class InnerFunctionsSniff

class InnerFunctionsSniff implements Sniff {
    
    /**
     * Returns an array of tokens this test wants to listen for.
     *
     * @return array<int|string>
     */
    public function register() {
        return [
            T_FUNCTION,
        ];
    }
    
    //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 = $phpcsFile->getTokens();
        if (isset($tokens[$stackPtr]['conditions']) === false) {
            return;
        }
        $conditions = $tokens[$stackPtr]['conditions'];
        $reversedConditions = array_reverse($conditions, true);
        $outerFuncToken = null;
        foreach ($reversedConditions as $condToken => $condition) {
            if ($condition === T_FUNCTION || $condition === T_CLOSURE) {
                $outerFuncToken = $condToken;
                break;
            }
            if (array_key_exists($condition, Tokens::$ooScopeTokens) === true) {
                // Ignore methods in OOP structures defined within functions.
                return;
            }
        }
        if ($outerFuncToken === null) {
            // Not a nested function.
            return;
        }
        $error = 'The use of inner functions is forbidden';
        $phpcsFile->addError($error, $stackPtr, 'NotAllowed');
    }
    
    //end process()

}