1import re
  2from collections import OrderedDict
  3from random import randint
  4
  5
  6def class_method_naughty_decorator(func):
  7    def wrapper(self, *args, **kwargs):
  8        try:
  9            res = func(self, *args, **kwargs)
 10            return res
 11        except:
 12            self.is_naughty = True
 13            raise
 14    return wrapper
 15
 16def init_decorator(init_func):
 17    def wrapper(self, *args, **kwargs):
 18        if init_func:
 19            init_func(self, *args, **kwargs)
 20        self.is_naughty = False
 21        self.age = 0
 22        Santa.detect_new_kid(self)
 23    return wrapper
 24
 25
 26class SingletonMeta(type):
 27
 28    _all_instances = {}
 29
 30    def __call__(cls, *args, **kwargs):
 31        if cls not in cls._all_instances:
 32            instance = super().__call__(*args, **kwargs)
 33            cls._all_instances[cls] = instance
 34        return cls._all_instances[cls]
 35
 36
 37class Kid(type):
 38
 39    def __new__(cls, name, bases, attr_dict):
 40        if '__call__' not in attr_dict:
 41            raise NotImplementedError("OK stands for OBICHAM KOCETO <3")
 42
 43        def age_up(self):
 44            self.age += 1
 45
 46        def be_good(self):
 47            self.is_naughty = False
 48
 49        original_init = attr_dict.get('__init__', None)
 50
 51        attr_dict['__init__'] = init_decorator(original_init)
 52        attr_dict['age_up'] = age_up
 53        attr_dict['be_good'] = be_good
 54
 55        for method_name, method in attr_dict.items():
 56            if callable(method) and not method_name.startswith('_'):
 57                attr_dict[method_name] = class_method_naughty_decorator(method)
 58
 59        return type.__new__(cls, name, bases, attr_dict)
 60
 61
 62class Santa(metaclass=SingletonMeta):
 63
 64    _all_kids = {} # id -> instance
 65    _gifts = OrderedDict() # id -> gift
 66
 67    @classmethod
 68    def detect_new_kid(cls, kid):
 69        cls._all_kids[id(kid)] = kid
 70
 71    @staticmethod
 72    def _get_signature(wish):
 73        target = re.search(r'^\s*(\d+)\s*$', wish, re.MULTILINE)
 74        return target.group(1)
 75
 76    @staticmethod
 77    def _get_gift(wish):
 78        if res := re.search(r'"([A-Za-z0-9 ]+)"', wish):
 79            return res.group(1)
 80        elif res := re.search(r'\'([A-Za-z0-9 ]+)\'', wish):
 81            return res.group(1)
 82
 83    def __call__(self, child, call):
 84        self._gifts[id(child)] = self._get_gift(call)
 85
 86    def __matmul__(self, letter):
 87        signature = int(self._get_signature(letter))
 88        self._gifts[signature] = self._get_gift(letter)
 89
 90    def __iter__(self):
 91        return SantaIter(list(self._gifts.values()))
 92
 93    def _post_xmas(self):
 94        """Age up all kids and make them well-behaved again"""
 95
 96        for kid in self._all_kids.values():
 97            kid.age_up()
 98            kid.be_good()
 99
100        self._gifts.clear()
101
102    def _get_most_frequent_gifts(self):
103
104        freq_dict = {}
105
106        for gift in self._gifts.values():
107            if gift not in freq_dict:
108                freq_dict[gift] = 1
109            else:
110                freq_dict[gift] += 1
111
112        max_freq = max(freq_dict.values())
113
114        return [gift for gift, count in freq_dict.items() if count == max_freq]
115
116    def _give_gifts(self):
117        most_freq_gifts = self._get_most_frequent_gifts()
118
119        for kid_id, kid in self._all_kids.items():
120            if kid.age < 5:
121                if kid.is_naughty:
122                    kid('coal')
123                elif kid_id in self._gifts.keys():
124                    kid(self._gifts[kid_id])
125                else:
126                    random_idx = randint(0, len(most_freq_gifts) - 1)
127                    kid(most_freq_gifts[random_idx])
128
129    def xmas(self):
130        if self._gifts:
131            self._give_gifts()
132        self._post_xmas()
133
134
135class SantaIter:
136
137    def __init__(self, gifts):
138        self.gifts = gifts
139        self.idx = 0
140
141    def __iter__(self):
142        return self
143
144    def __next__(self):
145        if self.idx < len(self.gifts):
146            curr = self.gifts[self.idx]
147            self.idx += 1
148            return curr
149        else:
150            self.idx = 0
151            raise StopIteration