class UnusedPrivateMethodSniff

class UnusedPrivateMethodSniff extends AbstractScopeSniff {
    
    /**
     * Constructor.
     */
    public function __construct() {
        parent::__construct([
            T_CLASS,
        ], [
            T_FUNCTION,
        ], false);
    }
    
    //end __construct()
    
    /**
     * Processes the tokens within the scope.
     *
     * @param \PHP_CodeSniffer\Files\File $phpcsFile The file being processed.
     * @param int                         $stackPtr  The position where this token was
     *                                               found.
     * @param int                         $currScope The position of the current scope.
     *
     * @return void
     */
    protected function processTokenWithinScope(File $phpcsFile, $stackPtr, $currScope) {
        // Only check private methods.
        $methodProperties = $phpcsFile->getMethodProperties($stackPtr);
        if ($methodProperties['scope'] !== 'private' || $methodProperties['is_static'] === true) {
            return;
        }
        $tokens = $phpcsFile->getTokens();
        $methodName = $phpcsFile->getDeclarationName($stackPtr);
        if ($methodName === '__construct') {
            return;
        }
        $classPtr = key($tokens[$stackPtr]['conditions']);
        // Search for direct $this->methodCall() or indirect callbacks [$this,
        // 'methodCall'].
        $current = $tokens[$classPtr]['scope_opener'];
        $end = $tokens[$classPtr]['scope_closer'];
        while (($current = $phpcsFile->findNext(T_VARIABLE, $current + 1, $end)) !== false) {
            if ($tokens[$current]['content'] !== '$this') {
                continue;
            }
            $next = $phpcsFile->findNext(Tokens::$emptyTokens, $current + 1, null, true);
            if ($next === false) {
                continue;
            }
            if ($tokens[$next]['code'] === T_OBJECT_OPERATOR) {
                $call = $phpcsFile->findNext(Tokens::$emptyTokens, $next + 1, null, true);
                // PHP method calls are case insensitive.
                if ($call === false || strcasecmp($tokens[$call]['content'], $methodName) !== 0) {
                    continue;
                }
                $parenthesis = $phpcsFile->findNext(Tokens::$emptyTokens, $call + 1, null, true);
                if ($parenthesis === false || $tokens[$parenthesis]['code'] !== T_OPEN_PARENTHESIS) {
                    continue;
                }
                // At this point this is a method call to the private method, so we
                // can stop.
                return;
            }
            else {
                if ($tokens[$next]['code'] === T_COMMA) {
                    $call = $phpcsFile->findNext(Tokens::$emptyTokens, $next + 1, null, true);
                    if ($call === false || substr($tokens[$call]['content'], 1, -1) !== $methodName) {
                        continue;
                    }
                    // At this point this is likely the private method as callback on a
                    // function such as array_filter().
                    return;
                }
            }
            
            //end if
        }
        
        //end while
        $warning = 'Unused private method %s()';
        $data = [
            $methodName,
        ];
        $phpcsFile->addWarning($warning, $stackPtr, 'UnusedMethod', $data);
    }
    
    //end processTokenWithinScope()
    
    /**
     * Process tokens outside of scope.
     *
     * @param \PHP_CodeSniffer\Files\File $phpcsFile The file being processed.
     * @param int                         $stackPtr  The position where this token was
     *                                               found.
     *
     * @return void
     */
    protected function processTokenOutsideScope(File $phpcsFile, $stackPtr) {
    }
    
    //end processTokenOutsideScope()

}