Add MessageReactionRemoveEmoji event and endpoint (#172)

disco/api/client.py

@@ -230,6 +230,9 @@ class APIClient(LoggingClass):
 
         self.http(route, obj)
 
+    def channels_messages_reactions_delete_emoji(self, channel, message, emoji):
+        self.http(Routes.CHANNELS_MESSAGES_REACTIONS_DELETE_EMOJI, dict(channel=channel, message=message, emoji=emoji))
+
     def channels_permissions_modify(self, channel, permission, allow, deny, typ, reason=None):
         self.http(Routes.CHANNELS_PERMISSIONS_MODIFY, dict(channel=channel, permission=permission), json={
             'allow': allow,

disco/api/http.py

@@ -54,6 +54,8 @@ class Routes(object):
     CHANNELS_MESSAGES_REACTIONS_DELETE_ME = (HTTPMethod.DELETE, CHANNELS + '/messages/{message}/reactions/{emoji}/@me')
     CHANNELS_MESSAGES_REACTIONS_DELETE_USER = (HTTPMethod.DELETE,
                                                CHANNELS + '/messages/{message}/reactions/{emoji}/{user}')
+    CHANNELS_MESSAGES_REACTIONS_DELETE_EMOJI = (HTTPMethod.DELETE,
+                                                CHANNELS + '/messages/{message}/reactions/{emoji}')
     CHANNELS_PERMISSIONS_MODIFY = (HTTPMethod.PUT, CHANNELS + '/permissions/{permission}')
     CHANNELS_PERMISSIONS_DELETE = (HTTPMethod.DELETE, CHANNELS + '/permissions/{permission}')
     CHANNELS_INVITES_LIST = (HTTPMethod.GET, CHANNELS + '/invites')

disco/gateway/events.py

@@ -716,3 +716,31 @@ class MessageReactionRemoveAll(GatewayEvent):
     @property
     def guild(self):
         return self.channel.guild
+
+
+class MessageReactionRemoveEmoji(GatewayEvent):
+    """
+    Sent when all reactions of a single emoji are removed from a message.
+    Attributes
+    ----------
+    guild_id : Snowflake
+        The guild ID the message is in.
+    channel_id : Snowflake
+        The channel ID the message is in.
+    message_id : Snowflake
+        The ID of the message for which the reaction was removed from.
+    emoji : :class:`disco.types.message.MessageReactionEmoji`
+        The emoji that was removed.
+    """
+    guild_id = Field(snowflake)
+    channel_id = Field(snowflake)
+    message_id = Field(snowflake)
+    emoji = Field(MessageReactionEmoji)
+
+    @property
+    def channel(self):
+        return self.client.state.channels.get(self.channel_id)
+
+    @property
+    def guild(self):
+        return self.channel.guild

disco/types/message.py

@@ -512,6 +512,22 @@ class Message(SlottedModel):
             emoji,
             user)
 
+    def delete_single_reaction(self, emoji):
+        """
+        Deletes all reactions of a single emoji from a message.
+        Parameters
+        ----------
+        emoji : `Emoji`|str
+            An emoji or string representing an emoji
+        """
+        if isinstance(emoji, Emoji):
+            emoji = emoji.to_string()
+
+        self.client.api.channels_messages_reactions_delete_emoji(
+            self.channel_id,
+            self.id,
+            emoji)
+
     def is_mentioned(self, entity):
         """
         Returns