package com.tiff.common.ui.datepicker;

import java.text.DateFormatSymbols;
import java.util.Calendar;
import java.util.Date;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.ControlAdapter;
import org.eclipse.swt.events.ControlEvent;
import org.eclipse.swt.events.KeyAdapter;
import org.eclipse.swt.events.KeyEvent;
import org.eclipse.swt.events.MouseAdapter;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.events.MouseMoveListener;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.TypedListener;

/**
 * The date picker panel
 * 
 * changes by sebthom
 * ~ setDate will fire the Selection event
 * + you can use setDate(null) to clear the selection,
 *   the calendar will display the current date, but
 *   getDate will return null until the user explicitely
 *   selects a date from the control
 * 
 * @author <a href="mailto:andy@tiff.ru">Andrey Onistchuk</a>
 */
public class DatePicker extends Composite {

	//~ Inner Classes
	// ----------------------------------------------------------
	private class DatePanel extends Canvas {
		//~ Instance fields
		// ----------------------------------------------------
		private int colSize;
		private Display display = Display.getCurrent();
		private int rowSize;
		private Calendar temp = Calendar.getInstance();

		//~ Constructors
		// -------------------------------------------------------
		public DatePanel(Composite parent, int style) {
			super(parent, style | SWT.NO_BACKGROUND | SWT.NO_REDRAW_RESIZE);

			GC gc = new GC(this);
			Point p = gc.stringExtent("Q");
			gc.dispose();
			colSize = p.x * 3;
			rowSize = (int) (p.y * 1.2);

			addPaintListener(new PaintListener() {
				public void paintControl(PaintEvent event) {
					onPaint(event);
				}
			});
			addControlListener(new ControlAdapter() {
				public void controlResized(ControlEvent e) {
					redraw();
				}
			});
			addKeyListener(new KeyAdapter() {
				public void keyPressed(KeyEvent e) {
					onKeyDown(e);
				}
			});
			addMouseListener(new MouseAdapter() {
				public void mouseDoubleClick(MouseEvent e) {
					doubleClick();
				}
				public void mouseDown(MouseEvent e) {
					onMouseDown(e);
				}
			});
			addMouseMoveListener(new MouseMoveListener() {
				public void mouseMove(MouseEvent e) {
					onMouseMove(e);
				}
			});
		}

		//~ Methods
		// ------------------------------------------------------------
		private int computeOffset(int day) {
			switch (day) {
				case Calendar.MONDAY :
					return 1;
				case Calendar.TUESDAY :
					return 2;
				case Calendar.WEDNESDAY :
					return 3;
				case Calendar.THURSDAY :
					return 4;
				case Calendar.FRIDAY :
					return 5;
				case Calendar.SATURDAY :
					return 6;
				case Calendar.SUNDAY :
					return 7;
			}
			return -1;
		}

		public Point computeSize(int wHint, int hHint, boolean changed) {
			return new Point(colSize * 7, rowSize * 7);
		}

		/**
		 * Method drawTextImage.
		 * 
		 * @param gc
		 * @param string
		 * @param object
		 * @param i
		 * @param i1
		 * @param i2
		 * @param colSize
		 * @param rowSize
		 */
		private void drawTextImage(GC gc, String string, int x, int y,
				int colSize, int rowSize) {
			gc.fillRectangle(x, y, colSize, rowSize);
			gc.drawString(string, x, y, true);
		}

		private int getDayFromPoint(int x, int y) {
			int result = -1;

			for (int i = 1; i <= 31; i++) {
				Point p = getDayPoint(i);
				Rectangle r = new Rectangle(p.x, p.y, colSize, rowSize);
				if (r.contains(x, y)) {
					result = i;
					break;
				}
			}
			return result;
		}

		private String getDayName(int day) {
			return dateSymbols.getShortWeekdays()[day];
		}

		private Point getDayPoint(int day) {
			syncTime();
			temp.set(Calendar.DAY_OF_MONTH, 1);

			int firstDayOffset = computeOffset(temp.get(Calendar.DAY_OF_WEEK))
					- 1;
			temp.set(Calendar.DAY_OF_MONTH, day);
			int dayOffset = computeOffset(temp.get(Calendar.DAY_OF_WEEK));
			int x = (dayOffset - 1) * colSize;
			int y = (1 + (((firstDayOffset + day) - 1) / 7)) * rowSize;

			return new Point(x, y);
		}

		private int getMaxDay() {
			syncTime();

			int day = 28;

			for (int i = 0; i < 10; i++) {
				temp.set(Calendar.DAY_OF_MONTH, day);

				if (temp.get(Calendar.MONTH) != cal.get(Calendar.MONTH)) {
					return day - 1;
				}
				day++;
			}
			return -1;
		}

		private void onKeyDown(KeyEvent e) {
			if (e.character == SWT.ESC) {
				dateSelected(false);
				return;
			}

