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LinedanceAfspiller/linedance-api/app/routers/alternatives.py
2026-04-11 00:38:04 +02:00

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from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session
from sqlalchemy import func
from pydantic import BaseModel
from app.core.database import get_db
from app.core.security import get_current_user
from app.models import User, SongDance, DanceAlternative, DanceAlternativeRating
router = APIRouter(prefix="/alternatives", tags=["alternatives"])
# Bayesiansk minimum — alternativer med færre ratings trækkes mod gennemsnittet
BAYESIAN_MIN_VOTES = 5
# ── Schemas ───────────────────────────────────────────────────────────────────
class AlternativeCreate(BaseModel):
song_dance_id: str # dans der foreslås alternativ TIL
alt_song_dance_id: str # den alternative dans
note: str = ""
class AlternativeOut(BaseModel):
id: str
song_dance_id: str
alt_song_dance_id: str
alt_dance_name: str
alt_song_title: str
created_by_username: str
note: str
my_score: int | None # den indloggede brugers egen rating
avg_score: float | None # simpelt gennemsnit (til visning)
bayesian_score: float # bruges til sortering
rating_count: int
model_config = {"from_attributes": True}
class RatingUpsert(BaseModel):
score: int # 1-5
# ── Hjælpefunktion: genberegn bayesian score ─────────────────────────────────
def _recalculate_bayesian(alternative: DanceAlternative, db: Session):
"""
Bayesiansk score: vægter gennemsnittet mod et globalt gennemsnit
når der er få ratings, så nye alternativer ikke dominerer listen.
Formel: (n × avg + m × global_avg) / (n + m)
n = antal ratings på dette alternativ
avg = gennemsnit for dette alternativ
m = BAYESIAN_MIN_VOTES (tillid-konstant)
global_avg = gennemsnit på tværs af ALLE ratings
"""
# Beregn stats for dette alternativ
result = db.query(
func.count(DanceAlternativeRating.id),
func.avg(DanceAlternativeRating.score),
).filter(DanceAlternativeRating.alternative_id == alternative.id).one()
n = result[0] or 0
avg = float(result[1]) if result[1] else 0.0
# Globalt gennemsnit på tværs af alle ratings
global_avg_result = db.query(func.avg(DanceAlternativeRating.score)).scalar()
global_avg = float(global_avg_result) if global_avg_result else 3.0 # 3.0 som neutral fallback
m = BAYESIAN_MIN_VOTES
bayesian = (n * avg + m * global_avg) / (n + m) if (n + m) > 0 else global_avg
alternative.bayesian_score = round(bayesian, 4)
db.flush()
# ── Endpoints ─────────────────────────────────────────────────────────────────
@router.post("/", status_code=201)
def create_alternative(
data: AlternativeCreate,
db: Session = Depends(get_db),
me: User = Depends(get_current_user),
):
"""Opret et nyt alternativ-dans forslag. Alle registrerede brugere kan bidrage."""
dance = db.query(SongDance).filter(SongDance.id == data.song_dance_id).first()
if not dance:
raise HTTPException(404, "Dans ikke fundet")
alt_dance = db.query(SongDance).filter(SongDance.id == data.alt_song_dance_id).first()
if not alt_dance:
raise HTTPException(404, "Alternativ-dans ikke fundet")
if data.song_dance_id == data.alt_song_dance_id:
raise HTTPException(400, "En dans kan ikke være sit eget alternativ")
# Undgå dubletter fra samme bruger
existing = db.query(DanceAlternative).filter_by(
song_dance_id=data.song_dance_id,
alt_song_dance_id=data.alt_song_dance_id,
created_by=me.id,
).first()
if existing:
raise HTTPException(400, "Du har allerede foreslået dette alternativ")
alt = DanceAlternative(
song_dance_id=data.song_dance_id,
alt_song_dance_id=data.alt_song_dance_id,
created_by=me.id,
note=data.note,
bayesian_score=3.0, # starter på globalt neutral
)
db.add(alt)
db.commit()
db.refresh(alt)
return {"id": alt.id, "detail": "Alternativ oprettet"}
@router.get("/for-dance/{song_dance_id}", response_model=list[AlternativeOut])
def list_alternatives_for_dance(
song_dance_id: str,
db: Session = Depends(get_db),
me: User = Depends(get_current_user),
):
"""
Hent alle alternativer til en given dans, sorteret efter bayesiansk score.
