/*

  * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.  Oracle designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Oracle in the LICENSE file that accompanied this code.

  *

  * This code 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

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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  */

 package java.text;

 import java.util.Calendar;

 import static java.util.GregorianCalendar.*;

 /**

  * {@code CalendarBuilder} keeps field-value pairs for setting

  * the calendar fields of the given {@code Calendar}. It has the

  * {@link Calendar#FIELD_COUNT FIELD_COUNT}-th field for the week year

  * support. Also {@code ISO_DAY_OF_WEEK} is used to specify

  * {@code DAY_OF_WEEK} in the ISO day of week numbering.

  *

  * <p>{@code CalendarBuilder} retains the semantic of the pseudo

  * timestamp for fields. {@code CalendarBuilder} uses a single

  * int array combining fields[] and stamp[] of {@code Calendar}.

  *

  * @author Masayoshi Okutsu

  */

 class CalendarBuilder {

     /*

      * Pseudo time stamp constants used in java.util.Calendar

      */

     private static final int UNSET = 0;

     private static final int COMPUTED = 1;

     private static final int MINIMUM_USER_STAMP = 2;

     private static final int MAX_FIELD = FIELD_COUNT + 1;

     public static final int WEEK_YEAR = FIELD_COUNT;

     public static final int ISO_DAY_OF_WEEK = 1000; // pseudo field index

     // stamp[] (lower half) and field[] (upper half) combined

     private final int[] field;

     private int nextStamp;

     private int maxFieldIndex;

     CalendarBuilder() {

         field = new int[MAX_FIELD * 2];

         nextStamp = MINIMUM_USER_STAMP;

         maxFieldIndex = -1;

     }

     CalendarBuilder set(int index, int value) {

         if (index == ISO_DAY_OF_WEEK) {

             index = DAY_OF_WEEK;

             value = toCalendarDayOfWeek(value);

         }

         field[index] = nextStamp++;

         field[MAX_FIELD + index] = value;

         if (index > maxFieldIndex && index < FIELD_COUNT) {

             maxFieldIndex = index;

         }

         return this;

     }

     CalendarBuilder addYear(int value) {

         field[MAX_FIELD + YEAR] += value;

         field[MAX_FIELD + WEEK_YEAR] += value;

         return this;

     }

     boolean isSet(int index) {

         if (index == ISO_DAY_OF_WEEK) {

             index = DAY_OF_WEEK;

         }

         return field[index] > UNSET;

     }

     Calendar establish(Calendar cal) {

         boolean weekDate = isSet(WEEK_YEAR)

                             && field[WEEK_YEAR] > field[YEAR];

         if (weekDate && !cal.isWeekDateSupported()) {

             // Use YEAR instead

             if (!isSet(YEAR)) {

                 set(YEAR, field[MAX_FIELD + WEEK_YEAR]);

             }

             weekDate = false;

         }

         cal.clear();

         // Set the fields from the min stamp to the max stamp so that

         // the field resolution works in the Calendar.

         for (int stamp = MINIMUM_USER_STAMP; stamp < nextStamp; stamp++) {

             for (int index = 0; index <= maxFieldIndex; index++) {

                 if (field[index] == stamp) {

                     cal.set(index, field[MAX_FIELD + index]);

                     break;

                 }

             }

         }

         if (weekDate) {

             int weekOfYear = isSet(WEEK_OF_YEAR) ? field[MAX_FIELD + WEEK_OF_YEAR] : 1;

             int dayOfWeek = isSet(DAY_OF_WEEK) ?

                                 field[MAX_FIELD + DAY_OF_WEEK] : cal.getFirstDayOfWeek();

             if (!isValidDayOfWeek(dayOfWeek) && cal.isLenient()) {

                 if (dayOfWeek >= 8) {

                     dayOfWeek--;

                     weekOfYear += dayOfWeek / 7;

                     dayOfWeek = (dayOfWeek % 7) + 1;

                 } else {

                     while (dayOfWeek <= 0) {

                         dayOfWeek += 7;

                         weekOfYear--;

                     }

                 }

                 dayOfWeek = toCalendarDayOfWeek(dayOfWeek);

             }

             cal.setWeekDate(field[MAX_FIELD + WEEK_YEAR], weekOfYear, dayOfWeek);

         }

         return cal;

     }

     public String toString() {

         StringBuilder sb = new StringBuilder();

         sb.append("CalendarBuilder:[");

         for (int i = 0; i < field.length; i++) {

             if (isSet(i)) {

                 sb.append(i).append('=').append(field[MAX_FIELD + i]).append(',');

             }

         }

         int lastIndex = sb.length() - 1;

         if (sb.charAt(lastIndex) == ',') {

             sb.setLength(lastIndex);

         }

         sb.append(']');

         return sb.toString();

     }

     static int toISODayOfWeek(int calendarDayOfWeek) {

         return calendarDayOfWeek == SUNDAY ? 7 : calendarDayOfWeek - 1;

     }

     static int toCalendarDayOfWeek(int isoDayOfWeek) {

         if (!isValidDayOfWeek(isoDayOfWeek)) {

             // adjust later for lenient mode

             return isoDayOfWeek;

         }

         return isoDayOfWeek == 7 ? SUNDAY : isoDayOfWeek + 1;

     }

     static boolean isValidDayOfWeek(int dayOfWeek) {

         return dayOfWeek > 0 && dayOfWeek <= 7;

     }

 }