			if ((e.character == ' ') || (e.character == '\r')) {
				dateSelected(true);
				return;
			}

			int day = cal.get(Calendar.DAY_OF_MONTH);
			int month = cal.get(Calendar.MONTH);
			int oldDay = day;
			int oldMonth = month;

			if (e.keyCode == SWT.ARROW_LEFT) {
				day--;
			}

			if (e.keyCode == SWT.ARROW_RIGHT) {
				day++;
			}

			if (e.keyCode == SWT.ARROW_UP) {
				day = ((day - 7) < 1 ? oldDay : day - 7);
			}

			if (e.keyCode == SWT.ARROW_DOWN) {
				day = ((day + 7) > getMaxDay() ? oldDay : day + 7);
			}

			if (e.keyCode == SWT.PAGE_UP) {
				month--;
			}

			if (e.keyCode == SWT.PAGE_DOWN) {
				month++;
			}

			cal.set(Calendar.MONTH, month);
			cal.set(Calendar.DAY_OF_MONTH, day);

			if ((day != oldDay) || (month != oldMonth)) {
				redraw();

				if (month != oldMonth) {
					updateMonthLabel();
				}
			}
		}

		private void onMouseDown(MouseEvent e) {
			int day = getDayFromPoint(e.x, e.y);

			if (day > 0) {
				cal.set(Calendar.DAY_OF_MONTH, day);
				dateSelected(true);
				updateDate();
			}
		}

		private void onMouseMove(MouseEvent e) {
			int day = getDayFromPoint(e.x, e.y);
			selection = day;
			updateDate();
		}

		private void onPaint(PaintEvent event) {
			Rectangle rect = getClientArea();
			GC gc0 = event.gc;
			Image image = new Image(display, rect.width, rect.height);
			GC gc = new GC(image);
			gc.setBackground(display
					.getSystemColor(SWT.COLOR_WIDGET_BACKGROUND));
			gc.fillRectangle(rect);

			int x = 0;
			int y = 0;

			for (int i = 0; i < 7; i++) {
				if (i == 6) {
					gc.setForeground(display.getSystemColor(SWT.COLOR_RED));
				}
				drawTextImage(gc, getDayName(1 + i), x, 0, colSize, rowSize);
				x += colSize;
			}

			gc.setForeground(display.getSystemColor(SWT.COLOR_BLACK));
			y += rowSize;
			gc.drawLine(0, 0, rect.width, 0);
			gc.drawLine(0, y - 1, rect.width, y - 1);

			syncTime();

			int day = 1;

			while (true) {
				temp.set(Calendar.DAY_OF_MONTH, day);

				if (temp.get(Calendar.MONTH) != cal.get(Calendar.MONTH)) {
					break;
				}

				int dayOffset = computeOffset(temp.get(Calendar.DAY_OF_WEEK));
				Point p = getDayPoint(day);

				if (day == cal.get(Calendar.DAY_OF_MONTH)) {
					gc.setForeground(display.getSystemColor(
							SWT.COLOR_LIST_SELECTION_TEXT));
					gc.setBackground(display.getSystemColor(
							SWT.COLOR_LIST_SELECTION));
				} else if (day == selection) {
					gc.setForeground(display.getSystemColor(
							SWT.COLOR_LIST_SELECTION_TEXT));
					gc.setBackground(display.getSystemColor(SWT.COLOR_BLACK));
				} else {
					gc.setBackground(display.getSystemColor(
							SWT.COLOR_WIDGET_BACKGROUND));
					gc.setForeground(display.getSystemColor(dayOffset == 7
							? SWT.COLOR_RED
							: SWT.COLOR_BLACK));
				}

				drawTextImage(gc, "" + day, p.x, p.y, colSize, rowSize);
				day++;
			}

			gc0.drawImage(image, 0, 0);
			gc.dispose();
			image.dispose();
		}

		private void syncTime() {
			temp.setTimeInMillis(cal.getTimeInMillis());
		}
	}

	//~ Instance fields
	// --------------------------------------------------------
	private Calendar cal = Calendar.getInstance();

	// sebthom
	private Date selectedDate;

	private DatePanel datePanel;
	private DateFormatSymbols dateSymbols = new DateFormatSymbols();
	private Label monthLabel;
	private int selection = -1;

	//~ Constructors
	// -----------------------------------------------------------
	public DatePicker(Composite parent, int style) {
		super(parent, style);

		GridLayout gridLayout = new GridLayout();
		gridLayout.numColumns = 5;
		gridLayout.verticalSpacing = gridLayout.horizontalSpacing = 0;
		gridLayout.marginHeight = gridLayout.marginWidth = 0;
		setBackground(Display.getCurrent().getSystemColor(SWT.COLOR_DARK_CYAN));
		setLayout(gridLayout);

		GridData gridData;

