Begin statistics creation

CHDataManagement/Extensions/Double+Rounded.swift

@@ -1,7 +1,14 @@
+import Foundation
+import _math
 
 extension Double {
 
     func rounded(to interval: Double) -> Double {
         (self / interval).rounded() * interval
     }
+
+    func rounded(decimals: Int) -> Double {
+        let factor = _math.pow(10.0, Double(decimals))
+        return (self * factor).rounded() / factor
+    }
 }

CHDataManagement/Extensions/TimeInterval+Extensions.swift

@@ -0,0 +1,25 @@
+import Foundation
+
+extension TimeInterval {
+
+    func duration(locale: Locale) -> String {
+        let totalMinutes = Int((self / 60).rounded(to: 5))
+        let hours = totalMinutes / 60
+        let minutes = totalMinutes % 60
+
+        let suffix = locale.identifier.hasPrefix("de") ? "Std" : "h"
+
+        return String(format: "%d:%02d ", hours, minutes) + suffix
+    }
+
+    func length(roundingToNearest interval: Double) -> String {
+        let rounded = Int(self.rounded(to: interval))
+        return "\(rounded) m"
+    }
+
+    func energy(roundingToNearest interval: Double) -> String {
+        let rounded = Int(self.rounded(to: interval))
+        return "\(rounded) kcal"
+    }
+
+}