"""基础响应模式"""
from typing import Generic, TypeVar, Optional, Any, List
from pydantic import BaseModel, Field
from datetime import datetime

DataT = TypeVar("DataT")


class ResponseModel(BaseModel, Generic[DataT]):
    """
    统一响应格式模型
    """

    code: int = Field(default=200, description="响应状态码")
    message: str = Field(default="success", description="响应消息")
    data: Optional[DataT] = Field(default=None, description="响应数据")
    request_id: Optional[str] = Field(default=None, description="请求ID")


class BaseSchema(BaseModel):
    """基础模式"""

    class Config:
        from_attributes = True  # Pydantic V2
        json_encoders = {datetime: lambda v: v.isoformat()}


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

    created_at: datetime
    updated_at: datetime


class IDMixin(BaseModel):
    """ID混入"""

    id: int


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

    page: int = Field(default=1, ge=1, description="页码")
    page_size: int = Field(default=20, ge=1, le=100, description="每页数量")

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

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


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

    items: list[DataT] = Field(default_factory=list, description="数据列表")
    total: int = Field(default=0, description="总数量")
    page: int = Field(default=1, description="当前页码")
    page_size: int = Field(default=20, description="每页数量")
    pages: int = Field(default=1, description="总页数")

    @classmethod
    def create(cls, items: list[DataT], total: int, page: int, page_size: int):
        """创建分页响应"""
        pages = (total + page_size - 1) // page_size if page_size > 0 else 1
        return cls(
            items=items, total=total, page=page, page_size=page_size, pages=pages
        )