/*
 * [IsHoliday.java]
 *
 * Summary: Find out if there is any holiday/celebration on a given date.
 *
 * Copyright: (c) 1999-2017 Roedy Green, Canadian Mind Products, http://mindprod.com
 *
 * Licence: This software may be copied and used freely for any purpose but military.
 *          http://mindprod.com/contact/nonmil.html
 *
 * Requires: JDK 1.8+
 *
 * Created with: JetBrains IntelliJ IDEA IDE http://www.jetbrains.com/idea/
 *
 * Version History:
 *  4.2 2008-12-03 add World AIDS day
 */
package com.mindprod.holidays;

import com.mindprod.common18.BigDate;

import static java.lang.System.*;

/**
 * Find out if there is any holiday/celebration on a given date.
 * <p/>
 * Lets you easily define a set of holidays, then rapidly determine if any given date is a holiday. It is quite easy to
 * specify which days you want considered holidays using methods like addHoliday where you specify the date or the name
 * of the Holiday, addAmericanFederalHolidays and addWeekDaysAsHolidays.
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 4.2 2008-12-03 add World AIDS day
 * @since 1999
 */
public final class IsHoliday
    {
    /**
     * true if debugging
     *
     * @noinspection WeakerAccess
     */
    static final boolean DEBUGGING = false;

    /**
     * ordinal of Jan 1 of first year to compute holidays.
     *
     * @noinspection WeakerAccess
     */
    protected int firstOrd;

    /**
     * First year in range to compute holidays.
     *
     * @noinspection WeakerAccess
     */
    protected int firstYear;

    /**
     * ordinal of Dec 31 of last year to compute holidays.
     *
     * @noinspection WeakerAccess
     */
    protected int lastOrd;

    /**
     * Last year in range to compute holidays.
     *
     * @noinspection WeakerAccess
     */
    protected int lastYear;

    /**
     * corresponding bit is true means day is a holiday.
     *
     * @noinspection WeakerAccess
     */
    protected java.util.BitSet holidayBits;

    /**
     * Constructor to define range of years over which we wish to compute holidays.
     *
     * @param firstYear first year to cover, must be > 0
     * @param lastYear  last year to cover
     *
     * @noinspection SameParameterValue, WeakerAccess, SameParameterValue, WeakerAccess
     */
    public IsHoliday( int firstYear, int lastYear )
        {
        // avoid problem of non-existent year 0, only support AD
        if ( firstYear < 1 )
            {
            throw new IllegalArgumentException( "firstYear="
                                                + firstYear
                                                + " must be > 0." );
            }
        if ( lastYear > BigDate.MAX_YEAR )
            {
            throw new IllegalArgumentException( "lastYear="
                                                + lastYear
                                                + " must be <= "
                                                + BigDate
                                                        .MAX_YEAR
                                                + "." );
            }
        if ( lastYear < firstYear )
            {
            throw new IllegalArgumentException( "firstYear="
                                                + firstYear
                                                + " must be <= lastYear="
                                                + lastYear
                                                + "." );
            }
        this.firstYear = firstYear;
        this.lastYear = lastYear;
        firstOrd = BigDate.toOrdinal( firstYear, 1, 1 );
        lastOrd = BigDate.toOrdinal( lastYear, 12, 31 );
        // starts off all zeros, nothing is declared a holiday yet
        holidayBits = new java.util.BitSet( lastOrd - firstOrd + 1 );
        } // end constructor

