Remove react-native; rewrite main screen in (native) swift

ios/Application/Platform/IosDates.swift

@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2016-2019 Álinson Santos Xavier <isoron@gmail.com>
+ *
+ * This file is part of Loop Habit Tracker.
+ *
+ * Loop Habit Tracker is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * Loop Habit Tracker is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+import Foundation
+
+class IosLocalDateFormatter : NSObject, LocalDateFormatter {
+    func shortWeekdayName(date: LocalDate) -> String {
+        let calendar = Calendar(identifier: .gregorian)
+        var dc = DateComponents()
+        dc.year = Int(date.year)
+        dc.month = Int(date.month)
+        dc.day = Int(date.day)
+        dc.hour = 13
+        dc.minute = 0
+        let d = calendar.date(from: dc)!
+        let fmt = DateFormatter()
+        fmt.dateFormat = "EEE"
+        return fmt.string(from: d)
+    }
+}
+
+class IosLocalDateCalculator : NSObject, LocalDateCalculator {
+    func plusDays(date: LocalDate, days: Int32) -> LocalDate {
+        let calendar = Calendar(identifier: .gregorian)
+        var dc = DateComponents()
+        dc.year = Int(date.year)
+        dc.month = Int(date.month)
+        dc.day = Int(date.day)
+        dc.hour = 13
+        dc.minute = 0
+        let d1 = calendar.date(from: dc)!
+        let d2 = d1.addingTimeInterval(24.0 * 60 * 60 * Double(days))
+        return LocalDate(year: Int32(calendar.component(.year, from: d2)),
+                         month: Int32(calendar.component(.month, from: d2)),
+                         day: Int32(calendar.component(.day, from: d2)))
+    }
+    
+    func minusDays(date: LocalDate, days: Int32) -> LocalDate {
+        return plusDays(date: date, days: -days)
+    }
+}