"""
Observations Celery tasks - SLA tracking and notifications.

This module implements tasks for:
- Checking overdue observations
- Sending SLA reminder emails
- Escalation handling
"""

import logging

from celery import shared_task
from django.utils import timezone

logger = logging.getLogger(__name__)


@shared_task
def check_overdue_observations():
    """
    Periodic task to check for overdue observations.

    Runs every 15 minutes (configured in config/celery.py).
    Updates is_overdue flag and sets breached_at for observations past their SLA deadline.
    """
    from apps.observations.models import Observation, ObservationStatus

    active_statuses = [
        ObservationStatus.NEW,
        ObservationStatus.TRIAGED,
        ObservationStatus.ASSIGNED,
        ObservationStatus.IN_PROGRESS,
    ]
    active_observations = Observation.objects.filter(
        status__in=active_statuses,
        due_at__isnull=False,
    ).select_related("hospital", "assigned_department")

    overdue_count = 0

    for observation in active_observations:
        if observation.check_overdue():
            overdue_count += 1
            logger.warning(
                f"Observation {observation.id} is overdue: {observation.tracking_code} (due: {observation.due_at})"
            )

    if overdue_count > 0:
        logger.info(f"Found {overdue_count} overdue observations")

    return {"overdue_count": overdue_count}


@shared_task
def send_observation_sla_reminders():
    """
    Periodic task to send SLA reminder emails for observations approaching deadline.

    Runs every hour (configured in config/celery.py).
    """
    from apps.observations.models import Observation, ObservationStatus, ObservationSLAConfig
    from apps.notifications.services import NotificationService

    now = timezone.now()
    active_statuses = [
        ObservationStatus.NEW,
        ObservationStatus.TRIAGED,
        ObservationStatus.ASSIGNED,
        ObservationStatus.IN_PROGRESS,
    ]

    active_observations = Observation.objects.filter(
        status__in=active_statuses,
        due_at__isnull=False,
        is_overdue=False,
    ).select_related("hospital", "assigned_to")

    first_reminder_count = 0
    second_reminder_count = 0

    for observation in active_observations:
        config = observation.get_sla_config()
        if not config:
            continue

        first_reminder_hours = config.get_first_reminder_hours_after()
        second_reminder_hours = config.get_second_reminder_hours_after()

        if first_reminder_hours > 0 and observation.reminder_sent_at is None:
            hours_since_creation = (now - observation.created_at).total_seconds() / 3600
            if hours_since_creation >= first_reminder_hours:
                if observation.assigned_to and observation.assigned_to.email:
                    try:
                        NotificationService.send_email(
                            email=observation.assigned_to.email,
                            subject=f"SLA Reminder - Observation {observation.tracking_code}",
                            message=f"Observation '{observation.title or observation.description[:50]}' is due at {observation.due_at}. Please take action.",
                            related_object=observation,
                        )
                        observation.reminder_sent_at = now
                        observation.save(update_fields=["reminder_sent_at"])
                        first_reminder_count += 1
                    except Exception as e:
                        logger.error(f"Failed to send observation reminder: {e}")

        if second_reminder_hours > 0 and observation.second_reminder_sent_at is None:
            hours_since_creation = (now - observation.created_at).total_seconds() / 3600
            if hours_since_creation >= second_reminder_hours:
                if observation.assigned_to and observation.assigned_to.email:
                    try:
                        NotificationService.send_email(
                            email=observation.assigned_to.email,
                            subject=f"URGENT: SLA Reminder - Observation {observation.tracking_code}",
                            message=f"Observation '{observation.title or observation.description[:50]}' is due at {observation.due_at}. URGENT action required.",
                            related_object=observation,
                        )
                        observation.second_reminder_sent_at = now
                        observation.save(update_fields=["second_reminder_sent_at"])
                        second_reminder_count += 1
                    except Exception as e:
                        logger.error(f"Failed to send second observation reminder: {e}")

    logger.info(
        f"Sent {first_reminder_count} first reminders and {second_reminder_count} second reminders for observations"
    )

    return {
        "first_reminder_count": first_reminder_count,
        "second_reminder_count": second_reminder_count,
    }