"""Notification engine.

Resolves templates for a domain event from the database, renders them and
dispatches through the configured provider. Business logic only emits events.
"""
from django.utils import timezone

from apps.notifications.models import NotificationLog, NotificationTemplate
from apps.notifications.providers import get_sms_provider, render_template


class NotificationService:
    def send_event(self, event: str, context: dict, recipient: str = "") -> list:
        results = []
        templates = NotificationTemplate.objects.filter(event=event, enabled=True)
        for template in templates:
            body = render_template(template.body, context)
            if template.channel == NotificationTemplate.Channel.SMS:
                results.append(self._send_sms(template, recipient, body))
        return results

    def _send_sms(self, template, recipient: str, body: str) -> dict:
        status = "sent"
        error = ""
        reference = ""
        try:
            reference = get_sms_provider().send(recipient, body)
        except Exception as exc:  # pragma: no cover - provider failures
            status = "failed"
            error = str(exc)
        NotificationLog.objects.create(
            template=template,
            recipient=recipient,
            channel="sms",
            status=status,
            error=error,
            sent_at=timezone.now() if status == "sent" else None,
        )
        return {"channel": "sms", "status": status, "reference": reference}