Handle number of batches / last batch

RiotSwiftUI/Modules/Room/PollHistory/PollHistoryModels.swift

@@ -44,6 +44,7 @@ struct PollHistoryViewState: BindableState {
     var isLoading = false
     var canLoadMoreContent = true
     var polls: [TimelinePollDetails]?
+    var numberOfFetchedBatches: UInt = 0
 }
 
 enum PollHistoryViewAction {

RiotSwiftUI/Modules/Room/PollHistory/PollHistoryViewModel.swift

@@ -29,6 +29,7 @@ final class PollHistoryViewModel: PollHistoryViewModelType, PollHistoryViewModel
     init(mode: PollHistoryMode, pollService: PollHistoryServiceProtocol) {
         self.pollService = pollService
         super.init(initialViewState: PollHistoryViewState(mode: mode))
+        state.canLoadMoreContent = pollService.hasNextBatch
     }
 
     // MARK: - Public
@@ -53,9 +54,8 @@ private extension PollHistoryViewModel {
         pollService
             .nextBatch()
             .collect()
-            .sink { [weak self] _ in
-                #warning("Handle errors")
-                self?.state.isLoading = false
+            .sink { [weak self] completion in
+                self?.handleBatchEnded(completion: completion)
             } receiveValue: { [weak self] polls in
                 self?.polls = polls
                 self?.updateViewState()
@@ -68,9 +68,8 @@ private extension PollHistoryViewModel {
         
         pollService
             .nextBatch()
-            .sink { [weak self] _ in
-                #warning("Handle errors")
-                self?.state.isLoading = false
+            .sink { [weak self] completion in
+                self?.handleBatchEnded(completion: completion)
             } receiveValue: { [weak self] poll in
                 self?.add(poll: poll)
                 self?.updateViewState()
@@ -78,6 +77,18 @@ private extension PollHistoryViewModel {
             .store(in: &subcriptions)
     }
     
+    func handleBatchEnded(completion: Subscribers.Completion<Error>) {
+        state.isLoading = false
+        state.canLoadMoreContent = pollService.hasNextBatch
+        
+        switch completion {
+        case .finished:
+            state.numberOfFetchedBatches += 1
+        case .failure(_):
+            #warning("Handle errors")
+        }
+    }
+    
     func setupUpdateSubscriptions() {
         subcriptions.removeAll()
         
@@ -125,7 +136,7 @@ private extension PollHistoryViewModel {
 
 extension PollHistoryViewModel.Context {
     var emptyPollsText: String {
-        let days = PollHistoryConstants.chunkSizeInDays
+        let days = PollHistoryConstants.chunkSizeInDays * viewState.numberOfFetchedBatches
         
         switch (viewState.bindings.mode, viewState.canLoadMoreContent) {
         case (.active, true):

RiotSwiftUI/Modules/Room/PollHistory/Service/MatrixSDK/PollHistoryService.swift

@@ -50,6 +50,10 @@ final class PollHistoryService: PollHistoryServiceProtocol {
     func nextBatch() -> AnyPublisher<TimelinePollDetails, Error> {
         currentBatchSubject?.eraseToAnyPublisher() ?? startPagination()
     }
+    
+    var hasNextBatch: Bool {
+        timeline.canPaginate(.backwards)
+    }
 }
 
 private extension PollHistoryService {

RiotSwiftUI/Modules/Room/PollHistory/Service/Mock/MockPollHistoryService.swift

@@ -17,6 +17,15 @@
 import Combine
 
 final class MockPollHistoryService: PollHistoryServiceProtocol {
+    lazy var nextBatchPublisher: AnyPublisher<TimelinePollDetails, Error> = (activePollsData + pastPollsData)
+        .publisher
+        .setFailureType(to: Error.self)
+        .eraseToAnyPublisher()
+    
+    func nextBatch() -> AnyPublisher<TimelinePollDetails, Error> {
+        nextBatchPublisher
+    }
+    
     var updatesPublisher: AnyPublisher<TimelinePollDetails, Never> = Empty().eraseToAnyPublisher()
     var updates: AnyPublisher<TimelinePollDetails, Never> {
         updatesPublisher
@@ -27,14 +36,7 @@ final class MockPollHistoryService: PollHistoryServiceProtocol {
         pollErrorPublisher
     }
     
-    lazy var nextBatchPublisher: AnyPublisher<TimelinePollDetails, Error> = (activePollsData + pastPollsData)
-        .publisher
-        .setFailureType(to: Error.self)
-        .eraseToAnyPublisher()
-    
-    func nextBatch() -> AnyPublisher<TimelinePollDetails, Error> {
-        nextBatchPublisher
-    }
+    var hasNextBatch: Bool = true
 }
 
 private extension MockPollHistoryService {

RiotSwiftUI/Modules/Room/PollHistory/Service/PollHistoryServiceProtocol.swift

@@ -27,4 +27,8 @@ protocol PollHistoryServiceProtocol {
     /// Publishes errors regarding poll aggregations.
     /// Note: `nextBatch()` will continue to publish new polls even if some poll isn't being aggregated correctly.
     var pollErrors: AnyPublisher<Error, Never> { get }
+    
+    /// Returns true every time the service can fetch another batch.
+    /// There is no guarantee the `nextBatch()` returned publisher will publish something anyway.
+    var hasNextBatch: Bool { get }
 }