prev = $phpcsFile->findPrevious(Tokens::$emptyTokens, ($stackPtr - 1), null, true);
        if ($prev !== false && isset($tokensToIgnore[$tokens[$prev]['code']]) === true) {
            // Not the use of a constant.
            return false;
        }

        if ($prev !== false
            && $tokens[$prev]['code'] === \T_NS_SEPARATOR
            && $tokens[($prev - 1)]['code'] === \T_STRING
        ) {
            // Namespaced constant of the same name.
            return false;
        }

        if ($prev !== false
            && $tokens[$prev]['code'] === \T_CONST
            && Scopes::isOOConstant($phpcsFile, $prev) === true
        ) {
            // Class constant declaration of the same name.
            return false;
        }

        /*
         * Deal with a number of variations of use statements.
         */
        for ($i = $stackPtr; $i > 0; $i--) {
            if ($tokens[$i]['line'] !== $tokens[$stackPtr]['line']) {
                break;
            }
        }

        $firstOnLine = $phpcsFile->findNext(Tokens::$emptyTokens, ($i + 1), null, true);
        if ($firstOnLine !== false && $tokens[$firstOnLine]['code'] === \T_USE) {
            $nextOnLine = $phpcsFile->findNext(Tokens::$emptyTokens, ($firstOnLine + 1), null, true);
            if ($nextOnLine !== false) {
                if (($tokens[$nextOnLine]['code'] === \T_STRING && $tokens[$nextOnLine]['content'] === 'const')) {
                    $hasNsSep = $phpcsFile->findNext(\T_NS_SEPARATOR, ($nextOnLine + 1), $stackPtr);
                    if ($hasNsSep !== false) {
                        // Namespaced const (group) use statement.
                        return false;
                    }
                } else {
                    // Not a const use statement.
                    return false;
                }
            }
        }

        return true;
    }
}