feat: load messages on scroll to top, and fix last message scrolling

src/app/chat/view.nim

@@ -1,6 +1,7 @@
 import NimQml
 import Tables
 import json
+import chronicles
 
 import ../../signals/types
 import ../../status/chat
@@ -10,6 +11,9 @@ import views/channels_list
 import views/message_list
 import views/chat_item
 
+logScope:
+  topics = "chats-view"
+
 QtObject:
   type
     ChatsView* = ref object of QAbstractListModel
@@ -77,15 +81,19 @@ QtObject:
   proc upsertChannel(self: ChatsView, channel: string) =
     if not self.messageList.hasKey(channel):
       self.messageList[channel] = newChatMessageList(channel)
+  
+  proc messagePushed*(self: ChatsView) {.signal.}
 
   proc pushMessage*(self:ChatsView, message: ChatMessage) =
     self.upsertChannel(message.chatId)
     self.messageList[message.chatId].add(message)
+    self.messagePushed()
 
   proc pushMessages*(self:ChatsView, messages: seq[Message]) =
     for msg in messages:
       self.upsertChannel(msg.chatId)
       self.messageList[msg.chatId].add(msg.toChatMessage())
+      self.messagePushed()
 
   proc getMessageList(self: ChatsView): QVariant {.slot.} =
     self.upsertChannel(self.activeChannel.id)
@@ -97,6 +105,7 @@ QtObject:
 
   proc pushChatItem*(self: ChatsView, chatItem: ChatItem) =
     discard self.chats.addChatItemToList(chatItem)
+    self.messagePushed()
 
   proc sendMessage*(self: ChatsView, message: string) {.slot.} =
     discard self.status.chat.sendMessage(self.activeChannel.id, message)
@@ -104,6 +113,13 @@ QtObject:
   proc joinChat*(self: ChatsView, channel: string, chatTypeInt: int): int {.slot.} =
     self.status.chat.join(channel, ChatType(chatTypeInt))
 
+  proc messagesLoaded*(self: ChatsView) {.signal.}
+
+  proc loadMoreMessages*(self: ChatsView) {.slot.} =
+    trace "Loading more messages", chaId = self.activeChannel.id
+    self.status.chat.chatMessages(self.activeChannel.id, false)
+    self.messagesLoaded();
+
   proc leaveActiveChat*(self: ChatsView) {.slot.} =
     self.status.chat.leave(self.activeChannel.id)
 

src/status/chat.nim

@@ -33,12 +33,14 @@ type
     events*: EventEmitter
     channels*: HashSet[string]
     filters*: Table[string, string]
+    msgCursor*: Table[string, string]
 
 proc newChatModel*(events: EventEmitter): ChatModel =
   result = ChatModel()
   result.events = events
   result.channels = initHashSet[string]()
   result.filters = initTable[string, string]()
+  result.msgCursor = initTable[string, string]()
 
 proc delete*(self: ChatModel) =
   discard
@@ -117,9 +119,17 @@ proc sendMessage*(self: ChatModel, chatId: string, msg: string): string =
   self.events.emit("messageSent", MsgArgs(message: msg, chatId: chatId, payload: parsedMessage))
   sentMessage
 
-proc chatMessages*(self: ChatModel, chatId: string) =
-  let msgs = status_chat.chatMessages(chatId)
-  self.events.emit("messagesLoaded", MsgsLoadedArgs(messages: msgs))
+proc chatMessages*(self: ChatModel, chatId: string, initialLoad:bool = true) =
+  if not self.msgCursor.hasKey(chatId):
+    self.msgCursor[chatId] = "";
+
+  # Messages were already loaded, since cursor will 
+  # be nil/empty if there are no more messages
+  if(not initialLoad and self.msgCursor[chatId] == ""): return
+
+  let messageTuple = status_chat.chatMessages(chatId, self.msgCursor[chatId])
+  self.msgCursor[chatId] = messageTuple[0];
+  self.events.emit("messagesLoaded", MsgsLoadedArgs(messages: messageTuple[1]))
 
 proc markAllChannelMessagesRead*(self: ChatModel, chatId: string): JsonNode =
   var response = status_chat.markAllRead(chatId)

src/status/libstatus/chat.nim

@@ -71,12 +71,22 @@ proc loadChats*(): seq[Chat] =
       if chat.active and chat.chatType != ChatType.Unknown:
         result.add(jsonChat.toChat)
 
-proc chatMessages*(chatId: string): seq[Message] =
-  result = @[]
-  let rpcResult = parseJson(callPrivateRPC("chatMessages".prefix, %* [chatId, nil, 1000]))["result"]
+proc chatMessages*(chatId: string, cursor: string = ""): (string, seq[Message]) =
+  var messages: seq[Message] = @[]
+  var cursorVal: JsonNode
+  
+  if cursor == "":
+    cursorVal = newJNull()
+  else:
+    cursorVal = newJString(cursor)
+
+  let rpcResult = parseJson(callPrivateRPC("chatMessages".prefix, %* [chatId, cursorVal, 20]))["result"]
+
   if rpcResult["messages"].kind != JNull:
     for jsonMsg in rpcResult["messages"]:
-      result.add(jsonMsg.toMessage)
+      messages.add(jsonMsg.toMessage)
+
+  return (rpcResult{"cursor"}.getStr, messages)
 
 # TODO this probably belongs in another file
 proc generateSymKeyFromPassword*(): string =

ui/app/AppLayouts/Chat/ChatColumn/ChatMessages.qml

@@ -13,6 +13,7 @@ ScrollView {
     id: scrollView
     
     property var messageList: MessagesData {}
+    property bool loadingMessages: false
 
     contentItem: chatLogView
     anchors.fill: parent
@@ -28,14 +29,36 @@ ScrollView {
         id: chatLogView
         Layout.fillWidth: true
         Layout.fillHeight: true
-        onCountChanged: {
-            if (!this.atYEnd) {
-                // User has scrolled up, we don't want to scroll back
-                return
+
+        Connections {
+            target: chatsModel
+            onMessagesLoaded: {
+                loadingMessages = false;
             }
+
+            onActiveChannelChanged: {
+                Qt.callLater( chatLogView.positionViewAtEnd )
+            }
+
+            onMessagePushed: {
+                if (!chatLogView.atYEnd) {
+                    // User has scrolled up, we don't want to scroll back
+                    return
+                }
             
-            Qt.callLater( chatLogView.positionViewAtEnd )
+                if(chatLogView.atYEnd)
+                    Qt.callLater( chatLogView.positionViewAtEnd )
+            }
         }
+
+        onContentYChanged: {
+            if(atYBeginning && !loadingMessages){
+                loadingMessages = true;
+                chatsModel.loadMoreMessages();
+            }
+        }
+
+
         model: messageListDelegate
         section.property: "fromAuthor"
         section.criteria: ViewSection.FullString