"""리더보드 API — 누적 포인트 1위 (docs/SCORING.md §3 랭킹 규칙).

1차 정렬: 누적 포인트. 동점: 정확스코어 횟수 → 적중률 → 참여수 → 최초도달.
주최측/임직원 배제(P1). 이메일은 마스킹하여 노출.
"""
from __future__ import annotations

from collections import defaultdict

from fastapi import APIRouter, Depends, Query
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from ..database import get_db
from ..models import UserPrediction
from ..scoring import SCORE, is_excluded
from ..schemas import LeaderboardOut, StandingOut

router = APIRouter(prefix="/api/leaderboard", tags=["leaderboard"])


def _mask(email: str) -> str:
    name, _, domain = email.partition("@")
    head = name[:2] if len(name) >= 2 else name
    return f"{head}{'*' * max(1, len(name) - 2)}@{domain}"


@router.get("", response_model=LeaderboardOut)
async def leaderboard(
    limit: int = Query(50, ge=1, le=200), db: AsyncSession = Depends(get_db)
) -> LeaderboardOut:
    rows = (
        await db.execute(
            select(UserPrediction).where(
                UserPrediction.points.is_not(None),
                UserPrediction.email.is_not(None),
            )
        )
    ).scalars().all()

    agg: dict[str, dict] = defaultdict(
        lambda: {"points": 0, "exact": 0, "played": 0, "first": None}
    )
    matches: set[str] = set()
    for r in rows:
        email = (r.email or "").strip().lower()
        if not email or is_excluded(email):
            continue
        matches.add(r.match_id)
        a = agg[email]
        a["points"] += r.points or 0
        a["played"] += 1
        if (r.points or 0) >= SCORE["EXACT"]:
            a["exact"] += 1
        ts = r.scored_at or r.created_at
        if a["first"] is None or (ts and ts < a["first"]):
            a["first"] = ts

    ranked = sorted(
        agg.items(),
        key=lambda kv: (
            -kv[1]["points"],
            -kv[1]["exact"],
            -(kv[1]["points"] / kv[1]["played"] if kv[1]["played"] else 0),
            -kv[1]["played"],
            kv[1]["first"].timestamp() if kv[1]["first"] else 0,
        ),
    )

    standings = [
        StandingOut(
            rank=i + 1,
            emailMasked=_mask(email),
            totalPoints=v["points"],
            exactCount=v["exact"],
            matchesPlayed=v["played"],
        )
        for i, (email, v) in enumerate(ranked[:limit])
    ]
    return LeaderboardOut(standings=standings, scoredMatches=len(matches))