"""APScheduler wrapper that ticks every minute and lets the checker decide
which feeds are due (per-feed intervals are evaluated in check_all_feeds)."""
from __future__ import annotations

import logging

from apscheduler.schedulers.asyncio import AsyncIOScheduler
from apscheduler.triggers.interval import IntervalTrigger

from datetime import datetime, timezone

from sqlmodel import Session, select

from . import delivery
from .checker import check_all_feeds
from .database import engine, get_settings
from .delivery import Message
from .models import DigestEntry, Feed, Notification

log = logging.getLogger("scheduler")

_scheduler: AsyncIOScheduler | None = None
_JOB_ID = "check-feeds"
_JOB_DIGEST = "send-digests"
# Fixed tick; per-feed/global intervals are honoured inside check_all_feeds.
_TICK_SECONDS = 60


async def send_due_digests() -> None:
    """Check each digest-enabled feed and send pending entries."""
    now = datetime.now(timezone.utc)
    with Session(engine) as session:
        settings = get_settings(session)
        feeds = session.exec(
            select(Feed).where(
                Feed.enabled == True,  # noqa: E712
                Feed.digest_enabled == True,  # noqa: E712
            )
        ).all()

    for feed in feeds:
        period_hours = max(1, feed.digest_period_hours)
        if feed.last_digest_at is not None:
            last = feed.last_digest_at.replace(tzinfo=timezone.utc) if feed.last_digest_at.tzinfo is None else feed.last_digest_at
            if (now - last).total_seconds() < period_hours * 3600:
                continue

        with Session(engine) as session:
            entries = session.exec(
                select(DigestEntry)
                .where(DigestEntry.feed_id == feed.id)
                .order_by(DigestEntry.created_at)
            ).all()
            if not entries:
                continue

            db_feed = session.get(Feed, feed.id)
            stg = get_settings(session)

            # Build digest message as Markdown list
            lines = [f"# 📡 {db_feed.title or 'Дайджест'}\n"]
            for e in entries:
                lines.append(f"**[{e.title}]({e.link})**")
                if e.body:
                    preview = e.body[:200].replace("\n", " ")
                    lines.append(f"> {preview}")
                lines.append("")

            digest_msg = Message(
                source=db_feed.title or "",
                title=f"Дайджест ({len(entries)} записей)",
                body="\n".join(lines),
                link="",
                image="",
                full_content=True,
            )

            result = await delivery.dispatch(db_feed, stg, digest_msg)

            session.add(
                Notification(
                    feed_id=db_feed.id,
                    feed_title=digest_msg.source,
                    title=digest_msg.title,
                    link="",
                    channels=",".join(result.channels),
                    ok=result.ok,
                    detail=result.detail,
                )
            )

            # Clear sent entries
            for e in entries:
                session.delete(e)

            db_feed.last_digest_at = now
            db_feed.last_checked = now
            db_feed.last_status = f"digest:{len(entries)}"
            session.commit()


def start(interval_minutes: int) -> None:
    global _scheduler
    if _scheduler is not None:
        return
    _scheduler = AsyncIOScheduler(timezone="UTC")
    _scheduler.add_job(
        check_all_feeds,
        trigger=IntervalTrigger(seconds=_TICK_SECONDS),
        id=_JOB_ID,
        max_instances=1,
        coalesce=True,
        replace_existing=True,
    )
    _scheduler.add_job(
        send_due_digests,
        trigger=IntervalTrigger(seconds=300),  # every 5 minutes
        id=_JOB_DIGEST,
        max_instances=1,
        coalesce=True,
    )
    _scheduler.start()
    log.info("Планировщик запущен (тик 60с), интервал по умолчанию %d мин", interval_minutes)


def reschedule(interval_minutes: int) -> None:
    # The global interval is read live by the checker each tick, so there is
    # nothing to reschedule — kept for API compatibility.
    log.info("Интервал по умолчанию изменён на %d мин", interval_minutes)


def shutdown() -> None:
    global _scheduler
    if _scheduler is not None:
        _scheduler.shutdown(wait=False)
        _scheduler = None