Bénévole : vœux d'artistes (entité Artist) et vœux de postes

Nouvelle entité `Artist` (nom + jour de passage), CRUD
`/editions/{id}/artists` (lecture ouverte à tout compte de l'édition,
écriture COORDINATION), unicité (édition, nom, date).

La fiche bénévole porte deux listes de vœux, sur le modèle de
`skill_codes` (None = inchangé, [] = vider) :
- `artist_ids` : artistes que le bénévole veut voir (`volunteer_artist`) ;
- `wished_position_ids` : postes qu'il voudrait tenir
  (`volunteer_position_wish`), distinct de l'affectation.

Un id étranger à l'édition renvoie 422 (`artist.unknown` /
`position.unknown`). Suppression d'un artiste : cascade sur les vœux.
Migration 0006. Jeu de démonstration et frontend inchangés (le front
suivra).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017uUsRg7XzopkCPWimwg9ZM

backend/app/api/volunteers.py

@@ -15,7 +15,18 @@ from app.auth.deps import (
     require_staff,
 )
 from app.db import get_session
-from app.models import Account, Edition, Role, Skill, Volunteer, VolunteerSkill
+from app.models import (
+    Account,
+    Artist,
+    Edition,
+    Position,
+    Role,
+    Skill,
+    Volunteer,
+    VolunteerArtist,
+    VolunteerPositionWish,
+    VolunteerSkill,
+)
 
 router = APIRouter(
     prefix="/editions/{edition_id}/volunteers", tags=["volunteers"]
@@ -40,10 +51,39 @@ def _skill_codes(session: Session, volunteer_id: uuid.UUID) -> list[str]:
     )
 
 
+def _artist_ids(session: Session, volunteer_id: uuid.UUID) -> list[uuid.UUID]:
+    return list(
+        session.exec(
+            select(Artist.id)
+            .join(VolunteerArtist, VolunteerArtist.artist_id == Artist.id)
+            .where(VolunteerArtist.volunteer_id == volunteer_id)
+            .order_by(Artist.performance_date, Artist.name)
+        )
+    )
+
+
+def _wished_position_ids(
+    session: Session, volunteer_id: uuid.UUID
+) -> list[uuid.UUID]:
+    return list(
+        session.exec(
+            select(Position.id)
+            .join(
+                VolunteerPositionWish,
+                VolunteerPositionWish.position_id == Position.id,
+            )
+            .where(VolunteerPositionWish.volunteer_id == volunteer_id)
+            .order_by(Position.name)
+        )
+    )
+
+
 def _read(session: Session, volunteer: Volunteer) -> VolunteerRead:
     return VolunteerRead(
         **volunteer.model_dump(),
         skill_codes=_skill_codes(session, volunteer.id),
+        artist_ids=_artist_ids(session, volunteer.id),
+        wished_position_ids=_wished_position_ids(session, volunteer.id),
     )
 
 
@@ -62,6 +102,63 @@ def _set_skills(
     )
 
 
+def _resolve_owned_ids(
+    session: Session, model, edition_id: uuid.UUID, ids: list[uuid.UUID], code: str
+) -> list[uuid.UUID]:
+    """Ordre d'entrée conservé, doublons retirés ; 422 si un id est étranger."""
+    wanted = list(dict.fromkeys(ids))
+    if wanted:
+        found = set(
+            session.exec(
+                select(model.id).where(
+                    model.edition_id == edition_id,
+                    model.id.in_(wanted),
+                )
+            )
+        )
+        if len(found) != len(wanted):
+            raise HTTPException(status_code=422, detail={"code": code})
+    return wanted
+
+
+def _set_artists(
+    session: Session, volunteer: Volunteer, artist_ids: list[uuid.UUID]
+) -> None:
+    ids = _resolve_owned_ids(
+        session, Artist, volunteer.edition_id, artist_ids, "artist.unknown"
+    )
+    replace_links(
+        session,
+        VolunteerArtist,
+        filter_column=VolunteerArtist.volunteer_id,
+        filter_value=volunteer.id,
+        pairs=[
+            {"volunteer_id": volunteer.id, "artist_id": aid} for aid in ids
+        ],
+    )
+
+
+def _set_wished_positions(
+    session: Session, volunteer: Volunteer, position_ids: list[uuid.UUID]
+) -> None:
+    ids = _resolve_owned_ids(
+        session,
+        Position,
+        volunteer.edition_id,
+        position_ids,
+        "position.unknown",
+    )
+    replace_links(
+        session,
+        VolunteerPositionWish,
+        filter_column=VolunteerPositionWish.volunteer_id,
+        filter_value=volunteer.id,
+        pairs=[
+            {"volunteer_id": volunteer.id, "position_id": pid} for pid in ids
+        ],
+    )
+
+
 @router.post("", response_model=VolunteerRead, status_code=status.HTTP_201_CREATED)
 def create_volunteer(
     payload: VolunteerCreate,
@@ -71,7 +168,9 @@ def create_volunteer(
 ) -> VolunteerRead:
     volunteer = Volunteer(
         edition_id=edition.id,
-        **payload.model_dump(exclude={"skill_codes"}),
+        **payload.model_dump(
+            exclude={"skill_codes", "artist_ids", "wished_position_ids"}
+        ),
     )
     session.add(volunteer)
     try:
@@ -82,6 +181,8 @@ def create_volunteer(
             status_code=409, detail={"code": "volunteer.duplicate_email"}
         ) from exc
     _set_skills(session, volunteer, payload.skill_codes)
+    _set_artists(session, volunteer, payload.artist_ids)
+    _set_wished_positions(session, volunteer, payload.wished_position_ids)
     session.commit()
     session.refresh(volunteer)
     return _read(session, volunteer)
@@ -124,6 +225,8 @@ def update_volunteer(
     volunteer = owned_or_404(session.get(Volunteer, volunteer_id), edition.id)
     changes = payload.model_dump(exclude_unset=True)
     skill_codes = changes.pop("skill_codes", None)
+    artist_ids = changes.pop("artist_ids", None)
+    wished_position_ids = changes.pop("wished_position_ids", None)
     for field, value in changes.items():
         setattr(volunteer, field, value)
     try:
@@ -135,6 +238,10 @@ def update_volunteer(
         ) from exc
     if skill_codes is not None:
         _set_skills(session, volunteer, skill_codes)
+    if artist_ids is not None:
+        _set_artists(session, volunteer, artist_ids)
+    if wished_position_ids is not None:
+        _set_wished_positions(session, volunteer, wished_position_ids)
     session.commit()
     session.refresh(volunteer)
     return _read(session, volunteer)