"""In-process boti: DB ucty botov a ich rozhodovacie "mozgy" z rl/players.py.

Bot je normalny hrac na sedadle -- ma riadok v tabulke `players` (aby
historia, standings a restore fungovali bez zmeny), ale ziadny socket.
Tahovu slucku botov ma api/__init__.py (_run_bot_turns); tu je len to,
co potrebuje DB a rl vrstvu.

Bezpecnost botich uctov: totp_secret je nahodny a nikde sa neuklada v
citatelnej podobe, totp_last_step sa nastavi na aktualny krok -- ucet tym
padom NIE JE "nedokoncena registracia" (viz auth._is_unconfirmed), takze
register_account ho odmietne prepisat a login bez secretu neprejde.
"""

import os
from random import Random

import pyotp
from sqlalchemy import select

from api import auth
from db import crypto
from db.db import async_session
from db.models import Player
from rl.players import HeuristicPlayer, RandomPlayer
from rl.pure_net import DEFAULT_WEIGHTS_PATH, PureNet, PureNeuralPlayer

# Prefix je konvencia na rozpoznanie bota (aj po restarte servera, kedy sa
# sedadla obnovuju z DB len ako (player_id, username)).
BOT_PREFIX = "bot:"
DEFAULT_KIND = "heuristic"

# Natrenovana siet -- vahy (rl/weights/, export z rl/export.py) sa nacitaju
# raz a zdielaju medzi botmi (PureNet je bezstavovy, len cita).
_pure_net: PureNet | None = None


def _neural_brain() -> PureNeuralPlayer:
    global _pure_net
    if _pure_net is None:
        _pure_net = PureNet.load()
    return PureNeuralPlayer(_pure_net)


def neural_available() -> bool:
    return os.path.exists(DEFAULT_WEIGHTS_PATH)


_BRAINS = {
    "heuristic": lambda: HeuristicPlayer(Random()),
    "random": lambda: RandomPlayer(Random()),
    "neural": _neural_brain,
}
BOT_KINDS = tuple(_BRAINS)


def available_kinds() -> tuple:
    """Druhy botov ponuknutelne na tomto serveri (neural len s vahami)."""
    return tuple(k for k in _BRAINS if k != "neural" or neural_available())


def is_bot_username(username: str) -> bool:
    return bool(username) and username.startswith(BOT_PREFIX)


def kind_of(username: str) -> str:
    """'bot:heuristic-2' -> 'heuristic'; neznamy druh padne na DEFAULT_KIND."""
    body = username[len(BOT_PREFIX):]
    kind = body.rsplit("-", 1)[0]
    return kind if kind in _BRAINS else DEFAULT_KIND


def make_brain(username: str):
    """Rozhodovaci objekt (guess/play rozhranie z rl/players.py) pre bota.

    Neural bez suboru vah (napr. restore hry na serveri bez exportu) padne
    na heuristiku -- sedadlo hra dalej, len inym mozgom.
    """
    kind = kind_of(username)
    if kind == "neural" and not neural_available():
        kind = DEFAULT_KIND
    return _BRAINS[kind]()


def _suffix_number(username: str) -> int:
    try:
        return int(username.rsplit("-", 1)[1])
    except (IndexError, ValueError):
        return 0


async def ensure_bot_account(kind: str, exclude_ids: set) -> dict:
    """Najde alebo zalozi boti ucet daneho druhu; vrati {player_id, username}.

    `exclude_ids` su ucty uz obsadene v danej hre -- kazde sedadlo potrebuje
    INY ucet (Game.playerN_id aj unikat v Guess predpokladaju 4 rozne ID).
    Ucty sa cisluju bot:<kind>-1, -2, ... a recykluju sa medzi hrami.
    """
    prefix = f"{BOT_PREFIX}{kind}-"
    async with async_session() as session:
        rows = (
            await session.scalars(
                select(Player).where(Player.username.like(prefix + "%"))
            )
        ).all()
        for player in sorted(rows, key=lambda p: _suffix_number(p.username)):
            if player.id not in exclude_ids:
                return {"player_id": player.id, "username": player.username}

        number = 1 + max((_suffix_number(p.username) for p in rows), default=0)
        username = f"{prefix}{number}"
        player = Player(
            username=username,
            # nahodny secret, ktory sa zahodi -- nikto sa zan neprihlasi
            totp_secret=crypto.encrypt(pyotp.random_base32()),
            # nenulovy last_step = ucet sa netvari ako nedokoncena registracia
            totp_last_step=auth._current_step(),
        )
        session.add(player)
        await session.commit()
        return {"player_id": player.id, "username": player.username}