Viser din egen rating og gennemsnittet.
"""
alternatives = (
db.query(DanceAlternative)
.filter(DanceAlternative.song_dance_id == song_dance_id)
.order_by(DanceAlternative.bayesian_score.desc())
.all()
)
result = []
for alt in alternatives:
# Din egen rating
my_rating = db.query(DanceAlternativeRating).filter_by(
alternative_id=alt.id, user_id=me.id
).first()
# Aggregeret stats
stats = db.query(
func.count(DanceAlternativeRating.id),
func.avg(DanceAlternativeRating.score),
).filter(DanceAlternativeRating.alternative_id == alt.id).one()
result.append(AlternativeOut(
id=alt.id,
song_dance_id=alt.song_dance_id,
alt_song_dance_id=alt.alt_song_dance_id,
alt_dance_name=alt.alt_song_dance.dance_name,
alt_song_title=alt.alt_song_dance.song.title,
created_by_username=alt.creator.username,
note=alt.note,
my_score=my_rating.score if my_rating else None,
avg_score=round(float(stats[1]), 1) if stats[1] else None,
bayesian_score=alt.bayesian_score,
rating_count=stats[0] or 0,
))
return result
@router.put("/{alternative_id}/rate")
def rate_alternative(
alternative_id: str,
data: RatingUpsert,
db: Session = Depends(get_db),
me: User = Depends(get_current_user),
):
"""Sæt eller opdater din rating (1-5) på et alternativ."""
if not 1 <= data.score <= 5:
raise HTTPException(400, "Score skal være mellem 1 og 5")
alt = db.query(DanceAlternative).filter(DanceAlternative.id == alternative_id).first()
if not alt:
raise HTTPException(404, "Alternativ ikke fundet")
# Upsert — opdater eksisterende rating eller opret ny
existing = db.query(DanceAlternativeRating).filter_by(
alternative_id=alternative_id, user_id=me.id
).first()
if existing:
existing.score = data.score
else:
db.add(DanceAlternativeRating(
alternative_id=alternative_id,
user_id=me.id,
score=data.score,
))
db.flush()
_recalculate_bayesian(alt, db)
db.commit()
return {
"detail": "Rating gemt",
"my_score": data.score,
"bayesian_score": alt.bayesian_score,
}
@router.delete("/{alternative_id}/rate", status_code=204)
def remove_rating(
alternative_id: str,
db: Session = Depends(get_db),
me: User = Depends(get_current_user),
):
"""Fjern din rating fra et alternativ."""
rating = db.query(DanceAlternativeRating).filter_by(
alternative_id=alternative_id, user_id=me.id
).first()
if not rating:
raise HTTPException(404, "Du har ikke rated dette alternativ")
alt = db.query(DanceAlternative).filter(DanceAlternative.id == alternative_id).first()
db.delete(rating)
db.flush()
_recalculate_bayesian(alt, db)
db.commit()
@router.delete("/{alternative_id}", status_code=204)
def delete_alternative(
alternative_id: str,
db: Session = Depends(get_db),
me: User = Depends(get_current_user),
):
"""Slet et alternativ — kun den der oprettede det."""
alt = db.query(DanceAlternative).filter(DanceAlternative.id == alternative_id).first()
if not alt:
raise HTTPException(404, "Alternativ ikke fundet")
if alt.created_by != me.id:
raise HTTPException(403, "Du kan kun slette dine egne forslag")
db.delete(alt)
db.commit()