    /**
     * test driver
     *
     * @param args not used
     */
    public static void main( String[] args )
        {
        if ( DEBUGGING )
            {
            // prepare list of holidays
            IsHoliday h = new IsHoliday( 1990, 2010 );
            h.addWeekendsAsHolidays();
            // add nearest weekday to the actual holiday, shift=true
            h.addAmericanFederalHolidays( HolInfo.SHIFTED );
            for ( int year = 1990; year <= 2010; year++ )
                {
                h.addHoliday( new GroundhogDay().when( year,
                        HolInfo.SHIFTED,
                        HolInfo.PROCLAIMED ) );
                h.addHoliday( new GeneralElectionDay().when( year,
                        HolInfo.SHIFTED,
                        HolInfo.PROCLAIMED ) );
                } // end for
            // declare New Year's eve for the millennium a holiday
            h.addHoliday( BigDate.toOrdinal( 1999, 12, 31 ) );
            // test if any given day is a holiday
            out.println( "Today "
                         + ( h.isHoliday( BigDate.localToday() )
                             ? "is"
                             : "is not" )
                         + " a holiday." );
            out.println( "2005-12-25 "
                         + ( h.isHoliday( BigDate.toOrdinal( 2005,
                    12,
                    25 ) )
                             ? "is"
                             : "is not" )
                         + " a holiday." );
            // count business days
            int startOrd = BigDate.toOrdinal( 1999, 1, 1 );
            int endOrd = BigDate.toOrdinal( 1999, 12, 31 );
            int count = 0;
            for ( int i = startOrd; i <= endOrd; i++ )
                {
                if ( !h.isHoliday( i ) )
                    {
                    count++;
                    }
                }
            out.println( "There were "
                         + count
                         + " business days in 1999" );
            } // end if
        } // end main

    /**
     * add all American Federal holidays To get a list of US Federal Statutory holidays see:
     * http://www.opm.gov/fedhol/1999.htm or http://aa.usno.navy.mil/AA/faq/docs/holidays.html.
     *
     * @param shift shift ACTUAL = false if you want the actual date of the holiday. SHIFTED = true if you want the date
     *              taken off work, usually the nearest weekday.
     *
     * @noinspection SameParameterValue, WeakerAccess, SameParameterValue, WeakerAccess
     */
    public void addAmericanFederalHolidays( boolean shift )
        {
        for ( int year = firstYear; year <= lastYear; year++ )
            {
            addHoliday( new NewYearsDay()
                    .when( year, shift, HolInfo.PROCLAIMED ) );
            addHoliday( new MartinLutherKingDay().when( year,
                    shift,
                    HolInfo.PROCLAIMED ) );
            // now obsolete, code handles switchover
            addHoliday( new LincolnsBirthday().when( year,
                    shift,
                    HolInfo.PROCLAIMED ) );
            addHoliday( new PresidentsDay().when( year,
                    shift,
                    HolInfo.PROCLAIMED ) );
            // now obsolete, code handles switchover
            addHoliday( new WashingtonsBirthday().when( year,
                    shift,
                    HolInfo.PROCLAIMED ) );
            addHoliday( new MemorialDay()
                    .when( year, shift, HolInfo.PROCLAIMED ) );
            addHoliday( new IndependenceDay().when( year,
                    shift,
                    HolInfo.PROCLAIMED ) );
            addHoliday( new LaborDay().when( year,
                    shift,
                    HolInfo.PROCLAIMED ) );
            addHoliday( new ColumbusDay()
                    .when( year, shift, HolInfo.PROCLAIMED ) );
            addHoliday( new VeteransDay()
                    .when( year, shift, HolInfo.PROCLAIMED ) );
            addHoliday( new AmericanThanksgiving().when( year,
                    shift,
                    HolInfo.PROCLAIMED ) );
            addHoliday( new Christmas().when( year,
                    shift,
                    HolInfo.PROCLAIMED ) );
            } // end for
        }/* end addAmericanFederalHolidays */

