feat(@desktop/chat): display fetch messages when needed

- it only applies to community chats

closes: #6731

src/app/modules/main/chat_section/chat_content/messages/controller.nim

@@ -176,6 +176,12 @@ proc init*(self: Controller) =
       return
     self.delegate.onChatMemberUpdated(args.id, args.admin, args.joined)
 
+  self.events.on(SIGNAL_MAILSERVER_SYNCED) do(e: Args):
+    let args = MailserverSyncedArgs(e)
+    if (args.chatId != self.chatId):
+      return
+    self.delegate.onMailserverSynced(args.syncedFrom)
+
 proc getMySectionId*(self: Controller): string =
   return self.sectionId
 

src/app/modules/main/chat_section/chat_content/messages/io_interface.nim

@@ -21,6 +21,9 @@ method getModuleAsVariant*(self: AccessInterface): QVariant {.base.} =
 method updateChatIdentifier*(self: AccessInterface) {.base.} =
   raise newException(ValueError, "No implementation available")
 
+method updateChatFetchMoreMessages*(self: AccessInterface) {.base.} =
+  raise newException(ValueError, "No implementation available")
+
 method newMessagesLoaded*(self: AccessInterface, messages: seq[MessageDto], reactions: seq[ReactionDto],
   pinnedMessages: seq[PinnedMessageDto]) {.base.} =
   raise newException(ValueError, "No implementation available")
@@ -130,3 +133,6 @@ method didIJoinedChat*(self: AccessInterface): bool {.base.} =
 
 method getMessages*(self: AccessInterface): seq[message_item.Item] =
   raise newException(ValueError, "No implementation available")
+
+method onMailserverSynced*(self: AccessInterface, syncedFrom: int64) =
+  raise newException(ValueError, "No implementation available")

src/app/modules/main/chat_section/chat_content/messages/module.nim

@@ -60,6 +60,7 @@ method isLoaded*(self: Module): bool =
   return self.moduleLoaded
 
 method viewDidLoad*(self: Module) =
+  if self.controller.getChatDetails().hasMoreMessagesToRequest():
     self.view.model().appendItem(self.createFetchMoreMessagesItem())
   self.view.model().appendItem(self.createChatIdentifierItem())
 
@@ -237,6 +238,7 @@ method newMessagesLoaded*(self: Module, messages: seq[MessageDto], reactions: se
       # messages are sorted from the most recent to the least recent one
       viewItems.add(item)
 
+    if self.controller.getChatDetails().hasMoreMessagesToRequest():
       viewItems.add(self.createFetchMoreMessagesItem())
     viewItems.add(self.createChatIdentifierItem())
     self.view.model().removeItem(FETCH_MORE_MESSAGES_MESSAGE_ID)
@@ -466,6 +468,12 @@ method updateChatIdentifier*(self: Module) =
   # Add new loaded messages
   self.view.model().appendItem(self.createChatIdentifierItem())
 
+method updateChatFetchMoreMessages*(self: Module) =
+  self.view.model().removeItem(FETCH_MORE_MESSAGES_MESSAGE_ID)
+
+  if (self.controller.getChatDetails().hasMoreMessagesToRequest()):
+    self.view.model().appendItem(self.createFetchMoreMessagesItem())
+
 method getLinkPreviewData*(self: Module, link: string, uuid: string): string =
   return self.controller.getLinkPreviewData(link, uuid)
 
@@ -507,3 +515,8 @@ method onChatMemberUpdated*(self: Module, publicKey: string, admin: bool, joined
 
 method getMessages*(self: Module): seq[message_item.Item] =
   return self.view.model().items
+
+method onMailserverSynced*(self: Module, syncedFrom: int64) =
+  let chatDto = self.controller.getChatDetails()
+  if (not chatDto.hasMoreMessagesToRequest(syncedFrom)):
+    self.view.model().removeItem(FETCH_MORE_MESSAGES_MESSAGE_ID)

src/app/modules/main/chat_section/chat_content/module.nim

@@ -340,6 +340,7 @@ method onNotificationsUpdated*(self: Module, hasUnreadMessages: bool, notificati
 
 method onChatEdited*(self: Module, chatDto: ChatDto) =
   self.view.updateChatDetails(chatDto.name, chatDto.description, chatDto.emoji, chatDto.color, chatDto.icon, chatDto.chatType == ChatType.OneToOne)
+  self.messagesModule.updateChatFetchMoreMessages()
   self.messagesModule.updateChatIdentifier()
 
