"""CRUD des postes.

`lead_account_id` (référent) ne peut désigner qu'un compte `Role.LEAD` de la
même édition — voir `_check_lead_account`. C'est le seul moyen de donner à un
bénévole une vue référent (`/mobile-referent`) à la connexion ; voir
`api/accounts.py:update_account` pour le faire passer de VOLUNTEER à LEAD."""

import uuid

from fastapi import APIRouter, Depends, HTTPException, Response, status
from sqlmodel import Session, select

from app.api._common import owned_or_404
from app.api._shiftgen import generate_missing_shifts
from app.api.deps import get_edition
from app.api.schemas import (
    GenerateShiftsResult,
    PositionCreate,
    PositionRead,
    PositionUpdate,
)
from app.auth.deps import (
    current_account_in_edition,
    ensure_can_write_position,
    require_coordinator,
    require_staff,
)
from app.db import get_session
from app.models import Account, Edition, Position, Role

router = APIRouter(
    prefix="/editions/{edition_id}/positions", tags=["positions"]
)


def _check_lead_account(
    session: Session, edition: Edition, lead_account_id: uuid.UUID | None
) -> None:
    """`lead_account_id` doit désigner un compte RÉFÉRENT (`Role.LEAD`) de
    cette même édition — sinon le poste se retrouve sans référent utilisable
    (cf. `ensure_can_write_position`, `auth/deps.py`)."""
    if lead_account_id is None:
        return
    lead = session.get(Account, lead_account_id)
    if lead is None or lead.edition_id != edition.id or lead.role is not Role.LEAD:
        raise HTTPException(
            status_code=422, detail={"code": "position.lead_must_be_referent_account"}
        )


@router.post("", response_model=PositionRead, status_code=status.HTTP_201_CREATED)
def create_position(
    payload: PositionCreate,
    edition: Edition = Depends(get_edition),
    _guard: Account = Depends(require_coordinator),
    session: Session = Depends(get_session),
) -> Position:
    _check_lead_account(session, edition, payload.lead_account_id)
    position = Position(edition_id=edition.id, **payload.model_dump())
    session.add(position)
    session.flush()
    # Un créneau à besoin 0/0 par jour et par créneau type de l'édition.
    generate_missing_shifts(session, edition, position)
    session.commit()
    session.refresh(position)
    return position


@router.get("", response_model=list[PositionRead])
def list_positions(
    edition: Edition = Depends(get_edition),
    _guard: Account = Depends(require_staff),
    session: Session = Depends(get_session),
) -> list[Position]:
    return list(
        session.exec(
            select(Position)
            .where(Position.edition_id == edition.id)
            .order_by(Position.name)
        )
    )


@router.get("/{position_id}", response_model=PositionRead)
def get_position(
    position_id: uuid.UUID,
    edition: Edition = Depends(get_edition),
    _guard: Account = Depends(require_staff),
    session: Session = Depends(get_session),
) -> Position:
    return owned_or_404(session.get(Position, position_id), edition.id)


@router.patch("/{position_id}", response_model=PositionRead)
def update_position(
    position_id: uuid.UUID,
    payload: PositionUpdate,
    edition: Edition = Depends(get_edition),
    account: Account = Depends(current_account_in_edition),
    session: Session = Depends(get_session),
) -> Position:
    position = owned_or_404(session.get(Position, position_id), edition.id)
    ensure_can_write_position(account, position)
    changes = payload.model_dump(exclude_unset=True)
    _check_lead_account(session, edition, changes.get("lead_account_id"))
    for field, value in changes.items():
        setattr(position, field, value)
    session.commit()
    session.refresh(position)
    return position


@router.post(
    "/{position_id}/generate-shifts", response_model=GenerateShiftsResult
)
def generate_shifts(
    position_id: uuid.UUID,
    edition: Edition = Depends(get_edition),
    account: Account = Depends(current_account_in_edition),
    session: Session = Depends(get_session),
) -> GenerateShiftsResult:
    """(Re)génère les créneaux manquants du poste après un ajout de créneau
    type ou une extension des dates de l'édition. N'écrase rien d'existant."""
    position = owned_or_404(session.get(Position, position_id), edition.id)
    ensure_can_write_position(account, position)
    created = generate_missing_shifts(session, edition, position)
    session.commit()
    return GenerateShiftsResult(created=created)


@router.delete("/{position_id}", status_code=status.HTTP_204_NO_CONTENT)
def delete_position(
    position_id: uuid.UUID,
    edition: Edition = Depends(get_edition),
    _guard: Account = Depends(require_coordinator),
    session: Session = Depends(get_session),
) -> Response:
    position = owned_or_404(session.get(Position, position_id), edition.id)
    session.delete(position)
    session.commit()
    return Response(status_code=status.HTTP_204_NO_CONTENT)