from dataclasses import dataclass, field, fields
from typing import Dict, List, Any, Optional, get_type_hints
import warnings

# Определим базовый класс для удобного наследования
@dataclass
class ForwardingBase:
    _forwarding: Dict[str, type] = field(default_factory=dict)
    _key_field: str = 'key'  # Поле, которое будет использоваться как ключ
    fixed: bool = False

    # Скрытые поля для хранения данных
    _key: Optional[str] = None
    other_data: Optional[Dict[str, Any]] = None

    # Пример поля, которое будет использоваться в _forwarding
    # Должно быть переопределено в дочерних классах
    key: Optional[str] = None

    def __post_init__(self):
        if self._key is not None:
            self.key = self._key

    @property
    def key(self) -> Optional[str]:
        return self._key

    @key.setter
    def key(self, value: str):
        self._key = value

    @classmethod
    def from_dict(cls, data: Dict[str, Any]) -> 'ForwardingBase':
        # Создаем экземпляр класса
        instance = cls()
        instance.fixed = data.get('fixed', False)
        instance.other_data = None

        # Список всех полей
        excluded_fields = {f.name for f in fields(ForwardingBase)}
        all_fields = {f.name for f in fields(cls) if f.name not in excluded_fields and not f.name.startswith('_')}

        # Обрабатываем поля из _forwarding
        handled_keys = set()
        field_values = {}

        for key, value in data.items():
            if key in handled_keys:
                continue

            if key in instance._forwarding:
                target_type = instance._forwarding[key]
                if isinstance(value, dict):
                    # Обрабатываем словарь
                    sub_instance = target_type.from_dict(value)
                    field_values[key] = sub_instance
                    handled_keys.add(key)
                elif isinstance(value, list):
                    # Обрабатываем список словарей
                    results = []
                    for item in value:
                        if isinstance(item, dict):
                            sub_instance = target_type.from_dict(item)
                            results.append(sub_instance)
                        else:
                            # Если элемент не словарь, записываем в other_data
                            warnings.warn(f"Non-dict value {item} in list for field '{key}' will be added to 'other_data'")
                            if instance.other_data is None:
                                instance.other_data = {}
                            instance.other_data[key] = item  # Сохраняем оригинал
                    field_values[key] = results
                    handled_keys.add(key)
                else:
                    # Если не словарь и не список, тоже добавляем в other_data
                    warnings.warn(f"Non-dict/list value {value} for field '{key}' will be added to 'other_data'")
                    if instance.other_data is None:
                        instance.other_data = {}
                    instance.other_data[key] = value
            else:
                # Обычное поле
                if key in all_fields:
                    field_values[key] = value
                    handled_keys.add(key)
                else:
                    # Неизвестное поле, добавляем в other_data
                    warnings.warn(f"Unknown field '{key}', adding to 'other_data'")
                    if instance.other_data is None:
                        instance.other_data = {}
                    instance.other_data[key] = value

        # Заполняем обычные поля
        for key, value in field_values.items():
            setattr(instance, key, value)

        # Устанавливаем ключ, если есть
        if hasattr(instance, '_key_field') and instance._key_field in data:
            instance.key = data[instance._key_field]

        # Проверяем флаг fixed и other_data
        if instance.fixed and instance.other_data is not None:
            raise ValueError("Cannot serialize with fixed=True and non-empty other_data")

        return instance

    def to_dict(self) -> Dict[str, Any]:
        result = {}
        excluded_fields = {f.name for f in fields(ForwardingBase)}
        field_names = [f.name for f in fields(self) if f.name not in excluded_fields and not f.name.startswith('_')]

        for field_name in field_names:
            if not hasattr(self, field_name):
                result[field_name] = None
                warnings.warn(f'object not have field {field_name}, something went wrong')
                continue
            value = getattr(self, field_name)
            if not value:
                result[field_name] = None
                warnings.warn(f'object not have data in field {field_name}, it may be correct situation')
                continue

            if field_name in self._forwarding:
                target_type = self._forwarding[field_name]
                result[field_name] = list()
                single = False
                if not isinstance(value, list):
                    single = True
                    value = [value]
                for v in value:
                    try:
                        v = v.to_dict()
                    except Exception as e:
                        warnings.warn(str(e))
                    finally:
                        result[field_name].append(v)
                if single: result[field_name] = result[field_name][0]
                continue
            else: result[field_name] = value

        # Добавляем other_data, если есть
        if self.other_data and isinstance(self.other_data, dict):
            for key, value in self.other_data.items():
                if key not in result:
                    result[key] = value
                else:
                    if not isinstance(result[key], list): result[key] = [result[key]]
                    if not isinstance(value, list): value = [value]
                    result[key].extend(value)

        return result

# Пример использования:
@dataclass
class Person(ForwardingBase):
    name: Optional[str] = None
    age: Optional[int] = None
    email: Optional[str] = None

    def __post_init__(self):
        super().__post_init__()
        self._forwarding = {}
        self._key_field = 'name'

@dataclass
class User(ForwardingBase):
    id: Optional[list] = None
    username: Optional[str] = None
    person: Optional[Person] = None

    def __post_init__(self):
        super().__post_init__()
        self._forwarding = {'person': Person}
        self._key_field = 'username'

# Пример десериализации:
if __name__ == "__main__":
    data = {
        "id": [1,2,3,4,5,6],
        "username": "user1",
        "person": None,
        "extra_field": "should_be_in_other_data"
    }

    user = User.from_dict(data)
    data2 = user.to_dict()
    print(user.to_dict())