"""统一响应格式封装"""
from typing import Any, Optional, Generic, TypeVar
from pydantic import BaseModel
from datetime import datetime

T = TypeVar("T")

class ApiResponse(BaseModel, Generic[T]):
    """统一 API 响应格式"""
    code: int = 0
    message: str = "success"
    data: Optional[T] = None
    timestamp: str = ""
    
    def __init__(self, code: int = 0, message: str = "success", data: T = None, **kwargs):
        super().__init__(
            code=code,
            message=message,
            data=data,
            timestamp=datetime.now().isoformat() + "Z"
        )
    
    @classmethod
    def success(cls, data: T = None, message: str = "success"):
        return cls(code=0, message=message, data=data)
    
    @classmethod
    def error(cls, code: int = 50000, message: str = "Internal error"):
        return cls(code=code, message=message, data=None)

class PaginatedData(BaseModel, Generic[T]):
    """分页数据封装"""
    items: list[T]
    total: int
    page: int
    page_size: int
    total_pages: int
    pagination: dict
    
    @classmethod
    def create(cls, items: list, page: int = 1, page_size: int = 20, total: int = 0):
        total_pages = (total + page_size - 1) // page_size if page_size > 0 else 0
        return cls(
            items=items,
            total=total,
            page=page,
            page_size=page_size,
            total_pages=total_pages,
            pagination={
                "page": page,
                "page_size": page_size,
                "total": total,
                "total_pages": total_pages
            }
        )