"""老师管理接口（需求 2.5）。"""

from __future__ import annotations

from typing import Annotated

from fastapi import APIRouter, Query

from app.core.deps import DbSession, ReadAccount, WriteAccount
from app.core.exceptions import BusinessError, ConflictError, NotFoundError
from app.core.response import ok
from app.core.response import Resp
from app.core.utils import parse_date
from app.dao.clazz_dao import ClazzDao
from app.dao.teacher_dao import TeacherDao
from app.model import Teacher
from app.schema.common import PageResult
from app.schema.teacher_schema import TeacherCreate, TeacherOut, TeacherUpdate

router = APIRouter(prefix="/teachers", tags=["2.5 老师管理"])


@router.get("", response_model=Resp[PageResult[TeacherOut]], summary="老师列表（含带班信息）")
def list_teachers(
    db: DbSession,
    _: ReadAccount,
    page: Annotated[int, Query(ge=1)] = 1,
    page_size: Annotated[int, Query(ge=1, le=200)] = 10,
    keyword: Annotated[str | None, Query(description="姓名/工号/电话")] = None,
    subject: Annotated[str | None, Query(description="授课方向")] = None,
    title: Annotated[str | None, Query(description="职称")] = None,
    gender: Annotated[int | None, Query(ge=1, le=2)] = None,
    class_id: Annotated[int | None, Query(description="带某个班的老师")] = None,
    order_by: Annotated[str, Query()] = "id",
    order: Annotated[str, Query(pattern="^(asc|desc)$")] = "desc",
):
    stmt = TeacherDao.build_stmt(
        keyword=keyword, subject=subject, title=title, gender=gender,
        class_id=class_id, order_by=order_by, order=order,
    )
    items, total, page, pages = TeacherDao.paginate(db, stmt, page, page_size)
    return ok({
        "total": total, "page": page, "page_size": page_size, "pages": pages,
        "items": [TeacherOut.model_validate(t) for t in items],
    })


@router.post("", response_model=Resp[TeacherOut], summary="新增老师")
def create_teacher(db: DbSession, _: WriteAccount, payload: TeacherCreate):
    teacher_no = (payload.teacher_no or "").strip()
    if not teacher_no:
        from datetime import date

        year = (parse_date(payload.hire_date, "入职时间") or date.today()).year
        teacher_no = TeacherDao.next_teacher_no(db, year)
    if TeacherDao.get_by_no(db, teacher_no, with_deleted=True):
        raise ConflictError(f"工号 {teacher_no} 已存在")

    teacher = Teacher(
        teacher_no=teacher_no,
        name=payload.name,
        gender=payload.gender,
        phone=payload.phone,
        email=payload.email,
        title=payload.title,
        subject=payload.subject,
        hire_date=parse_date(payload.hire_date, "入职时间"),
        remark=payload.remark,
    )
    if payload.class_ids:
        teacher.classes = _resolve_classes(db, payload.class_ids)

    db.add(teacher)
    db.commit()
    db.refresh(teacher)
    return ok(TeacherOut.model_validate(teacher), msg=f"老师 {teacher.name} 已加入，工号 {teacher.teacher_no}")


@router.get("/{teacher_id}", response_model=Resp[TeacherOut], summary="老师详情")
def get_teacher(db: DbSession, _: ReadAccount, teacher_id: int):
    return ok(TeacherOut.model_validate(TeacherDao.get_or_404(db, teacher_id, "老师")))


@router.put("/{teacher_id}", response_model=Resp[TeacherOut], summary="更新老师（含带班关系）")
def update_teacher(db: DbSession, _: WriteAccount, teacher_id: int, payload: TeacherUpdate):
    teacher = TeacherDao.get_or_404(db, teacher_id, "老师")
    data = payload.model_dump(exclude_unset=True)
    if "hire_date" in data:
        teacher.hire_date = parse_date(data.pop("hire_date"), "入职时间")
    class_ids = data.pop("class_ids", None)

    for key, value in data.items():
        if value is not None and hasattr(teacher, key):
            setattr(teacher, key, value)

    if class_ids is not None:
        teacher.classes = _resolve_classes(db, class_ids)

    db.commit()
    db.refresh(teacher)
    return ok(TeacherOut.model_validate(teacher), msg="更新成功")


@router.delete("/{teacher_id}", summary="逻辑删除老师（仍带班时拒绝）")
def delete_teacher(db: DbSession, _: WriteAccount, teacher_id: int):
    teacher = TeacherDao.get_or_404(db, teacher_id, "老师")
    if teacher.class_names:
        raise BusinessError(
            f"老师「{teacher.name}」还在带 {len(teacher.class_names)} 个班："
            f"{'、'.join(teacher.class_names)}。请先解除带班关系"
        )
    teacher.soft_delete()
    db.commit()
    return ok(msg=f"已删除老师 {teacher.name}")


def _resolve_classes(db, class_ids: list[int]) -> list:
    all_classes = {c.id: c for c in ClazzDao.all(db, ClazzDao.build_stmt())}
    missing = [cid for cid in class_ids if cid not in all_classes]
    if missing:
        raise NotFoundError(f"班级不存在：{missing}")
    return [all_classes[cid] for cid in class_ids]