1import re
  2
  3
  4class Singleton(type):
  5    """Metaclass for making only one instance for class"""
  6    _instance = {}
  7
  8    def __call__(cls, *args, **kwargs):
  9        """Create new instance"""
 10        if cls not in cls._instance:
 11            cls._instance[cls] = super(Singleton, cls).__call__(*args, **kwargs)
 12        return cls._instance[cls]
 13
 14
 15class Santa(metaclass=Singleton):
 16    """Class representing a white-bearded old man, bearer of gifts and coal"""
 17    _wishes = {}
 18    kids = []
 19    bad_kids = []
 20
 21    @staticmethod
 22    def _read_wish(wish):
 23        """Read wish"""
 24        gift = re.search(r'("[a-zA-Z0-9\s]+")|(\'[a-zA-Z0-9\s]+\')', wish)
 25        return gift.group()[1:-1]
 26    @staticmethod
 27    def _read_id(wish):
 28        """Read id from wish"""
 29        kid_id = re.search(r'^\s*(\d+)\s*$', wish, re.MULTILINE)
 30        return int(kid_id.group())
 31
 32    def __call__(self, child, wish):
 33        """Receive wishes during phone call"""
 34        gift = self._read_wish(wish)
 35        self._wishes[child] = gift
 36
 37    def __matmul__(self, wish):
 38        """Handle wish from letter"""
 39        gift = self._read_wish(wish)
 40        kid_id = self._read_id(wish)
 41        for kid in self.kids:
 42            if id(kid) == kid_id:
 43                self._wishes[kid] = gift
 44
 45    def __iter__(self):
 46        """Allow to iterate Santa"""
 47        return iter(list(self._wishes.values()))
 48
 49    def _most_wanted(self):
 50        """Find most wanted gift for this year"""
 51        wish_counts = {}
 52        most_wanted_wish = None
 53        for wish in self._wishes.values():
 54            if wish not in wish_counts:
 55                wish_counts[wish] = 0
 56            wish_counts[wish] += 1
 57            if most_wanted_wish is None or wish_counts[wish] > wish_counts[most_wanted_wish]:
 58                most_wanted_wish = wish
 59        return most_wanted_wish
 60
 61    def xmas(self):
 62        """Handle the distribution"""
 63        for kid in self.kids:
 64            kid.years += 1
 65        if not self._wishes:
 66            return
 67        default_gift = self._most_wanted()
 68        for kid in self.kids[:]:
 69            if kid.years > 5:
 70                self.kids.remove(kid)
 71            else:
 72                if kid in self.bad_kids:
 73                    kid('coal')
 74                else:
 75                    gift = self._wishes.get(kid, default_gift)
 76                    kid(gift)
 77        self._wishes.clear()
 78        self.bad_kids.clear()
 79
 80    def add_to_kids(self, kid):
 81        """Add kids to santa list"""
 82        self.kids.append(kid)
 83
 84    def add_to_bad_kids(self, kid):
 85        """Add kids to bad kids"""
 86        if kid not in self.bad_kids:
 87            self.bad_kids.append(kid)
 88
 89
 90class Kid(type):
 91    """Metaclass for creating Kids"""
 92
 93    def __call__(cls, *args, **kwargs):
 94        """Create new Kid"""
 95        santa = Santa()
 96        instance = super().__call__(*args, **kwargs)
 97        santa.add_to_kids(instance)
 98        instance.years = 0
 99        return instance
100
101    @staticmethod
102    def _decorator(func):
103        """Decorator that catches bad kids"""
104        santa = Santa()
105
106        def wrapper(*args, **kwargs):
107            result = None
108            try:
109                result = func(*args, **kwargs)
110            except Exception as e:
111                santa.add_to_bad_kids(args[0])
112                raise e
113            return result
114
115        return wrapper
116
117    @staticmethod
118    def _check_key(key):
119        """Check if the function is public"""
120        if re.match(r'^[^_]', key):
121            return True
122        return False
123
124    def __new__(cls, name, bases, attr_dict):
125        """Call decorator to help Santa punish bad kids"""
126        if '__call__' not in attr_dict:
127            raise NotImplementedError()
128
129        for key, value in attr_dict.items():
130            if callable(value) and cls._check_key(key):
131                attr_dict[key] = cls._decorator(value)
132        return super().__new__(cls, name, bases, attr_dict)