add lots of group dm features (#1208)

* group dm stuff

* minor doc changes

src/structures/ClientUser.js

@@ -301,6 +301,29 @@ class ClientUser extends User {
     }
   }
 
+  /**
+   * An object containing either a user or access token, and an optional nickname
+   * @typedef {Object} GroupDMRecipientOptions
+   * @property {UserResolvable|Snowflake} [user] User to add to the group dm
+   * (only available if a user is creating the dm)
+   * @property {string} [accessToken] Access token to use to add a user to the group dm
+   * (only available if a bot is creating the dm)
+   * @property {string} [nick] Permanent nickname (only available if a bot is creating the dm)
+   */
+
+  /**
+   * Create a group dm
+   * @param {GroupDMRecipientOptions[]} recipients The recipients
+   * @returns {Promise<GroupDMChannel>}
+   */
+  createGroupDM(recipients) {
+    return this.client.rest.methods.createGroupDM({
+      recipients: recipients.map(u => this.client.resolver.resolveUserID(u.user)),
+      accessTokens: recipients.map(u => u.accessToken),
+      nicks: recipients.map(u => u.nick),
+    });
+  }
+
   /**
    * @param {Invite|string} invite Invite or code to accept
    * @returns {Promise<Guild>} Joined guild

src/structures/GroupDMChannel.js

@@ -58,6 +58,24 @@ class GroupDMChannel extends Channel {
      */
     this.ownerID = data.owner_id;
 
+    /**
+     * If the dm is managed by an application
+     * @type {boolean}
+     */
+    this.managed = data.managed;
+
+    /**
+     * Application ID of the application that made this group dm, if applicable
+     * @type {?string}
+     */
+    this.applicationID = data.application_id;
+
+    /**
+     * Nicknames for group members
+     * @type {?Collection<Snowflake, String>}
+     */
+    if (data.nicks) this.nicks = new Collection(data.nicks.map(n => [n.id, n.nick]));
+
     if (!this.recipients) {
       /**
        * A collection of the recipients of this DM, mapped by their ID.
@@ -106,6 +124,20 @@ class GroupDMChannel extends Channel {
     return equal;
   }
 
+  /**
+   * Add a user to the dm
+   * @param {UserResolvable|String} accessTokenOrID Access token or user resolvable
+   * @param {string} [nick] Permanent nickname to give the user (only available if a bot is creating the dm)
+   */
+
+  addUser(accessTokenOrID, nick) {
+    return this.client.rest.methods.addUserToGroupDM(this, {
+      nick,
+      id: this.client.resolver.resolveUserID(accessTokenOrID),
+      accessToken: accessTokenOrID,
+    });
+  }
+
   /**
    * When concatenated with a string, this automatically concatenates the channel's name instead of the Channel object.
    * @returns {string}