class NestingLevelSniff

class NestingLevelSniff implements Sniff {
    
    /**
     * A nesting level higher than this value will throw a warning.
     *
     * @var integer
     */
    public $nestingLevel = 5;
    
    /**
     * A nesting level higher than this value will throw an error.
     *
     * @var integer
     */
    public $absoluteNestingLevel = 10;
    
    /**
     * 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 = $phpcsFile->getTokens();
        // Ignore abstract methods.
        if (isset($tokens[$stackPtr]['scope_opener']) === false) {
            return;
        }
        // Detect start and end of this function definition.
        $start = $tokens[$stackPtr]['scope_opener'];
        $end = $tokens[$stackPtr]['scope_closer'];
        $nestingLevel = 0;
        // Find the maximum nesting level of any token in the function.
        for ($i = $start + 1; $i < $end; $i++) {
            $level = $tokens[$i]['level'];
            if ($nestingLevel < $level) {
                $nestingLevel = $level;
            }
        }
        // We subtract the nesting level of the function itself.
        $nestingLevel = $nestingLevel - $tokens[$stackPtr]['level'] - 1;
        if ($nestingLevel > $this->absoluteNestingLevel) {
            $error = 'Function\'s nesting level (%s) exceeds allowed maximum of %s';
            $data = [
                $nestingLevel,
                $this->absoluteNestingLevel,
            ];
            $phpcsFile->addError($error, $stackPtr, 'MaxExceeded', $data);
        }
        else {
            if ($nestingLevel > $this->nestingLevel) {
                $warning = 'Function\'s nesting level (%s) exceeds %s; consider refactoring the function';
                $data = [
                    $nestingLevel,
                    $this->nestingLevel,
                ];
                $phpcsFile->addWarning($warning, $stackPtr, 'TooHigh', $data);
            }
        }
    }
    
    //end process()

}