from typing import Type, TypeVar, Dict, Any, Union, Optional
from pydantic import BaseModel, model_validator

# 定义一个通用类型变量，用于表示任意 Pydantic 模型
ModelType = TypeVar("ModelType", bound=BaseModel)

class ModelField:
    """
    通用的字段类型，用于将字典自动转换为指定的 Pydantic 模型对象。
    """
    def __init__(self, model_class: Type[ModelType]):
        self.model_class = model_class

    def __call__(self, value: Any) -> ModelType:
        if isinstance(value, dict):
            return self.model_class(**value)
        elif isinstance(value, self.model_class):
            return value
        else:
            raise ValueError(f"Expected dict or {self.model_class}, got {type(value)}")

class AutoLoadModel(BaseModel):
    """
    基类，用于自动加载嵌套的 Pydantic 模型对象。
    """
    @model_validator(mode='before')
    def auto_load_nested_models(cls, values: Dict[str, Any]) -> Dict[str, Any]:
        for field_name, field in cls.model_fields.items():
            field_type = field.annotation
            if hasattr(field_type, "__origin__") and field_type.__origin__ is Union:
                # 处理 Union 类型（如 Optional）
                field_type = next(t for t in field_type.__args__ if t is not type(None))
            if isinstance(field_type, type) and issubclass(field_type, BaseModel):
                # 如果字段是 Pydantic 模型类型，则递归处理
                field_value = values.get(field_name)
                if isinstance(field_value, dict):
                    values[field_name] = field_type(**field_value)
                elif isinstance(field_value, list):
                    values[field_name] = [field_type(**item) if isinstance(item, dict) else item for item in field_value]
            elif isinstance(field_type, dict) and hasattr(field_type, "get") and callable(field_type.get):
                # 处理 Dict 类型，检查值是否为 Pydantic 模型
                field_value = values.get(field_name)
                if isinstance(field_value, dict):
                    for key, value in field_value.items():
                        if isinstance(value, dict):
                            values[field_name][key] = field_type(value)
        return values