ForbiddenStarsApp/backend/app/services/stats_service.py

"""Статистика и рейтинги. Считается «вживую» (объём данных мал, кэш не нужен).

Рейтинг — функция упорядоченной истории (scoring.replay), поэтому витрины не агрегируют
SQL, а проигрывают завершённые партии: одна загрузка истории на запрос, из неё же
считаются игры, победы, среднее место и разбивки. Цепочек две: общая — по всем партиям
приложения, групповая — только по партиям группы (это разные числа)."""
from __future__ import annotations

from collections import defaultdict

from sqlalchemy import func
from sqlmodel import Session, select

from app.core.timeutil import iso_utc
from app.models import Expansion, Faction, Group, GroupMember, Match, MatchParticipant, User
from app.services import faction_service, group_service, membership_service, user_service
from app.services.scoring import (
    FACTION_MIN_GAMES,
    MIN_GAMES,
    RatedMatch,
    RatedSeat,
    Replay,
    leaderboard_sort_key,
    replay,
)


def load_history(session: Session, group_id: int | None = None) -> list[RatedMatch]:
    """Завершённые партии в порядке проигрывания: дата игры, момент завершения, id.

    Один запрос на партии с участниками. In_progress в рейтинг не входят: мест у них нет."""
    stmt = (
        select(Match, MatchParticipant)
        .join(MatchParticipant, MatchParticipant.match_id == Match.id)
        .where(Match.status == "finished")
    )
    if group_id is not None:
        stmt = stmt.where(Match.group_id == group_id)
    stmt = stmt.order_by(Match.played_at, Match.finished_at, Match.id, MatchParticipant.id)

    history: list[RatedMatch] = []
    current: Match | None = None
    seats: list[RatedSeat] = []

    def flush() -> None:
        if current is not None and seats:
            history.append(
                RatedMatch(
                    seats=tuple(seats),
                    win_reason=current.win_reason,
                    end_round=current.end_round,
                    nine_rounds_rule=current.nine_rounds_rule,
                    id=current.id,  # type: ignore[arg-type]
                    group_id=current.group_id,
                    played_at=current.played_at,
                    finished_at=current.finished_at,
                )
            )

    for m, p in session.exec(stmt).all():
        if current is None or m.id != current.id:
            flush()
            current, seats = m, []
        if p.place is None:  # у завершённой партии мест без значения не бывает
            continue
        seats.append(
            RatedSeat(
                user_id=p.user_id,
                place=p.place,
                faction_id=p.faction_id,
                eliminated=p.eliminated,
                objectives=p.objectives,
                worlds=p.worlds,
            )
        )
    flush()
    return history


def _for_group(history: list[RatedMatch], group_id: int) -> list[RatedMatch]:
    return [m for m in history if m.group_id == group_id]


def _user_seats(history: list[RatedMatch], user_id: int) -> list[tuple[RatedMatch, RatedSeat]]:
    return [(m, s) for m in history for s in m.seats if s.user_id == user_id]


def _summary(seats: list[tuple[RatedMatch, RatedSeat]], rating: float | None) -> dict:
    """Итог игрока: игры, победы, винрейт, среднее место и рейтинг целым числом.

    В расчёте рейтинг без округления (иначе ошибка копилась бы по цепочке партий),
    показывается — целым."""
    games = len(seats)
    if games == 0:
        return {"games": 0, "wins": 0, "win_rate": 0.0, "avg_place": None, "score": None}
    wins = sum(1 for _m, s in seats if s.place == 1)
    return {
        "games": games,
        "wins": wins,
        "win_rate": round(wins / games, 4),
        "avg_place": round(sum(s.place for _m, s in seats) / games, 2),
        "score": None if rating is None else round(rating),
    }


def leaderboard(
    session: Session,
    group_id: int | None = None,
    *,
    history: list[RatedMatch] | None = None,
    rep: Replay | None = None,
) -> dict:
    """Топ: общий или группы. history/rep — уже посчитанные (home их переиспользует)."""
    if history is None:
        history = load_history(session, group_id)
    if rep is None:
        rep = replay(history)

    by_user: dict[int, list[tuple[RatedMatch, RatedSeat]]] = defaultdict(list)
    for m in history:
        for s in m.seats:
            by_user[s.user_id].append((m, s))
    users = (
        {u.id: u for u in session.exec(select(User).where(User.id.in_(list(by_user)))).all()}
        if by_user
        else {}
    )

