# scheme/students.py
# 学生模块的请求/响应模型
from datetime import date
from typing import List, Optional

from pydantic import BaseModel, Field, field_validator


# -------------------- 请求体模型 -----------------------------
class StudentAdd(BaseModel):
    """创建学生：stu_id 不传则按规则自动生成（入学年份+班级号+序号）"""
    stu_id: Optional[int] = Field(None, ge=1, description="学号（不传则自动生成）")
    class_id: int = Field(..., ge=1, description="学生班级ID")
    stu_name: str = Field(..., min_length=1, max_length=10, description="学生姓名")
    native_place: str = Field(..., min_length=1, description="籍贯")
    graduate_school: str = Field(..., min_length=1, description="毕业院校")
    major: str = Field(..., min_length=1, description="专业")
    enroll_time: date = Field(..., description="入学时间 YYYY-MM-DD")
    graduate_time: date = Field(..., description="毕业时间 YYYY-MM-DD")
    education: str = Field(..., description="学历：大专/本科/硕士等")
    age: int = Field(..., ge=15, le=60, description="年龄")
    gender: str = Field(..., description="性别：男/女")
    advisor_id: int = Field(..., ge=1, description="顾问编号")
    status: str = Field("在读", description="状态：在读/进入就业/已就业")

    @field_validator("gender")
    @classmethod
    def validate_gender(cls, v):
        if v not in ("男", "女"):
            raise ValueError(f"gender 必须是 男/女，当前值: {v}")
        return v

    @field_validator("status")
    @classmethod
    def validate_status(cls, v):
        allowed = ["在读", "进入就业", "已就业"]
        if v not in allowed:
            raise ValueError(f"status 必须是 {allowed} 之一，当前值: {v}")
        return v


class StudentUpdate(BaseModel):
    """更新学生：只更新显式传入的非 None 字段；class_id/advisor_id 不允许改（保持归属一致性）"""
    stu_name: Optional[str] = Field(None, min_length=1, max_length=10, description="学生姓名")
    native_place: Optional[str] = Field(None, min_length=1, description="籍贯")
    graduate_school: Optional[str] = Field(None, min_length=1, description="毕业院校")
    major: Optional[str] = Field(None, min_length=1, description="专业")
    enroll_time: Optional[date] = Field(None, description="入学时间")
    graduate_time: Optional[date] = Field(None, description="毕业时间")
    education: Optional[str] = Field(None, description="学历")
    age: Optional[int] = Field(None, ge=15, le=60, description="年龄")
    gender: Optional[str] = Field(None, description="性别：男/女")
    status: Optional[str] = Field(None, description="状态：在读/进入就业/已就业")

    @field_validator("gender")
    @classmethod
    def validate_gender(cls, v):
        if v is not None and v not in ("男", "女"):
            raise ValueError(f"gender 必须是 男/女，当前值: {v}")
        return v

    @field_validator("status")
    @classmethod
    def validate_status(cls, v):
        allowed = ["在读", "进入就业", "已就业"]
        if v is not None and v not in allowed:
            raise ValueError(f"status 必须是 {allowed} 之一，当前值: {v}")
        return v


# -------------------- 响应模型 ----------------------------
class StudentResponse(BaseModel):
    stu_id: int
    stu_name: str
    native_place: str
    graduate_school: str
    major: str
    enroll_time: date
    graduate_time: date
    education: str
    age: int
    gender: str
    class_id: int
    advisor_id: int
    status: str
    class_name: Optional[str] = Field(None, description="冗余展示：班级名称")
    advisor_name: Optional[str] = Field(None, description="冗余展示：顾问姓名")

    class Config:
        from_attributes = True


class StudentListResponse(BaseModel):
    total: int
    items: List[StudentResponse]