import json
import logging
import traceback
from datetime import datetime, timezone
from pathlib import Path

from apscheduler.schedulers.asyncio import AsyncIOScheduler

from app.config import Settings
from app.database import (
    get_db,
    get_pending_brief_items,
    mark_brief_items_sent,
    run_retention_cleanup,
)
from app.lib.utils.brief_html import build_brief_html
from app.lib.utils.notifier import _build_sendmail_payload, send_developer_alert

logger = logging.getLogger(__name__)


class RenewalScheduler:
    def __init__(self, subscription_manager, settings: Settings) -> None:
        self._scheduler = AsyncIOScheduler()
        self._manager = subscription_manager
        self._settings = settings

    def _renewal_interval_seconds(self) -> int:
        # Renew at 80% of the subscription lifetime minus 15 minutes.
        # With the default 4230-minute expiry that fires roughly every 53.5 hours,
        # well before Graph's expiry and the 60-minute cutoff in ensure_subscription.
        return int(self._settings.subscription_expiry_minutes * 60 * 0.80) - 900

    def start(self, subscription_id: str) -> None:
        interval_seconds = self._renewal_interval_seconds()
        self._scheduler.add_job(
            self._renew_job,
            trigger="interval",
            seconds=interval_seconds,
            id="subscription_renewal",
            replace_existing=True,
            args=[subscription_id],
        )
        self._scheduler.add_job(
            self._send_daily_brief,
            trigger="cron",
            hour=18,
            minute=0,
            timezone="America/Chicago",
            id="daily_brief",
            replace_existing=True,
        )
        self._scheduler.add_job(
            self._run_retention,
            trigger="cron",
            hour=2,
            minute=0,
            id="retention_cleanup",
            replace_existing=True,
        )
        self._scheduler.start()
        logger.info(
            "Renewal scheduler started; will renew subscription every %d seconds",
            interval_seconds,
        )

    async def _renew_job(self, subscription_id: str) -> None:
        logger.info("Renewing subscription %s", subscription_id)
        try:
            await self._manager.renew_subscription(subscription_id)
        except Exception:
            logger.warning(
                "Renewal failed for %s; attempting to recreate subscription", subscription_id
            )
            try:
                folder_id = await self._get_folder_id()
                new_id = await self._manager.ensure_subscription(folder_id)
                self._reschedule(new_id)
            except Exception:
                tb = traceback.format_exc()
                logger.exception("Failed to recreate subscription after renewal failure")
                await send_developer_alert(
                    self._settings,
                    subject="[RCM] Subscription renewal and recreation both failed",
                    body=(
                        f"Subscription ID: {subscription_id}\n\n"
                        f"Renewal failed and the attempt to recreate the subscription "
                        f"also failed. Email notifications are NOT being received.\n\n"
                        f"{tb}"
                    ),
                )

    async def _get_folder_id(self) -> str:
        async with get_db(self._manager._db_path) as conn:
            from app.database import get_active_subscription
            sub = await get_active_subscription(conn)
            if sub:
                return sub["folder_id"]
        raise RuntimeError("No active subscription found to determine folder_id for recreation")

    def _reschedule(self, new_subscription_id: str) -> None:
        interval_seconds = self._renewal_interval_seconds()
        self._scheduler.reschedule_job(
            "subscription_renewal",
            trigger="interval",
            seconds=interval_seconds,
            args=[new_subscription_id],
        )
        logger.info("Rescheduled renewal for new subscription %s", new_subscription_id)

    async def _send_daily_brief(self) -> None:
        db_path = self._settings.database_path
        async with get_db(db_path) as conn:
            items = await get_pending_brief_items(conn)

        if not items:
            logger.info("Daily brief: no pending items, skipping send")
            return

        recipients = self._settings.brief_recipient_list()
        if not recipients:
            logger.warning("Daily brief: BRIEF_RECIPIENTS not configured, skipping send")
            return

        html = build_brief_html(items)
        path, payload = _build_sendmail_payload(
            recipients=recipients,
            subject=f"RCM Email Automation — Daily Brief {datetime.now(timezone.utc).strftime('%Y-%m-%d')}",
            body_html=html,
            mailbox_user=self._settings.mailbox_user,
        )

        try:
            await self._manager._client.post(path, payload)
            ids = [item["id"] for item in items]
            async with get_db(db_path) as conn:
                await mark_brief_items_sent(conn, ids)
            logger.info("Daily brief sent to %d recipient(s), %d item(s)", len(recipients), len(items))
        except Exception:
            tb = traceback.format_exc()
            logger.exception("Daily brief send failed; items will retry tomorrow")
            await send_developer_alert(
                self._settings,
                subject="[RCM] Daily brief send failed",
                body=(
                    f"The daily brief could not be sent. "
                    f"{len(items)} item(s) remain pending and will retry tomorrow.\n\n"
                    f"{tb}"
                ),
            )

    async def _run_retention(self) -> None:
        db_path = self._settings.database_path
        try:
            async with get_db(db_path) as conn:
                await run_retention_cleanup(conn)
            logger.info("Retention cleanup complete")
        except Exception:
            tb = traceback.format_exc()
            logger.exception("Retention cleanup failed")
            await send_developer_alert(
                self._settings,
                subject="[RCM] Retention cleanup failed",
                body=f"The scheduled retention cleanup job raised an exception.\n\n{tb}",
            )

        try:
            _cleanup_log_files(self._settings.log_path)
        except Exception:
            logger.exception("Log file cleanup failed")

    def shutdown(self) -> None:
        if self._scheduler.running:
            self._scheduler.shutdown(wait=False)


def _cleanup_log_files(log_path: Path) -> None:
    cutoff = datetime.now(timezone.utc).replace(tzinfo=None)
    for log_file in log_path.glob("processor.log.*"):
        suffix = log_file.suffix.lstrip(".")
        try:
            file_date = datetime.strptime(suffix, "%Y-%m-%d")
            age_days = (cutoff - file_date).days
            if age_days > 365:
                log_file.unlink()
                logger.info("Deleted old log file %s", log_file)
        except ValueError:
            logger.debug("Skipping log file with unrecognised date suffix: %s", log_file)