import { google } from "googleapis";
import type { NextApiRequest, NextApiResponse } from "next";

import { WEBAPP_URL_FOR_OAUTH, CAL_URL } from "@calcom/lib/constants";
import { getSafeRedirectUrl } from "@calcom/lib/getSafeRedirectUrl";
import prisma from "@calcom/prisma";

import getAppKeysFromSlug from "../../_utils/getAppKeysFromSlug";
import getInstalledAppPath from "../../_utils/getInstalledAppPath";
import { decodeOAuthState } from "../../_utils/oauth/decodeOAuthState";

let client_id = "";
let client_secret = "";

export default async function handler(req: NextApiRequest, res: NextApiResponse) {
  const { code } = req.query;
  const state = decodeOAuthState(req);

  if (typeof code !== "string") {
    res.status(400).json({ message: "`code` must be a string" });
    return;
  }

  if (!req.session?.user?.id) {
    return res.status(401).json({ message: "You must be logged in to do this" });
  }

  const appKeys = await getAppKeysFromSlug("google-calendar");
  if (typeof appKeys.client_id === "string") client_id = appKeys.client_id;
  if (typeof appKeys.client_secret === "string") client_secret = appKeys.client_secret;
  if (!client_id) return res.status(400).json({ message: "Google client_id missing." });
  if (!client_secret) return res.status(400).json({ message: "Google client_secret missing." });

  const redirect_uri = `${WEBAPP_URL_FOR_OAUTH}/api/integrations/googlecalendar/callback`;

  const oAuth2Client = new google.auth.OAuth2(client_id, client_secret, redirect_uri);

  let key = "";

  if (code) {
    const token = await oAuth2Client.getToken(code);
    key = token.res?.data;

    await prisma.credential.create({
      data: {
        type: "google_calendar",
        key,
        userId: req.session.user.id,
        appId: "google-calendar",
      },
    });
  }

  if (state?.installGoogleVideo) {
    const existingGoogleMeetCredential = await prisma.credential.findFirst({
      where: {
        userId: req.session.user.id,
        type: "google_video",
      },
    });

    if (!existingGoogleMeetCredential) {
      await prisma.credential.create({
        data: {
          type: "google_video",
          key: {},
          userId: req.session.user.id,
          appId: "google-meet",
        },
      });

      res.redirect(
        getSafeRedirectUrl(`${CAL_URL}/apps/installed/conferencing?hl=google-meet`) ??
          getInstalledAppPath({ variant: "conferencing", slug: "google-meet" })
      );
    }
  }
  res.redirect(
    getSafeRedirectUrl(state?.returnTo) ??
      getInstalledAppPath({ variant: "calendar", slug: "google-calendar" })
  );
}