"""
Celery tasks for documentation delay tracking and notifications.

These tasks run periodically to check for overdue documentation
and send alerts to senior therapists.
"""

from celery import shared_task
from django.utils import timezone
from django.utils.translation import gettext as _

from core.documentation_tracking import DocumentationDelayTracker
from notifications.models import Notification


@shared_task(name='core.check_documentation_delays')
def check_documentation_delays():
    """
    Check all documentation trackers and update their status.
    Runs daily to calculate days overdue and update statuses.
    """
    trackers = DocumentationDelayTracker.objects.filter(
        status__in=[
            DocumentationDelayTracker.Status.PENDING,
            DocumentationDelayTracker.Status.OVERDUE,
        ]
    )
    
    updated_count = 0
    for tracker in trackers:
        tracker.update_status()
        updated_count += 1
    
    return f"Updated {updated_count} documentation trackers"


@shared_task(name='core.send_documentation_delay_alerts')
def send_documentation_delay_alerts():
    """
    Send alerts to senior therapists for overdue documentation (>5 working days).
    Runs daily to notify seniors of pending documentation.
    """
    from notifications.models import Notification
    
    # Get documentation that needs alerts
    pending_alerts = DocumentationDelayTracker.get_pending_alerts()
    
    alerts_sent = 0
    for tracker in pending_alerts:
        # Create in-app notification for senior therapist
        notification = Notification.objects.create(
            user=tracker.senior_therapist,
            title=_("Overdue Documentation Alert"),
            message=_(
                f"{tracker.assigned_to.get_full_name()} has overdue documentation: "
                f"{tracker.get_document_type_display()} is {tracker.days_overdue} working days overdue. "
                f"Due date was {tracker.due_date.strftime('%Y-%m-%d')}."
            ),
            notification_type=Notification.NotificationType.WARNING,
            related_object_type='documentation_tracker',
            related_object_id=tracker.id,
        )
        
        # Record that alert was sent
        tracker.send_alert()
        alerts_sent += 1
        
        # Escalate if >10 days overdue
        if tracker.days_overdue >= 10 and not tracker.escalated_at:
            # Find Clinical Coordinator or Admin to escalate to
            from core.models import User
            
            coordinator = User.objects.filter(
                tenant=tracker.tenant,
                role='ADMIN',  # Or CLINICAL_COORDINATOR if that role exists
                is_active=True
            ).first()
            
            if coordinator:
                tracker.escalate(coordinator)
                
                # Send escalation notification
                Notification.objects.create(
                    user=coordinator,
                    title=_("Documentation Escalation"),
                    message=_(
                        f"Documentation has been escalated: {tracker.assigned_to.get_full_name()} "
                        f"has {tracker.get_document_type_display()} that is {tracker.days_overdue} "
                        f"working days overdue. Senior therapist: {tracker.senior_therapist.get_full_name()}."
                    ),
                    notification_type=Notification.NotificationType.ERROR,
                    related_object_type='documentation_tracker',
                    related_object_id=tracker.id,
                )
    
    return f"Sent {alerts_sent} documentation delay alerts"


@shared_task(name='core.send_documentation_reminder_to_therapist')
def send_documentation_reminder_to_therapist(tracker_id):
    """
    Send reminder to therapist about pending documentation.
    
    Args:
        tracker_id: UUID of DocumentationDelayTracker
    """
    try:
        tracker = DocumentationDelayTracker.objects.get(id=tracker_id)
        
        # Create notification for assigned therapist
        Notification.objects.create(
            user=tracker.assigned_to,
            title=_("Documentation Reminder"),
            message=_(
                f"Reminder: You have pending {tracker.get_document_type_display()} "
                f"due on {tracker.due_date.strftime('%Y-%m-%d')}. "
                f"Please complete it as soon as possible."
            ),
            notification_type=Notification.NotificationType.INFO,
            related_object_type='documentation_tracker',
            related_object_id=tracker.id,
        )
        
        return f"Sent reminder to {tracker.assigned_to.get_full_name()}"
    
    except DocumentationDelayTracker.DoesNotExist:
        return f"Tracker {tracker_id} not found"


@shared_task(name='core.generate_senior_weekly_summary')
def generate_senior_weekly_summary():
    """
    Generate weekly summary for senior therapists showing:
    - Pending documentation from their team
    - Overdue items
    - Completion statistics
    
    Runs every Monday morning.
    """
    from core.models import User
    from django.db.models import Count, Q
    
    # Get all senior therapists
    seniors = User.objects.filter(
        role__in=['DOCTOR', 'ADMIN'],  # Senior roles
        is_active=True
    )
    
    summaries_sent = 0
    for senior in seniors:
        # Get documentation stats for this senior's team
        all_docs = DocumentationDelayTracker.objects.filter(
            senior_therapist=senior
        )
        
        pending = all_docs.filter(status=DocumentationDelayTracker.Status.PENDING).count()
        overdue = all_docs.filter(status=DocumentationDelayTracker.Status.OVERDUE).count()
        escalated = all_docs.filter(status=DocumentationDelayTracker.Status.ESCALATED).count()
        completed_this_week = all_docs.filter(
            status=DocumentationDelayTracker.Status.COMPLETED,
            completed_at__gte=timezone.now() - timedelta(days=7)
        ).count()
        
        # Create weekly summary notification
        message = _(
            f"Weekly Documentation Summary:\n\n"
            f"✓ Completed this week: {completed_this_week}\n"
            f"⏳ Pending: {pending}\n"
            f"⚠️ Overdue (>5 days): {overdue}\n"
            f"🔴 Escalated (>10 days): {escalated}\n\n"
            f"Please review overdue items and follow up with your team."
        )
        
        Notification.objects.create(
            user=senior,
            title=_("Weekly Documentation Summary"),
            message=message,
            notification_type=Notification.NotificationType.INFO,
        )
        
        summaries_sent += 1
    
    return f"Sent weekly summaries to {summaries_sent} senior therapists"


@shared_task(name='core.cleanup_completed_trackers')
def cleanup_completed_trackers(days=90):
    """
    Archive or delete completed documentation trackers older than specified days.
    
    Args:
        days: Number of days to keep completed trackers (default: 90)
    """
    cutoff_date = timezone.now() - timedelta(days=days)
    
    old_trackers = DocumentationDelayTracker.objects.filter(
        status=DocumentationDelayTracker.Status.COMPLETED,
        completed_at__lt=cutoff_date
    )
    
    count = old_trackers.count()
    old_trackers.delete()
    
    return f"Cleaned up {count} old documentation trackers"