Implement pagination in recents list service

Riot/Modules/Common/Recents/Service/MatrixSDK/RecentsListService.swift

@@ -223,6 +223,21 @@ public class RecentsListService: NSObject, RecentsListServiceProtocol {
         return visibleFetchers.reduce(0, { $0 + ($1.data?.counts.numberOfRooms ?? 0) })
     }
     
+    public func paginate(inSection section: RecentsListServiceSection) {
+        guard let fetcher = fetcher(forSection: section) else {
+            return
+        }
+        guard let data = fetcher.data else {
+            //  first page is not fetched yet
+            return
+        }
+        guard data.paginationOptions != .none else {
+            //  pagination is not enabled
+            return
+        }
+        fetcher.paginate()
+    }
+    
     public func updateMode(_ mode: RecentsDataSourceMode) {
         self.mode = mode
         if let fetcher = favoritedRoomListDataFetcher {
@@ -341,6 +356,44 @@ public class RecentsListService: NSObject, RecentsListServiceProtocol {
         return fetcherTypesForMode[mode]?.contains(.suggested) ?? false
     }
     
+    private func fetcher(forSection section: RecentsListServiceSection) -> MXRoomListDataFetcher? {
+        switch section {
+        case .invited:
+            return invitedRoomListDataFetcher
+        case .favorited:
+            return favoritedRoomListDataFetcher
+        case .people:
+            return directRoomListDataFetcher
+        case .conversation:
+            return conversationRoomListDataFetcher
+        case .lowPriority:
+            return lowPriorityRoomListDataFetcher
+        case .serverNotice:
+            return serverNoticeRoomListDataFetcher
+        case .suggested:
+            return suggestedRoomListDataFetcher
+        }
+    }
+    
+    private func section(forFetcher fetcher: MXRoomListDataFetcher) -> RecentsListServiceSection? {
+        if fetcher === invitedRoomListDataFetcher {
+            return .invited
+        } else if fetcher === favoritedRoomListDataFetcher {
+            return .favorited
+        } else if fetcher === directRoomListDataFetcher {
+            return .people
+        } else if fetcher === conversationRoomListDataFetcher {
+            return .conversation
+        } else if fetcher === lowPriorityRoomListDataFetcher {
+            return .lowPriority
+        } else if fetcher === serverNoticeRoomListDataFetcher {
+            return .serverNotice
+        } else if fetcher === suggestedRoomListDataFetcher {
+            return .suggested
+        }
+        return nil
+    }
+    
     private func createCommonRoomListDataFetcher(withDataTypes dataTypes: MXRoomSummaryDataTypes = [],
                                                  onlySuggested: Bool = false,
                                                  paginate: Bool = true) -> MXRoomListDataFetcher {
@@ -454,7 +507,10 @@ public class RecentsListService: NSObject, RecentsListServiceProtocol {
     }
     
     private func notifyDataChange(on fetcher: MXRoomListDataFetcher) {
-        multicastDelegate.invoke({ $0.serviceDidChangeData(self) })
+        if let section = section(forFetcher: fetcher) {
+            multicastDelegate.invoke { $0.recentsListServiceDidChangeData?(self, forSection: section) }
+        }
+        multicastDelegate.invoke { $0.recentsListServiceDidChangeData?(self) }
     }
     
     deinit {

Riot/Modules/Common/Recents/Service/Mock/MockRecentsListService.swift

@@ -170,6 +170,10 @@ public class MockRecentsListService: NSObject, RecentsListServiceProtocol {
         }
     }
     
+    public func paginate(inSection section: RecentsListServiceSection) {
+        //  no-op
+    }
+    
     public func updateMode(_ mode: RecentsDataSourceMode) {
         self.mode = mode
         notifyDataChange()
@@ -210,7 +214,7 @@ public class MockRecentsListService: NSObject, RecentsListServiceProtocol {
     }
     
     private func notifyDataChange() {
-        multicastDelegate.invoke({ $0.serviceDidChangeData(self) })
+        multicastDelegate.invoke({ $0.recentsListServiceDidChangeData?(self) })
     }
     
 }

Riot/Modules/Common/Recents/Service/RecentsListServiceDelegate.swift

@@ -21,5 +21,11 @@ public protocol RecentsListServiceDelegate: AnyObject {
     
     /// Delegate method to be called when service data updated
     /// - Parameter service: service object
-    func serviceDidChangeData(_ service: RecentsListServiceProtocol)
+    @objc optional func recentsListServiceDidChangeData(_ service: RecentsListServiceProtocol)
+    
+    /// Delegate method to be called when a specific section data updated. Called for each updated section before `recentsListServiceDidChangeData` if implemented.
+    /// - Parameter service: service object
+    /// - Parameter section: updated section
+    @objc optional func recentsListServiceDidChangeData(_ service: RecentsListServiceProtocol,
+                                                        forSection section: RecentsListServiceSection)
 }

Riot/Modules/Common/Recents/Service/RecentsListServiceProtocol.swift

@@ -87,6 +87,11 @@ public protocol RecentsListServiceProtocol {
     /// Stop service. Do not use after stopping.
     func stop()
     
+    //  MARK: Pagination
+    
+    /// Paginate in the given section.
+    func paginate(inSection section: RecentsListServiceSection)
+    
     //  MARK: - Delegate
     
     /// Add delegate instance for the service

Riot/Modules/Common/Recents/Service/RecentsListServiceSection.swift

@@ -0,0 +1,28 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Foundation
+
+@objc
+public enum RecentsListServiceSection: Int {
+    case invited
+    case favorited
+    case people
+    case conversation
+    case lowPriority
+    case serverNotice
+    case suggested
+}