    rows = []
    for uid, seats in by_user.items():
        u = users[uid]
        rows.append(
            {
                "user_id": uid,
                "nickname": u.nickname,
                **_summary(seats, rep.ratings[uid]),
                "rating": rep.ratings[uid],  # только для сортировки
                "avatar_url": user_service.avatar_url_for(u.id, u.avatar_path, u.updated_at),  # type: ignore[arg-type]
            }
        )
    qualified = sorted((r for r in rows if r["games"] >= MIN_GAMES), key=leaderboard_sort_key)
    provisional = sorted((r for r in rows if r["games"] < MIN_GAMES), key=leaderboard_sort_key)
    for i, r in enumerate(qualified, start=1):
        r["rank"] = i
    for r in provisional:
        r["rank"] = None
    for r in rows:
        del r["rating"]
    return {
        "entries": qualified,
        "provisional": provisional,
        "min_games": MIN_GAMES,
    }


def _faction_breakdown(
    session: Session, seats: list[tuple[RatedMatch, RatedSeat]], rep: Replay, user_id: int
) -> list[dict]:
    by_faction: dict[int, list[tuple[RatedMatch, RatedSeat]]] = defaultdict(list)
    for m, s in seats:
        by_faction[s.faction_id].append((m, s))
    if not by_faction:
        return []
    meta = {
        f.id: (f, code)
        for f, code in session.exec(
            select(Faction, Expansion.code)
            .join(Expansion, Expansion.id == Faction.expansion_id)
            .where(Faction.id.in_(list(by_faction)))
        ).all()
    }
    out = []
    for fid, group in by_faction.items():
        faction, expansion_code = meta[fid]
        perf = sum(rep.perf[(m.id, user_id)] for m, _s in group) / len(group)
        out.append(
            {
                "faction_id": fid,
                "code": faction.code,
                "name_ru": faction.name_ru,
                "expansion_code": expansion_code,
                **{k: v for k, v in _summary(group, None).items() if k != "score"},
                # Средний результат относительно ожидания (S − E) × 100: насколько игрок
                # на фракции выступает выше рейтинговых шансов — без привязки к рейтингу.
                "score": round(perf * 100, 1),
                "name_ru_prepositional": faction_service.prepositional(
                    faction.code, faction.name_ru
                ),
            }
        )
    out.sort(key=lambda f: (-f["games"], -(f["score"] or 0.0)))
    return out


def _recent_form(seats: list[tuple[RatedMatch, RatedSeat]], limit: int = 5) -> list[dict]:
    recent = sorted(seats, key=lambda ms: (str(ms[0].played_at), ms[0].id), reverse=True)
    return [
        {
            "place": s.place,
            "player_count": len(m.seats),
            "played_at": str(m.played_at),
        }
        for m, s in recent[:limit]
    ]


def _favorite_faction(session: Session, user_id: int) -> dict | None:
    """Любимая фракция игрока: личный выбор в профиле, а не вывод из статистики."""
    user = session.get(User, user_id)
    if user is None or user.favorite_faction_id is None:
        return None
    faction = session.get(Faction, user.favorite_faction_id)
    if faction is None:
        return None
    return {
        "id": faction.id,
        "code": faction.code,
        "name_ru": faction.name_ru,
        "expansion_id": faction.expansion_id,
    }


def _overall(history: list[RatedMatch], rep: Replay, user_id: int) -> dict:
    return _summary(_user_seats(history, user_id), rep.ratings.get(user_id))


def profile_stats(
    session: Session,
    user_id: int,
    group_id: int | None = None,
    *,
    history: list[RatedMatch] | None = None,
    rep: Replay | None = None,
) -> dict:
    """Витрина профиля. history/rep — общая цепочка, уже посчитанная (home их переиспользует);
    с group_id считается групповая цепочка."""
    if history is None:
        history = load_history(session)
    if group_id is not None:
        history, rep = _for_group(history, group_id), None
    if rep is None:
        rep = replay(history)
    seats = _user_seats(history, user_id)
    factions = _faction_breakdown(session, seats, rep, user_id)
    qualified = [f for f in factions if f["games"] >= FACTION_MIN_GAMES]
    best = max(qualified, key=lambda f: f["score"]) if qualified else None
    worst = min(qualified, key=lambda f: f["score"]) if qualified else None
    # «Чаще всего играет на» — самая игранная фракция по всей истории, включая
    # рандомные раздачи.
    main = max(factions, key=lambda f: f["games"]) if factions else None
    return {
        "user_id": user_id,
        "overall": _summary(seats, rep.ratings.get(user_id)),
        "factions": factions,
        "best_faction": best,
        "worst_faction": worst,
        "favorite_faction": _favorite_faction(session, user_id),
        "main_faction": main,
        "recent_form": _recent_form(seats),
        "min_games": MIN_GAMES,
    }


