import logging


class SomeSyntaxError(Exception): pass


class SyntaxError(SomeSyntaxError):
    bracket = None
    idx = -1
    
    def __init__(self, bracket, idx):
        assert isinstance(bracket, str)
        assert isinstance(idx, int)
        
        self.bracket = bracket
        self.idx = idx
        
    def __str__(self):
        return 'Wrong bracket "%s" at index %d' % (self.bracket, self.idx)
    

def check_syntax(text):
    """
    Проверяет синтакс скобок.
    
    Не учитывает кавычки!
    """
    if not text:
        return True
        
    logger = logging.getLogger('Syntaxer')
        
    good_pairs_map = {
        '{': '}',
        '[': ']',
        '(': ')',
    }

    _opened_brackets_stack = []
    idx = -1
    for c in text:
        idx += 1
        if not _opened_brackets_stack:
            if c in good_pairs_map.values():
                raise SyntaxError(c, idx)
                
            elif c in good_pairs_map.keys():
                _opened_brackets_stack.append(c)
                logger.debug('First opening bracket: %s at %s' % (c, idx))
                continue
        else:
            if c in good_pairs_map.keys():
                _opened_brackets_stack.append(c)
                logger.debug('Next opening bracket with %s at %s' % (c, idx))
                continue
            
            elif c in good_pairs_map.values():
                if c == good_pairs_map.get(_opened_brackets_stack[-1]):
                    _opened_brackets_stack.pop()
                    logger.debug('Found closing bracket "%s" at %s' % (c, idx))
                    continue
                
                else:
                    raise SyntaxError(c, idx)
                    
    if _opened_brackets_stack:
        raise SomeSyntaxError('Not closed brackets: %d' % len(_opened_brackets_stack))

    return True
    

import unittest

class SyntaxCheckerTest(unittest.TestCase):
    def test_ok(self):
        self.assertTrue(check_syntax('{()}[]'))
        
    def test_should_fail_on_wrong_closing_bracket(self):
        with self.assertRaises(SomeSyntaxError):
            check_syntax('{[}}')
    
    def test_should_fail_on_missing_closing_bracket(self):
        with self.assertRaises(SomeSyntaxError):
            check_syntax('{}[')

    def test_should_fail_on_single_opening_bracket(self):
        with self.assertRaises(SomeSyntaxError):
            check_syntax('{')
            
    def test_should_fail_on_single_close_bracket(self):
        with self.assertRaises(SomeSyntaxError):
            check_syntax(')')
        
        
if __name__ == '__main__':
    import sys
    if len(sys.argv) >= 2:
        if '-d' in sys.argv[1:]:
            logging.basicConfig(level=logging.DEBUG)
            
        try:
            if check_syntax(sys.argv[-1]):
                print('Syntax is ok!')
        except SomeSyntaxError as ex:
            print(ex)
    else:
        print('Run with string, -d for debug...')