    /**
     * add all Canadian Federal holidays To get a list of US Federal Statutory holidays see:
     * http://www.opm.gov/fedhol/1999.htm or http://aa.usno.navy.mil/AA/faq/docs/holidays.html.
     *
     * @param shift shift ACTUAL = false if you want the actual date of the holiday. SHIFTED = true if you want the date
     *              taken off work, usually the nearest weekday.
     */
    public void addCanadianFederalHolidays( boolean shift )
        {
        for ( int year = firstYear; year <= lastYear; year++ )
            {
            /* want shifted days that you take the day off if falls on a weekend */
            addHoliday( new NewYearsDay()
                    .when( year, shift, HolInfo.PROCLAIMED ) );
            addHoliday( new GoodFriday().when( year,
                    shift,
                    HolInfo.PROCLAIMED ) );
            addHoliday( new EasterMonday().when( year,
                    shift,
                    HolInfo.PROCLAIMED ) );
            addHoliday( new VictoriaDay().when( year, shift ) );
            addHoliday( new CanadaDay().when( year,
                    shift,
                    HolInfo.PROCLAIMED ) );
            addHoliday( new LabourDay().when( year,
                    shift,
                    HolInfo.PROCLAIMED ) );
            addHoliday( new CanadianThanksgiving().when( year,
                    shift,
                    HolInfo.PROCLAIMED ) );
            addHoliday( new RemembranceDay().when( year,
                    shift,
                    HolInfo.PROCLAIMED ) );
            addHoliday( new Christmas().when( year,
                    shift,
                    HolInfo.PROCLAIMED ) );
            addHoliday( new BoxingDay().when( year,
                    shift,
                    HolInfo.PROCLAIMED ) );
            } // end for
        }/* end addCanadianFederalHolidays */

    /**
     * add another holiday to the holiday table.
     *
     * @param ordinal day to add as a holiday measured in days since 1970-01-01. Note you must add it once for each
     *                year in the range. We do not presume it falls the same day each year.
     *
     * @noinspection WeakerAccess
     */
    public void addHoliday( int ordinal )
        {
        if ( ordinal < firstOrd || ordinal > lastOrd )
            {
            // just ignore out of range or NULL_ORDINAL.
            // It is possible for shifted dates to wander a tad out of range.
            return;
            }
        holidayBits.set( ordinal - firstOrd );
        } // end addHoliday

    /**
     * add all Saturdays and Sundays in the year range as holidays
     *
     * @noinspection WeakerAccess
     */
    public void addWeekendsAsHolidays()
        {
        int ordFirstSunday = BigDate.ordinalOfnthXXXDay( 1/* first */, BigDate.SUNDAY, firstYear, BigDate.JAN );
        for ( int i = ordFirstSunday; i <= lastOrd; i += 7 )
            {
            addHoliday( i );
            } // end for
        int ordFirstSaturday = BigDate.ordinalOfnthXXXDay( 1/* first */, BigDate.SATURDAY, firstYear, BigDate.JAN );
        for ( int i = ordFirstSaturday; i <= lastOrd; i += 7 )
            {
            addHoliday( i );
            } // end for
        }/* end addWeekendsAsHolidays */

    /**
     * get first year in range to compute the holidays.
     *
     * @return year yyyy.
     */
    public int getFirstYear()
        {
        return firstYear;
        }

    /**
     * Get last year in range to compute holidays.
     *
     * @return year YYYY.
     */
    public int getLastYear()
        {
        return lastYear;
        }

    /**
     * Is the given day a holiday? What constitutes a holiday is determined by the setHoliday calls
     *
     * @param bigDate date to test
     *
     * @return true if that day is a holiday
     * @noinspection WeakerAccess
     */
    public boolean isHoliday( BigDate bigDate )
        {
        return isHoliday( bigDate.getOrdinal() );
        } // end isHoliday

    /**
     * Is the given day a holiday? What constitutes a holiday is determined by the setHoliday calls
     *
     * @param ordinal days since 1970-01-01
     *
     * @return true if that day is a holiday.
     * @noinspection WeakerAccess
     */
    public boolean isHoliday( int ordinal )
        {
        if ( ordinal < firstOrd || ordinal > lastOrd )
            {
            throw new IllegalArgumentException( "out of range ordinal date: "
                                                + ordinal );
            }
        return holidayBits.get( ordinal - firstOrd );
        } // end isHoliday
    }