 method onChatRenamed*(self: Module, newName: string) =

src/app_service/service/chat/dto/chat.nim

@@ -75,6 +75,7 @@ type ChatDto* = object
   joined*: int64 # indicates when the user joined the chat last time
   syncedTo*: int64
   syncedFrom*: int64
+  firstMessageTimestamp: int64 # valid only for community chats, 0 - undefined, 1 - no messages, >1 valid timestamps
   canPost*: bool
   position*: int
   categoryId*: string
@@ -132,6 +133,7 @@ proc `$`*(self: ChatDto): string =
     canPost: {self.canPost},
     syncedTo: {self.syncedTo},
     syncedFrom: {self.syncedFrom},
+    firstMessageTimestamp: {self.firstMessageTimestamp},
     categoryId: {self.categoryId},
     position: {self.position},
     highlight: {self.highlight}
@@ -219,6 +221,7 @@ proc toChatDto*(jsonObj: JsonNode): ChatDto =
   discard jsonObj.getProp("joined", result.joined)
   discard jsonObj.getProp("syncedTo", result.syncedTo)
   discard jsonObj.getProp("syncedFrom", result.syncedFrom)
+  discard jsonObj.getProp("firstMessageTimestamp", result.firstMessageTimestamp)
   discard jsonObj.getProp("highlight", result.highlight)
   var permissionObj: JsonNode
   if(jsonObj.getProp("permissions", permissionObj)):
@@ -309,3 +312,21 @@ proc isPublicChat*(chatDto: ChatDto): bool =
 
 proc isOneToOneChat*(chatDto: ChatDto): bool =
   return chatDto.chatType == ChatType.OneToOne
+
+proc hasMoreMessagesToRequest*(chatDto: ChatDto, syncedFrom: int64): bool =
+  # only for community chat we can determine the first message ever sent to the chat
+  if chatDto.chatType != ChatType.CommunityChat:
+    return true
+
+  const firstMessageTimestampUndefined = 0
+  const firstMessageTimestampNoMessages = 1
+
+  if chatDto.firstMessageTimestamp == firstMessageTimestampUndefined:
+    return true
+  if chatDto.firstMessageTimestamp == firstMessageTimestampNoMessages:
+    return false
+
+  return syncedFrom > chatDto.firstMessageTimestamp
+
+proc hasMoreMessagesToRequest*(chatDto: ChatDto): bool =
+  chatDto.hasMoreMessagesToRequest(chatDto.syncedFrom)

src/app_service/service/mailservers/service.nim

@@ -22,6 +22,10 @@ type
 
   MailserverAvailableArgs* = ref object of Args
 
+  MailserverSyncedArgs* = ref object of Args
+    chatId*: string
+    syncedFrom*: int64
+
   RequestMoreMessagesTaskArg = ref object of QObjectTaskArg
     chatId*: string
 
@@ -33,12 +37,27 @@ type
 const SIGNAL_ACTIVE_MAILSERVER_CHANGED* = "activeMailserverChanged"
 const SIGNAL_MAILSERVER_AVAILABLE* = "mailserverAvailable"
 const SIGNAL_MAILSERVER_NOT_WORKING* = "mailserverNotWorking"
+const SIGNAL_MAILSERVER_SYNCED* = "mailserverSynced"
 
 const requestMoreMessagesTask: Task = proc(argEncoded: string) {.gcsafe, nimcall.} =
   let arg = decode[RequestMoreMessagesTaskArg](argEncoded)
   try:
     info "Requesting additional message history for chat", chatId=arg.chatId
-    discard status_mailservers.syncChatFromSyncedFrom(arg.chatId)
+    let response = status_mailservers.syncChatFromSyncedFrom(arg.chatId)
+
+    if(not response.error.isNil):
+      error "Could not request additional messages due to error", errDescription = response.error.message
+
+    let syncedFrom = response.result.getInt()
+    if(syncedFrom != 0):
+      let resultJson = %* {
+        "chatId": arg.chatId,
+        "syncedFrom": syncedFrom
+      }
+      arg.finish(%resultJson)
+    else:
+      warn "Syncing mailserver failed", errDescription=arg.chatId
+
   except Exception as e:
     warn "Could not request additional messages due to error", errDescription=e.msg
 
@@ -88,11 +107,20 @@ QtObject:
       let fleet = self.settingsService.getFleet()
       discard self.settingsService.pinMailserver(MAILSERVER_ADDRESS, fleet)
 
+  proc mailserverSynced*(self: Service, syncInfo: string) {.slot.} =
+    let syncInfoParsed = parseJson(syncInfo)
+    let signalData = MailserverSyncedArgs(
+      chatId: syncInfoParsed["chatId"].getStr(),
+      syncedFrom: syncInfoParsed["syncedFrom"].getInt()
+      )
+    self.events.emit(SIGNAL_MAILSERVER_SYNCED, signalData)
+
   proc requestMoreMessages*(self: Service, chatId: string) =
     let arg = RequestMoreMessagesTaskArg(
       tptr: cast[ByteAddress](requestMoreMessagesTask),
       vptr: cast[ByteAddress](self.vptr),
-      chatId: chatId
+      chatId: chatId,
+      slot: "mailserverSynced"
     )
     self.threadpool.start(arg)