import {PERMISSIONS} from "@/constants/userPermissions";
import {app, adminApp} from "@/firebase";
import {Group, User} from "@/interfaces/user";
import {sessionOptions} from "@/lib/session";
import {collection, deleteDoc, doc, getDoc, getDocs, getFirestore, query, setDoc, where} from "firebase/firestore";
import {getAuth} from "firebase-admin/auth";
import {withIronSessionApiRoute} from "iron-session/next";
import {NextApiRequest, NextApiResponse} from "next";
import {getPermissions, getPermissionDocs} from "@/utils/permissions.be";

const db = getFirestore(app);
const auth = getAuth(adminApp);

export default withIronSessionApiRoute(user, sessionOptions);

async function user(req: NextApiRequest, res: NextApiResponse) {
	if (req.method === "GET") return get(req, res);
	if (req.method === "DELETE") return del(req, res);

	res.status(404).json(undefined);
}

async function del(req: NextApiRequest, res: NextApiResponse) {
	if (!req.session.user) {
		res.status(401).json({ok: false});
		return;
	}

	const {id} = req.query as {id: string};

	const docUser = await getDoc(doc(db, "users", req.session.user.id));
	if (!docUser.exists()) {
		res.status(401).json({ok: false});
		return;
	}

	const user = docUser.data() as User;

	const docTargetUser = await getDoc(doc(db, "users", id));
	if (!docTargetUser.exists()) {
		res.status(404).json({ok: false});
		return;
	}

	const targetUser = {...docTargetUser.data(), id: docTargetUser.id} as User;

	if (user.type === "corporate" && (targetUser.type === "student" || targetUser.type === "teacher")) {
		res.json({ok: true});

		const userParticipantGroup = await getDocs(query(collection(db, "groups"), where("participants", "array-contains", id)));
		await Promise.all([
			...userParticipantGroup.docs
				.filter((x) => (x.data() as Group).admin === user.id)
				.map(
					async (x) =>
						await setDoc(
							x.ref,
							{
								participants: x.data().participants.filter((y: string) => y !== id),
							},
							{merge: true},
						),
				),
		]);

		return;
	}

	const permission = PERMISSIONS.deleteUser[targetUser.type];
	if (!permission.list.includes(user.type)) {
		res.status(403).json({ok: false});
		return;
	}

	res.json({ok: true});

	await auth.deleteUser(id);
	await deleteDoc(doc(db, "users", id));
	const userCodeDocs = await getDocs(query(collection(db, "codes"), where("userId", "==", id)));
	const userParticipantGroup = await getDocs(query(collection(db, "groups"), where("participants", "array-contains", id)));
	const userGroupAdminDocs = await getDocs(query(collection(db, "groups"), where("admin", "==", id)));
	const userStatsDocs = await getDocs(query(collection(db, "stats"), where("user", "==", id)));

	await Promise.all([
		...userCodeDocs.docs.map(async (x) => await deleteDoc(x.ref)),
		...userGroupAdminDocs.docs.map(async (x) => await deleteDoc(x.ref)),
		...userStatsDocs.docs.map(async (x) => await deleteDoc(x.ref)),
		...userParticipantGroup.docs.map(
			async (x) =>
				await setDoc(
					x.ref,
					{
						participants: x.data().participants.filter((y: string) => y !== id),
					},
					{merge: true},
				),
		),
	]);
}

async function get(req: NextApiRequest, res: NextApiResponse) {
	if (req.session.user) {
		const docUser = await getDoc(doc(db, "users", req.session.user.id));
		if (!docUser.exists()) {
			res.status(401).json(undefined);
			return;
		}

		const user = docUser.data() as User;
		await setDoc(docUser.ref, {lastLogin: new Date().toISOString()}, {merge: true});

		req.session.user = {
			...user,
			id: req.session.user.id,
			lastLogin: new Date(),
		};
		await req.session.save();

		res.json({...user, id: req.session.user.id});
	} else {
		res.status(401).json(undefined);
	}
}