Fix: rtl/ltr range corners, add methods for set first weekday from current locale and system preseted weekday

Sources/Internal/Data/Data.MonthView.swift

@@ -22,6 +22,7 @@ extension [Data.MonthView] {
         createDatesRange()
             .map(createMonthDate)
             .map(createMonthViewData)
+            .reversed()
     }
 }
 private extension [Data.MonthView] {
@@ -93,3 +94,4 @@ private extension Data.MonthView {
 private extension Data.MonthView {
     static var weekdaysNumber: Int { MWeekday.allCases.count }
 }
+

Sources/Public/Configurables/Public+CalendarConfig.swift

@@ -24,6 +24,32 @@ public extension CalendarConfig {
     /// Sets the first day of the week.
     /// DEFAULT:: Monday
     func firstWeekday(_ value: MWeekday) -> Self { MCalendar.firstWeekday = value; return self }
+
+    /// Sets the first day of the system week.
+    /// DEFAULT:: System weekday
+    func firstSystemWeekday() -> Self {
+        return firstWeekday(MWeekday(rawValue: Calendar.current.firstWeekday) ?? .monday)
+    }
+
+    /// Sets the first day of the week based on the country Code
+    /// DEFAULT:: US
+    func firstWeekday(for countryCode: String = "US") -> Self {
+        let weekday = WeekdayRule.firstWeekday(for: countryCode)
+        return firstWeekday(weekday)
+    }
+
+    /// Sets the first day of the week based on the device locale
+    /// DEFAULT:: Current
+    func firstWeekday(for locale: Locale = Locale.current) -> Self {
+        var countryCode: String
+
+        if #available(iOS 16, *) {
+            countryCode = locale.region?.identifier ?? "US"
+        } else {
+            countryCode = locale.identifier
+        }
+        return firstWeekday(for: countryCode)
+    }
 
     /// Sets the locale of the calendar.
     /// DEFAULT: AutoupdatingCurrent

Sources/Public/Enums/Public+MWeekday.swift

@@ -9,3 +9,52 @@
 
 
 public enum MWeekday: Int { case sunday = 1, monday, tuesday, wednesday, thursday, friday, saturday }
+
+public enum WeekdayRule {
+    enum StartDay {
+        case sunday, saturday, monday
+    }
+
+    static func firstWeekday(for countryCode: String) -> MWeekday {
+        let startDay = startDay(for: countryCode)
+        switch startDay {
+        case .sunday: return .sunday
+        case .saturday: return .saturday
+        case .monday: return .monday
+        }
+    }
+
+    private static func startDay(for countryCode: String) -> StartDay {
+        let country = countryCode.uppercased()
+
+        // 🇺🇸 SUNDAY - ~50% of the world
+        let sundayCountries = [
+            // North America
+            "US", "CA", "MX",
+            // South America
+            "BR", "AR", "CL", "CO", "PE", "VE", "BO", "UY", "PY", "EC", "GY", "SR", "GF",
+            // Asia
+            "IN", "CN", "JP", "KR", "PH", "VN", "TH", "ID", "MY", "SG",
+            // Middle East
+            "IL",
+            // Oceania
+            "AU", "NZ"
+        ]
+
+        // 🇸🇦 SATURDAY - Muslim countries
+        let saturdayCountries = [
+            // Persian Gulf
+            "SA", "QA", "KW", "OM", "BH", "AE", // UAE partially switched to Sunday
+            // North Africa
+            "EG", "LY", "DZ", "MA", "TN",
+            // Others
+            "AF", "IQ", "YE", "SO"
+        ]
+
+        if sundayCountries.contains(country) { return .sunday }
+        if saturdayCountries.contains(country) { return .saturday }
+
+        // Default: Monday (Europe, Russia, majority)
+        return .monday
+    }
+}

Sources/Public/View Protocols/Public+DayView.swift

@@ -62,8 +62,10 @@ private extension DayView {
 }
 private extension DayView {
     var rangeSelectionViewCorners: RoundedRectangle.Corner { 
-        if isBeginningOfRange() { return [.topLeft, .bottomLeft] }
-        if isEndOfRange() { return [.topRight, .bottomRight] }
+        if isBeginningOfRange() && isInterfaceLTR() { return [.topLeft, .bottomLeft] }
+        if isEndOfRange() && isInterfaceLTR() { return [.topRight, .bottomRight] }
+        if isBeginningOfRange() && !isInterfaceLTR() { return [.topRight, .bottomRight] }
+        if isEndOfRange() && !isInterfaceLTR() { return [.topLeft, .bottomLeft] }
 
         return []
     }
@@ -99,6 +101,7 @@ public extension DayView {
     func isBeginningOfRange() -> Bool { date.isSame(.day, as: selectedRange?.wrappedValue?.getRange()?.lowerBound) }
     func isEndOfRange() -> Bool { date.isSame(.day, as: selectedRange?.wrappedValue?.getRange()?.upperBound) }
     func isWithinRange() -> Bool { selectedRange?.wrappedValue?.isRangeCompleted() == true && selectedRange?.wrappedValue?.contains(date) == true }
+    func isInterfaceLTR() -> Bool { UIApplication.shared.userInterfaceLayoutDirection == .leftToRight }
 }
 
 // MARK: - Others