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vynl/backend/app/services/recommender.py

191 lines
6.8 KiB
Python

import json
from datetime import datetime, timezone, timedelta
import anthropic
from sqlalchemy import select, func
from sqlalchemy.ext.asyncio import AsyncSession
from app.core.config import settings
from app.models.track import Track
from app.models.playlist import Playlist
from app.models.recommendation import Recommendation
from app.models.user import User
def build_taste_profile(tracks: list[Track]) -> dict:
"""Analyze tracks to build a taste profile summary."""
if not tracks:
return {}
genres_count: dict[str, int] = {}
total_energy = 0.0
total_dance = 0.0
total_valence = 0.0
total_tempo = 0.0
count_features = 0
for t in tracks:
if t.genres:
for g in t.genres:
genres_count[g] = genres_count.get(g, 0) + 1
if t.energy is not None:
total_energy += t.energy
total_dance += t.danceability or 0
total_valence += t.valence or 0
total_tempo += t.tempo or 0
count_features += 1
top_genres = sorted(genres_count.items(), key=lambda x: x[1], reverse=True)[:10]
n = max(count_features, 1)
return {
"top_genres": [{"name": g, "count": c} for g, c in top_genres],
"avg_energy": round(total_energy / n, 3),
"avg_danceability": round(total_dance / n, 3),
"avg_valence": round(total_valence / n, 3),
"avg_tempo": round(total_tempo / n, 1),
"track_count": len(tracks),
"sample_artists": list({t.artist for t in tracks[:20]}),
"sample_tracks": [f"{t.artist} - {t.title}" for t in tracks[:15]],
}
async def get_daily_rec_count(db: AsyncSession, user_id: int) -> int:
"""Count recommendations generated today for rate limiting."""
today_start = datetime.now(timezone.utc).replace(hour=0, minute=0, second=0, microsecond=0)
result = await db.execute(
select(func.count(Recommendation.id)).where(
Recommendation.user_id == user_id,
Recommendation.created_at >= today_start,
)
)
return result.scalar() or 0
async def generate_recommendations(
db: AsyncSession,
user: User,
playlist_id: int | None = None,
query: str | None = None,
) -> tuple[list[Recommendation], int | None]:
"""Generate AI music recommendations using Claude."""
# Rate limit check for free users
remaining = None
if not user.is_pro:
used_today = await get_daily_rec_count(db, user.id)
remaining = max(0, settings.FREE_DAILY_RECOMMENDATIONS - used_today)
if remaining <= 0:
return [], 0
# Gather context
taste_context = ""
existing_tracks = set()
if playlist_id:
result = await db.execute(
select(Playlist).where(Playlist.id == playlist_id, Playlist.user_id == user.id)
)
playlist = result.scalar_one_or_none()
if playlist:
result = await db.execute(
select(Track).where(Track.playlist_id == playlist.id)
)
tracks = list(result.scalars().all())
existing_tracks = {f"{t.artist} - {t.title}".lower() for t in tracks}
profile = build_taste_profile(tracks)
taste_context = f"Taste profile from playlist '{playlist.name}':\n{json.dumps(profile, indent=2)}"
else:
# Gather from all user playlists
result = await db.execute(
select(Playlist).where(Playlist.user_id == user.id)
)
playlists = list(result.scalars().all())
all_tracks = []
for p in playlists:
result = await db.execute(select(Track).where(Track.playlist_id == p.id))
all_tracks.extend(result.scalars().all())
existing_tracks = {f"{t.artist} - {t.title}".lower() for t in all_tracks}
if all_tracks:
profile = build_taste_profile(all_tracks)
taste_context = f"Taste profile from {len(all_tracks)} tracks:\n{json.dumps(profile, indent=2)}"
# Build prompt
user_request = query or "Find me music I'll love based on my taste profile. Prioritize lesser-known artists and hidden gems."
prompt = f"""You are Vynl, an AI music discovery assistant. You help people discover new music they'll love.
{taste_context}
User request: {user_request}
Already in their library (do NOT recommend these):
{', '.join(list(existing_tracks)[:50]) if existing_tracks else 'None provided'}
Respond with exactly 5 music recommendations as a JSON array. Each item should have:
- "title": song title
- "artist": artist name
- "album": album name (if known)
- "reason": A warm, personal 2-3 sentence explanation of WHY they'll love this track. Reference specific qualities from their taste profile. Be specific about sonic qualities, not generic.
- "score": confidence score 0.0-1.0
IMPORTANT: Strongly prioritize independent and underground artists who release music on Bandcamp. Think DIY, indie labels, self-released artists, and the kind of music you'd find crate-digging on Bandcamp. Mix in some Bandcamp-type artists alongside any well-known recommendations. Focus on real discovery — lesser-known artists, deep cuts, and hidden gems over obvious popular choices.
Return ONLY the JSON array, no other text."""
# Call Claude API
client = anthropic.Anthropic(api_key=settings.ANTHROPIC_API_KEY)
message = client.messages.create(
model="claude-haiku-4-5-20251001",
max_tokens=2000,
messages=[{"role": "user", "content": prompt}],
)
# Parse response
response_text = message.content[0].text.strip()
# Handle potential markdown code blocks
if response_text.startswith("```"):
response_text = response_text.split("\n", 1)[1]
response_text = response_text.rsplit("```", 1)[0]
try:
recs_data = json.loads(response_text)
except json.JSONDecodeError:
return [], remaining
# Search Bandcamp for each recommendation to attach real links
from app.services.bandcamp import search_bandcamp
# Save to DB
recommendations = []
for rec in recs_data[:5]:
bandcamp_url = None
try:
results = await search_bandcamp(
f"{rec.get('artist', '')} {rec.get('title', '')}", item_type="t"
)
if results:
bandcamp_url = results[0].get("bandcamp_url")
except Exception:
pass
r = Recommendation(
user_id=user.id,
playlist_id=playlist_id,
title=rec.get("title", "Unknown"),
artist=rec.get("artist", "Unknown"),
album=rec.get("album"),
reason=rec.get("reason", ""),
score=rec.get("score"),
query=query,
bandcamp_url=bandcamp_url,
)
db.add(r)
recommendations.append(r)
await db.flush()
if remaining is not None:
remaining = max(0, remaining - len(recommendations))
return recommendations, remaining