/*

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

/**

 * RuleDay class represents the value of the "ON" field.  The day of

 * week values start from 1 following the {@link java.util.Calendar}

 * convention.

 *

 * @since 1.4

 */

class RuleDay {

    private static final Map<String,DayOfWeek> abbreviations = new HashMap<String,DayOfWeek>(7);

    static {

        for (DayOfWeek day : DayOfWeek.values()) {

            abbreviations.put(day.getAbbr(), day);

        }

    }

    private String dayName = null;

    private DayOfWeek dow;

    private boolean lastOne = false;

    private int soonerOrLater = 0;

    private int thanDayOfMonth; // day of month (e.g., 8 for "Sun>=8")

    RuleDay() {

    }

    RuleDay(int day) {

        thanDayOfMonth = day;

    }

    int getDay() {

        return thanDayOfMonth;

    }

    /**

     * @return the day of week value (1-based)

     */

    int getDayOfWeekNum() {

        return dow.value();

    }

    /**

     * @return true if this rule day represents the last day of

     * week. (e.g., lastSun).

     */

    boolean isLast() {

        return lastOne;

    }

    /**

     * @return true if this rule day represents the day of week on or

     * later than (after) the {@link #getDay}. (e.g., Sun>=1)

     */

    boolean isLater() {

        return soonerOrLater > 0;

    }

    /**

     * @return true if this rule day represents the day of week on or

     * earlier than (before) the {@link #getDay}. (e.g., Sun<=15)

     */

    boolean isEarlier() {

        return soonerOrLater < 0;

    }

    /**

     * @return true if this rule day represents an exact day.

     */

    boolean isExact() {

        return soonerOrLater == 0;

    }

    /**

     * Parses the "ON" field and constructs a RuleDay.

     * @param day an "ON" field string (e.g., "Sun>=1")

     * @return a RuleDay representing the given "ON" field

     */

    static RuleDay parse(String day) {

        RuleDay d = new RuleDay();

        if (day.startsWith("last")) {

            d.lastOne = true;

            d.dayName = day.substring(4);

            d.dow = getDOW(d.dayName);

        } else {

            int index;

            if ((index = day.indexOf(">=")) != -1) {

                d.dayName = day.substring(0, index);

                d.dow = getDOW(d.dayName);

                d.soonerOrLater = 1; // greater or equal

                d.thanDayOfMonth = Integer.parseInt(day.substring(index+2));

            } else if ((index = day.indexOf("<=")) != -1) {

                d.dayName = day.substring(0, index);

                d.dow = getDOW(d.dayName);

                d.soonerOrLater = -1; // less or equal

                d.thanDayOfMonth = Integer.parseInt(day.substring(index+2));

            } else {

                // it should be an integer value.

                d.thanDayOfMonth = Integer.parseInt(day);

            }

        }

        return d;

    }

    /**

     * Converts this RuleDay to the SimpleTimeZone day rule.

     * @return the converted SimpleTimeZone day rule

     */

    int getDayForSimpleTimeZone() {

        if (isLast()) {

            return -1;

        }

        return isEarlier() ? -getDay() : getDay();

    }

    /**

     * Converts this RuleDay to the SimpleTimeZone day-of-week rule.

     * @return the SimpleTimeZone day-of-week rule value

     */

    int getDayOfWeekForSimpleTimeZoneInt() {

        if (isEarlier() || isLater()) {

            return -getDayOfWeekNum();

        }

        return isLast() ? getDayOfWeekNum() : 0;

    }

    /**

     * @return the string representation of the {@link

     * #getDayOfWeekForSimpleTimeZoneInt} value

     */

    String getDayOfWeekForSimpleTimeZone() {

        int d = getDayOfWeekForSimpleTimeZoneInt();

        if (d == 0) {

            return "0";

        }

        String sign = "";

        if (d < 0) {

            sign = "-";

            d = -d;

        }

        return sign + toString(d);

    }

    private static DayOfWeek getDOW(String abbr) {

        return abbreviations.get(abbr);

    }

    /**

     * Converts the specified day of week value to the day-of-week

     * name defined in {@link java.util.Calenda}.

     * @param dow 1-based day of week value

     * @return the Calendar day of week name with "Calendar." prefix.

     * @throws IllegalArgumentException if the specified dow value is out of range.

     */

    static String toString(int dow) {

        if (dow >= DayOfWeek.SUNDAY.value() && dow <= DayOfWeek.SATURDAY.value()) {

            return "Calendar." + DayOfWeek.values()[dow - 1];

        }

        throw new IllegalArgumentException("wrong Day_of_Week number: " + dow);

    }

}