Use Calendar to compute target dates

RiotSwiftUI/Modules/Room/PollHistory/PollHistoryModels.swift

@@ -18,7 +18,6 @@
 
 enum PollHistoryConstants {
     static let chunkSizeInDays: UInt = 30
-    static let oneDayInSeconds: TimeInterval = 8.6 * 10e3
 }
 
 enum PollHistoryViewModelResult: Equatable {

RiotSwiftUI/Modules/Room/PollHistory/PollHistoryViewModel.swift

@@ -142,8 +142,10 @@ extension PollHistoryViewModel.Context {
         }
     }
     
-    var syncedPastDays: UInt {
-        let timeDelta = max(viewState.syncStartDate.timeIntervalSince(viewState.syncedUpTo), 0)
-        return UInt((timeDelta / PollHistoryConstants.oneDayInSeconds).rounded())
+    var syncedPastDays: Int {
+        guard let days = Calendar.current.dateComponents([.day], from: viewState.syncedUpTo, to: viewState.syncStartDate).day else {
+            return 0
+        }
+        return max(0, days)
     }
 }

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

@@ -119,7 +119,7 @@ private extension PollHistoryService {
     
     func startPagination() -> AnyPublisher<TimelinePollDetails, Error> {
         let startingTimestamp = oldestEventDate
-        targetTimestamp = startingTimestamp.subtractingDays(chunkSizeInDays)
+        targetTimestamp = startingTimestamp.subtractingDays(chunkSizeInDays) ?? startingTimestamp
         
         let batchSubject = PassthroughSubject<TimelinePollDetails, Error>()
         currentBatchSubject = batchSubject
@@ -190,8 +190,8 @@ private extension PollHistoryService {
 }
 
 private extension Date {
-    func subtractingDays(_ days: UInt) -> Date {
-        addingTimeInterval(-TimeInterval(days) * PollHistoryConstants.oneDayInSeconds)
+    func subtractingDays(_ days: UInt) -> Date? {
+        Calendar.current.date(byAdding: DateComponents(day: -Int(days)), to: self)
     }
 }