"""Zapis a citanie historie hier nad `db/`.

Cita hodnoty z ciste-Python enginu (bridzik.Bridzik) a uklada ich do DB.
Engine sa neupravuje -- pouzivame len jeho existujuce metody.
"""

from datetime import datetime, timezone
from random import shuffle

from sqlalchemy import func, or_, select

from bridzik import Bridzik, Round, Series
from db.db import async_session
from db.models import Game, Guess, Player


async def record_game_started(gid: str, name: str, player_ids: list[int]) -> None:
    """Zapise riadok Game so 4 ID hracov (podla sedadla). Idempotentne."""
    async with async_session() as session:
        if await session.get(Game, gid) is not None:
            return
        session.add(
            Game(
                id=gid,
                name=name,
                player0_id=player_ids[0],
                player1_id=player_ids[1],
                player2_id=player_ids[2],
                player3_id=player_ids[3],
            )
        )
        await session.commit()


async def record_completed_rounds(gid: str, core) -> None:
    """Zapise 4 Guess-y za kazde nove dohrate kolo; po dohrani hry vyplni ended_at.

    Idempotentne: kola uz zapisane v DB sa preskakuju.
    """
    async with async_session() as session:
        game = await session.get(Game, gid)
        if game is None:
            return

        rows = await session.execute(
            select(Guess.series_number, Guess.round_number)
            .where(Guess.game_id == gid)
            .distinct()
        )
        already = {(r.series_number, r.round_number) for r in rows}

        for series in core.series:
            for rnd in series.rounds:
                if not rnd.is_completed():
                    continue
                key = (series.series_number, rnd.round_number)
                if key in already:
                    continue
                points = rnd.get_points_summary()  # list[4], body za kolo
                for seat in range(4):
                    session.add(
                        Guess(
                            game_id=gid,
                            player_id=game.player_id_for_seat(seat),
                            series_number=series.series_number,
                            round_number=rnd.round_number,
                            guess=rnd.guesses[seat],
                            points=points[seat],
                        )
                    )

        # Priebezne uloz aktualnu poziciu hry (na restore).
        last_series = core.series[-1]
        game.series = last_series.series_number
        game.round = last_series.get_last_round().round_number

        if core.is_completed() and game.ended_at is None:
            game.ended_at = datetime.now(timezone.utc)

        await session.commit()


async def get_standings(gid: str) -> list[list[list[int]]]:
    """Body po seriach/kolach z DB v tvare, ktory caka frontend: standings[serie][kolo]
    = [body sedadiel 0..3]. Pouziva sa v game_status, aby skore sedelo aj po restarte.
    """
    async with async_session() as session:
        game = await session.get(Game, gid)
        if game is None:
            return []
        seat_of = {
            game.player0_id: 0,
            game.player1_id: 1,
            game.player2_id: 2,
            game.player3_id: 3,
        }
        rows = (
            await session.scalars(
                select(Guess)
                .where(Guess.game_id == gid)
                .order_by(Guess.series_number, Guess.round_number)
            )
        ).all()

        series_map: dict[int, dict[int, list[int]]] = {}
        for gz in rows:
            rounds = series_map.setdefault(gz.series_number, {})
            points = rounds.setdefault(gz.round_number, [0, 0, 0, 0])
            seat = seat_of.get(gz.player_id)
            if seat is not None:
                points[seat] = gz.points

        return [
            [series_map[s][r] for r in sorted(series_map[s])]
            for s in sorted(series_map)
        ]


async def get_player_history(player_id: int) -> list[dict]:
    """Zoznam hier daneho hraca (najnovsie prve) so sumarom jeho bodov."""
    async with async_session() as session:
        stmt = (
            select(Game)
            .where(
                or_(
                    Game.player0_id == player_id,
                    Game.player1_id == player_id,
                    Game.player2_id == player_id,
                    Game.player3_id == player_id,
                )
            )
            .order_by(Game.created_at.desc())
        )
        games = (await session.scalars(stmt)).all()

        result = []
        for g in games:
            seat_ids = [g.player0_id, g.player1_id, g.player2_id, g.player3_id]
            usernames = await _usernames_for(session, seat_ids)
            total = await session.scalar(
                select(func.coalesce(func.sum(Guess.points), 0)).where(
                    Guess.game_id == g.id, Guess.player_id == player_id
                )
            )
            result.append(
                {
                    "gid": g.id,
                    "created_at": g.created_at.isoformat() if g.created_at else None,
                    "ended_at": g.ended_at.isoformat() if g.ended_at else None,
                    "players": [usernames[pid] for pid in seat_ids],
                    "my_points": int(total or 0),
                }
            )
        return result


