meta-builder.js

/**
 * @file Helper class for constructing {@link Tinode.GetQuery}.
 *
 * @copyright 2015-2022 Tinode LLC.
 */
'use strict';

/**
 * Helper class for constructing {@link Tinode.GetQuery}.
 *
 * @class MetaGetBuilder
 * @memberof Tinode
 *
 * @param {Tinode.Topic} parent topic which instantiated this builder.
 */
export default class MetaGetBuilder {
  constructor(parent) {
    this.topic = parent;
    this.what = {};
  }

  // Get timestamp of the most recent desc update.
  #get_desc_ims() {
    return this.topic._deleted ? undefined : this.topic.updated;
  }

  // Get timestamp of the most recent subs update.
  #get_subs_ims() {
    if (this.topic.isP2PType()) {
      return this.#get_desc_ims();
    }
    return this.topic._deleted ? undefined : this.topic._lastSubsUpdate;
  }
  /**
   * Add query parameters to fetch messages within explicit limits.
   * @memberof Tinode.MetaGetBuilder#
   *
   * @param {number=} since - messages newer than this (inclusive);
   * @param {number=} before - older than this (exclusive)
   * @param {number=} limit - number of messages to fetch
   * @returns {Tinode.MetaGetBuilder} <code>this</code> object.
   */
  withData(since, before, limit) {
    this.what['data'] = {
      since: since,
      before: before,
      limit: limit
    };
    return this;
  }
  /**
   * Add query parameters to fetch messages newer than the latest saved message.
   * @memberof Tinode.MetaGetBuilder#
   *
   * @param {number=} limit - number of messages to fetch
   *
   * @returns {Tinode.MetaGetBuilder} <code>this</code> object.
   */
  withLaterData(limit) {
    return this.withData(this.topic._maxSeq > 0 ? this.topic._maxSeq + 1 : undefined, undefined, limit);
  }
  /**
   * Add query parameters to fetch messages older than the earliest saved message.
   * @memberof Tinode.MetaGetBuilder#
   *
   * @param {number=} limit - maximum number of messages to fetch.
   *
   * @returns {Tinode.MetaGetBuilder} <code>this</code> object.
   */
  withEarlierData(limit) {
    return this.withData(undefined, this.topic._minSeq > 0 ? this.topic._minSeq : undefined, limit);
  }
  /**
   * Add query parameters to fetch topic description if it's newer than the given timestamp.
   * @memberof Tinode.MetaGetBuilder#
   *
   * @param {Date=} ims - fetch messages newer than this timestamp.
   *
   * @returns {Tinode.MetaGetBuilder} <code>this</code> object.
   */
  withDesc(ims) {
    this.what['desc'] = {
      ims: ims
    };
    return this;
  }
  /**
   * Add query parameters to fetch topic description if it's newer than the last update.
   * @memberof Tinode.MetaGetBuilder#
   *
   * @returns {Tinode.MetaGetBuilder} <code>this</code> object.
   */
  withLaterDesc() {
    return this.withDesc(this.#get_desc_ims());
  }
  /**
   * Add query parameters to fetch subscriptions.
   * @memberof Tinode.MetaGetBuilder#
   *
   * @param {Date=} ims - fetch subscriptions modified more recently than this timestamp
   * @param {number=} limit - maximum number of subscriptions to fetch.
   * @param {string=} userOrTopic - user ID or topic name to fetch for fetching one subscription.
   *
   * @returns {Tinode.MetaGetBuilder} <code>this</code> object.
   */
  withSub(ims, limit, userOrTopic) {
    const opts = {
      ims: ims,
      limit: limit
    };
    if (this.topic.getType() == 'me') {
      opts.topic = userOrTopic;
    } else {
      opts.user = userOrTopic;
    }
    this.what['sub'] = opts;
    return this;
  }
  /**
   * Add query parameters to fetch a single subscription.
   * @memberof Tinode.MetaGetBuilder#
   *
   * @param {Date=} ims - fetch subscriptions modified more recently than this timestamp
