"""就业管理接口（需求 2.3、4.3）。

需求里给的示例路径是 /employment/students/{id}、/employment/class/{id}，
这里在同一套语义下改成标准 REST 写法（资源在复数、动作用方法表达），
同时对老路径做了兼容别名，见文件末尾。
"""

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
from app.core.response import Resp, ok
from app.dao.employment_dao import EmploymentDao
from app.dao.student_dao import StudentDao
from app.schema.common import PageResult
from app.schema.employment_schema import (
    EmploymentCreate,
    EmploymentOut,
    EmploymentRegisterResult,
    EmploymentUpdate,
)
from app.service.employment_service import EmploymentService

router = APIRouter(prefix="/employments", tags=["2.3 学生就业管理"])
legacy_router = APIRouter(prefix="/employment", tags=["2.3 学生就业管理（需求示例路径）"], include_in_schema=False)


@router.get("", response_model=Resp[PageResult[EmploymentOut]], summary="就业信息列表（按编号/公司/薪资区间多条件查询）")
def list_employments(
    db: DbSession,
    _: ReadAccount,
    page: Annotated[int, Query(ge=1)] = 1,
    page_size: Annotated[int, Query(ge=1, le=200)] = 10,
    stu_id: Annotated[int | None, Query(description="学生ID")] = None,
    class_id: Annotated[int | None, Query(description="班级ID")] = None,
    company: Annotated[str | None, Query(description="公司名称，模糊匹配")] = None,
    salary_min: Annotated[float | None, Query(ge=0, description="薪资下限")] = None,
    salary_max: Annotated[float | None, Query(ge=0, description="薪资上限")] = None,
    has_offer: Annotated[bool | None, Query(description="是否已下发 offer")] = None,
    has_open: Annotated[bool | None, Query(description="是否已开放就业")] = None,
    keyword: Annotated[str | None, Query(description="姓名/学号/公司/城市")] = None,
    order_by: Annotated[str, Query(description="id/salary/open_date/offer_date/company/student_name")] = "id",
    order: Annotated[str, Query(pattern="^(asc|desc)$")] = "desc",
):
    if salary_min is not None and salary_max is not None and salary_min > salary_max:
        salary_min, salary_max = salary_max, salary_min      # 顺序写反了自动纠正

    stmt = EmploymentDao.build_stmt(
        stu_id=stu_id, class_id=class_id, company=company, salary_min=salary_min,
        salary_max=salary_max, has_offer=has_offer, has_open=has_open,
        keyword=keyword, order_by=order_by, order=order,
    )
    items, total, page, pages = EmploymentDao.paginate(db, stmt, page, page_size)
    return ok({
        "total": total, "page": page, "page_size": page_size, "pages": pages,
        "items": [EmploymentOut.model_validate(e) for e in items],
    })


def _status_msg(action: str, changed: bool, before: str | None, after: str | None) -> str:
    if not changed:
        return action
    return f"{action}，学生状态：{before} → {after}"


@router.post("", response_model=Resp[EmploymentRegisterResult], summary="登记就业信息（事务内同步学生状态）")
def register_employment(db: DbSession, _: WriteAccount, payload: EmploymentCreate):
    employment, created, changed, before, after = EmploymentService.register(db, payload)
    db.commit()
    db.refresh(employment)
    msg = _status_msg("就业信息登记成功" if created else "就业信息已更新", changed, before, after)
    return ok(
        {
            "employment": EmploymentOut.model_validate(employment),
            "created": created,
            "status_changed": changed,
            "from_status_text": before,
            "to_status_text": after,
            "msg": msg,
        },
        msg=msg,
    )


@router.get("/student/{stu_id}", response_model=Resp[EmploymentOut], summary="查询某个学生的就业信息")
def employment_of_student(db: DbSession, _: ReadAccount, stu_id: int):
    StudentDao.get_or_404(db, stu_id, "学生")
    employment = EmploymentDao.get_by_stu_id(db, stu_id)
    if employment is None:
        return Resp.fail("该学生还没有登记就业信息", 404)
    return ok(EmploymentOut.model_validate(employment))


