// @flow
import { uniqBy } from "lodash";
import { User, Event, Team } from "../models";
import mailer from "../mailer";
import { sequelize } from "../sequelize";

type Invite = { name: string, email: string };

export default async function userInviter({
  user,
  invites,
  ip,
}: {
  user: User,
  invites: Invite[],
  ip: string,
}): Promise<{ sent: Invite[], users: User[] }> {
  const team = await Team.findByPk(user.teamId);

  // filter out empties and obvious non-emails
  const compactedInvites = invites.filter(
    (invite) => !!invite.email.trim() && invite.email.match("@")
  );

  // normalize to lowercase and remove duplicates
  const normalizedInvites = uniqBy(
    compactedInvites.map((invite) => ({
      ...invite,
      email: invite.email.toLowerCase(),
    })),
    "email"
  );

  // filter out any existing users in the system
  const emails = normalizedInvites.map((invite) => invite.email);
  const existingUsers = await User.findAll({
    where: {
      teamId: user.teamId,
      email: emails,
    },
  });
  const existingEmails = existingUsers.map((user) => user.email);
  const filteredInvites = normalizedInvites.filter(
    (invite) => !existingEmails.includes(invite.email)
  );

  let users = [];

  // send and record remaining invites
  await Promise.all(
    filteredInvites.map(async (invite) => {
      const transaction = await sequelize.transaction();
      try {
        const newUser = await User.create(
          {
            teamId: user.teamId,
            name: invite.name,
            email: invite.email,
            service: null,
          },
          { transaction }
        );
        users.push(newUser);
        await Event.create(
          {
            name: "users.invite",
            actorId: user.id,
            teamId: user.teamId,
            data: {
              email: invite.email,
              name: invite.name,
            },
            ip,
          },
          { transaction }
        );
        await mailer.invite({
          to: invite.email,
          name: invite.name,
          actorName: user.name,
          actorEmail: user.email,
          teamName: team.name,
          teamUrl: team.url,
        });
        await transaction.commit();
      } catch (err) {
        await transaction.rollback();
        throw err;
      }
    })
  );

  return { sent: filteredInvites, users };
}