/*
 *  Copyright (c) 2012 Sam Harwell, Tunnel Vision Laboratories LLC
 *  All rights reserved.
 *
 *  The source code of this document is proprietary work, and is not licensed for
 *  distribution. For information about licensing, contact Sam Harwell at:
 *      sam@tunnelvisionlabs.com
 */
package org.antlr.netbeans.editor.navigation;

import java.awt.Color;
import java.awt.Insets;
import java.awt.Rectangle;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JEditorPane;
import javax.swing.SwingUtilities;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.EditorKit;
import javax.swing.text.html.HTMLEditorKit;

/**
 *  HTML documentation view.
 *  Javadoc content is displayed in JEditorPane pane using HTMLEditorKit.
 *
 *  @author  Martin Roskanin
 *  @since   03/2002
 */
class HTMLDocView extends JEditorPane {
    // -J-Dorg.antlr.netbeans.editor.navigation.HTMLDocView.level=FINE
    private static final Logger LOGGER = Logger.getLogger(HTMLDocView.class.getName());
    
    private HTMLEditorKit htmlKit;
    
    /** Creates a new instance of HTMLJavaDocView */
    public HTMLDocView(Color bgColor) {
        setEditable(false);
        setFocusable(true);
        setBackground(bgColor);
        setMargin(new Insets(0,3,3,3));
    }

    /** Sets the javadoc content as HTML document */
    public void setContent(final String content, final String reference) {
        SwingUtilities.invokeLater(new Runnable(){
            @Override
            public void run(){
                Reader in = new StringReader("<HTML><BODY>"+content+"</BODY></HTML>");//NOI18N                
                try{
                    setContentType("text/html"); //NOI18N
                    Document doc = getDocument();
                    doc.remove(0, doc.getLength());
                    getEditorKit().read(in, getDocument(), 0);  //!!! still too expensive to be called from AWT
                    setCaretPosition(0);
                    if (reference != null) {
                        SwingUtilities.invokeLater(new Runnable(){
                            @Override
                            public void run(){
                                scrollToReference(reference);
                            }
                        });
                    } else {
                        scrollRectToVisible(new Rectangle(0,0,0,0));
                    }
                } catch (IOException | BadLocationException ioe) {
                    LOGGER.log(Level.WARNING, "An exception occurred while setting HTML content.", ioe);
                }
            }
        });
    }
    
    @Override
    protected EditorKit createDefaultEditorKit() {
        // it is extremelly slow to init it
        if (htmlKit == null){
            htmlKit= new HTMLEditorKit ();
            setEditorKit(htmlKit);

            // override the Swing default CSS to make the HTMLEditorKit use the
            // same font as the rest of the UI.
            
            // XXX the style sheet is shared by all HTMLEditorKits.  We must
            // detect if it has been tweaked by ourselves or someone else
            // (template description for example) and avoid doing the same
            // thing again
            
            if (htmlKit.getStyleSheet().getStyleSheets() != null)
                return htmlKit;
            
            javax.swing.text.html.StyleSheet css = new javax.swing.text.html.StyleSheet();
            java.awt.Font f = getFont();
            css.addRule(new StringBuffer("body { font-size: ").append(f.getSize()) // NOI18N
                        .append("; font-family: ").append(f.getName()).append("; }").toString()); // NOI18N
            css.addStyleSheet(htmlKit.getStyleSheet());
            htmlKit.setStyleSheet(css);
        }
        return htmlKit;
    }
}