/*   DateSelector.java
 *   May 17, 2003
 *   Copyright (C) 2003 QuantumHyperSpace
 *   www.quantumhyperspace.com
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
 
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import java.text.*;
 
/** DateSelector provides a graphical user interface 
 *  for selection of a Date from a calendar. A calendar 
 *  is displayed for the current month. The user can 
 *  move the current month forward or in reverse. The 
 *  calling class should use the mthod getDate() or 
 *  getCalendar() to obtain a date. These methods will 
 *  wait until a date selection is confirmed. The 
 *  calling class can either use the Date or Gregoriran 
 *  Calendar object directly or request various string 
 *  or int value options of the selected month, day of 
 *  month, and year. A DateSelector can be initialized 
 *  with an optional string message. 
 *  How to use this class:
 *      DateSelector dateSelector = new DateSelector("Pick a Date");
 *      Date date = dateSelector.getDate();
 *   or
 *      Calendar calendar = dateSelector.getGregorianCalendar();
 *   or 
 *      Date date = new DateSelector("Select a Date").getDate();
 *   or 
 *      String message = "Select the Date you want to leave";
 *      Calendar calendar = new DateSelector(message).getGregorianCalendar();
 *
 *  @author Charles Bell
 *  @version May 17, 2003
 */
public class DateSelector extends JFrame implements ActionListener{
	
    private final String[] months = {"January","February",
            "March","April","May","June","July","August",
            "September","October","November","December"};
 
    private final String[] weekdays = {"Sunday","Monday",
            "Tuesday","Wednesday","Thursday","Friday","Saturday"};
 
    private boolean debug = false;
    private JLabel monthLabel; 
    private JLabel yearLabel; 
    private JPanel calendarPanel;
    private Font titleFont = new Font("SansSerif",Font.BOLD,20);
 
    protected int selectedDay = -1;
    protected int month = -1;
    protected int year = -1;
    protected String dateSelection = "";
    private String message = "";
    private boolean dateSelected = false;
 
    
    /**	Constructs a DateSelector.
    */
    public DateSelector(){
        super("Select a Date");
        init();
    }
    
    /**	Constructs a DateSelector using the string message.
    */
    public DateSelector(String message){
        super(message);
        init();
    }
 
    /**	Runs this as a demonstration application.
    */
    public static void main(String[] args){
        DateSelector dateSelector = new DateSelector("Select a Date");
        Date date = dateSelector.getDate();
        if (date != null){
            System.out.println("You selected " + DateFormat.getDateInstance().format(date));
            System.out.println("You selected " + DateFormat.getDateInstance().format(date));
            System.out.println("You selected " + dateSelector.getDateSelection());
            System.out.println("You selected year " + dateSelector.getYearSelection());
            System.out.println("You selected the month of " + dateSelector.getMonthSelection());
            System.out.println("Your selected day of week " + dateSelector.getSelectedDayOfWeek());
            System.out.println("Your selected day of month " + dateSelector.getDayOfMonthSelection());
            System.out.println("Your selected year number " + dateSelector.getSelectedYear());
            System.out.println("Your selected month index " + dateSelector.getSelectedMonth());
            System.out.println("Your selected day number " + dateSelector.getSelectedDay());
        }
        Calendar calendar = dateSelector.getGregorianCalendar();
        if (calendar != null){
            if (dateSelector.isOnWeekend(calendar)){
                System.out.println("Your selected date is on the week end.");
            }else{
                System.out.println("Your selected date is not on a week end.");
            }
            System.out.println("Era: " + calendar.get(Calendar.ERA));
            System.out.println("Year: " + calendar.get(Calendar.YEAR));
            System.out.println("Month index: " + calendar.get(Calendar.MONTH));
            System.out.println("Week of Year: " + calendar.get(Calendar.WEEK_OF_YEAR));
            System.out.println("Week of month: " + calendar.get(Calendar.WEEK_OF_MONTH));
            System.out.println("Date: " + calendar.get(Calendar.DATE));
            System.out.println("Day of month: " + calendar.get(Calendar.DAY_OF_MONTH));
            System.out.println("Day of month: " + calendar.get(Calendar.DAY_OF_YEAR));
            System.out.println("Day of week: " + calendar.get(Calendar.DAY_OF_WEEK));
            System.out.println("Day of week in month: "
                + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH));
        }else{
            System.out.println("No date was selected.");
        }
        System.exit(0);
        
