/*
 *  SWTDayChooser.java  - A day chooser component for SWT
 *  Author: Mark Bryan Yu
 *  Modified by: Sergey Prigogin
 *  swtcalendar.sourceforge.net
 *
 *  Permission is hereby granted, free of charge, to any person obtaining a copy of
 *  this software and associated documentation files (the "Software"), to deal in the
 *  Software without restriction, including without limitation the rights to use, copy,
 *  modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
 *  and to permit persons to whom the Software is furnished to do so, subject to the
 *  following conditions:
 *
 *  The above copyright notice and this permission notice shall be included in all copies
 *  or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 *  INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 *  PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL SIMON TATHAM BE LIABLE FOR ANY CLAIM,
 *  DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 *  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
package org.vafada.swtcalendar;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.*;

import java.text.DateFormatSymbols;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;
import java.util.Locale;

public class SWTDayChooser extends Composite
        implements MouseListener, FocusListener, TraverseListener, KeyListener {
    /**
     * Style constant for making Sundays red.
     */
    public static final int RED_SUNDAY = 1 << 24;     // == SWT.EMBEDDED
    /**
     * Style constant for making Saturdays red.
     */
    public static final int RED_SATURDAY = 1 << 28;   // == SWT.VIRTUAL
    /**
     * Style constant for making weekends red.
     */
    public static final int RED_WEEKEND = RED_SATURDAY | RED_SUNDAY;

    private Label[] dayTitles;
    private DayControl[] days;
    private int dayOffset;
    private Color activeSelectionBackground;
    private Color inactiveSelectionBackground;
    private Color activeSelectionForeground;
    private Color inactiveSelectionForeground;
    private Color otherMonthColor;
    private Calendar calendar;
    private Calendar today;
    private Locale locale;
    private List listeners;
    private int style;

    public SWTDayChooser(Composite parent, int style) {
        super(parent, style & ~RED_WEEKEND);
        this.style = style;
        listeners = new ArrayList(3);

        setBackground(getDisplay().getSystemColor(SWT.COLOR_WHITE));

        otherMonthColor = new Color(getDisplay(), 128, 128, 128);
        activeSelectionBackground = getDisplay().getSystemColor(SWT.COLOR_LIST_SELECTION);
        inactiveSelectionBackground = getDisplay().getSystemColor(SWT.COLOR_GRAY);
        activeSelectionForeground = getDisplay().getSystemColor(SWT.COLOR_LIST_SELECTION_TEXT);
        inactiveSelectionForeground = getForeground();

        locale = Locale.getDefault();

        GridLayout gridLayout = new GridLayout();
        gridLayout.makeColumnsEqualWidth = true;
        gridLayout.numColumns = 7;
        gridLayout.marginHeight = 0;
        gridLayout.marginWidth = 0;
        gridLayout.horizontalSpacing = 0;
        gridLayout.verticalSpacing = 0;
        setLayout(gridLayout);

        dayTitles = new Label[7];
        for (int i = 0; i < dayTitles.length; i++) {
            Label label = new Label(this, SWT.CENTER);
            dayTitles[i] = label;
            label.setLayoutData(new GridData(GridData.HORIZONTAL_ALIGN_FILL));
            label.addMouseListener(this);
        }
        {
            final Composite spacer = new Composite(this, SWT.NO_FOCUS);
            spacer.setBackground(getBackground());
            final GridData gridData = new GridData(GridData.FILL_HORIZONTAL);
            gridData.heightHint = 2;
            gridData.horizontalSpan = 7;
            spacer.setLayoutData(gridData);
            spacer.setLayout(new GridLayout());
            spacer.addMouseListener(this);
        }

        {
            final Label label = new Label(this, SWT.HORIZONTAL | SWT.SEPARATOR);
            final GridData gridData = new GridData(GridData.FILL_HORIZONTAL);
            gridData.horizontalSpan = 7;
            label.setLayoutData(gridData);
        }

        days = new DayControl[42];
        for (int i = 0; i < days.length; i++) {
            DayControl day = new DayControl(this);
            days[i] = day;
            day.setLayoutData(new GridData(GridData.HORIZONTAL_ALIGN_FILL | GridData.VERTICAL_ALIGN_FILL));
            day.addMouseListener(this);
        }

        setTabList(new Control[0]);

        setFont(parent.getFont());

        init();

        addMouseListener(this);
        addFocusListener(this);
        addTraverseListener(this);
        addKeyListener(this);

        addDisposeListener(new DisposeListener() {
            public void widgetDisposed(DisposeEvent event) {
                otherMonthColor.dispose();
            }
        });
    }

