# api/employment.py
# 就业模块接口：就业开放登记、offer登记（状态联动）、多条件查询、修改、删除
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.employment_dao import EmploymentDAO
from dao.students_dao import StudentDAO
from database import get_db
from model.user import User
from scheme.employment import (
    EmploymentOpen,
    OfferAdd,
    EmploymentUpdate,
    OfferResponse,
    EmploymentResponse,
    EmploymentListResponse,
)

router = APIRouter()


def _can_manage_student_employment(db: Session, user: User, student) -> bool:
    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


def _check_student_manage(db: Session, user: User, stu_id: int):
    """公共校验：学生存在 + 操作者有权管理该学生就业信息"""
    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_employment(db, user, student):
        raise HTTPException(status_code=403, detail="教师只能管理自己所带班级学生的就业信息")
    return student


def _to_response(db_base) -> EmploymentResponse:
    resp = EmploymentResponse.model_validate(db_base)
    resp.offers = [OfferResponse.model_validate(o) for o in (db_base.offers or [])]
    return resp


# ---------- 登记就业开放 ----------
@router.post("/open", response_model=EmploymentResponse, summary="登记就业开放（学生状态联动→进入就业）")
async def open_employment(
    body: EmploymentOpen,
    db: Session = Depends(get_db),
    current_user: User = Depends(require_roles("admin", "teacher")),
):
    _check_student_manage(db, current_user, body.stu_id)
    existing = EmploymentDAO.get_base(db, body.stu_id)
    if existing:
        raise HTTPException(status_code=409, detail="该学生已登记就业开放，请勿重复登记")
    db_base = EmploymentDAO.open_employment(db, body.stu_id, body.employment_open_time)
    return _to_response(db_base)


# ---------- 登记 offer ----------
@router.post("/offer", response_model=EmploymentResponse, summary="登记offer（学生状态联动→已就业）")
async def add_offer(
    body: OfferAdd,
    db: Session = Depends(get_db),
    current_user: User = Depends(require_roles("admin", "teacher")),
):
    _check_student_manage(db, current_user, body.stu_id)
    db_base = EmploymentDAO.get_base(db, body.stu_id)
    if db_base is None:
        raise HTTPException(status_code=404, detail="该学生尚未登记就业开放，请先调用 /employment/open")
    if body.offer_time < db_base.employment_open_time:
        raise HTTPException(status_code=400, detail="offer下发时间不能早于就业开放时间")
    EmploymentDAO.add_offer(db, body.stu_id, body.offer_time, body.company_name, body.salary)
    return _to_response(EmploymentDAO.get_base(db, body.stu_id))


# ---------- 查询学生就业信息 ----------
@router.get("/students/{stu_id}", response_model=EmploymentResponse, summary="查询学生就业信息")
async def get_student_employment(
    stu_id: int,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    if current_user.role == "student" and current_user.stu_id != stu_id:
        raise HTTPException(status_code=403, detail="学生角色只能查看自己的就业信息")
    db_base = EmploymentDAO.get_by_student(db, stu_id)
    if db_base is None:
        raise HTTPException(status_code=404, detail="该学生暂无就业信息")
    return _to_response(db_base)


# ---------- 查询班级就业信息 ----------
@router.get("/class/{class_id}", response_model=EmploymentListResponse, summary="查询班级学生就业信息")
async def get_class_employment(
    class_id: int,
    skip: int = Query(0, ge=0),
    limit: int = Query(100, ge=1, le=200),
    db: Session = Depends(get_db),
    current_user: User = Depends(require_roles("admin", "teacher")),
):
    total, items = EmploymentDAO.get_by_class(db, class_id, skip=skip, limit=limit)
    return EmploymentListResponse(total=total, items=[_to_response(b) for b in items])


# ---------- 多条件查询就业信息 ----------
@router.get("/total_query", response_model=EmploymentListResponse, summary="多条件查询就业信息（学号/公司/薪资范围）")
async def query_employment(
    skip: int = Query(0, ge=0),
    limit: int = Query(100, ge=1, le=200),
    stu_id: int = Query(None, ge=1, description="按学号精确查询"),
    company_name: str = Query(None, description="按公司名称模糊查询"),
    salary_min: float = Query(None, ge=0, description="薪资下限"),
    salary_max: float = Query(None, ge=0, description="薪资上限"),
    db: Session = Depends(get_db),
    current_user: User = Depends(require_roles("admin", "teacher")),
):
    total, items = EmploymentDAO.get_all(
        db,
        skip=skip,
        limit=limit,
        stu_id=stu_id,
        company_name=company_name,
        salary_min=salary_min,
        salary_max=salary_max,
    )
    return EmploymentListResponse(total=total, items=[_to_response(b) for b in items])


# ---------- 修改就业基础信息 ----------
@router.put("/update", response_model=EmploymentResponse, summary="修改学生就业基础信息")
async def update_employment(
    body: EmploymentUpdate,
    stu_id: int = Query(..., ge=1, description="学生编号"),
    db: Session = Depends(get_db),
    current_user: User = Depends(require_roles("admin", "teacher")),
):
    _check_student_manage(db, current_user, stu_id)
    update_data = body.model_dump(exclude_unset=True, exclude_none=True)
    if not update_data:
        raise HTTPException(status_code=400, detail="至少提供一个要修改的字段")
    db_base = EmploymentDAO.update_base(db, stu_id, update_data)
    if db_base is None:
        raise HTTPException(status_code=404, detail="该学生暂无就业信息")
    return _to_response(db_base)


# ---------- 删除就业信息 ----------
@router.delete("/delete", status_code=204, summary="删除学生就业信息（逻辑删除，状态回退为在读）")
async def delete_employment(
    stu_id: int = Query(..., ge=1, description="学生编号"),
    db: Session = Depends(get_db),
    current_user: User = Depends(require_roles("admin", "teacher")),
):
    _check_student_manage(db, current_user, stu_id)
    success = EmploymentDAO.delete_light(db, stu_id)
    if not success:
        raise HTTPException(status_code=404, detail="该学生暂无就业信息")
    return None