from pydantic import BaseModel, Field, model_validator, field_validator, ConfigDict
from datetime import date
from typing import Optional

#id用cls_id来拼接生成，不用请求体过滤
#------------新增请求体-------------
class StudentCreate(BaseModel):
    cls_id: int | str = Field(..., description="班级ID，6位数字")
    name:         str = Field(..., min_length=1, max_length=20, description="姓名")
    gender:       str = Field(..., min_length=1, max_length=1, description="性别")
    age:          int = Field(..., ge=1, le=100, description="年龄")
    hometown: Optional[str] = Field(None, min_length=3, max_length=50, description="籍贯")
    grad_school:  str = Field(..., min_length=1, max_length=50, description="毕业院校")
    major:        str = Field(..., min_length=1, max_length=50, description="专业名称")
    education:    str = Field(..., min_length=1, max_length=20, description="学历")
    enr_date:    date = Field(..., description="入学日期")
    grad_date:   date = Field(..., description="毕业日期")
    advisor_id:   str = Field(..., min_length=1, max_length=15, description="顾问编号")
#校验入学时间必须比毕业时间小
    @model_validator(mode='after')
    def check_dates(self):
        if self.grad_date <= self.enr_date:
            raise ValueError("毕业日期必须晚于入学日期")
        return self
# 校验传入的6位数是不是都是数字/都转化为字符串判断
    @field_validator("cls_id", mode="before")
    def convert_str(cls, v):
        # 不管前端传数字还是字符串，统一转字符串
        v = str(v)
        if len(v) != 6 or not v.isdigit():
            raise ValueError("班级ID必须是6位纯数字")
        return v
#------------修改请求体-------------
class StudentUpdate(BaseModel):
    cls_id:      Optional[int|str] = Field(None, description="班级ID，6位数字")
    name:        Optional[str] = Field(None, min_length=1, max_length=20, description="姓名")
    gender:      Optional[str] = Field(None, min_length=1, max_length=1, description="性别")
    age:         Optional[int] = Field(None, ge=1, le=100, description="年龄")
    hometown:    Optional[str] = Field(None, min_length=3, max_length=50, description="籍贯")
    grad_school: Optional[str] = Field(None, min_length=1, max_length=50, description="毕业院校")
    major:       Optional[str] = Field(None, min_length=1, max_length=50, description="专业名称")
    education:   Optional[str] = Field(None, min_length=1, max_length=20, description="学历")
    enr_date:    Optional[date]= Field(None, description="入学日期")
    grad_date:   Optional[date]= Field(None, description="毕业日期")
    advisor_id:  Optional[str] = Field(None, min_length=1, max_length=15, description="顾问编号")

    @field_validator("cls_id", mode="before")
    def convert_str(cls, v):
        # 更新：不传cls_id(v=None)直接返回，跳过校验
        if v is None:
            return v
        v = str(v)
        if len(v) != 6 or not v.isdigit():
            raise ValueError("班级ID必须是6位纯数字")
        return v

    @model_validator(mode='after')
    def check_dates(self):
        # 只在两个日期【都传了，不为None】的时候，才校验大小，传单个时在api层校验
        if self.grad_date is not None and self.enr_date is not None:
            if self.grad_date <= self.enr_date:
                raise ValueError("毕业日期必须晚于入学日期")
        return self
#--------------响应体模型--------------
class StudentResponse(BaseModel):
    id:          str
    cls_id:      str
    name:        str
    gender:      str
    age:         int
    hometown: Optional[str]
    grad_school: Optional[str]
    major:       Optional[str]
    education:   Optional[str]
    enr_date:    Optional[date]
    grad_date:   Optional[date]
    advisor_id:  Optional[str]
    state:       Optional[str]

    model_config = ConfigDict(from_attributes=True)  # 支持 ORM 对象转换