package com.onaro.sanscreen.client.view.topology;

import ilog.views.IlvManagerView;
import ilog.views.IlvManagerViewDecoration;
import ilog.views.swing.IlvJScrollManagerView;

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;

/**
 * A means to paint an error message across the center of the given topology scroll view. Based on TopologyWatermark
 *
 * @author Joshuae
 */
public class TopologyErrorMessage implements IlvManagerViewDecoration {
    /** Error message's font size.
     */
    private static final int FONT_SIZE = 40;

    /** Opaqueness of the text displayed in the error message.
     */
    private static final AlphaComposite alpha = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.25f);

    /** Error message's font type.
     */
    private static final Font font = new Font(Font.SANS_SERIF, Font.BOLD, FONT_SIZE);

    private volatile String message = "";

    /** A panel containing an two scrollbars.*/
    private IlvJScrollManagerView netGraphScrollManager;




    /**
     * Constructor.
     *
     * @param netGraphScrollManager ILog scroll manager.
     */
    public TopologyErrorMessage(IlvJScrollManagerView netGraphScrollManager) {
        this.netGraphScrollManager = netGraphScrollManager;
    }

    /**
     * Logic that take place during the rendering of the <code>netGraphScrollManager</code>
     */
    public void paint(final Graphics g, final IlvManagerView ilvManagerView) {
        Graphics2D g2 = (Graphics2D) g;

        // Setting for the: geometry, coordinate transformations, color management, and text layout.
        g2.setComposite(alpha);
        g2.setColor(Color.BLACK);
        g2.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
        g2.setFont(font);
        FontMetrics fm = g.getFontMetrics();

        // useful measurements.
        int height = netGraphScrollManager.getHeight();
        int width = netGraphScrollManager.getWidth();
        int fontHeight = fm.getHeight();
        int stringWidth = fm.stringWidth(message);

        g.drawString(message, (width - stringWidth)/2, (height - fontHeight)/2);
    }

    public void setMessage(String message) {
        if (message == null) {
            throw new IllegalArgumentException("message cannot be null");
        }
        this.message = message;
    }
}