// -----------------------------------------------------------------------------
// MonthView.java
// -----------------------------------------------------------------------------

/*
 * =============================================================================
 * Copyright (c) 1998-2007 Jeffrey M. Hunter. All rights reserved.
 * 
 * All source code and material located at the Internet address of
 * http://www.idevelopment.info is the copyright of Jeffrey M. Hunter and
 * is protected under copyright laws of the United States. This source code may
 * not be hosted on any other site without my express, prior, written
 * permission. Application to host any of the material elsewhere can be made by
 * contacting me at jhunter@idevelopment.info.
 *
 * I have made every effort and taken great care in making sure that the source
 * code and other content included on my web site is technically accurate, but I
 * disclaim any and all responsibility for any loss, damage or destruction of
 * data or any other property which may arise from relying on it. I will in no
 * case be liable for any monetary damages arising from such loss, damage or
 * destruction.
 * 
 * As with any code, ensure to test this code in a development environment 
 * before attempting to run it in production.
 * =============================================================================
 */

import java.util.*;
import java.text.*;

/**
 * -----------------------------------------------------------------------------
 * Used to provide an example of several Date features used to produce a
 * convenient view of a month in compact form.
 * 
 * @version 1.0
 * @author  Jeffrey M. Hunter  (jhunter@idevelopment.info)
 * @author  http://www.idevelopment.info
 * -----------------------------------------------------------------------------
 */
 
public class MonthView {

    /** List names of the month */
    public final static String[] months = {
        "January" , "February" , "March",
        "April"   , "May"      , "June",
        "July"    , "August"   , "September",
        "October" , "November" , "December"
    };


    /** List the days in each month */
    public final static int dom[] = {
        31, 28, 31,  /* jan, feb, mar */
        30, 31, 30,  /* apr, may, jun */
        31, 31, 30,  /* jul, aug, sep */
        31, 30, 31   /* oct, nov, dec */
    };


    /**
     * Helper utility used to print
     * a String to STDOUT.
     * @param s String that will be printed to STDOUT.
     */
    private void printMonth(int mm, int yy) {

        // The number of days to leave blank at
        // the start of this month.
        int leadSpaces = 0;

        System.out.println();
        System.out.println("  " + months[mm] + " " + yy);

        if (mm < 0 || mm > 11) {
            throw new IllegalArgumentException(
                "Month " + mm + " bad, must be 0-11");
        }

        GregorianCalendar cal = new GregorianCalendar(yy, mm, 1);

        System.out.println("Su Mo Tu We Th Fr Sa");

        // Compute how much to leave before before the first day of the month.
        // getDay() returns 0 for Sunday.
        leadSpaces = cal.get(Calendar.DAY_OF_WEEK)-1;

        int daysInMonth = dom[mm];

        if (cal.isLeapYear(cal.get(Calendar.YEAR)) && mm == 1) {
            ++daysInMonth;
        }

        // Blank out the labels before 1st day of the month
        for (int i = 0; i < leadSpaces; i++) {
            System.out.print("   ");
        }

        for (int i = 1; i <= daysInMonth; i++) {

            // This "if" statement is simpler than messing with NumberFormat
            if (i<=9) {
                System.out.print(" ");
            }
            System.out.print(i);

            if ((leadSpaces + i) % 7 == 0) { // Wrap if EOL
                System.out.println();
            } else {
                System.out.print(" ");
            }

        }
        System.out.println();
    }



    /**
     * Sole entry point to the class and application.
     * @param args Array of String arguments.
     */
    public static void main(String[] args) {

        int month, year;

        MonthView mv = new MonthView();

        if (args.length == 2) {
            mv.printMonth(Integer.parseInt(args[0])-1, Integer.parseInt(args[1]));
        } else {
            Calendar today = Calendar.getInstance();
            mv.printMonth(today.get(Calendar.MONTH), today.get(Calendar.YEAR));
        }

    }

}