@router.get("/class/{class_id}", summary="查询某个班级的就业情况（含班级就业率）")
def employment_of_class(db: DbSession, _: ReadAccount, class_id: int):
    from app.dao.clazz_dao import ClazzDao

    klass = ClazzDao.get_or_404(db, class_id, "班级")
    stmt = EmploymentDao.build_stmt(class_id=class_id, order_by="salary", order="desc")
    items = EmploymentDao.all(db, stmt)
    students_total = len([s for s in StudentDao.all(db, StudentDao.build_stmt(class_id=class_id, order_by="id", order="asc"))])
    offered = [e for e in items if e.offer_date]
    salaries = [float(e.salary) for e in items if e.salary is not None]
    return ok({
        "class_id": klass.id,
        "class_name": klass.name,
        "student_total": students_total,
        "open_count": len([e for e in items if e.open_date]),
        "offer_count": len(offered),
        "employment_rate": round(len(offered) / students_total * 100, 1) if students_total else 0.0,
        "avg_salary": round(sum(salaries) / len(salaries), 2) if salaries else None,
        "items": [EmploymentOut.model_validate(e) for e in items],
    })


@router.put("/{employment_id}", response_model=Resp[EmploymentRegisterResult], summary="修改就业信息")
def update_employment(db: DbSession, _: WriteAccount, employment_id: int, payload: EmploymentUpdate):
    employment = EmploymentDao.get_or_404(db, employment_id, "就业记录")
    employment, changed, before, after = EmploymentService.update(db, employment, payload)
    db.commit()
    db.refresh(employment)
    msg = _status_msg("修改成功", changed, before, after)
    return ok(
        {
            "employment": EmploymentOut.model_validate(employment),
            "created": False,
            "status_changed": changed,
            "from_status_text": before,
            "to_status_text": after,
            "msg": msg,
        },
        msg=msg,
    )


@router.delete("/{employment_id}", summary="删除就业信息（学生状态回退到在读）")
def delete_employment(db: DbSession, _: WriteAccount, employment_id: int):
    employment = EmploymentDao.get_or_404(db, employment_id, "就业记录")
    changed, before, after = EmploymentService.delete(db, employment)
    db.commit()
    msg = _status_msg("已删除就业记录", changed, before, after)
    return ok(
        {"status_changed": changed, "from_status_text": before, "to_status_text": after, "msg": msg},
        msg=msg,
    )


# ----------------------------------------------------------------- 兼容老路径
@legacy_router.get("/students/{stu_id}", summary="[兼容] 获取学生就业信息")
def legacy_get_student_employment(db: DbSession, account: ReadAccount, stu_id: int):
    return employment_of_student(db, account, stu_id)


@legacy_router.post("/students/{stu_id}", summary="[兼容] 添加/更新就业信息")
def legacy_add_student_employment(db: DbSession, account: WriteAccount, stu_id: int, payload: EmploymentUpdate):
    body = payload.model_dump(exclude_unset=True)
    body["stu_id"] = stu_id
    try:
        create_payload = EmploymentCreate(**body)
    except Exception as exc:  # noqa: BLE001
        raise BusinessError(
            "登记就业至少需要 就业开放时间 / offer 时间 / 公司 / 薪资 中的一项"
        ) from exc
    employment, created, changed, before, after = EmploymentService.register(db, create_payload)
    db.commit()
    db.refresh(employment)
    msg = _status_msg("登记成功" if created else "已更新", changed, before, after)
    return ok(
        {
            "employment": EmploymentOut.model_validate(employment),
            "created": created,
            "status_changed": changed,
            "from_status_text": before,
            "to_status_text": after,
        },
        msg=msg,
    )


@legacy_router.get("/class/{class_id}", summary="[兼容] 获取班级学生就业信息")
def legacy_class_employment(db: DbSession, account: ReadAccount, class_id: int):
    return employment_of_class(db, account, class_id)