"""
基础Schema
"""
from datetime import datetime
from typing import Optional, TypeVar, Generic, List
from pydantic import BaseModel

T = TypeVar("T")


class ResponseModel(BaseModel, Generic[T]):
    """统一响应模型"""
    code: int = 200
    message: str = "success"
    data: Optional[T] = None
    timestamp: datetime = datetime.utcnow()
    
    class Config:
        from_attributes = True


class PaginationParams(BaseModel):
    """分页参数"""
    page: int = 1
    page_size: int = 20


class PaginatedData(BaseModel, Generic[T]):
    """分页数据"""
    items: List[T]
    total: int
    page: int
    page_size: int
    total_pages: int


class PaginatedResponse(ResponseModel[PaginatedData[T]], Generic[T]):
    """分页响应模型"""
    pass


class ErrorResponse(BaseModel):
    """错误响应"""
    code: int
    message: str
    data: Optional[dict] = None
    timestamp: datetime = datetime.utcnow()