async def get_game_detail(gid: str) -> dict | None:
    """Detail hry: tipy a body po kolach (won = points > 0)."""
    async with async_session() as session:
        game = await session.get(Game, gid)
        if game is None:
            return None
        seat_ids = [game.player0_id, game.player1_id, game.player2_id, game.player3_id]
        usernames = await _usernames_for(session, seat_ids)

        guesses = (
            await session.scalars(
                select(Guess)
                .where(Guess.game_id == gid)
                .order_by(Guess.series_number, Guess.round_number, Guess.player_id)
            )
        ).all()

        return {
            "gid": game.id,
            "created_at": game.created_at.isoformat() if game.created_at else None,
            "ended_at": game.ended_at.isoformat() if game.ended_at else None,
            "players": [
                {"player_id": pid, "username": usernames[pid]} for pid in seat_ids
            ],
            "rounds": [
                {
                    "series_number": gz.series_number,
                    "round_number": gz.round_number,
                    "player_id": gz.player_id,
                    "username": usernames.get(gz.player_id),
                    "guess": gz.guess,
                    "points": gz.points,
                    "won": gz.points > 0,
                }
                for gz in guesses
            ],
        }


async def _usernames_for(session, player_ids: list[int]) -> dict[int, str]:
    rows = await session.scalars(
        select(Player).where(Player.id.in_(set(player_ids)))
    )
    return {p.id: p.username for p in rows}


# --- restore ---------------------------------------------------------------

def rebuild_core(series_number: int, round_number: int, shuffler=shuffle) -> Bridzik:
    """Postavi Bridzik na danu poziciu (zaciatok kola), karty rozda nanovo.

    Vsetko ostatne (rotacia first_player, pocet kariet) je deterministicke z
    dvojice (series_number, round_number), takze tieto dve cisla staci na obnovu
    hracej kostry. Tipy a rozohrate kopky aktualneho kola sa NEobnovuju -- kolo
    sa zacne odznova; historicke body si vola get_game_detail z tabulky Guess.
    """
    core = Bridzik(shuffler=shuffler)
    # Doplnaj serie az po cielovu (kazda nova zacne svojim kolom 0).
    while core.series[-1].series_number < series_number:
        core.series.append(Series(len(core.series), shuffler=shuffler))
    # V poslednej serii doplnaj kola az po cielove (Round rozda karty nanovo).
    last = core.series[-1]
    while last.get_last_round().round_number < round_number:
        rn = len(last.rounds)
        last.rounds.append(Round(rn, (last.first_player + rn) % 4, shuffler=shuffler))
    return core


async def restore_game_core(gid: str, shuffler=shuffle) -> Bridzik | None:
    """Nacita poziciu hry z DB a vrati obnoveny Bridzik (alebo None)."""
    async with async_session() as session:
        game = await session.get(Game, gid)
        if game is None:
            return None
        return rebuild_core(game.series, game.round, shuffler=shuffler)


async def mark_game_ended(gid: str) -> None:
    """Natrvalo ukonci hru (host ju zrusil, ked sa nedohra). Uz sa neobnovi."""
    async with async_session() as session:
        game = await session.get(Game, gid)
        if game is not None and game.ended_at is None:
            game.ended_at = datetime.now(timezone.utc)
            await session.commit()


async def get_unfinished_games() -> list[dict]:
    """Nedohrate hry (ended_at IS NULL) aj s obnovenym jadrom -- na obnovu pri starte.

    Vracia per hru: gid, name, sedadla (player_id + username podla poradia 0..3)
    a uz postaveny Bridzik na ulozenej pozicii.
    """
    async with async_session() as session:
        games = (
            await session.scalars(select(Game).where(Game.ended_at.is_(None)))
        ).all()

        result = []
        for g in games:
            seat_ids = [g.player0_id, g.player1_id, g.player2_id, g.player3_id]
            usernames = await _usernames_for(session, seat_ids)
            result.append(
                {
                    "gid": g.id,
                    "name": g.name,
                    "seats": [(pid, usernames.get(pid, "?")) for pid in seat_ids],
                    "core": rebuild_core(g.series, g.round),
                }
            )
        return result