package org.madore.damlengine;

import java.util.Map;
import java.util.HashMap;

public final class Calendar {

    public final static int monthTab[] = {
	-59, -28, 0, 31, 61, 92, 122, 153, 184, 214, 245, 275
    };

    public static long julianDateMarch1(int year) {
	return 1721120 + year*365 + year/4 - year/100 + year/400;
    }

    public static boolean isLeap(int year) {
	return (year%4==0) && ((!(year%100==0))||(year%400==0));
    }

    public static long julianDate(int year, int month, int day) {
	return julianDateMarch1(year)
	    + monthTab[month-1]
	    - ((month<=2 && isLeap(year))?1:0)
	    + (day-1);
    }

    public static int dateDowNumber(int year, int month, int day) {
	// 0 = Monday ... 6 = Sunday
	return (int)((julianDate(year, month, day))%7);
    }

    public final static String dowNamesEn[] = {
	"Monday", "Tuesday", "Wednesday", "Thursday",
	"Friday", "Saturday", "Sunday"
    };

    public final static String dowNamesFr[] = {
	"lundi", "mardi", "mercredi", "jeudi",
	"vendredi", "samedi", "dimanche"
    };

    public final static String dowNamesDe[] = {
	"Montag", "Dienstag", "Mittwoch", "Donnerstag",
	"Freitag", "Samstag", "Sonntag"
    };

    public final static String dowNamesIa[] = {
	"lunedi", "martedi", "mercuridi", "jovedi",
	"venerdi", "saturdi", "dominica"
    };

    public final static Map<String,String[]> dowNames;

    static {
	dowNames = new HashMap<String,String[]>();
	dowNames.put("en", dowNamesEn);
	dowNames.put("fr", dowNamesFr);
	dowNames.put("de", dowNamesDe);
	dowNames.put("ia", dowNamesIa);
    }

    public static String dowName(String lang, int dowNumber) {
	String[] dowNamesL = dowNames.get(lang);
	if ( dowNamesL == null )
	    return null;
	else
	    return dowNamesL[dowNumber];
    }

    public static String dateDowName(String lang,
				     int year, int month, int day) {
	int dowNumber = dateDowNumber(year, month, day);
	return dowName(lang, dowNumber);
    }

}