#29 issue fixed.

Author: sadeghgoo

Sources/MagicTimer/MagicTimer.swift

@@ -45,7 +45,20 @@ public class MagicTimer {
     }
 
     /// Timer count mode. Default is `.stopWatch`. Checkout ```MagicTimerMode```.
-    public var countMode: MagicTimerMode = .stopWatch
+    public var countMode: MagicTimerMode = .stopWatch {
+        didSet {
+            switch countMode {
+            case .stopWatch:
+                break
+            case .countDown(let fromSeconds):
+                // Checking if defaultValue plus fromSeconds not going to invalid format(negative seconds).
+                guard (defultValue + fromSeconds).truncatingRemainder(dividingBy: effectiveValue).isEqual(to: .zero) else {
+                    fatalError("The time does not lead to a valid format. Use valid effetiveValue")
+                }
+                counter.totalCountedValue = fromSeconds
+            }
+        }
+    }
 
     /// Timer default value. Default is 0.
     public var defultValue: TimeInterval = 0 {
@@ -169,27 +182,19 @@ public class MagicTimer {
     private func observeScheduleTimer() {
         executive.scheduleTimerHandler = { [weak self] in
             guard let self else { return }
-            
-            switch self.countMode {
+            switch countMode {
             case .stopWatch:
-                self.counter.add()
-                self.elapsedTime = self.counter.totalCountedValue
-            case .countDown(let fromSeconds):
-                // Checking if defaultValue plus fromSeconds not going to invalid format(negative seconds).
-                guard (self.defultValue + fromSeconds).truncatingRemainder(dividingBy: self.effectiveValue).isEqual(to: .zero) else {
-                    fatalError("The time does not lead to a valid format. Use valid effetiveValue")
-                }
-                
-                self.counter.totalCountedValue = fromSeconds
+                counter.add()
+            case .countDown(_):
                 guard counter.totalCountedValue.isBiggerThan(.zero) else {
                     executive.suspand {
                         self.lastState = .stopped
                     }
                     return
                 }
                 counter.subtract()
-                elapsedTime = self.counter.totalCountedValue
             }
+            elapsedTime = counter.totalCountedValue
         }
     }
 }

Sources/MagicTimer/MagicTimerBackgroundCalculator.swift

@@ -16,8 +16,11 @@ public final class MagicTimerBackgroundCalculator: MagicTimerBackgroundCalculato
     public var isActiveBackgroundMode: Bool = true
     public var backgroundTimeCalculateHandler: ((TimeInterval) -> Void)?
 
+    private var shouldCalculate: Bool = false
+    
     public init() {
         NotificationCenter.default.addObserver(self, selector: #selector(willEnterForegroundNotification), name: UIApplication.willEnterForegroundNotification, object: nil)
+        NotificationCenter.default.addObserver(self, selector: #selector(willEnterBackgroundNotification), name: UIApplication.didEnterBackgroundNotification, object: nil)
     }
 
     deinit {
@@ -30,17 +33,22 @@ public final class MagicTimerBackgroundCalculator: MagicTimerBackgroundCalculato
 
     private func calculateDateDiffrence() -> TimeInterval? {
         guard let timerFiredDate else { return nil }
-        let validTimeSubtraction = abs(timerFiredDate - Date())
+        let validTimeSubtraction = floor(abs(timerFiredDate - Date()))
         return validTimeSubtraction.convertToTimeInterval()
     }
 
     @objc
     private func willEnterForegroundNotification() {
-        guard isActiveBackgroundMode else { return }
+        guard isActiveBackgroundMode, shouldCalculate else { return }
 
         if let timeInterval = calculateDateDiffrence() {
             backgroundTimeCalculateHandler?(timeInterval)
         }
     }
+    
+    @objc
+    private func willEnterBackgroundNotification() {
+        shouldCalculate = true
+    }
 }