package net.sf.openrocket.gui.components;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Rectangle;

import javax.swing.JEditorPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.ScrollPaneConstants;
import javax.swing.SwingUtilities;

public class DescriptionArea extends JScrollPane {
	
	private final JEditorPane editorPane;
	
	
	/**
	 * Construct a description area with the specified number of rows, default description font size,
	 * being opaque.
	 * 
	 * @param rows	the number of rows
	 */
	public DescriptionArea(int rows) {
		this("", rows, -1);
	}
	
	/**
	 * Construct a description area with the specified number of rows and size, being opaque.
	 * 
	 * @param rows	the number of rows.
	 * @param size	the font size difference compared to the default font size.
	 */
	public DescriptionArea(int rows, float size) {
		this("", rows, size);
	}
	
	/**
	 * Construct an opaque description area with the specified number of rows, size and text, being opaque.
	 * 
	 * @param text	the initial text.
	 * @param rows	the number of rows.
	 * @param size	the font size difference compared to the default font size.
	 */
	public DescriptionArea(String text, int rows, float size) {
		this(text, rows, size, true);
	}
	
	/**
	 * Constructor with all options.
	 * 
	 * @param text		the text for the description area.
	 * @param rows		the number of rows to set
	 * @param size		the relative font size in points (positive or negative)
	 * @param opaque	if <code>false</code> the background color will be set to the background color
	 * 					of a default JPanel (simulation non-opaque)
	 */
	public DescriptionArea(String text, int rows, float size, boolean opaque) {
		super(ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,
				ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
		
		editorPane = new JEditorPane("text/html", "");
		Font font = editorPane.getFont();
		editorPane.setFont(font.deriveFont(font.getSize2D() + size));
		editorPane.setEditable(false);
		
		if (!opaque) {
			Color bg = new JPanel().getBackground();
			editorPane.setBackground(new Color(bg.getRed(), bg.getGreen(), bg.getBlue()));
			this.setOpaque(true);
		}
		
		// Calculate correct height
		editorPane.setText("abc");
		Dimension oneline = editorPane.getPreferredSize();
		editorPane.setText("abc<br>def");
		Dimension twolines = editorPane.getPreferredSize();
		editorPane.setText("");
		
		int lineheight = twolines.height - oneline.height;
		int extraheight = oneline.height - lineheight;
		
		Dimension dim = editorPane.getPreferredSize();
		dim.height = lineheight * rows + extraheight + 2;
		this.setPreferredSize(dim);
		
		this.setViewportView(editorPane);
		this.setText(text);
	}
	
	public void setText(String txt) {
		editorPane.setText(txt);
		editorPane.revalidate();
		SwingUtilities.invokeLater(new Runnable() {
			
			@Override
			public void run() {
				editorPane.scrollRectToVisible(new Rectangle(0, 0, 1, 1));
			}
			
		});
		editorPane.scrollRectToVisible(new Rectangle(0, 0, 1, 1));
	}
	
}