feat: add support for autocomplete interactions (#6672)

Co-authored-by: Suneet Tipirneni <suneettipirneni@icloud.com>

src/structures/AutocompleteInteraction.js

@@ -0,0 +1,107 @@
+'use strict';
+
+const CommandInteractionOptionResolver = require('./CommandInteractionOptionResolver');
+const Interaction = require('./Interaction');
+const { InteractionResponseTypes, ApplicationCommandOptionTypes } = require('../util/Constants');
+
+/**
+ * Represents an autocomplete interaction.
+ * @extends {Interaction}
+ */
+class AutocompleteInteraction extends Interaction {
+  constructor(client, data) {
+    super(client, data);
+
+    /**
+     * The id of the channel this interaction was sent in
+     * @type {Snowflake}
+     * @name AutocompleteInteraction#channelId
+     */
+
+    /**
+     * The invoked application command's id
+     * @type {Snowflake}
+     */
+    this.commandId = data.data.id;
+
+    /**
+     * The invoked application command's name
+     * @type {string}
+     */
+    this.commandName = data.data.name;
+
+    /**
+     * Whether this interaction has already received a response
+     * @type {boolean}
+     */
+    this.responded = false;
+
+    /**
+     * The options passed to the command
+     * @type {CommandInteractionOptionResolver}
+     */
+    this.options = new CommandInteractionOptionResolver(
+      this.client,
+      data.data.options?.map(option => this.transformOption(option, data.data.resolved)) ?? [],
+    );
+  }
+
+  /**
+   * The invoked application command, if it was fetched before
+   * @type {?ApplicationCommand}
+   */
+  get command() {
+    const id = this.commandId;
+    return this.guild?.commands.cache.get(id) ?? this.client.application.commands.cache.get(id) ?? null;
+  }
+
+  /**
+   * Transforms an option received from the API.
+   * @param {APIApplicationCommandOption} option The received option
+   * @returns {CommandInteractionOption}
+   * @private
+   */
+  transformOption(option) {
+    const result = {
+      name: option.name,
+      type: ApplicationCommandOptionTypes[option.type],
+    };
+
+    if ('value' in option) result.value = option.value;
+    if ('options' in option) result.options = option.options.map(opt => this.transformOption(opt));
+    if ('focused' in option) result.focused = option.focused;
+
+    return result;
+  }
+
+  /**
+   * Sends results for the autocomplete of this interaction.
+   * @param {ApplicationCommandOptionChoice[]} options The options for the autocomplete
+   * @returns {Promise<void>}
+   * @example
+   * // respond to autocomplete interaction
+   * interaction.respond([
+   *  {
+   *    name: 'Option 1',
+   *    value: 'option1',
+   *  },
+   * ])
+   *  .then(console.log)
+   *  .catch(console.error);
+   */
+  async respond(options) {
+    if (this.responded) throw new Error('INTERACTION_ALREADY_REPLIED');
+
+    await this.client.api.interactions(this.id, this.token).callback.post({
+      data: {
+        type: InteractionResponseTypes.APPLICATION_COMMAND_AUTOCOMPLETE_RESULT,
+        data: {
+          choices: options,
+        },
+      },
+    });
+    this.responded = true;
+  }
+}
+
+module.exports = AutocompleteInteraction;