"""
基础 Schema 定义

定义通用的响应模式和基础配置。
"""

from datetime import datetime
from typing import Any, Generic, TypeVar

from pydantic import BaseModel, ConfigDict

DataT = TypeVar("DataT")


class BaseSchema(BaseModel):
    """基础 Schema 配置"""

    model_config = ConfigDict(
        from_attributes=True,  # 支持从 ORM 对象创建
        populate_by_name=True,  # 支持字段别名
        str_strip_whitespace=True,  # 自动去除字符串首尾空白
    )


class TimestampMixin(BaseModel):
    """时间戳混入"""

    created_at: datetime
    updated_at: datetime


class APIResponse(BaseModel, Generic[DataT]):
    """统一 API 响应格式"""

    success: bool = True
    message: str = "操作成功"
    data: DataT | None = None

    @classmethod
    def ok(cls, data: DataT | None = None, message: str = "操作成功") -> "APIResponse[DataT]":
        """成功响应"""
        return cls(success=True, message=message, data=data)

    @classmethod
    def error(cls, message: str = "操作失败", data: DataT | None = None) -> "APIResponse[DataT]":
        """错误响应"""
        return cls(success=False, message=message, data=data)


class ErrorResponse(BaseModel):
    """错误响应"""

    success: bool = False
    message: str
    code: str
    details: dict[str, Any] = {}


class PaginationParams(BaseModel):
    """分页参数"""

    page: int = 1
    page_size: int = 20

    @property
    def offset(self) -> int:
        """计算偏移量"""
        return (self.page - 1) * self.page_size

    @property
    def limit(self) -> int:
        """获取限制数量"""
        return self.page_size


class PaginatedResponse(BaseModel, Generic[DataT]):
    """分页响应"""

    items: list[DataT]
    total: int
    page: int
    page_size: int
    total_pages: int

    @classmethod
    def create(
        cls,
        items: list[DataT],
        total: int,
        page: int,
        page_size: int,
    ) -> "PaginatedResponse[DataT]":
        """创建分页响应"""
        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,
        )