    }
 
    /**	Initializes the graphical user interface. Sets up JPanel
     *	components to hold the "Prev" and "Next" buttons used to 
     *	move the desired month forward or reverse. Starts with 
     *	the current month. The column titles are added for each 
     *	day of the week.
     */
    public void init(){
        GregorianCalendar today = new GregorianCalendar();
        month = today.get(Calendar.MONTH);
        year = today.get(Calendar.YEAR);
        setDefaultCloseOperation(WindowConstants.HIDE_ON_CLOSE);
 
        JPanel controlPanel = new JPanel();
        controlPanel.setLayout(new GridLayout(3,1));
        JPanel top = new JPanel();
        JButton prevMonthButton = new JButton("Prev");
        JButton nextMonthButton = new JButton("Next");
        prevMonthButton.addActionListener(this);
        nextMonthButton.addActionListener(this);
        top.add(prevMonthButton);
        top.add(nextMonthButton);
 
        JPanel middle = new JPanel();
        monthLabel = new JLabel();
        yearLabel = new JLabel();
        monthLabel.setFont(titleFont); 
        yearLabel.setFont(titleFont); 
        middle.add(monthLabel);
        middle.add(new JLabel(" "));
        middle.add(yearLabel);
 
        JPanel bottom = new JPanel();
        bottom.setLayout(new GridLayout(1,7,5,5));
 
        bottom.add(new JLabel("Sun",SwingConstants.CENTER));
        bottom.add(new JLabel("Mon",SwingConstants.CENTER));
        bottom.add(new JLabel("Tue",SwingConstants.CENTER));
        bottom.add(new JLabel("Wed",SwingConstants.CENTER));
        bottom.add(new JLabel("Thu",SwingConstants.CENTER));
        bottom.add(new JLabel("Fri",SwingConstants.CENTER));
        bottom.add(new JLabel("Sat",SwingConstants.CENTER));
        controlPanel.add(top);
        controlPanel.add(middle);
        controlPanel.add(bottom);
 
        getContentPane().add(controlPanel,"North");
 
        calendarPanel = new JPanel();
        getContentPane().add(calendarPanel,"Center");
        updateCalendarDisplay(month, year);
        setLocationRelativeTo(null);
        pack();
        show();
    }
    
    /** Waits until a date is selected then returns
     *  the selected date as a Date object.
     *  Returns null if no date is selected.
     */
    public Date getDate(){
        Date date = null;
        while ((!dateSelected) && (isVisible())){
            try{
                Thread.sleep(100);
            }catch(InterruptedException ie){
                System.err.println("Sleep thread interrupted.");
            }
        }
        if (dateSelected) date = new GregorianCalendar(year, month, selectedDay).getTime();
        return date;
    }
    
    /** Waits until a date is selected then returns the 
     *  selected date as a GregorianCalendar object.
     *  Returns null if no date is selected.
     */
    public GregorianCalendar getGregorianCalendar(){
        GregorianCalendar calendar = null;
        while ((!dateSelected) && (isVisible())){
            try{
                Thread.sleep(100);
            }catch(InterruptedException ie){
                System.err.println("Sleep thread interrupted.");
            }
        }
        if (dateSelected) calendar = new GregorianCalendar(year, month, selectedDay);
        return calendar;
    }
    
