//Copyright (c) 2011 Kenneth Evans
//
//Permission is hereby granted, free of charge, to any person obtaining
//a copy of this software and associated documentation files (the
//"Software"), to deal in the Software without restriction, including
//without limitation the rights to use, copy, modify, merge, publish,
//distribute, sublicense, and/or sell copies of the Software, and to
//permit persons to whom the Software is furnished to do so, subject to
//the following conditions:
//
//The above copyright notice and this permission notice shall be included
//in all copies or substantial portions of the Software.
//
//THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
//EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
//MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
//IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
//CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
//TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
//SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

package net.kenevans.dilbert;

import java.util.Calendar;
import java.util.Date;

/**
 * Class to manage a day represented by the year, month, and day-of-the-month.
 * These values are defines as for a Calendar. That is, the month starts with 0
 * for January.
 * 
 * @see java.util.Calendar
 */
class CalendarDay implements Comparable<CalendarDay>
{
    public int year;
    public int month;
    public int day;

    /**
     * Constructor.
     * 
     * @param year
     * @param month
     * @param day
     */
    public CalendarDay(int year, int month, int day) {
        set(year, month, day);
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString() {
        // Note the month starts with 1 for the string output
        return String.format("%04d-%02d-%02d", year, month + 1, day);
    }

    /**
     * Get the Date corresponding to this instance.
     * 
     * @return
     */
    public Date getDate() {
        Calendar cal = getCalendar();
        return cal.getTime();
    }

    /**
     * Set the values for this instance from the given Date.
     * 
     * @param date
     */
    public void set(Date date) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        set(cal);
    }

    /**
     * Get the Calendar corresponding to this instance.
     * 
     * @return
     */
    public Calendar getCalendar() {
        Calendar cal = Calendar.getInstance();
        cal.set(Calendar.MILLISECOND, 0);
        cal.set(year, month, day, 0, 0, 0);
        return cal;
    }

    /**
     * Set the values for this instance from the given Calendar.
     * 
     * @param cal
     */
    public void set(Calendar cal) {
        year = cal.get(Calendar.YEAR);
        month = cal.get(Calendar.MONTH);
        day = cal.get(Calendar.DAY_OF_MONTH);
    }

    /**
     * Sets the values for this instance. The MILLISECOND field is set to 0.
     * 
     * @param year
     * @param month
     * @param day
     */
    public void set(int year, int month, int day) {
        // Use the Calendar to recalculate the fields
        Calendar cal = Calendar.getInstance();
        cal.set(Calendar.MILLISECOND, 0);
        cal.set(year, month, day, 0, 0, 0);
        set(cal);
    }

    /**
     * Returns a new CalendarDay with its values incremented by the specified
     * number of days from this one. If the amount is negative, it decrements
     * the values. The year, month, and day will be adjusted to proper values.
     * (Dec 31, 2012 incremented by 1 is Jan 1, 2013.)
     * 
     * @param number The amount by which to increment.
     */
    public CalendarDay incrementDay(int number) {
        return new CalendarDay(year, month, day + number);
    }

    /**
     * Returns a CalendarDay representing the current day.
     * 
     * @return
     */
    public static CalendarDay now() {
        Calendar cal = Calendar.getInstance();
        int year = cal.get(Calendar.YEAR);
        int month = cal.get(Calendar.MONTH);
        int day = cal.get(Calendar.DAY_OF_MONTH);
        return new CalendarDay(year, month, day);
    }

    /**
     * Returns a CalendarDay representing the first strip, which was on on April
     * 16, 1989.
     * 
     * @return
     */
    public static CalendarDay first() {
        return new CalendarDay(1989, 3, 16);
    }

    public int compareTo(CalendarDay cDay) {
        // Note that we could probably use Calendar.before() here,
        // provided the hour, min, sec, and MILLISECONDS are zeroed.
        // This way assumes the two CalendarDays are normalized correctly.
        if(year < cDay.year) {
            return -1;
        }
        if(year > cDay.year) {
            return 1;
        }
        // Years are the same
        if(month < cDay.month) {
            return -1;
        }
        if(month > cDay.month) {
            return 1;
        }
        // Months are the same
        if(day < cDay.day) {
            return -1;
        }
        if(day > cDay.day) {
            return 1;
        }
        return 0;
    }

}