from datetime import datetime, timedelta
from typing import List, Optional

import structlog
from sentry_sdk import capture_exception

from ee.tasks.subscriptions.email_subscriptions import send_email_subscription_report
from ee.tasks.subscriptions.slack_subscriptions import send_slack_subscription_report
from ee.tasks.subscriptions.subscription_utils import generate_assets
from posthog.celery import app
from posthog.internal_metrics import incr
from posthog.models.subscription import Subscription

logger = structlog.get_logger(__name__)


def _deliver_subscription_report(
    subscription_id: int, new_emails: Optional[List[str]] = None, invite_message: Optional[str] = None
) -> None:
    is_invite = new_emails is not None

    if is_invite and not new_emails:
        return

    subscription = (
        Subscription.objects.prefetch_related("dashboard__insights")
        .select_related("created_by", "insight", "dashboard",)
        .get(pk=subscription_id)
    )

    if subscription.target_type == "email":
        insights, assets = generate_assets(subscription)

        # Send emails
        emails_to_send = new_emails or subscription.target_value.split(",")

        for email in emails_to_send:
            try:
                send_email_subscription_report(
                    email,
                    subscription,
                    assets,
                    invite_message=invite_message or "" if is_invite else None,
                    total_asset_count=len(insights),
                )
                incr("subscription_email_send_success")
            except Exception as e:
                logger.error(e)
                capture_exception(e)
                incr("subscription_email_send_failure")

    elif subscription.target_type == "slack":
        insights, assets = generate_assets(subscription)
        try:
            send_slack_subscription_report(
                subscription, assets, total_asset_count=len(insights),
            )
            incr("subscription_slack_send_success")
        except Exception as e:
            incr("subscription_slack_send_failure")
            logger.error(e)
    else:
        raise NotImplementedError(f"{subscription.target_type} is not supported")

    if not is_invite:
        subscription.set_next_delivery_date(subscription.next_delivery_date)
        subscription.save()


@app.task()
def schedule_all_subscriptions() -> None:
    """
    Schedule all past notifications (with a buffer) to be delivered
    NOTE: This task is scheduled hourly just before the hour allowing for the 15 minute timedelta to cover
    all upcoming hourly scheduled subscriptions
    """
    now_with_buffer = datetime.utcnow() + timedelta(minutes=15)
    subscriptions = Subscription.objects.filter(next_delivery_date__lte=now_with_buffer, deleted=False).all()

    for subscription in subscriptions:
        deliver_subscription_report.delay(subscription.id)


@app.task()
def deliver_subscription_report(subscription_id: int) -> None:
    return _deliver_subscription_report(subscription_id)


@app.task()
def deliver_new_subscription(subscription_id: int, new_emails: List[str], invite_message: Optional[str] = None) -> None:
    if not new_emails:
        return
    return _deliver_subscription_report(subscription_id, new_emails, invite_message)