	
    /**	Updates the calendar display according to the input month and year.
     *	The Calendar title is updated with the string value of the month 
     *	and year. A placeholder JButton is inserted into the columns not 
     *	used for the first and last week of the month. The gridlayout 
     *	changes depending on the number of weeks in the month.
     *	A JButton is added for each day of the month.
     */
    public void updateCalendarDisplay(int month, int year){
        if (debug) System.out.println("Debug:  Month: " + month + " Year: " + year);
        monthLabel.setText(months[month]); 
        yearLabel.setText(String.valueOf(year)); 
        calendarPanel.removeAll();
        GregorianCalendar today = new GregorianCalendar();
        GregorianCalendar firstDayOfMonth = new GregorianCalendar(year,month,1);
        GregorianCalendar lastDayOfMonth = new GregorianCalendar(year,month,firstDayOfMonth.getActualMaximum(Calendar.DAY_OF_MONTH));
        int weeksInMonth = lastDayOfMonth.get(Calendar.WEEK_OF_MONTH);
        if (debug) System.out.println("Debug:  weeksInMonth: " + weeksInMonth);
        calendarPanel.setLayout(new GridLayout(weeksInMonth,7,3,3));
        int firstDayInFirstWeek = firstDayOfMonth.get(Calendar.DAY_OF_WEEK);
        if (debug) System.out.println("Debug:  firstDayInFirstWeek: " + firstDayInFirstWeek);
        for (int i = 1;i<firstDayInFirstWeek;i++){
            JButton blank = new JButton("--");
            blank.setEnabled(false);
            calendarPanel.add(blank);
        }
        /* Since the roll function starts over, 
         * have to do all but the last day 
         * and do last day outside of for loop.
         */
        for (GregorianCalendar currentDay = firstDayOfMonth;!currentDay.equals(lastDayOfMonth) ;currentDay.roll(Calendar.DAY_OF_MONTH,1)){
            JButton nextButton = new JButton(String.valueOf(currentDay.get(Calendar.DAY_OF_MONTH)));
            if (isOnWeekend(currentDay)) nextButton.setForeground(Color.blue);
            if (compare(currentDay,today)) nextButton.setForeground(Color.red);
            nextButton.addActionListener(this);
            calendarPanel.add(nextButton);
        }
        /* Now do the last day of the month. */
        JButton lastDayButton = new JButton(String.valueOf(lastDayOfMonth.get(Calendar.DAY_OF_MONTH)));
        if (isOnWeekend(lastDayOfMonth)) lastDayButton.setForeground(Color.blue);
        if (compare(lastDayOfMonth,today)) lastDayButton.setForeground(Color.red);
        lastDayButton.addActionListener(this);
        calendarPanel.add(lastDayButton);
        int lastDayInLastWeek = lastDayOfMonth.get(Calendar.DAY_OF_WEEK);
        if (debug) System.out.println("Debug: lastDayInLastWeek: " + lastDayInLastWeek);
        for (int i = lastDayInLastWeek+1;i<=7;i++){
            JButton blank = new JButton("--");
            blank.setEnabled(false);
            calendarPanel.add(blank);
        }
        calendarPanel.validate();
        pack();
    }
 
    /**	Implements ActionListener interface. Responds to Previous 	
    *	and Next button commands. Responds to day of month selection 
    *	which ends Thread execution. The user can either move the 
    *	month selection forward or in reverse. Once a day is selected
    *	and confirmed the thread stops and the frame is hidden.
    *	The calling program can request the selected date using any
    *	of several options.
    */
    public void actionPerformed(ActionEvent actionevent){
        String actionString = actionevent.getActionCommand();
        if (debug) System.out.println("Debug: actionString: " + actionString);
        if (actionString.compareTo("Prev") == 0) {
            month = month - 1;
            if (month < 0){
                month = 11;
                year = year - 1;
            }
            updateCalendarDisplay(month,year);
        }else if (actionString.compareTo("Next") == 0) {
            month = month + 1;
            if (month == 12){
                month = 0;
                year = year + 1;
            }
            updateCalendarDisplay(month,year);
        }else{
            if (getInt(actionString) > 0) {
                selectedDay = getInt(actionString);
                dateSelection = String.valueOf(month + 1) + "-" + String.valueOf(selectedDay) + "-" + String.valueOf(year);
                if (debug) System.out.println("Debug: Date Selection : " + dateSelection);
                if (debug) System.out.println("Debug: Month: " + String.valueOf(month) + " Day: " + actionString + " Year: " + String.valueOf(year));
            }
            if (confirmSelection()) {
                hide();
                dateSelected = true;
            }
        }
    }
 