		// previous year
		Button prevYear = new Button(this, SWT.FLAT);
		gridData = new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING);
		gridData.heightHint = gridData.widthHint = 20;
		prevYear.setLayoutData(gridData);
		prevYear.setText("<<");
		prevYear.setSelection(false);
		prevYear.addSelectionListener(new SelectionAdapter() {
			public void widgetSelected(SelectionEvent e) {
				cal.roll(Calendar.YEAR, -1);
				updateDate();
			}
		});

		// previous month
		Button prevMonth = new Button(this, SWT.FLAT);
		gridData = new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING);
		gridData.heightHint = gridData.widthHint = 20;
		prevMonth.setLayoutData(gridData);
		prevMonth.setText("<");
		prevMonth.addSelectionListener(new SelectionAdapter() {
			public void widgetSelected(SelectionEvent e) {
				cal.roll(Calendar.MONTH, -1);
				updateDate();
			}
		});

		// current month
		monthLabel = new Label(this, SWT.CENTER);
		gridData = new GridData(GridData.FILL_HORIZONTAL | GridData.CENTER);
		gridData.heightHint = prevYear.computeSize(20, 20).y;
		gridData.grabExcessHorizontalSpace = true;
		monthLabel.setLayoutData(gridData);

		// next month
		Button nextMonth = new Button(this, SWT.FLAT);
		gridData = new GridData(GridData.HORIZONTAL_ALIGN_END);
		gridData.heightHint = gridData.widthHint = 20;
		nextMonth.setLayoutData(gridData);
		nextMonth.setText(">");
		nextMonth.addSelectionListener(new SelectionAdapter() {
			public void widgetSelected(SelectionEvent e) {
				cal.roll(Calendar.MONTH, 1);
				updateDate();
			}
		});

		// next year
		Button nextYear = new Button(this, SWT.FLAT);
		gridData = new GridData(GridData.HORIZONTAL_ALIGN_END);
		gridData.heightHint = gridData.widthHint = 20;
		nextYear.setLayoutData(gridData);
		nextYear.setText(">>");
		nextYear.addSelectionListener(new SelectionAdapter() {
			public void widgetSelected(SelectionEvent e) {
				cal.roll(Calendar.YEAR, 1);
				updateDate();
			}
		});

		// a panel
		datePanel = new DatePanel(this, SWT.NONE);
		gridData = new GridData(GridData.HORIZONTAL_ALIGN_FILL);
		gridData.horizontalSpan = 5;
		datePanel.setLayoutData(gridData);

		updateDate();
	}

	//~ Methods
	// ----------------------------------------------------------------
	public void addSelectionListener(SelectionListener listener) {
		checkWidget();

		if (listener == null) {
			SWT.error(SWT.ERROR_NULL_ARGUMENT);
		}
		TypedListener typedListener = new TypedListener(listener);
		addListener(SWT.Selection, typedListener);
		addListener(SWT.DefaultSelection, typedListener);
	}

	public Point computeSize(int wHint, int hHint, boolean changed) {
		Point pSize = datePanel.computeSize(wHint, hHint, changed);
		Point labelSize = monthLabel.computeSize(wHint, hHint, changed);

		int x = (pSize.x < (labelSize.x + 80) ? labelSize.x + 80 : pSize.x);
		int y = (pSize.y < (labelSize.y + 20) ? labelSize.y + 20 : pSize.y);
		return new Point(x, y);
	}

	private void dateSelected(boolean good) {
		// sebthom
		if (good)
			selectedDate = cal.getTime();

		Event event = new Event();
		event.doit = good;
		notifyListeners(SWT.Selection, event);
	}

	private void doubleClick() {
		Event event = new Event();
		event.doit = true;
		notifyListeners(SWT.MouseDoubleClick, event);
	}

	private String getCurrentMonthName() {
		StringBuffer sb = new StringBuffer();
		sb.append(getMonthName(cal.get(Calendar.MONTH)));
		sb.append(", ");
		sb.append(cal.get(Calendar.YEAR));
		return sb.toString();
	}

	public Date getDate() {
		// sebthom
		//return cal.getTime();
		return selectedDate;
	}

	private String getMonthName(int month) {
		return dateSymbols.getMonths()[month];
	}

	public void removeSelectionListener(SelectionListener listener) {
		checkWidget();

		if (listener == null) {
			SWT.error(SWT.ERROR_NULL_ARGUMENT);
		}
		removeListener(SWT.Selection, listener);
		removeListener(SWT.DefaultSelection, listener);
	}

	public void reset() {
		cal = Calendar.getInstance();
		updateDate();
	}

	public void setDate(Date date) {
		// sebthom
		//cal.setTime(date);
		selectedDate = date;
		cal.setTime(selectedDate == null ? new Date() : date);

		updateMonthLabel();
		redraw();
	}

	private void updateDate() {
		datePanel.redraw();
		updateMonthLabel();
	}

	private void updateMonthLabel() {
		monthLabel.setText(getCurrentMonthName());
	}
}