Switched to discrete timeline items that directly expose view builders.

ElementX/Sources/Services/Timeline/RoomTimelineController.swift

@@ -14,13 +14,20 @@ enum RoomTimelineControllerCallback {
     case updatedTimelineItems
 }
 
+private var sectionTitleDateFormatter: DateFormatter = {
+    let dateFormatter = DateFormatter()
+    dateFormatter.dateStyle = .long
+    dateFormatter.timeStyle = .none
+    return dateFormatter
+}()
+
 class RoomTimelineController: RoomTimelineControllerProtocol {
     private let timelineProvider: RoomTimelineProvider
     private var cancellables = Set<AnyCancellable>()
     
     let callbacks = PassthroughSubject<RoomTimelineControllerCallback, Never>()
     
-    private(set) var timelineItems = [RoomTimelineItemProtocol]()
+    private(set) var timelineItems = [RoomTimelineItem]()
     
     init(timelineProvider: RoomTimelineProvider) {
         self.timelineProvider = timelineProvider
@@ -30,13 +37,36 @@ class RoomTimelineController: RoomTimelineControllerProtocol {
             
             switch callback {
             case .updatedMessages:
-                self.timelineItems = self.timelineProvider.messages.map { message in
+                var newTimelineItems = [RoomTimelineItem]()
+                
+                var previousMessage: Message?
+                var previousSender: String?
+                for message in self.timelineProvider.messages {
                     let timestamp = Date(timeIntervalSince1970: TimeInterval(message.originServerTs()))
-                    return TextRoomTimelineItem(id: message.id(),
-                                                senderDisplayName: message.sender(),
-                                                text: message.content(),
-                                                originServerTs: timestamp)
+                    
+                    let areMessagesFromTheSameDay = self.haveSameDay(lhs: previousMessage, rhs: message)
+//                    let shouldAddSectionHeader = !areMessagesFromTheSameDay
+//                    
+//                    if shouldAddSectionHeader {
+//                        newTimelineItems.append(RoomTimelineItem.sectionTitle(id: message.id(),
+//                                                                              text: sectionTitleDateFormatter.string(from: timestamp)))
+//                    }
+                    
+                    let areMessagesFromTheSameSender = previousSender == message.sender()
+                    let shouldShowSenderDetails = !areMessagesFromTheSameSender || !areMessagesFromTheSameDay
+
+                    newTimelineItems.append(RoomTimelineItem.text(id: message.id(),
+                                                                  senderDisplayName: message.sender(),
+                                                                  text: message.content(),
+                                                                  originServerTs: timestamp,
+                                                                  shouldShowSenderDetails: shouldShowSenderDetails))
+                    
+                    previousMessage = message
+                    previousSender = message.sender()
                 }
+                
+                self.timelineItems = newTimelineItems
+                
                 self.callbacks.send(.updatedTimelineItems)
             }
         }.store(in: &cancellables)
@@ -45,4 +75,18 @@ class RoomTimelineController: RoomTimelineControllerProtocol {
     func paginateBackwards(_ count: UInt) {
         timelineProvider.paginateBackwards(count)
     }
+    
+    // MARK: - Private
+    
+    private func haveSameDay(lhs: Message?, rhs: Message?) -> Bool {
+        guard let lhs = lhs, let rhs = rhs else {
+            return false
+        }
+        
+        let lhsTimestamp = Date(timeIntervalSince1970: TimeInterval(lhs.originServerTs()))
+        let rhsTimestamp = Date(timeIntervalSince1970: TimeInterval(rhs.originServerTs()))
+        
+        return Calendar.current.isDate(lhsTimestamp, inSameDayAs: rhsTimestamp)
+        
+    }
 }