/*
 * Copyright (c) 2004-2011 Marco Maccaferri and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Marco Maccaferri - initial API and implementation
 */

package org.eclipsetrader.ui.internal.views;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;

/**
 * Display a 5-bands pressure bar.
 *
 * @since 1.0
 */
public class PressureBar {

    private Canvas canvas;

    private long[] leftWeights;
    private long[] rightWeights;

    private Color separatorColor;
    private Color[] bandColors;

    private int separatorWidth = 3;

    PressureBar() {
    }

    public PressureBar(Composite parent, int style) {
        canvas = new Canvas(parent, style | SWT.DOUBLE_BUFFERED);
        canvas.setBackground(parent.getDisplay().getSystemColor(SWT.COLOR_WIDGET_NORMAL_SHADOW));
        canvas.addPaintListener(new PaintListener() {

            @Override
            public void paintControl(PaintEvent event) {
                try {
                    onPaintControl(event);
                } catch (Exception e) {
                    // TODO Log exception
                    e.printStackTrace();
                } catch (Error e) {
                    // TODO Log error
                    e.printStackTrace();
                }
            }
        });

        separatorColor = Display.getCurrent().getSystemColor(SWT.COLOR_BLACK);
        bandColors = new Color[] {
                Display.getCurrent().getSystemColor(SWT.COLOR_YELLOW),
                Display.getCurrent().getSystemColor(SWT.COLOR_GREEN),
                Display.getCurrent().getSystemColor(SWT.COLOR_CYAN),
                Display.getCurrent().getSystemColor(SWT.COLOR_DARK_RED),
                Display.getCurrent().getSystemColor(SWT.COLOR_BLUE),
        };
    }

    public Color getSeparatorColor() {
        return separatorColor;
    }

    public void setSeparatorColor(Color indicatorColor) {
        this.separatorColor = indicatorColor;
        canvas.redraw();
    }

    public Color[] getBandColors() {
        return bandColors;
    }

    public void setBandColors(Color[] bandColors) {
        this.bandColors = bandColors;
        canvas.redraw();
    }

    public void setWeights(long[] leftWeights, long[] rightWeights) {
        this.leftWeights = leftWeights;
        this.rightWeights = rightWeights;
        canvas.redraw();
    }

    protected void onPaintControl(PaintEvent e) {
        Rectangle clientArea = ((Control) e.widget).getBounds();

        if (leftWeights != null && rightWeights != null) {
            int x = 0;
            int index = 0;
            int[] widths = getBandWidths(leftWeights, rightWeights, clientArea);

            for (int i = leftWeights.length - 1; i >= 0; i--) {
                e.gc.setBackground(bandColors[i]);
                e.gc.fillRectangle(x, 0, widths[i + index], clientArea.height);
                x += widths[i + index];
            }
            index += leftWeights.length;

            e.gc.setBackground(separatorColor);
            e.gc.fillRectangle(x, 0, widths[index], clientArea.height);
            x += widths[index++];

            for (int i = 0; i < rightWeights.length && i < 5; i++) {
                e.gc.setBackground(bandColors[i]);
                e.gc.fillRectangle(x, 0, widths[i + index], clientArea.height);
                x += widths[i + index];
            }
        }
    }

    protected int[] getBandWidths(long[] leftWeights, long[] rightWeights, Rectangle clientArea) {
        double total = 0;
        for (int i = 0; i < leftWeights.length; i++) {
            total += leftWeights[i];
        }
        for (int i = 0; i < rightWeights.length; i++) {
            total += rightWeights[i];
        }

        int bands = leftWeights.length + 1 + rightWeights.length;
        int[] widths = new int[bands];
        int maxWidth = clientArea.width - separatorWidth;
        int last = maxWidth;
        int index = 0;

        for (int i = 0; i < leftWeights.length; i++, index++) {
            widths[index] = (int) (maxWidth / total * leftWeights[i]);
            last -= widths[index];
        }
        widths[index++] = separatorWidth;
        for (int i = 0; i < rightWeights.length - 1; i++, index++) {
            widths[index] = (int) (maxWidth / total * rightWeights[i]);
            last -= widths[index];
        }
        if (index < widths.length) {
            widths[index] = last;
        }

        return widths;
    }

    public Control getControl() {
        return canvas;
    }

    public int getSeparatorWidth() {
        return separatorWidth;
    }

    public void setSeparatorWidth(int separatorWidth) {
        this.separatorWidth = separatorWidth;
        canvas.redraw();
    }
}