import fractionalIndex from "fractional-index";
import { Sequelize, WhereOptions } from "sequelize";
import { sequelize } from "@server/database/sequelize";
import { Star, User, Event } from "@server/models";

type Props = {
  /** The user creating the star */
  user: User;
  /** The document to star */
  documentId: string;
  /** The sorted index for the star in the sidebar If no index is provided then it will be at the end */
  index?: string;
  /** The IP address of the user creating the star */
  ip: string;
};

/**
 * This command creates a "starred" document via the star relation. Stars are
 * only visible to the user that created them.
 *
 * @param Props The properties of the star to create
 * @returns Star The star that was created
 */
export default async function starCreator({
  user,
  documentId,
  ip,
  ...rest
}: Props): Promise<Star> {
  let { index } = rest;
  const where: WhereOptions<Star> = {
    userId: user.id,
  };

  if (!index) {
    const stars = await Star.findAll({
      where,
      attributes: ["id", "index", "updatedAt"],
      limit: 1,
      order: [
        // using LC_COLLATE:"C" because we need byte order to drive the sorting
        // find only the first star so we can create an index before it
        Sequelize.literal('"star"."index" collate "C"'),
        ["updatedAt", "DESC"],
      ],
    });

    // create a star at the beginning of the list
    index = fractionalIndex(null, stars.length ? stars[0].index : null);
  }

  const transaction = await sequelize.transaction();
  let star;

  try {
    const response = await Star.findOrCreate({
      where: {
        userId: user.id,
        documentId,
      },
      defaults: {
        index,
      },
      transaction,
    });
    star = response[0];

    if (response[1]) {
      await Event.create(
        {
          name: "stars.create",
          modelId: star.id,
          userId: user.id,
          actorId: user.id,
          documentId,
          ip,
        },
        { transaction }
      );
    }

    await transaction.commit();
  } catch (err) {
    await transaction.rollback();
    throw err;
  }

  return star;
}