Added ServerMessage{Editor,Actioner}

README.md

@@ -7,6 +7,13 @@ and frontend together.
 
 ## Backend
 
+Methods implemented by the backend that have frontend containers as arguments
+should not do any IO. If IO is a must, they should be ran in goroutines, then
+call the container callbacks when done. Other interface methods can do IO
+normally.
+
+*Note:* IO in most cases usually refer to networking, but they should include
+files and such as well.
 
 
 ### Service
@@ -116,6 +123,8 @@ A server is any entity that is usually a channel or a guild.
 -   ServerList and/or ServerMessage
 -   ServerNickname
 -   Icon (optional)
+-   ServerMessageEditor
+-   ServerMessageActioner
 
 
 

cchat.go

@@ -143,8 +143,9 @@ type Server interface {
 
 // ServerNickname extends Server to add a specific user nickname into a server.
 // The frontend should not traverse up the server tree, and thus the backend
-// must handle nickname inheritance. By default, the session name should be
+// must handle nickname inheritance. This also means that servers that don't
-// used.
+// implement ServerMessage also don't need to implement ServerNickname. By
+// default, the session name should be used.
 type ServerNickname interface {
 	Nickname(LabelContainer) error
 }
@@ -152,6 +153,9 @@ type ServerNickname interface {
 // Icon is an extra interface that an interface could implement for an icon.
 // Typically, Service would return the service logo, Session would return the
 // user's avatar, and Server would return the server icon.
+//
+// For session, the avatar should be the same as the one returned by messages
+// sent by the current user.
 type Icon interface {
 	Icon(IconContainer) error
 }
@@ -189,6 +193,29 @@ type ServerMessageSender interface {
 	SendMessage(SendableMessage) error
 }
 
+// ServerMessageEditor optionally extends ServerMessage to add message editing
+// capability to the server. These functions can have IO, and the frontend
+// should take care of running them in goroutines.
+type ServerMessageEditor interface {
+	// RawMessageContent gets the original message text for editing.
+	RawMessageContent(id string) (string, error)
+	// EditMessage edits the message with the given ID to the given content,
+	// which is the edited string from RawMessageContent.
+	EditMessage(id, content string) error
+}
+
+// ServerMessageActioner optionally extends ServerMessage to add custom message
+// action capabilities to the server. Similarly to ServerMessageEditor, these
+// functions can have IO.
+type ServerMessageActioner interface {
+	// MessageActions returns a list of possible actions in pretty strings that
+	// the frontend will use to directly display.
+	MessageActions() []string
+	// DoMessageAction executes a message action on the given messageID, which
+	// would be taken from MessageHeader.ID().
+	DoMessageAction(action, messageID string) error
+}
+
 // ServerMessageSendCompleter optionally extends ServerMessageSender to add
 // autocompletion into the message composer.
 type ServerMessageSendCompleter interface {