173 lines
6.0 KiB
Python
173 lines
6.0 KiB
Python
"""Comparison endpoints – matchmaking and ELO updates."""
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import random
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from fastapi import APIRouter, Depends, HTTPException
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from sqlalchemy import text
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from sqlalchemy.orm import Session
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from app.config import load_sql, settings
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from app.database import get_db
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from app.elo import calculate_elo
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from app.models import Comparison, EloRating
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from app.queries import LISTING_SELECT, row_to_listing
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from app.schemas import (
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CompareRequest,
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CompareResponse,
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ComparisonHistoryItem,
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MatchupResponse,
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StatsResponse,
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)
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router = APIRouter()
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SAMPLE_JOIN = f" inner join {settings.ELO_SCHEMA}.sample_listings as s on l.global_id = s.global_id"
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@router.get("/matchup", response_model=MatchupResponse)
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def get_matchup(
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status: str | None = None,
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db: Session = Depends(get_db),
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):
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"""Return a weighted-random pair of listings for comparison."""
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query = LISTING_SELECT + SAMPLE_JOIN
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params: dict = {"default_elo": settings.DEFAULT_ELO}
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if status and status != "all":
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query += " where l.status = :status"
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params["status"] = status
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result = db.execute(text(query), params)
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listings = [row_to_listing(row) for row in result]
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if len(listings) < 2:
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raise HTTPException(
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status_code=400,
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detail="Not enough listings for comparison (need at least 2).",
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)
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recent = db.execute(text(load_sql("recent_pairs.sql")))
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recent_pairs = {frozenset([r.listing_a_id, r.listing_b_id]) for r in recent}
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weights = [1.0 / (x.comparison_count + 1) ** 1.5 for x in listings]
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first = random.choices(listings, weights=weights, k=1)[0]
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remaining = [x for x in listings if x.global_id != first.global_id]
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remaining_weights = [1.0 / (x.comparison_count + 1) ** 1.5 for x in remaining]
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second = remaining[0]
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for _ in range(20):
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candidate = random.choices(remaining, weights=remaining_weights, k=1)[0]
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if frozenset([first.global_id, candidate.global_id]) not in recent_pairs:
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second = candidate
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break
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else:
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second = random.choices(remaining, weights=remaining_weights, k=1)[0]
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return MatchupResponse(listing_a=first, listing_b=second)
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@router.post("/compare", response_model=CompareResponse)
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def submit_comparison(body: CompareRequest, db: Session = Depends(get_db)):
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"""Record a comparison result and update ELO ratings."""
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if body.winner_id == body.loser_id:
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raise HTTPException(status_code=400, detail="Winner and loser must differ.")
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def get_or_create_rating(global_id: str) -> EloRating:
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rating = db.query(EloRating).filter_by(global_id=global_id).first()
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if not rating:
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rating = EloRating(global_id=global_id, elo_rating=settings.DEFAULT_ELO)
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db.add(rating)
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db.flush()
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return rating
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winner_rating = get_or_create_rating(body.winner_id)
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loser_rating = get_or_create_rating(body.loser_id)
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elo_w_before = winner_rating.elo_rating
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elo_l_before = loser_rating.elo_rating
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new_elo_w, new_elo_l = calculate_elo(elo_w_before, elo_l_before, settings.K_FACTOR)
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winner_rating.elo_rating = new_elo_w
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winner_rating.comparison_count += 1
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winner_rating.wins += 1
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loser_rating.elo_rating = new_elo_l
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loser_rating.comparison_count += 1
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loser_rating.losses += 1
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db.add(
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Comparison(
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listing_a_id=body.winner_id,
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listing_b_id=body.loser_id,
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winner_id=body.winner_id,
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elo_a_before=elo_w_before,
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elo_b_before=elo_l_before,
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elo_a_after=new_elo_w,
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elo_b_after=new_elo_l,
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)
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)
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db.commit()
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return CompareResponse(
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winner_id=body.winner_id,
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loser_id=body.loser_id,
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elo_change=round(new_elo_w - elo_w_before, 1),
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new_winner_elo=round(new_elo_w, 1),
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new_loser_elo=round(new_elo_l, 1),
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)
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def _row_to_history(r) -> ComparisonHistoryItem:
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return ComparisonHistoryItem(
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id=r.id,
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listing_a_title=r.listing_a_title,
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listing_b_title=r.listing_b_title,
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winner_title=r.winner_title,
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listing_a_id=r.listing_a_id,
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listing_b_id=r.listing_b_id,
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winner_id=r.winner_id,
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elo_a_before=round(r.elo_a_before, 1),
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elo_b_before=round(r.elo_b_before, 1),
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elo_a_after=round(r.elo_a_after, 1),
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elo_b_after=round(r.elo_b_after, 1),
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created_at=r.created_at,
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)
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@router.get("/history", response_model=list[ComparisonHistoryItem])
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def get_history(limit: int = 50, db: Session = Depends(get_db)):
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"""Return recent comparisons."""
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rows = db.execute(text(load_sql("history.sql")), {"limit": limit})
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return [_row_to_history(r) for r in rows]
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@router.get("/stats", response_model=StatsResponse)
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def get_stats(db: Session = Depends(get_db)):
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"""Return aggregate statistics about comparisons and ratings."""
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total_comparisons = db.execute(text(load_sql("count_comparisons.sql"))).scalar() or 0
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total_rated = db.execute(text(load_sql("count_rated.sql"))).scalar() or 0
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total_listings = db.execute(text(load_sql("count_listings.sql"))).scalar() or 0
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elo_agg = db.execute(text(load_sql("elo_aggregates.sql"))).first()
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avg_elo = round(float(elo_agg[0]), 1) if elo_agg and elo_agg[0] else None
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max_elo = round(float(elo_agg[1]), 1) if elo_agg and elo_agg[1] else None
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min_elo = round(float(elo_agg[2]), 1) if elo_agg and elo_agg[2] else None
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dist_rows = db.execute(text(load_sql("elo_distribution.sql")))
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elo_distribution = [
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{"bucket": f"{int(r.bucket)}-{int(r.bucket) + 49}", "count": r.count} for r in dist_rows
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]
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recent_rows = db.execute(text(load_sql("history.sql")), {"limit": 10})
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recent_comparisons = [_row_to_history(r) for r in recent_rows]
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return StatsResponse(
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total_comparisons=total_comparisons,
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total_rated_listings=total_rated,
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total_listings=total_listings,
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avg_elo=avg_elo,
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max_elo=max_elo,
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min_elo=min_elo,
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elo_distribution=elo_distribution,
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recent_comparisons=recent_comparisons,
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)
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