class DuplicateClassDefinitionSniff

class DuplicateClassDefinitionSniff implements Sniff {
    
    /**
     * A list of tokenizers this sniff supports.
     *
     * @var array
     */
    public $supportedTokenizers = [
        'CSS',
    ];
    
    /**
     * Returns the token types that this sniff is interested in.
     *
     * @return array<int|string>
     */
    public function register() {
        return [
            T_OPEN_TAG,
        ];
    }
    
    //end register()
    
    /**
     * Processes the tokens that this sniff is interested in.
     *
     * @param \PHP_CodeSniffer\Files\File $phpcsFile The file where the token was found.
     * @param int                         $stackPtr  The position in the stack where
     *                                               the token was found.
     *
     * @return void
     */
    public function process(File $phpcsFile, $stackPtr) {
        $tokens = $phpcsFile->getTokens();
        // Find the content of each class definition name.
        $classNames = [];
        $next = $phpcsFile->findNext(T_OPEN_CURLY_BRACKET, $stackPtr + 1);
        if ($next === false) {
            // No class definitions in the file.
            return;
        }
        // Save the class names in a "scope",
        // to prevent false positives with @media blocks.
        $scope = 'main';
        $find = [
            T_CLOSE_CURLY_BRACKET,
            T_OPEN_CURLY_BRACKET,
            T_OPEN_TAG,
        ];
        while ($next !== false) {
            $prev = $phpcsFile->findPrevious($find, $next - 1);
            // Check if an inner block was closed.
            $beforePrev = $phpcsFile->findPrevious(Tokens::$emptyTokens, $prev - 1, null, true);
            if ($beforePrev !== false && $tokens[$beforePrev]['code'] === T_CLOSE_CURLY_BRACKET) {
                $scope = 'main';
            }
            // Create a sorted name for the class so we can compare classes
            // even when the individual names are all over the place.
            $name = '';
            for ($i = $prev + 1; $i < $next; $i++) {
                $name .= $tokens[$i]['content'];
            }
            $name = trim($name);
            $name = str_replace("\n", ' ', $name);
            $name = preg_replace('|[\\s]+|', ' ', $name);
            $name = preg_replace('|\\s*/\\*.*\\*/\\s*|', '', $name);
            $name = str_replace(', ', ',', $name);
            $names = explode(',', $name);
            sort($names);
            $name = implode(',', $names);
            if ($name[0] === '@') {
                // Media block has its own "scope".
                $scope = $name;
            }
            else {
                if (isset($classNames[$scope][$name]) === true) {
                    $first = $classNames[$scope][$name];
                    $error = 'Duplicate class definition found; first defined on line %s';
                    $data = [
                        $tokens[$first]['line'],
                    ];
                    $phpcsFile->addError($error, $next, 'Found', $data);
                }
                else {
                    $classNames[$scope][$name] = $next;
                }
            }
            $next = $phpcsFile->findNext(T_OPEN_CURLY_BRACKET, $next + 1);
        }
        
        //end while
    }
    
    //end process()

}