/*
 * [BlackFriday.java]
 *
 * Summary: Calculate when American Black Friday occurs.
 *
 * 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:
 *  1.0 2009-11-23 initial version
 */
package com.mindprod.holidays;

import com.mindprod.common18.BigDate;

/**
 * Calculate when American Black Friday occurs.
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 1.0 2009-11-23 initial version
 * @since 2009-11-23
 */
public final class BlackFriday extends HolInfo
    {
    /**
     * @inheritDoc
     */
    public String getAuthority()
        {
        return "http://en.wikipedia.org/wiki/Black_Friday_(shopping)";
        }

    /**
     * @inheritDoc
     */
    public int getFirstYear( int base )
        {
        return 1960;
        }

    /**
     * @inheritDoc
     */
    public String getName()
        {
        return "Black Friday";
        }

    /**
     * @inheritDoc
     */
    public String getRule()
        {
        return "Friday after American Thanksgiving. Start of Christmas shopping spree.";
        }

    /**
     * @inheritDoc
     */
    public int when( int year, boolean shift, int base )
        {
        if ( !isYearValid( year, base ) )
            {
            return BigDate.NULL_ORDINAL;
            }
        if ( year < 1960 )
            {
            return BigDate.NULL_ORDINAL;
            }
        // day after Thanksgiving Thursday
        return BigDate.ordinalOfnthXXXDay( 4/* fourth */, BigDate.THURSDAY, year, BigDate.NOV ) + 1;
        } // end when.
    }