"""Account activity and the shared transaction lock for channel ownership."""
from __future__ import annotations

import hashlib
from datetime import datetime, timedelta

from sqlalchemy import func, select, text, update

from .models import HockeyWebSession, MatchParticipant

ACCOUNT_IDLE_SECONDS = 2 * 60 * 60


def lock_account(session, user_id: str) -> None:
    if session.get_bind().dialect.name == "postgresql":
        key = int.from_bytes(hashlib.sha256(("hockey-channel:" + user_id).encode()).digest()[:8], "big", signed=True)
        session.execute(text("SELECT pg_advisory_xact_lock(:key)"), {"key": key})
    else:
        session.execute(update(MatchParticipant).where(MatchParticipant.user_id == user_id)
                        .values(last_seen_at=MatchParticipant.last_seen_at))


def account_is_idle(session, user_id: str, now: datetime) -> bool:
    # All browser logins of this account count, including the last action before
    # logout. Polling, OperatorSession timestamps and Agent traffic never count.
    latest = session.scalar(select(func.max(HockeyWebSession.last_activity_at)).where(
        HockeyWebSession.wfl_user_id == user_id))
    # Header-based development/test auth has no persisted browser logins.
    return latest is not None and latest <= now - timedelta(seconds=ACCOUNT_IDLE_SECONDS)