"""
Signals for QI Projects.

- Sends a notification when a task is assigned.
"""

import logging

from django.db.models.signals import post_save
from django.dispatch import receiver

logger = logging.getLogger(__name__)


@receiver(post_save, sender="projects.QIProjectTask")
def notify_task_assignment(sender, instance, created, **kwargs):
    """Notify the assignee when a QI task is assigned (email + in-app).

    Fires only on new task creation with an assignee. send_email also creates
    the matching in-app notification, so no separate call is needed.
    """
    if not instance.assigned_to:
        return

    # Only notify on new assignments (creation with an assignee)
    if not created:
        return

    user = getattr(instance.assigned_to, "user", None)
    if not user or not getattr(user, "email", None):
        return

    try:
        from django.conf import settings
        from apps.notifications.services import NotificationService

        project_url = f"{getattr(settings, 'SITE_URL', 'http://localhost:8000').rstrip('/')}/projects/{instance.project.id}/"
        due = instance.due_date.strftime("%Y-%m-%d") if instance.due_date else None

        message = f"You have been assigned a task in project '{instance.project.name}'."
        if due:
            message += f"\nDue date: {due}"
        message += f"\n\nTask: {instance.title}\nOpen: {project_url}"

        html_message = f"""
<div style="font-family: 'Segoe UI', Tahoma, sans-serif; max-width: 600px; margin: 0 auto; border: 1px solid #e5e7eb; border-radius: 8px; overflow: hidden;">
    <div style="padding: 20px;">
        <h2 style="color: #005696; font-size: 18px; margin: 0 0 12px 0;">New QI Task Assigned</h2>
        <p style="margin: 0 0 12px 0;">You have been assigned a task in project <strong>{instance.project.name}</strong>.</p>
        <p style="margin: 0 0 12px 0;"><strong>Task:</strong> {instance.title}</p>
        {'<p style="margin: 0 0 12px 0;"><strong>Due date:</strong> ' + due + '</p>' if due else ''}
        <div style="text-align: center; margin: 20px 0;">
            <a href="{project_url}" style="background: #005696; color: white; padding: 10px 24px; border-radius: 8px; text-decoration: none; font-weight: 600;">Open Project</a>
        </div>
    </div>
</div>
"""

        NotificationService.send_email(
            email=user.email,
            subject=f"New QI Task: {instance.title}",
            message=message,
            html_message=html_message,
            related_object=instance,
            metadata={
                "notification_type": "qi_task_assigned",
                "task_id": str(instance.id),
                "project_id": str(instance.project.id),
            },
            notification_type="qi_task_assigned",
            user=user,
        )
    except Exception as e:
        logger.warning(f"Failed to send QI task notification: {e}")