import { readFile, writeFile } from "node:fs/promises";
import webPush from "web-push";

webPush.setVapidDetails(
	"mailto:webmaster@hornwitser.no",
	process.env.NUXT_PUBLIC_VAPID_PUBLIC_KEY!,
	process.env.NUXT_VAPID_PRIVATE_KEY!,
)

export async function sendPush(title: string, body: string) {
	const payload = JSON.stringify({ title, body });
	let subscriptions: PushSubscriptionJSON[];
	try {
		subscriptions = JSON.parse(await readFile("push-subscriptions.json", "utf-8"));
	} catch (err: any) {
		if (err.code !== "ENOENT") {
			console.log(`Dropping "${payload}", no push subscribers`);
			return;
		}
		subscriptions = [];
	}
	console.log(`Sending "${payload}" to ${subscriptions.length} subscribers`);
	const removeIndexes = [];
	for (let index = 0; index < subscriptions.length; index += 1) {
		const subscription = subscriptions[index];
		try {
			await webPush.sendNotification(
				subscription as webPush.PushSubscription,
				payload,
				{
					TTL: 3600,
					urgency: "high",
				}
			)
		} catch (err: any) {
			console.error("Received error sending push notice:", err.message, err?.statusCode)
			console.error(err);
			if (err?.statusCode >= 400 && err?.statusCode < 500) {
				removeIndexes.push(index)
			}
		}
	}
	if (removeIndexes.length) {
		console.log(`Removing indexes ${removeIndexes} from subscriptions`)
		removeIndexes.reverse();
		for (const index of removeIndexes) {
			subscriptions.splice(index, 1);
		}
		await writeFile(
			"push-subscriptions.json",
			JSON.stringify(subscriptions, undefined, "\t"),
			"utf-8"
		);
	}
	console.log("Push notices sent");
}