Reaction history: Implement view model.

2026-04-20 16:42:44 +02:00 · 2019-07-30 17:14:01 +02:00
parent 275c912d0a
commit fb6f808a9b
5 changed files with 289 additions and 0 deletions
@@ -0,0 +1,179 @@
+// File created from ScreenTemplate
+// $ createScreen.sh ReactionHistory ReactionHistory
+/*
+ Copyright 2019 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
+
+final class ReactionHistoryViewModel: ReactionHistoryViewModelType {
+    
+    // MARK: - Constants
+    
+    private enum Pagination {
+        static let count: UInt = 30
+    }
+    
+    // MARK: - Properties
+    
+    // MARK: Private
+
+    private let session: MXSession
+    private let roomId: String
+    private let eventId: String
+    private let aggregations: MXAggregations
+    private let eventFormatter: MXKEventFormatter
+    private let reactionsFormattingQueue: DispatchQueue
+    
+    private var reactionHistoryViewDataList: [ReactionHistoryViewData] = []
+    private var operation: MXHTTPOperation?
+    private var nextBatch: String?
+    private var viewState: ReactionHistoryViewState?
+    
+    private lazy var roomMembers: MXRoomMembers? = {
+        return buildRoomMembers()
+    }()
+    
+    // MARK: Public
+
+    weak var viewDelegate: ReactionHistoryViewModelViewDelegate?
+    weak var coordinatorDelegate: ReactionHistoryViewModelCoordinatorDelegate?
+    
+    // MARK: - Setup
+    
+    init(session: MXSession, roomId: String, eventId: String) {
+        self.session = session
+        self.aggregations = session.aggregations
+        self.roomId = roomId
+        self.eventId = eventId
+        self.eventFormatter = EventFormatter(matrixSession: session)
+        self.reactionsFormattingQueue = DispatchQueue(label: "\(type(of: self)).reactionsFormattingQueue")
+    }
+    
+    // MARK: - Public
+    
+    func process(viewAction: ReactionHistoryViewAction) {
+        switch viewAction {
+        case .loadMore:
+            self.loadMoreHistory()
+        case .close:
+            self.coordinatorDelegate?.reactionHistoryViewModelDidClose(self)
+        }
+    }
+    
+    // MARK: - Private
+    
+    
+    private func canLoadMoreHistory() -> Bool {
+        guard let viewState = self.viewState else {
+            return true
+        }
+        
+        let canLoadMoreHistory: Bool
+        
+        switch viewState {
+        case .loading:
+            canLoadMoreHistory = false
+        case .loaded(reactionHistoryViewDataList: _, allDataLoaded: let allDataLoaded):
+            canLoadMoreHistory = !allDataLoaded
+        default:
+            canLoadMoreHistory = true
+        }
+        
+        return canLoadMoreHistory
+    }
+    
+    private func loadMoreHistory() {
+        guard self.canLoadMoreHistory() else {
+            print("[ReactionHistoryViewModel] loadMoreHistory: pending loading or all data loaded")
+            return
+        }
+        
+        guard self.operation == nil else {
+            print("[ReactionHistoryViewModel] loadMoreHistory: operation already pending")
+            return
+        }
+        
+        self.update(viewState: .loading)
+        
+        self.operation = self.aggregations.reactionsEvents(forEvent: self.eventId, inRoom: self.roomId, from: self.nextBatch, limit: Pagination.count, success: { [weak self] (response) in
+            guard let self = self else {
+                return
+            }
+            
+            self.nextBatch = response.nextBatch
+            self.operation = nil
+            
+            self.process(reactionEvents: response.chunk, nextBatch: response.nextBatch)
+            
+        }, failure: { [weak self] error in
+            guard let self = self else {
+                return
+            }
+            
+            self.operation = nil
+            self.update(viewState: .error(error))
+        })
+    }
+    
+    private func process(reactionEvents: [MXEvent], nextBatch: String?) {
+        self.reactionsFormattingQueue.async {
+            
+            let reactionHistoryList = reactionEvents.compactMap { (reactionEvent) -> ReactionHistoryViewData? in
+                return self.reactionHistoryViewData(from: reactionEvent)
+            }
+            
+            self.reactionHistoryViewDataList.append(contentsOf: reactionHistoryList)
+            
+            let allDataLoaded = nextBatch == nil
+            
+            DispatchQueue.main.async {
+                self.update(viewState: .loaded(reactionHistoryViewDataList: self.reactionHistoryViewDataList, allDataLoaded: allDataLoaded))
+            }
+        }
+    }
+    
+    private func reactionHistoryViewData(from reactionEvent: MXEvent) -> ReactionHistoryViewData? {
+        guard let userId = reactionEvent.sender,
+            let reaction = reactionEvent.relatesTo?.key,
+            let reactionDateString = self.eventFormatter.dateString(fromTimestamp: reactionEvent.originServerTs, withTime: true) else {
+            return nil
+        }
+        
+        let userDisplayName = self.userDisplayName(from: userId) ?? userId
+        
+        return ReactionHistoryViewData(reaction: reaction, userDisplayName: userDisplayName, dateString: reactionDateString)
+    }
+    
+    private func userDisplayName(from userId: String) -> String? {
+        guard let roomMembers = self.roomMembers else {
+            return nil
+        }
+        let roomMember = roomMembers.member(withUserId: userId)
+        return roomMember?.displayname
+    }
+    
+    private func buildRoomMembers() -> MXRoomMembers? {
+        guard let room = self.session.room(withRoomId: self.roomId) else {
+            return nil
+        }
+        return room.dangerousSyncState?.members
+    }
+    
+    private func update(viewState: ReactionHistoryViewState) {
+        self.viewState = viewState
+        self.viewDelegate?.reactionHistoryViewModel(self, didUpdateViewState: viewState)
+    }
+}