import logging

from django.template.loader import render_to_string

from notifier.models import Notifier
from notifier.registry import get_notifier_backend

logger = logging.getLogger(__name__)


def render_notification_content(*, notifier: Notifier, payload: dict) -> str:
    content = render_to_string(notifier.get_template_name(), payload or {}).strip()
    if not content:
        raise ValueError("通知模板渲染结果不能为空")
    return content


def send_notification_with_notifier(*, notifier: Notifier, payload: dict) -> dict:
    content = render_notification_content(notifier=notifier, payload=payload)
    backend = get_notifier_backend(notifier.channel)
    backend_result = backend.notify(notifier=notifier, content=content, context=payload)
    result = {
        "notifier_id": notifier.id,
        "notifier_name": notifier.name,
        "event_key": notifier.event_key,
        "channel": notifier.channel,
        "template_key": notifier.template_key,
        "status": "sent",
        **backend_result,
    }
    logger.info("[notifier.services] notification sent: %s", result)
    return result


def dispatch_notification_event(*, event_key: str, merchant_id: int, payload: dict | None = None) -> list[dict]:
    notifiers = list(
        Notifier.objects.filter(
            merchant_id=merchant_id,
            event_key=event_key,
            is_enabled=True,
        ).order_by("id")
    )
    if not notifiers:
        logger.info(
            "[notifier.services] no enabled notifier matched: event_key=%s merchant_id=%s",
            event_key,
            merchant_id,
        )
        return []

    results = []
    for notifier in notifiers:
        try:
            results.append(send_notification_with_notifier(notifier=notifier, payload=payload or {}))
        except Exception as exc:
            logger.exception(
                "[notifier.services] notification failed: notifier_id=%s event_key=%s merchant_id=%s",
                notifier.id,
                event_key,
                merchant_id,
            )
            results.append(
                {
                    "notifier_id": notifier.id,
                    "notifier_name": notifier.name,
                    "event_key": notifier.event_key,
                    "channel": notifier.channel,
                    "template_key": notifier.template_key,
                    "status": "failed",
                    "error": str(exc),
                }
            )
    return results


def enqueue_notification_event(*, event_key: str, merchant_id: int, payload: dict | None = None) -> str | None:
    from notifier.tasks import dispatch_notification_event_task

    try:
        async_result = dispatch_notification_event_task.delay(
            event_key=event_key,
            merchant_id=merchant_id,
            payload=payload or {},
        )
    except Exception:
        logger.exception(
            "[notifier.services] queue notification task failed: event_key=%s merchant_id=%s",
            event_key,
            merchant_id,
        )
        return None

    logger.info(
        "[notifier.services] queued notification task: event_key=%s merchant_id=%s task_id=%s",
        event_key,
        merchant_id,
        async_result.id,
    )
    return async_result.id