def group_stats(session: Session, group_id: int) -> dict:
    history = load_history(session, group_id)
    board = leaderboard(session, group_id, history=history, rep=replay(history))
    last_played = max((m.played_at for m in history), default=None)

    games: dict[int, int] = defaultdict(int)
    wins: dict[int, int] = defaultdict(int)
    for m in history:
        for s in m.seats:
            games[s.faction_id] += 1
            wins[s.faction_id] += s.place == 1
    available_ids = group_service.available_faction_ids(session, group_id)
    factions = sorted(
        session.exec(select(Faction)).all(), key=lambda f: (-games[f.id], f.sort_order)  # type: ignore[index]
    )
    faction_meta = [
        {
            "faction_id": f.id,
            "code": f.code,
            "name_ru": f.name_ru,
            "games": games[f.id],  # type: ignore[index]
            "wins": wins[f.id],  # type: ignore[index]
            "available": f.id in available_ids,
        }
        for f in factions
    ]

    # Участники без завершённых партий — отдельным блоком (нули, rank=null).
    played_ids = {e["user_id"] for e in board["entries"]} | {
        e["user_id"] for e in board["provisional"]
    }
    inactive = []
    for _m, u in membership_service.list_members(session, group_id):
        if u.id in played_ids:
            continue
        inactive.append(
            {
                "user_id": u.id,
                "nickname": u.nickname,
                "games": 0,
                "wins": 0,
                "win_rate": 0.0,
                "avg_place": None,
                "score": None,
                "rank": None,
                "avatar_url": user_service.avatar_url_for(u.id, u.avatar_path, u.updated_at),
            }
        )

    return {
        "group_id": group_id,
        "total_matches": len(history),
        "last_match_at": str(last_played) if last_played else None,
        "leaderboard": board["entries"],
        "provisional": board["provisional"],
        "inactive": inactive,
        "faction_meta": faction_meta,
        "min_games": MIN_GAMES,
    }


def _participant_row(p: MatchParticipant, u: User, f: Faction) -> dict:
    return {
        "user_id": u.id,
        "nickname": u.nickname,
        "faction_id": f.id,
        "faction_name": f.name_ru,
        "place": p.place,
        "eliminated": p.eliminated,
        "was_random": p.was_random,
        "comment": p.comment,
        "objectives": p.objectives,
        "worlds": p.worlds,
    }


def _participants_by_match(session: Session, match_ids: list[int]) -> dict[int, list[dict]]:
    """Участники сразу всей страницы партий: иначе запрос на каждую партию (N+1)."""
    if not match_ids:
        return {}
    rows = session.exec(
        select(MatchParticipant, User, Faction)
        .join(User, User.id == MatchParticipant.user_id)
        .join(Faction, Faction.id == MatchParticipant.faction_id)
        .where(MatchParticipant.match_id.in_(match_ids))
        # place может быть NULL (партия идёт) — NULL уходит в конец сортировки.
        .order_by(MatchParticipant.place.is_(None), MatchParticipant.place, User.nickname)
    ).all()
    out: dict[int, list[dict]] = {}
    for p, u, f in rows:
        out.setdefault(p.match_id, []).append(_participant_row(p, u, f))
    return out


def _match_items(session: Session, matches) -> list[dict]:
    """Элементы списка партий (общее для списка группы и истории игрока)."""
    by_match = _participants_by_match(session, [m.id for m in matches])

