"use server";
import webPush from "web-push";
import { Schedule } from "@/app/schedule/types";
import { readFile, writeFile } from "fs/promises";
import { broadcastUpdate } from "./streams";

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

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");
}

export async function createEvent(formData: FormData) {
	const schedule: Schedule = JSON.parse(await readFile("schedule.json", "utf-8"));
	const id = formData.get("id") as string;
	const name = formData.get("name") as string;
	const description = formData.get("description") as string;
	const start = formData.get("start") as string;
	const end = formData.get("end") as string;
	const location = formData.get("location") as string;
	schedule.events.push({
		name,
		id,
		description,
		slots: [
			{
				id: `${id}-1`,
				start: start + "Z",
				end: end + "Z",
				locations: [location],
			}
		]
	});
	broadcastUpdate(schedule);
	await writeFile("schedule.json", JSON.stringify(schedule, null, "\t"), "utf-8");
	await sendPush("New event", `${name} will start at ${start}`);
}

export async function modifyEvent(formData: FormData) {
	const schedule: Schedule = JSON.parse(await readFile("schedule.json", "utf-8"));
	const id = formData.get("id") as string;
	const name = formData.get("name") as string;
	const description = formData.get("description") as string;
	const start = formData.get("start") as string;
	const end = formData.get("end") as string;
	const location = formData.get("location") as string;
	const index = schedule.events.findIndex(event => event.id === id);
	if (index === -1) {
		throw Error("No such event");
	}
	const timeChanged = schedule.events[index].slots[0].start !== start + "Z";
	schedule.events[index] = {
		name,
		id,
		description,
		slots: [
			{
				id: `${id}-1`,
				start: start + "Z",
				end: end + "Z",
				locations: [location],
			}
		]
	};
	broadcastUpdate(schedule);
	await writeFile("schedule.json", JSON.stringify(schedule, null, "\t"), "utf-8");
	if (timeChanged)
		await sendPush(`New time for ${name}`, `${name} will now start at ${start}`);
}

export async function deleteEvent(formData: FormData) {
	const schedule: Schedule = JSON.parse(await readFile("schedule.json", "utf-8"));
	const id = formData.get("id") as string;
	const index = schedule.events.findIndex(event => event.id === id);
	if (index === -1) {
		throw Error("No such event");
	}
	schedule.events.splice(index, 1);
	broadcastUpdate(schedule);
	await writeFile("schedule.json", JSON.stringify(schedule, null, "\t"), "utf-8");
}