    protected void init() {
        calendar = Calendar.getInstance(locale);
        calendar.setLenient(true);
        today = (Calendar) calendar.clone();
        int firstDayOfWeek = calendar.getFirstDayOfWeek();
        DateFormatSymbols dateFormatSymbols = new DateFormatSymbols(locale);
        String[] dayNames = dateFormatSymbols.getShortWeekdays();
        int minLength = Integer.MAX_VALUE;
        for (int i = 0; i < dayNames.length; i++) {
            int len = dayNames[i].length();
            if (len > 0 && len < minLength) {
                minLength = len;
            }
        }
        if (minLength > 2) {
            for (int i = 0; i < dayNames.length; i++) {
                if (dayNames[i].length() > 0) {
					//as suggested by yunjie liu, Because in Chinese the dayNames display as *** ,but only the third word are the keywords.
                    if (locale.equals(Locale.CHINA)) {
						if (dayNames[i].length() > 2) {
							dayNames[i] = dayNames[i].substring(2, 3);
						}
					}else {
						if (dayNames[i].length() > 0) {
							dayNames[i] = dayNames[i].substring(0, 1);
						}
					}
                }
            }
        }

        int d = firstDayOfWeek;
        for (int i = 0; i < dayTitles.length; i++) {
            Label label = dayTitles[i];
            label.setText(dayNames[d]);
            label.setBackground(getBackground());
            if (d == Calendar.SUNDAY && (style & RED_SUNDAY) != 0 ||
                    d == Calendar.SATURDAY && (style & RED_SATURDAY) != 0) {
                label.setForeground(getDisplay().getSystemColor(SWT.COLOR_DARK_RED));
            } else {
                label.setForeground(getForeground());
            }

            d++;
            if (d > dayTitles.length) {
                d -= dayTitles.length;
            }
        }

        drawDays();
    }

    protected void drawDays() {
        calendar.get(Calendar.DAY_OF_YEAR); // Force calendar update
        Calendar cal = (Calendar) calendar.clone();
        int firstDayOfWeek = cal.getFirstDayOfWeek();
        cal.set(Calendar.DAY_OF_MONTH, 1);

        dayOffset = firstDayOfWeek - cal.get(Calendar.DAY_OF_WEEK);
        if (dayOffset >= 0) {
            dayOffset -= 7;
        }
        cal.add(Calendar.DAY_OF_MONTH, dayOffset);

        Color foregroundColor = getForeground();
        for (int i = 0; i < days.length; cal.add(Calendar.DAY_OF_MONTH, 1)) {
            DayControl dayControl = days[i++];
            dayControl.setText(Integer.toString(cal.get(Calendar.DAY_OF_MONTH)));
            if (isSameDay(cal, today)) {
                dayControl.setBorderColor(getDisplay().getSystemColor(SWT.COLOR_BLACK));
            } else {
                dayControl.setBorderColor(getBackground());
            }

            if (isSameMonth(cal, calendar)) {
                int d = cal.get(Calendar.DAY_OF_WEEK);
                if (d == Calendar.SUNDAY && (style & RED_SUNDAY) != 0 ||
                        d == Calendar.SATURDAY && (style & RED_SATURDAY) != 0) {
                    dayControl.setForeground(getDisplay().getSystemColor(SWT.COLOR_DARK_RED));
                } else {
                    dayControl.setForeground(foregroundColor);
                }
            } else {
                dayControl.setForeground(otherMonthColor);
            }

            if (isSameDay(cal, calendar)) {
                dayControl.setBackground(getSelectionBackgroundColor());
                dayControl.setForeground(getSelectionForegroundColor());
            } else {
                dayControl.setBackground(getBackground());
            }
        }
    }

    private static boolean isSameDay(Calendar cal1, Calendar cal2) {
        return cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR) &&
                cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR);
    }

    private static boolean isSameMonth(Calendar cal1, Calendar cal2) {
        return cal1.get(Calendar.MONTH) == cal2.get(Calendar.MONTH) &&
                cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR);
    }

    public void setMonth(int month) {
        calendar.set(Calendar.MONTH, month);
        drawDays();
        dateChanged();
    }

    public void setYear(int year) {
        calendar.set(Calendar.YEAR, year);
        drawDays();
        dateChanged();
    }

    public void setCalendar(Calendar cal) {
        calendar = (Calendar) cal.clone();
        calendar.setLenient(true);
        drawDays();
        dateChanged();
    }

    /* (non-Javadoc)
     * @see org.eclipse.swt.events.MouseListener#mouseDown(org.eclipse.swt.events.MouseEvent)
     */
    public void mouseDown(MouseEvent event) {
        if (event.button == 1) { // Left click
            setFocus();

            if (event.widget instanceof DayControl) {
                int index = findDay(event.widget);
                selectDay(index + 1 + dayOffset);
            }
        }
    }

    /* (non-Javadoc)
     * @see org.eclipse.swt.events.MouseListener#mouseDoubleClick(org.eclipse.swt.events.MouseEvent)
     */
    public void mouseDoubleClick(MouseEvent event) {
    }

    /* (non-Javadoc)
     * @see org.eclipse.swt.events.MouseListener#mouseUp(org.eclipse.swt.events.MouseEvent)
     */
    public void mouseUp(MouseEvent event) {
    }

    /* (non-Javadoc)