Increased date time adapter compatibility

projects/picker/src/lib/date-time/adapter/date-time-adapter.class.ts

@@ -34,6 +34,9 @@ export abstract class DateTimeAdapter<T> {
         return this._localeChanges;
     }
 
+	public firstMonthOfTheYear: number;
+	public firstDayOfTheWeek: number;
+
     /** total milliseconds in a day. */
     protected readonly millisecondsInDay = 86400000;
 

projects/picker/src/lib/date-time/adapter/native-date-time-adapter.class.ts

@@ -26,6 +26,9 @@ const ISO_8601_REGEX = /^\d{4}-\d{2}-\d{2}(?:T\d{2}:\d{2}:\d{2}(?:\.\d+)?(?:Z|(?
 
 @Injectable()
 export class NativeDateTimeAdapter extends DateTimeAdapter<Date> {
+ 	public firstMonthOfTheYear: number = 0;
+ 	public firstDayOfTheWeek: number = 0;
+
     /** Whether to clamp the date between 1 and 9999 to avoid IE and Edge errors. */
     private readonly _clampDate: boolean;
 

projects/picker/src/lib/date-time/adapter/unix-timestamp-adapter/unix-timestamp-date-time-adapter.class.ts

@@ -11,7 +11,9 @@ import {DEFAULT_DATE_NAMES, DEFAULT_DAY_OF_WEEK_NAMES, DEFAULT_MONTH_NAMES, SUPP
 
 @Injectable()
 export class UnixTimestampDateTimeAdapter extends DateTimeAdapter<number> {
-
+	public firstMonthOfTheYear: number = 0;
+	public firstDayOfTheWeek: number = 0;
+
     constructor(
         @Optional()
         @Inject(OWL_DATE_TIME_LOCALE)

projects/picker/src/lib/date-time/calendar-month-view.component.ts

@@ -480,8 +480,8 @@ export class OwlMonthViewComponent<T>
         });
 
         this._weekdays = weekdays
-            .slice(firstDayOfWeek)
-            .concat(weekdays.slice(0, firstDayOfWeek));
+            .slice(firstDayOfWeek-this.dateTimeAdapter.firstDayOfTheWeek)
+            .concat(weekdays.slice(0, firstDayOfWeek-this.dateTimeAdapter.firstDayOfTheWeek));
 
         this.dateNames = this.dateTimeAdapter.getDateNames();
 

projects/picker/src/lib/date-time/calendar-multi-year-view.component.ts

@@ -253,7 +253,7 @@ export class OwlMultiYearViewComponent<T> implements OnInit, AfterContentInit {
     }
 
     private selectYear( year: number ): void {
-        this.yearSelected.emit(this.dateTimeAdapter.createDate(year, 0, 1));
+        this.yearSelected.emit(this.dateTimeAdapter.createDate(year, this.dateTimeAdapter.firstMonthOfTheYear, 1));
         const firstDateOfMonth = this.dateTimeAdapter.createDate(
             year,
             this.dateTimeAdapter.getMonth(this.pickerMoment),
@@ -395,7 +395,7 @@ export class OwlMultiYearViewComponent<T> implements OnInit, AfterContentInit {
      * Creates an CalendarCell for the given year.
      */
     private createYearCell( year: number ): CalendarCell {
-        const startDateOfYear = this.dateTimeAdapter.createDate(year, 0, 1);
+        const startDateOfYear = this.dateTimeAdapter.createDate(year, this.dateTimeAdapter.firstMonthOfTheYear, 1);
         const ariaLabel = this.dateTimeAdapter.getYearName(startDateOfYear);
         const cellClass = 'owl-dt-year-' + year;
         return new CalendarCell(year, year.toString(), ariaLabel, this.isYearEnabled(year), false, cellClass);
@@ -434,7 +434,7 @@ export class OwlMultiYearViewComponent<T> implements OnInit, AfterContentInit {
             return true;
         }
 
-        const firstOfYear = this.dateTimeAdapter.createDate(year, 0, 1);
+        const firstOfYear = this.dateTimeAdapter.createDate(year, this.dateTimeAdapter.firstMonthOfTheYear, 1);
 
         // If any date in the year is enabled count the year as enabled.
         for (let date = firstOfYear; this.dateTimeAdapter.getYear(date) === year;

projects/picker/src/lib/date-time/calendar-year-view.component.ts

@@ -407,7 +407,7 @@ export class OwlYearViewComponent<T>
             const row = [];
 
             for (let j = 0; j < MONTHS_PER_ROW; j++) {
-                const month = j + i * MONTHS_PER_ROW;
+                const month = j + i * MONTHS_PER_ROW + this.dateTimeAdapter.firstMonthOfTheYear;
                 const monthCell = this.createMonthCell(month);
                 row.push(monthCell);
             }
@@ -434,7 +434,7 @@ export class OwlYearViewComponent<T>
         const cellClass = 'owl-dt-month-' + month;
         return new CalendarCell(
             month,
-            this.monthNames[month],
+            this.monthNames[month-this.dateTimeAdapter.firstMonthOfTheYear],
             ariaLabel,
             this.isMonthEnabled(month),
             false,