// Next.js API route support: https://nextjs.org/docs/api-routes/introduction
import type { NextApiRequest, NextApiResponse } from "next";
import client from "@/lib/mongodb";
import { ObjectId } from 'mongodb';
import { withIronSessionApiRoute } from "iron-session/next";
import { sessionOptions } from "@/lib/session";
import { Code, Group, Type } from "@/interfaces/user";
import { PERMISSIONS } from "@/constants/userPermissions";
import { prepareMailer, prepareMailOptions } from "@/email";

const db = client.db(process.env.MONGODB_DB);

export default withIronSessionApiRoute(handler, sessionOptions);

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

	return res.status(404).json({ ok: false });
}

async function get(req: NextApiRequest, res: NextApiResponse) {
	if (!req.session.user) {
		res.status(401).json({ ok: false, reason: "You must be logged in to generate a code!" });
		return;
	}

	const { creator } = req.query as { creator?: string };
	const snapshot = await db.collection("codes").find(creator ? { creator: creator } : {}).toArray();

	res.status(200).json(snapshot);
}

async function post(req: NextApiRequest, res: NextApiResponse) {
	if (!req.session.user) {
		res.status(401).json({ ok: false, reason: "You must be logged in to generate a code!" });
		return;
	}

	const { type, codes, infos, expiryDate } = req.body as {
		type: Type;
		codes: string[];
		infos?: { email: string; name: string; passport_id?: string }[];
		expiryDate: null | Date;
	};
	const permission = PERMISSIONS.generateCode[type];

	if (!permission.includes(req.session.user.type)) {
		res.status(403).json({
			ok: false,
			reason: "Your account type does not have permissions to generate a code for that type of user!",
		});
		return;
	}

	const userCodes = await db.collection("codes").find<Code>({ creator: req.session.user.id }).toArray()
	const creatorGroupsSnapshot = await db.collection("groups").find<Group>({ admin: req.session.user.id }).toArray()

	const creatorGroups = creatorGroupsSnapshot.filter((x) => x.name === "Students" || x.name === "Teachers" || x.name === "Corporate");
	const usersInGroups = creatorGroups.flatMap((x) => x.participants);


	if (req.session.user.type === "corporate") {
		const totalCodes = userCodes.filter((x) => !x.userId || !usersInGroups.includes(x.userId)).length + usersInGroups.length + codes.length;
		const allowedCodes = req.session.user.corporateInformation?.companyInformation.userAmount || 0;

		if (totalCodes > allowedCodes) {
			res.status(403).json({
				ok: false,
				reason: `You have or would have exceeded your amount of allowed codes, you currently are allowed to generate ${allowedCodes - userCodes.length
					} codes.`,
			});
			return;
		}
	}

	const codePromises = codes.map(async (code, index) => {
		const codeRef = await db.collection("codes").findOne<Code>({ _id: new ObjectId(code) });
		let codeInformation = {
			type,
			code,
			creator: req.session.user!.id,
			creationDate: new Date().toISOString(),
			expiryDate,
		};

		if (infos && infos.length > index) {
			const { email, name, passport_id } = infos[index];
			const previousCode = userCodes.find((x) => x.email === email) as Code;

			const transport = prepareMailer();
			const mailOptions = prepareMailOptions(
				{
					type,
					code: previousCode ? previousCode.code : code,
					environment: process.env.ENVIRONMENT,
				},
				[email.toLowerCase().trim()],
				"EnCoach Registration",
				"main",
			);

			try {
				await transport.sendMail(mailOptions);

				if (!previousCode && codeRef) {
					await db.collection("codes").updateOne(
						{ _id: new ObjectId(codeRef._id) },
						{
							$set: {
								...codeInformation,
								email: email.trim().toLowerCase(),
								name: name.trim(),
								...(passport_id ? { passport_id: passport_id.trim() } : {}),
							}
						}
					);
				}

				return true;
			} catch (e) {
				return false;
			}
		} else {
			// upsert: true -> if it doesnt exist insert
			await db.collection("codes").updateOne(
				{ _id: new ObjectId(code) },
				{ $set: codeInformation },
				{ upsert: true }
			);
		}
	});

	Promise.all(codePromises).then((results) => {
		res.status(200).json({ ok: true, valid: results.filter((x) => x).length });
	});
}

async function del(req: NextApiRequest, res: NextApiResponse) {
	if (!req.session.user) {
		res.status(401).json({ ok: false, reason: "You must be logged in to generate a code!" });
		return;
	}

	const codes = req.query.code as string[];

	for (const code of codes) {
		const snapshot = await db.collection("codes").findOne<Code>({ _id: new ObjectId(code as string) });
		if (!snapshot) continue;

		await db.collection("codes").deleteOne({ _id: snapshot._id });
	}

	res.status(200).json({ codes });
}