Start work on adding reaction support

src/client/actions/ActionsManager.js

@@ -6,6 +6,8 @@ class ActionsManager {
     this.register('MessageDelete');
     this.register('MessageDeleteBulk');
     this.register('MessageUpdate');
+    this.register('MessageReactionAdd');
+    this.register('MessageReactionRemove');
     this.register('ChannelCreate');
     this.register('ChannelDelete');
     this.register('ChannelUpdate');

src/client/actions/MessageReactionAdd.js

@@ -0,0 +1,38 @@
+const Action = require('./Action');
+const Constants = require('../../util/Constants');
+
+/*
+{ user_id: 'id',
+     message_id: 'id',
+     emoji: { name: '<27>', id: null },
+     channel_id: 'id' } }
+*/
+
+class MessageReactionAdd extends Action {
+  handle(data) {
+    const user = this.client.users.get(data.user_id);
+    if (!user) return false;
+
+    const channel = this.client.channels.get(data.channel_id);
+    if (!channel || channel.type === 'voice') return false;
+
+    const message = channel.messages.get(data.message_id);
+    if (!message) return false;
+
+    if (!data.emoji) return false;
+
+    const reaction = message._addReaction(data.emoji, user);
+
+    if (reaction) {
+      this.client.emit(Constants.Events.MESSAGE_REACTION_ADD, reaction, user);
+    }
+
+    return {
+      message,
+      reaction,
+      user,
+    };
+  }
+}
+
+module.exports = MessageReactionAdd;

src/client/actions/MessageReactionRemove.js

@@ -0,0 +1,38 @@
+const Action = require('./Action');
+const Constants = require('../../util/Constants');
+
+/*
+{ user_id: 'id',
+     message_id: 'id',
+     emoji: { name: '<27>', id: null },
+     channel_id: 'id' } }
+*/
+
+class MessageReactionRemove extends Action {
+  handle(data) {
+    const user = this.client.users.get(data.user_id);
+    if (!user) return false;
+
+    const channel = this.client.channels.get(data.channel_id);
+    if (!channel || channel.type === 'voice') return false;
+
+    const message = channel.messages.get(data.message_id);
+    if (!message) return false;
+
+    if (!data.emoji) return false;
+
+    const reaction = message._removeReaction(data.emoji, user);
+
+    if (reaction) {
+      this.client.emit(Constants.Events.MESSAGE_REACTION_REMOVE, reaction, user);
+    }
+
+    return {
+      message,
+      reaction,
+      user,
+    };
+  }
+}
+
+module.exports = MessageReactionRemove;

src/client/rest/RESTMethods.js

@@ -1,6 +1,7 @@
 const Constants = require('../../util/Constants');
 const Collection = require('../../util/Collection');
 const splitMessage = require('../../util/SplitMessage');
+const parseEmoji = require('../../util/ParseEmoji');
 
 const requireStructure = name => require(`../../structures/${name}`);
 const User = requireStructure('User');
@@ -720,6 +721,36 @@ class RESTMethods {
         .catch(reject);
     });
   }
+
+  addMessageReaction(channelID, messageID, emoji) {
+    return new Promise((resolve, reject) => {
+      this.rest.makeRequest('put', Constants.Endpoints.selfMessageReaction(channelID, messageID, emoji), true)
+        .then(() => {
+          resolve(this.rest.client.actions.MessageReactionAdd.handle({
+            user_id: this.rest.client.user.id,
+            message_id: messageID,
+            emoji: parseEmoji(emoji),
+            channel_id: channelID,
+          }).reaction);
+        })
+        .catch(reject);
+    });
+  }
+
+  removeMessageReaction(channelID, messageID, emoji) {
+    return new Promise((resolve, reject) => {
+      this.rest.makeRequest('delete', Constants.Endpoints.selfMessageReaction(channelID, messageID, emoji), true)
+        .then(() => {
+          resolve(this.rest.client.actions.MessageReactionRemove.handle({
+            user_id: this.rest.client.user.id,
+            message_id: messageID,
+            emoji: parseEmoji(emoji),
+            channel_id: channelID,
+          }).reaction);
+        })
+        .catch(reject);
+    });
+  }
 }
 
 module.exports = RESTMethods;

src/client/websocket/packets/WebSocketPacketManager.js

@@ -44,6 +44,8 @@ class WebSocketPacketManager {
     this.register(Constants.WSEvents.GUILD_SYNC, 'GuildSync');
     this.register(Constants.WSEvents.RELATIONSHIP_ADD, 'RelationshipAdd');
     this.register(Constants.WSEvents.RELATIONSHIP_REMOVE, 'RelationshipRemove');
+    this.register(Constants.WSEvents.MESSAGE_REACTION_ADD, 'MessageReactionAdd');
+    this.register(Constants.WSEvents.MESSAGE_REACTION_REMOVE, 'MessageReactionRemove');
   }
 
   get client() {

src/client/websocket/packets/handlers/MessageReactionAdd.js

@@ -0,0 +1,11 @@
+const AbstractHandler = require('./AbstractHandler');
+
+class MessageReactionAddHandler extends AbstractHandler {
+  handle(packet) {
+    const client = this.packetManager.client;
+    const data = packet.d;
+    client.actions.MessageReactionAdd.handle(data);
+  }
+}
+
+module.exports = MessageReactionAddHandler;

src/client/websocket/packets/handlers/MessageReactionRemove.js

@@ -0,0 +1,11 @@
+const AbstractHandler = require('./AbstractHandler');
+
+class MessageReactionRemove extends AbstractHandler {
+  handle(packet) {
+    const client = this.packetManager.client;
+    const data = packet.d;
+    client.actions.MessageReactionRemove.handle(data);
+  }
+}
+
+module.exports = MessageReactionRemove;

src/structures/Message.js

@@ -3,6 +3,7 @@ const Embed = require('./MessageEmbed');
 const Collection = require('../util/Collection');
 const Constants = require('../util/Constants');
 const escapeMarkdown = require('../util/EscapeMarkdown');
+const MessageReaction = require('./MessageReaction');
 
