"""Live-sync supervisor (refactor §4, transitional).

Runs inside the sync worker: on startup it launches one :class:`AccountRunner`
per live account. This step (v2 §9.2) only extracts the per-account loops into a
runner; account discovery is still startup-only and is replaced by the lease
claimer in a later step.
"""

from __future__ import annotations

import asyncio
import logging
import uuid
from typing import Any

from sqlalchemy import select

from app.db import session_scope
from app.models import Account
from app.sync.runner import AccountRunner

logger = logging.getLogger(__name__)


async def _live_account_ids() -> list[uuid.UUID]:
    async with session_scope() as session:
        return list(await session.scalars(select(Account.id).where(Account.state == "live")))


async def start_supervisor(ctx: dict[str, Any]) -> None:
    """Launch an AccountRunner per live account (called from the worker on_startup)."""
    runners: dict[uuid.UUID, AccountRunner] = {}
    for account_id in await _live_account_ids():
        runner = AccountRunner(account_id)
        runner.start()
        runners[account_id] = runner
    ctx["runners"] = runners
    logger.info("live supervisor started for %d account(s)", len(runners))


async def stop_supervisor(ctx: dict[str, Any]) -> None:
    """Stop and tear down all account runners (called from the worker on_shutdown)."""
    runners: dict[uuid.UUID, AccountRunner] = ctx.get("runners", {})
    if runners:
        await asyncio.gather(*(r.stop() for r in runners.values()), return_exceptions=True)
    ctx["runners"] = {}