# api/students.py
# 学生模块接口：增、查（多条件分页）、改、逻辑删除
from typing import Optional

from fastapi import APIRouter, Depends, HTTPException, Query
from sqlalchemy.orm import Session

from core.deps import get_current_user, require_roles, get_teacher_class_ids
from dao.students_dao import StudentDAO
from database import get_db
from model.user import User
from scheme.students import StudentAdd, StudentUpdate, StudentResponse, StudentListResponse

router = APIRouter()


def _can_read_student(user: User, student) -> bool:
    """学生角色只能读取自己的信息"""
    if user.role == "student":
        return user.stu_id == student.stu_id
    return True


def _can_manage_student(db: Session, user: User, student) -> bool:
    """教师角色只能管理自己所带班级的学生；管理员不受限"""
    if user.role == "admin":
        return True
    if user.role == "teacher":
        return student.class_id in get_teacher_class_ids(db, user.teacher_id)
    return False


# ---------- 创建新学生 ----------
@router.post("/add", response_model=StudentResponse, summary="创建学生（学号可自动生成）")
async def add_student(
    student: StudentAdd,
    db: Session = Depends(get_db),
    current_user: User = Depends(require_roles("admin", "teacher")),
):
    # 外键校验：班级 / 顾问
    if not StudentDAO.inspect_class_id_unq(db, student.class_id):
        raise HTTPException(status_code=404, detail="班级ID不存在，或已被软删除")
    if not StudentDAO.inspect_advisor_id_unq(db, student.advisor_id):
        raise HTTPException(status_code=404, detail="顾问ID不存在，或已被软删除")
    # 教师只能给自己班上的学生建档
    if current_user.role == "teacher" and student.class_id not in get_teacher_class_ids(
        db, current_user.teacher_id
    ):
        raise HTTPException(status_code=403, detail="教师只能管理自己所带班级的学生")
    # 主键校验（显式传入学号时）
    if student.stu_id is not None:
        existing = StudentDAO.inspect_student_id_unq(db, student.stu_id)
        if existing:
            raise HTTPException(status_code=409, detail="学号已存在（包括软删除记录）")
    return StudentDAO.add_student(db, student)


# ---------- 查询学生列表（多条件 + 分页） ----------
@router.get("/total_query", response_model=StudentListResponse, summary="查询学生列表（多条件筛选+分页）")
async def get_students(
    skip: int = Query(0, ge=0, description="跳过的记录数"),
    limit: int = Query(100, ge=1, le=200, description="返回的最大记录数"),
    stu_id: Optional[int] = Query(None, description="按学号精确查询"),
    stu_name: Optional[str] = Query(None, description="按姓名模糊查询"),
    class_id: Optional[int] = Query(None, description="按班级ID筛选"),
    gender: Optional[str] = Query(None, description="按性别筛选：男/女"),
    status: Optional[str] = Query(None, description="按状态筛选：在读/进入就业/已就业"),
    education: Optional[str] = Query(None, description="按学历筛选"),
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    total, items = StudentDAO.get_all(
        db,
        skip=skip,
        limit=limit,
        stu_id=stu_id,
        stu_name=stu_name,
        class_id=class_id,
        gender=gender,
        status=status,
        education=education,
    )
    # 学生角色只能看到自己
    if current_user.role == "student":
        items = [s for s in items if s.stu_id == current_user.stu_id]
        total = len(items)
    return StudentListResponse(
        total=total,
        items=[StudentResponse.model_validate(s) for s in items],
    )


# ---------- 根据 ID 查询单个学生 ----------
@router.get("/single_query", response_model=StudentResponse, summary="根据学号查询学生")
async def get_student(
    stu_id: int = Query(..., ge=1, description="学号"),
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    student = StudentDAO.get_active(db, stu_id)
    if student is None:
        raise HTTPException(status_code=404, detail="学生不存在，或已被软删除")
    if not _can_read_student(current_user, student):
        raise HTTPException(status_code=403, detail="学生角色只能查看自己的信息")
    resp = StudentResponse.model_validate(student)
    # 联表补充班级名与顾问名
    if student.classes:
        resp.class_name = student.classes.class_name
    if student.advisor:
        resp.advisor_name = student.advisor.advisor_name
    return resp


# ---------- 更新学生信息 ----------
@router.put("/update", response_model=StudentResponse, summary="更新学生信息")
async def update_student(
    student_data: StudentUpdate,
    stu_id: int = Query(..., ge=1, description="要更新的学号"),
    db: Session = Depends(get_db),
    current_user: User = Depends(require_roles("admin", "teacher")),
):
    student = StudentDAO.get_active(db, stu_id)
    if student is None:
        raise HTTPException(status_code=404, detail="学生不存在，或已被软删除")
    if not _can_manage_student(db, current_user, student):
        raise HTTPException(status_code=403, detail="教师只能管理自己所带班级的学生")
    updated = StudentDAO.update(db, stu_id, student_data)
    return StudentResponse.model_validate(updated)


# ---------- 逻辑删除学生 ----------
@router.delete("/delete", status_code=204, summary="逻辑删除学生")
async def delete_student(
    stu_id: int = Query(..., ge=1, description="要删除的学号"),
    db: Session = Depends(get_db),
    current_user: User = Depends(require_roles("admin", "teacher")),
):
    student = StudentDAO.get_active(db, stu_id)
    if student is None:
        raise HTTPException(status_code=404, detail="学生不存在，或已被软删除")
    if not _can_manage_student(db, current_user, student):
        raise HTTPException(status_code=403, detail="教师只能管理自己所带班级的学生")
    success = StudentDAO.delete_light(db, stu_id)
    if not success:
        raise HTTPException(status_code=404, detail="学生不存在")
    return None