   * @param {string=} userOrTopic - user ID or topic name to fetch for fetching one subscription.
   *
   * @returns {Tinode.MetaGetBuilder} <code>this</code> object.
   */
  withOneSub(ims, userOrTopic) {
    return this.withSub(ims, undefined, userOrTopic);
  }
  /**
   * Add query parameters to fetch a single subscription if it's been updated since the last update.
   * @memberof Tinode.MetaGetBuilder#
   *
   * @param {string=} userOrTopic - user ID or topic name to fetch for fetching one subscription.
   *
   * @returns {Tinode.MetaGetBuilder} <code>this</code> object.
   */
  withLaterOneSub(userOrTopic) {
    return this.withOneSub(this.topic._lastSubsUpdate, userOrTopic);
  }
  /**
   * Add query parameters to fetch subscriptions updated since the last update.
   * @memberof Tinode.MetaGetBuilder#
   *
   * @param {number=} limit - maximum number of subscriptions to fetch.
   *
   * @returns {Tinode.MetaGetBuilder} <code>this</code> object.
   */
  withLaterSub(limit) {
    return this.withSub(this.#get_subs_ims(), limit);
  }
  /**
   * Add query parameters to fetch topic tags.
   * @memberof Tinode.MetaGetBuilder#
   *
   * @returns {Tinode.MetaGetBuilder} <code>this</code> object.
   */
  withTags() {
    this.what['tags'] = true;
    return this;
  }
  /**
   * Add query parameters to fetch user's credentials. <code>'me'</code> topic only.
   * @memberof Tinode.MetaGetBuilder#
   *
   * @returns {Tinode.MetaGetBuilder} <code>this</code> object.
   */
  withCred() {
    if (this.topic.getType() == 'me') {
      this.what['cred'] = true;
    } else {
      this.topic._tinode.logger("ERROR: Invalid topic type for MetaGetBuilder:withCreds", this.topic.getType());
    }
    return this;
  }
  /**
   * Add query parameters to fetch deleted messages within explicit limits. Any/all parameters can be null.
   * @memberof Tinode.MetaGetBuilder#
   *
   * @param {number=} since - ids of messages deleted since this 'del' id (inclusive)
   * @param {number=} limit - number of deleted message ids to fetch
   *
   * @returns {Tinode.MetaGetBuilder} <code>this</code> object.
   */
  withDel(since, limit) {
    if (since || limit) {
      this.what['del'] = {
        since: since,
        limit: limit
      };
    }
    return this;
  }
  /**
   * Add query parameters to fetch messages deleted after the saved <code>'del'</code> id.
   * @memberof Tinode.MetaGetBuilder#
   *
   * @param {number=} limit - number of deleted message ids to fetch
   *
   * @returns {Tinode.MetaGetBuilder} <code>this</code> object.
   */
  withLaterDel(limit) {
    // Specify 'since' only if we have already received some messages. If
    // we have no locally cached messages then we don't care if any messages were deleted.
    return this.withDel(this.topic._maxSeq > 0 ? this.topic._maxDel + 1 : undefined, limit);
  }

  /**
   * Extract subquery: get an object that contains specified subquery.
   * @memberof Tinode.MetaGetBuilder#
   * @param {string} what - subquery to return: one of 'data', 'sub', 'desc', 'tags', 'cred', 'del'.
   * @returns {Object} requested subquery or <code>undefined</code>.
   */
  extract(what) {
    return this.what[what];
  }

  /**
   * Construct parameters.
   * @memberof Tinode.MetaGetBuilder#
   *
   * @returns {Tinode.GetQuery} Get query
   */
  build() {
    const what = [];
    let params = {};
    ['data', 'sub', 'desc', 'tags', 'cred', 'del'].forEach((key) => {
      if (this.what.hasOwnProperty(key)) {
        what.push(key);
        if (Object.getOwnPropertyNames(this.what[key]).length > 0) {
          params[key] = this.what[key];
        }
      }
    });
    if (what.length > 0) {
      params.what = what.join(' ');
    } else {
      params = undefined;
    }
    return params;
  }
}