Add ability to pass custom calendar

JTCalendar/JTCalendarManager.h

@@ -34,6 +34,7 @@
 @property (nonatomic, readonly) JTCalendarScrollManager * _Nullable scrollManager;
 
 - (instancetype _Nullable )initWithLocale:(NSLocale *_Nullable)locale andTimeZone:(NSTimeZone *_Nullable)timeZone;
+- (instancetype _Nullable )initWithCalendar:(NSCalendar *_Nullable)calendar;
 
 - (NSDate *_Nonnull)date;
 - (void)setDate:(NSDate *_Nullable)date;

JTCalendar/JTCalendarManager.m

@@ -22,14 +22,35 @@ - (instancetype)initWithLocale:(NSLocale *)locale andTimeZone:(NSTimeZone *)time
     if(!self){
         return nil;
     }
-    [self commonInit:locale andTimeZone:timeZone];
+
+#ifdef __IPHONE_8_0
+    NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
+#else
+    NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
+#endif
+
+    calendar.timeZone = timeZone;
+    calendar.locale = locale;
+
+    [self commonInit:calendar];
+
+    return self;
+}
+
+- (instancetype _Nullable )initWithCalendar:(NSCalendar *_Nullable)calendar
+{
+    self = [super init];
+    if(!self){
+        return nil;
+    }
+    [self commonInit:calendar];
 
     return self;
 }
 
-- (void)commonInit:(NSLocale *)locale andTimeZone:(NSTimeZone *)timeZone
+- (void)commonInit:(NSCalendar *)calendar
 {
-    _dateHelper = [[JTDateHelper alloc] initWithLocale:locale andTimeZone:timeZone];
+    _dateHelper = [[JTDateHelper alloc] initWithCalendar:calendar];
     _settings = [JTCalendarSettings new];
 
     _delegateManager = [JTCalendarDelegateManager new];

JTCalendar/JTDateHelper.h

@@ -9,7 +9,7 @@
 
 @interface JTDateHelper : NSObject
 
-- initWithLocale:(NSLocale *)locale andTimeZone:(NSTimeZone *)timeZone;
+- initWithCalendar:(NSCalendar *)calendar;
 
 - (NSCalendar *)calendar;
 - (NSDateFormatter *)createDateFormatter;

JTCalendar/JTDateHelper.m

@@ -9,39 +9,21 @@
 
 @interface JTDateHelper (){
     NSCalendar *_calendar;
-    NSLocale *_locale;
-    NSTimeZone *_timeZone;
 }
 
 @end
 
 @implementation JTDateHelper
 
-- (instancetype)initWithLocale:(NSLocale *)locale andTimeZone:(NSTimeZone *)timeZone
+- (instancetype)initWithCalendar:(NSCalendar *)calendar
 {
     self = [super init];
     if (self) {
-        _locale = locale;
-        _timeZone = timeZone;
+        _calendar = calendar;
     }
     return self;
 }
 
-- (NSCalendar *)calendar
-{
-    if(!_calendar){
-#ifdef __IPHONE_8_0
-        _calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
-#else
-        _calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
-#endif
-        _calendar.timeZone = _timeZone;
-        _calendar.locale = _locale;
-    }
-
-    return _calendar;
-}
-
 - (NSDateFormatter *)createDateFormatter
 {
     NSDateFormatter *dateFormatter = [NSDateFormatter new];
@@ -52,6 +34,10 @@ - (NSDateFormatter *)createDateFormatter
     return dateFormatter;
 }
 
+- (NSCalendar *)calendar {
+    return _calendar;
+}
+
 #pragma mark - Operations
 
 - (NSDate *)addToDate:(NSDate *)date months:(NSInteger)months