import { createClient } from "@supabase/supabase-js";
import { envvars, schedules } from "@trigger.dev/sdk";
import * as webpush from "web-push";

const isExpiredSubscriptionError = (error: unknown) => {
	const statusCode =
		typeof error === "object" &&
		error !== null &&
		"statusCode" in error &&
		typeof error.statusCode === "number"
			? error.statusCode
			: null;

	return statusCode === 404 || statusCode === 410;
};

const subscriptionEndpoint = (subscription: unknown) =>
	typeof subscription === "object" &&
	subscription !== null &&
	"endpoint" in subscription &&
	typeof subscription.endpoint === "string" &&
	subscription.endpoint.length
		? subscription.endpoint
		: null;

export const notificationsTask = schedules.task({
	id: "notifications",
	run: async (_payload, { ctx }) => {
		const environment = ctx.environment.slug;
		const triggerProjectReference = ctx.project.ref;
		const supabase = createClient(
			(
				await envvars.retrieve(
					triggerProjectReference,
					environment,
					"SUPABASE_URL",
				)
			).value,
			(
				await envvars.retrieve(
					triggerProjectReference,
					environment,
					"SUPABASE_SERVICE_ROLE_KEY",
				)
			).value,
		);
		const getUserSubscriptions = async () => {
			const { data, error } = await supabase
				.from("user_notifications")
				.select("*");

			if (error) return [];

			return data;
		};
		const deleteUserSubscription = async (
			userId: number,
			fingerprint: string,
		) => {
			await supabase
				.from("user_notifications")
				.delete()
				.eq("user_id", userId)
				.eq("fingerprint", fingerprint);
		};

		const transientErrors: unknown[] = [];
		const seenEndpoints = new Set<string>();

		webpush.setVapidDetails(
			(
				await envvars.retrieve(
					triggerProjectReference,
					environment,
					"VAPID_SUBJECT",
				)
			).value,
			(
				await envvars.retrieve(
					triggerProjectReference,
					environment,
					"VAPID_PUBLIC_KEY",
				)
			).value,
			(
				await envvars.retrieve(
					triggerProjectReference,
					environment,
					"VAPID_PRIVATE_KEY",
				)
			).value,
		);

		for (const subscription of await getUserSubscriptions()) {
			const endpoint = subscriptionEndpoint(subscription.subscription);

			if (endpoint) {
				if (seenEndpoints.has(endpoint)) continue;

				seenEndpoints.add(endpoint);
			}

			try {
				await webpush.sendNotification(subscription.subscription, ".");
			} catch (error) {
				if (isExpiredSubscriptionError(error))
					await deleteUserSubscription(
						subscription.user_id,
						subscription.fingerprint,
					);
				else transientErrors.push(error);

				console.error(error);
			}
		}

		if (transientErrors.length > 0)
			throw new Error("Transient push delivery failures occurred", {
				cause: transientErrors[0],
			});

		return {};
	},
});