    /**	Returns the selected date string in format 
     *  month-day-year.
     *	eg: 2-16-2002
     */
    public String getDateSelection(){
        return dateSelection;
    }
 
    /**	Returns the selected date string in format 
     *  monthstring daystring, yearstring
     *	eg: February 16, 2002
     */
    public String getSelectionString(){
        return getMonthSelection() + " " 
            + getDayOfMonthSelection()
            + ", " + getYearSelection();
    }
 
    /**	Returns the selected month value 
     *  or -1 if no date has been selected.
     *	January corresponds to 0;
     *	December corresponds to 11;
     */
    public int getSelectedMonth(){
        return month;
    }
 
    /**	Returns the selected month value. 
     *	January corresponds to months[0];
     *	December corresponds to months[11];
     */
    public String getMonthSelection(){
        return months[month];
    }
 
    /**	Returns the selected day value starting with 1
     *  or -1 if no date has been selected.
     */
    public int getSelectedDay(){
        return selectedDay;
    }
    
    /**	Returns the selected day of week string.
     */
    public String getSelectedDayOfWeek(){
        return weekdays[new GregorianCalendar(year, month, selectedDay).get(Calendar.DAY_OF_WEEK)-1];
    }
 
    /**	Returns the selected day string starting with 1.
     */
    public String getDayOfMonthSelection(){
        return String.valueOf(selectedDay);
    }
 
    /**	Returns the selected 4 digit year value 
     *  or -1 if no date has been selected.
     */
    public int getSelectedYear(){
        return year;
    }
 
    /**	Returns the selected 4 digit year string.
     */
    public String getYearSelection(){
        return String.valueOf(year);
    }
 
    /**	Converts the input string into an integer. 
     *  Returns -1 of unsuccessful.
     */
    private int getInt(String s){
        int n = -1;
        try{
            n = Integer.parseInt(s);
        }catch(NumberFormatException nfe){
            n = -1;
            System.err.println("NumberFormatException: " + nfe.getMessage());
        }
        return n;
    }
 
    /**	Determines if the input Calendar object 
     *  corresponds to either a Saturday or Sunday.
     */
    public boolean isOnWeekend(Calendar calendar){
        return ((calendar.get(Calendar.DAY_OF_WEEK) == Calendar.SATURDAY) ||
                (calendar.get(Calendar.DAY_OF_WEEK) == Calendar.SUNDAY));
    }
 
    /**	Converts the input string into an integer. 
     *  Returns -1 of unsuccessful.
     */
    private boolean compare(GregorianCalendar first, GregorianCalendar second){
        return ((first.get(Calendar.DAY_OF_MONTH) == second.get(Calendar.DAY_OF_MONTH))
                && (first.get(Calendar.MONTH) == second.get(Calendar.MONTH))
                && (first.get(Calendar.YEAR) == second.get(Calendar.YEAR)));
    }
 
    /**	Confirms the date selection using a 
     *  JOptionPane ConfirmDialog.
     */
    public boolean confirmSelection(){
        return (JOptionPane.showConfirmDialog(null,"Select " + getSelectionString() + "?", "Select " + getSelectionString() + "?", JOptionPane.OK_CANCEL_OPTION) == JOptionPane.OK_OPTION);
    }
}