Switched to discrete timeline items that directly expose view builders.

ElementX/Sources/Services/Timeline/MockRoomTimelineController.swift

@@ -10,8 +10,10 @@ import Foundation
 import Combine
 
 class MockRoomTimelineController: RoomTimelineControllerProtocol {
-    let timelineItems: [RoomTimelineItemProtocol] = [TextRoomTimelineItem(id: UUID().uuidString, senderDisplayName: "Anne", text: "You rock!", originServerTs: .now),
-                                                     TextRoomTimelineItem(id: UUID().uuidString, senderDisplayName: "Bob", text: "You rule!", originServerTs: .now)]
+    let timelineItems: [RoomTimelineItem] = [RoomTimelineItem.text(id: UUID().uuidString, senderDisplayName: "Anne", text: "You rock!", originServerTs: .now, shouldShowSenderDetails: true),
+                                             RoomTimelineItem.text(id: UUID().uuidString, senderDisplayName: "Anne", text: "Some other message from Anne", originServerTs: .now, shouldShowSenderDetails: false),
+                                             RoomTimelineItem.sectionTitle(id: UUID().uuidString, text: "The next day"),
+                                             RoomTimelineItem.text(id: UUID().uuidString, senderDisplayName: "Bob", text: "You rule!", originServerTs: .now, shouldShowSenderDetails: true)]
     let callbacks = PassthroughSubject<RoomTimelineControllerCallback, Never>()
     
     func paginateBackwards(_ count: UInt) {

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)
+        
+    }
 }

ElementX/Sources/Services/Timeline/RoomTimelineControllerProtocol.swift

@@ -10,7 +10,7 @@ import Foundation
 import Combine
 
 protocol RoomTimelineControllerProtocol {
-    var timelineItems: [RoomTimelineItemProtocol] { get }
+    var timelineItems: [RoomTimelineItem] { get }
     var callbacks: PassthroughSubject<RoomTimelineControllerCallback, Never> { get }
     
     func paginateBackwards(_ count: UInt)

ElementX/Sources/Services/Timeline/TimelineItems/RoomTimelineItem.swift

@@ -0,0 +1,84 @@
+//
+//  TextRoomTimelineItem.swift
+//  ElementX
+//
+//  Created by Stefan Ceriu on 04.03.2022.
+//  Copyright © 2022 Element. All rights reserved.
+//
+
+import Foundation
+import SwiftUI
+
+private var dateFormatter: DateFormatter = {
+    let dateFormatter = DateFormatter()
+    dateFormatter.dateStyle = .none
+    dateFormatter.timeStyle = .short
+    return dateFormatter
+}()
+
+enum RoomTimelineItem: Identifiable, Equatable {
+    case text(id: String, senderDisplayName: String, text: String, originServerTs: Date, shouldShowSenderDetails: Bool)
+    case sectionTitle(id: String, text: String)
+    
+    var id: String {
+        switch self {
+        case .text(let id, _, _, _, _):
+            return id
+        case .sectionTitle(let id, _):
+            return id
+        }
+    }
+}
+
+extension RoomTimelineItem: View {
+    var body: some View {
+        switch self {
+        case .text(let id, let senderDisplayName, let text, let originServerTs, let shouldShowSenderDetails):
+            VStack(alignment: .leading) {
+                if shouldShowSenderDetails {
+                    HStack {
+                        Text(senderDisplayName)
+                            .font(.footnote)
+                            .bold()
+                        Spacer()
+                        Text(dateFormatter.string(from: originServerTs))
+                            .font(.footnote)
+                    }
+                    Divider()
+                    Spacer()
+                }
+                Text(text)
+            }
+            .listRowSeparator(.hidden)
+            .id(id)
+        case .sectionTitle(let id, let text):
+            LabelledDivider(label: text)
+                .id(id)
+        }
+    }
+}
+
+struct LabelledDivider: View {
+
+    let label: String
+    let color: Color
+
+    init(label: String, color: Color = .gray) {
+        self.label = label
+        self.color = color
+    }
+
+    var body: some View {
+        HStack {
+            line
+            Text(label)
+                .foregroundColor(color)
+                .fixedSize()
+            line
+        }
+    }
+
+    var line: some View {
+        VStack { Divider().background(color) }
+    }
+}

ElementX/Sources/Services/Timeline/TimelineItems/RoomTimelineItemProtocol.swift

@@ -1,16 +0,0 @@
-//
-//  RoomTimelineItemProtocol.swift
-//  ElementX
-//
-//  Created by Stefan Ceriu on 04.03.2022.
-//  Copyright © 2022 Element. All rights reserved.
-//
-
-import Foundation
-
-protocol RoomTimelineItemProtocol {
-    var id: String { get }
-    var senderDisplayName: String { get }
-    var text: String { get }
-    var originServerTs: Date { get }
-}

ElementX/Sources/Services/Timeline/TimelineItems/TextRoomTimelineItem.swift

@@ -1,16 +0,0 @@
-//
-//  TextRoomTimelineItem.swift
-//  ElementX
-//
-//  Created by Stefan Ceriu on 04.03.2022.
-//  Copyright © 2022 Element. All rights reserved.
-//
-
-import Foundation
-
-struct TextRoomTimelineItem: RoomTimelineItemProtocol {
-    let id: String
-    let senderDisplayName: String
-    let text: String
-    let originServerTs: Date
-}