from __future__ import annotations

"""公共Pydantic模型：提供AppModel基类（统一配置）与SourceMetadata第三方数据来源元数据。"""

from datetime import datetime,timezone
from pydantic import BaseModel,Field,ConfigDict

def utc_now()->datetime:
    """返回带时区的 UTC时间。"""
    return datetime.now(timezone.utc)

class AppModel(BaseModel):
    """项目中所有 Pydantic 模型的基础类。"""

    model_config = ConfigDict(
        extra="ignore",
        str_strip_whitespace = True,
        validate_assignment = True,
    )

class SourceMetadata(AppModel):
    """第三方数据来源信息。"""
    provider: str 
    status: str | None = None
    search_id: str | None = None
    retrieved_at: datetime = Field(default_factory=utc_now)
    currency:str | None = None
    is_cached:bool | None = None