# steward/ansible/scheduler.py
"""Fire due Ansible schedules. Driven by the core ScheduledTask loop (~60s)."""
from __future__ import annotations

import logging
from datetime import datetime, timezone

from sqlalchemy import select

from steward.ansible.runner import trigger_run
from steward.models.ansible_schedule import AnsibleSchedule

logger = logging.getLogger(__name__)


def is_due(schedule: AnsibleSchedule, now: datetime) -> bool:
    """True when an enabled schedule has never run or its interval has elapsed.

    Cadence is measured from the previous *fire* time (last_run_at), not run
    completion, so a long-running playbook doesn't cause catch-up storms.
    """
    if not schedule.enabled:
        return False
    if schedule.last_run_at is None:
        return True
    return (now - schedule.last_run_at).total_seconds() >= schedule.interval_seconds


async def run_due_schedules(app) -> int:
    """Trigger every due schedule once. Returns the number launched."""
    now = datetime.now(timezone.utc)
    async with app.db_sessionmaker() as db:
        schedules = (await db.execute(
            select(AnsibleSchedule).where(AnsibleSchedule.enabled.is_(True))
        )).scalars().all()

    fired = 0
    for s in schedules:
        if not is_due(s, now):
            continue
        run = None
        err: str | None = None
        try:
            run, _source, err = await trigger_run(
                app,
                source_name=s.source_name,
                playbook_path=s.playbook_path,
                inventory_scope=s.inventory_scope,
                params=s.params,
                triggered_by=None,
            )
        except Exception:
            logger.exception("Schedule %s (%s) failed to launch", s.id, s.name)
            err = "launch error"

        async with app.db_sessionmaker() as db:
            async with db.begin():
                fresh = await db.get(AnsibleSchedule, s.id)
                if fresh:
                    fresh.last_run_at = now
                    fresh.last_run_id = run.id if run else None
                    fresh.last_error = err
        if run:
            fired += 1
            logger.info("Schedule %s (%s) fired run %s", s.id, s.name, run.id)
    return fired