    items = []
    for m in matches:
        parts = by_match.get(m.id, [])
        items.append(
            {
                "id": m.id,
                "status": m.status,
                "played_at": str(m.played_at),
                "started_at": iso_utc(m.started_at),
                "finished_at": iso_utc(m.finished_at),
                "duration_minutes": m.duration_minutes,
                "win_reason": m.win_reason,
                "player_count": m.player_count,
                "overall_comment": m.overall_comment,
                "created_by": m.created_by,
                "participants": parts,
            }
        )
    return items


def group_match_list(session: Session, group_id: int, limit: int = 20, offset: int = 0) -> dict:
    total = session.exec(
        select(func.count()).select_from(Match).where(Match.group_id == group_id)
    ).one()
    matches = session.exec(
        select(Match)
        .where(Match.group_id == group_id)
        .order_by(Match.played_at.desc(), Match.id.desc())
        .offset(offset)
        .limit(limit)
    ).all()
    return {
        "items": _match_items(session, matches),
        "total": total,
        "limit": limit,
        "offset": offset,
    }


def user_match_list(
    session: Session,
    user_id: int,
    limit: int = 20,
    offset: int = 0,
    best_only: bool = False,
) -> dict:
    """История партий игрока: только ЗАВЕРШЁННЫЕ, свежие сверху.

    best_only — одна лучшая партия: наибольший прирост рейтинга в общей цепочке
    (учитывает и соперников, и ход партии); при равенстве берём более свежую."""
    if best_only:
        history = load_history(session)
        rep = replay(history)
        candidates = [
            (rep.delta[(m.id, user_id)], m.played_at, m.id) for m, _s in _user_seats(history, user_id)
        ]
        matches = [session.get(Match, max(candidates)[2])] if candidates else []
        return {
            "items": _match_items(session, matches),
            "total": len(matches),
            "limit": 1,
            "offset": 0,
        }

    where = (MatchParticipant.user_id == user_id, Match.status == "finished")
    total = session.exec(
        select(func.count())
        .select_from(Match)
        .join(MatchParticipant, MatchParticipant.match_id == Match.id)
        .where(*where)
    ).one()
    matches = session.exec(
        select(Match)
        .join(MatchParticipant, MatchParticipant.match_id == Match.id)
        .where(*where)
        .order_by(Match.played_at.desc(), Match.id.desc())
        .offset(offset)
        .limit(limit)
    ).all()
    return {
        "items": _match_items(session, matches),
        "total": total,
        "limit": limit,
        "offset": offset,
    }


def user_in_progress_matches(session: Session, user_id: int) -> list[dict]:
    """Незавершённые партии во всех группах, где состоит пользователь (новые сверху)."""
    group_ids = list(
        session.exec(select(GroupMember.group_id).where(GroupMember.user_id == user_id)).all()
    )
    if not group_ids:
        return []
    rows = session.exec(
        select(Match, Group.name)
        .join(Group, Group.id == Match.group_id)
        .where(Match.status == "in_progress", Match.group_id.in_(group_ids))
        .order_by(Match.started_at.desc(), Match.id.desc())
    ).all()
    by_match = _participants_by_match(session, [m.id for m, _ in rows])
    out = []
    for m, gname in rows:
        parts = by_match.get(m.id, [])
        out.append(
            {
                "id": m.id,
                "group_id": m.group_id,
                "group_name": gname,
                "started_at": iso_utc(m.started_at),
                "player_count": m.player_count,
                "participants": parts,
            }
        )
    return out


def home(session: Session, user_id: int, active_group_id: int | None, leaderboard_limit: int = 10) -> dict:
    # История грузится и общая цепочка проигрывается один раз: из них и топ, и профиль;
    # итог по активной группе — отдельная (групповая) цепочка по срезу той же истории.
    history = load_history(session)
    rep = replay(history)
    board = leaderboard(session, history=history, rep=rep)
    profile = profile_stats(session, user_id, history=history, rep=rep)
    active_group_brief = None
    if active_group_id is not None:
        group = session.get(Group, active_group_id)
        if group is not None:
            group_history = _for_group(history, active_group_id)
            active_group_brief = {
                "id": group.id,
                "name": group.name,
                **_overall(group_history, replay(group_history), user_id),
            }
    return {
        "leaderboard": board["entries"][:leaderboard_limit],
        "provisional": board["provisional"][:leaderboard_limit],
        "profile": profile,
        "active_group": active_group_brief,
        "in_progress": user_in_progress_matches(session, user_id),
        "min_games": MIN_GAMES,
    }