 /**
  * Represents a Message on Discord
@@ -148,6 +149,42 @@ class Message {
     }
 
     this._edits = [];
+
+    /**
+     * A collection of Reactions to this Message, mapped by the reaction "id".
+     * @type {Collection<string, MessageReaction>}
+     */
+    this.reactions = new Collection();
+  }
+
+  _addReaction(emoji, user) {
+    const emojiID = emoji.id || emoji;
+    let reaction;
+    if (this.reactions.has(emojiID)) {
+      reaction = this.reactions.get(emojiID);
+    } else {
+      reaction = new MessageReaction(this, emoji, 0);
+      this.reactions.set(emojiID, reaction);
+    }
+    if (!reaction.users.has(user.id)) {
+      reaction.users.set(user.id, user);
+      reaction.count++;
+      return reaction;
+    }
+    return null;
+  }
+
+  _removeReaction(emoji, user) {
+    const emojiID = emoji.id || emoji;
+    if (this.reactions.has(emojiID)) {
+      const reaction = this.reactions.get(emojiID);
+      if (reaction.users.has(user.id)) {
+        reaction.users.delete(user.id);
+        reaction.count--;
+        return reaction;
+      }
+    }
+    return null;
   }
 
   patch(data) { // eslint-disable-line complexity
@@ -266,7 +303,11 @@ class Message {
       });
   }
 
- /**
+  addReaction(emoji) {
+    return this.client.rest.methods.addMessageReaction(this.channel.id, this.id, emoji);
+  }
+
+  /**
    * An array of cached versions of the message, including the current version.
    * Sorted from latest (first) to oldest (last).
    * @type {Message[]}

src/structures/MessageReaction.js

@@ -0,0 +1,41 @@
+const Collection = require('../util/Collection');
+const parseEmoji = require('../util/ParseEmoji');
+
+/**
+ * Represents a reaction to a message
+ */
+class MessageReaction {
+  constructor(message, emoji, count) {
+    /**
+     * The message that this reaction refers to
+     * @type {Message}
+     */
+    this.message = message;
+    /**
+     * The emoji of this reaction, if this is a string it is a plain unicode emoji.
+     * @type {Emoji}
+     */
+    this.emoji = emoji;
+    /**
+     * The number of people that have given the same reaction.
+     * @type {number}
+     */
+    this.count = count || 0;
+    /**
+     * The users that have given this reaction, mapped by their ID.
+     * @type {Collection<string, User>}
+     */
+    this.users = new Collection();
+  }
+
+  /**
+   * If the client has given this reaction to a message, it is removed.
+   * @returns {Promise<MessageReaction>}
+   */
+  remove() {
+    const message = this.message;
+    return message.client.rest.methods.removeMessageReaction(message.channel.id, message.id, parseEmoji(this.emoji));
+  }
+}
+
+module.exports = MessageReaction;

src/util/Constants.js

@@ -115,6 +115,15 @@ const Endpoints = exports.Endpoints = {
   channelMessage: (channelID, messageID) => `${Endpoints.channelMessages(channelID)}/${messageID}`,
   channelWebhooks: (channelID) => `${Endpoints.channel(channelID)}/webhooks`,
 
+  // message reactions
+  messageReactions: (channelID, messageID) => `${Endpoints.channelMessage(channelID, messageID)}/reactions`,
+  messageReaction:
+    (channel, msg, emoji, limit) =>
+          `${Endpoints.messageReactions(channel, msg)}/${emoji}` +
+          `${limit ? `?limit=${limit}` : ''}`,
+  selfMessageReaction: (channel, msg, emoji, limit) =>
+          `${Endpoints.messageReaction(channel, msg, emoji, limit)}/@me`,
+
   // webhooks
   webhook: (webhookID, token) => `${API}/webhooks/${webhookID}${token ? `/${token}` : ''}`,
 };
@@ -187,6 +196,8 @@ exports.Events = {
   MESSAGE_DELETE: 'messageDelete',
   MESSAGE_UPDATE: 'messageUpdate',
   MESSAGE_BULK_DELETE: 'messageDeleteBulk',
+  MESSAGE_REACTION_ADD: 'messageReactionAdd',
+  MESSAGE_REACTION_REMOVE: 'messageReactionRemove',
   USER_UPDATE: 'userUpdate',
   PRESENCE_UPDATE: 'presenceUpdate',
   VOICE_STATE_UPDATE: 'voiceStateUpdate',
@@ -222,6 +233,8 @@ exports.WSEvents = {
   MESSAGE_DELETE: 'MESSAGE_DELETE',
   MESSAGE_UPDATE: 'MESSAGE_UPDATE',
   MESSAGE_DELETE_BULK: 'MESSAGE_DELETE_BULK',
+  MESSAGE_REACTION_ADD: 'MESSAGE_REACTION_ADD',
+  MESSAGE_REACTION_REMOVE: 'MESSAGE_REACTION_REMOVE',
   USER_UPDATE: 'USER_UPDATE',
   PRESENCE_UPDATE: 'PRESENCE_UPDATE',
   VOICE_STATE_UPDATE: 'VOICE_STATE_UPDATE',

src/util/parseEmoji.js

@@ -0,0 +1,11 @@
+module.exports = function parseEmoji(text) {
+  if (text.includes(':')) {
+    const [name, id] = text.split(':');
+    return { name, id };
+  } else {
+    return {
+      name: text,
+      id: null,
+    };
+  }
+};