/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.rubypeople.rdt.internal.ui.text;

import java.io.IOException;
import java.io.Reader;

import org.eclipse.swt.SWT;
import org.eclipse.swt.SWTError;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.widgets.Display;

/**
 * Provides a set of convenience methods for creating HTML pages.
 */
public class HTMLPrinter {

	private static RGB BG_COLOR_RGB = null;

	static {
		final Display display = Display.getDefault();
		if (display != null && !display.isDisposed()) {
			try {
				display.asyncExec(new Runnable() {

					/*
					 * @see java.lang.Runnable#run()
					 */
					public void run() {
						BG_COLOR_RGB = display.getSystemColor(SWT.COLOR_INFO_BACKGROUND).getRGB();
					}
				});
			} catch (SWTError err) {
				// see: https://bugs.eclipse.org/bugs/show_bug.cgi?id=45294
				if (err.code != SWT.ERROR_DEVICE_DISPOSED) throw err;
			}
		}
	}

	private HTMLPrinter() {}

	private static String replace(String text, char c, String s) {

		int previous = 0;
		int current = text.indexOf(c, previous);

		if (current == -1) return text;

		StringBuffer buffer = new StringBuffer();
		while (current > -1) {
			buffer.append(text.substring(previous, current));
			buffer.append(s);
			previous = current + 1;
			current = text.indexOf(c, previous);
		}
		buffer.append(text.substring(previous));

		return buffer.toString();
	}

	public static String convertToHTMLContent(String content) {
		content = replace(content, '&', "&"); //$NON-NLS-1$
		content = replace(content, '"', """); //$NON-NLS-1$
		content = replace(content, '<', "<"); //$NON-NLS-1$
		return replace(content, '>', ">"); //$NON-NLS-1$
	}

	public static String read(Reader rd) {

		StringBuffer buffer = new StringBuffer();
		char[] readBuffer = new char[2048];

		try {
			int n = rd.read(readBuffer);
			while (n > 0) {
				buffer.append(readBuffer, 0, n);
				n = rd.read(readBuffer);
			}
			return buffer.toString();
		} catch (IOException x) {}

		return null;
	}

	public static void insertStyles(StringBuffer buffer, String[] styles) {
		if (styles == null || styles.length == 0) return;

		StringBuffer styleBuf = new StringBuffer(10 * styles.length);
		for (int i = 0; styles != null && i < styles.length; i++) {
			styleBuf.append(" style=\""); //$NON-NLS-1$
			styleBuf.append(styles[i]);
			styleBuf.append('"');
		}

		// Find insertion index
		int index = buffer.indexOf("<body "); //$NON-NLS-1$
		if (index == -1) return;

		buffer.insert(index + 5, styleBuf);
	}

	public static void insertPageProlog(StringBuffer buffer, int position, RGB bgRGB) {
		if (bgRGB == null)
			insertPageProlog(buffer, position);
		else {
			StringBuffer pageProlog = new StringBuffer(60);
			pageProlog.append("<html><body text=\"#000000\" bgcolor=\""); //$NON-NLS-1$
			appendColor(pageProlog, bgRGB);
			pageProlog.append("\"><font size=-1>"); //$NON-NLS-1$
			buffer.insert(position, pageProlog.toString());
		}
	}
	
	public static void insertPageProlog(StringBuffer buffer, int position, String styleSheet) {
		insertPageProlog(buffer, position, getBgColor(), styleSheet); 
	}
	
	public static void insertPageProlog(StringBuffer buffer, int position, RGB bgRGB, String styleSheet) {
		
		if (bgRGB == null)
			insertPageProlog(buffer, position, styleSheet);
		else {
			StringBuffer pageProlog= new StringBuffer(300);
			
			pageProlog.append("<html>"); //$NON-NLS-1$
			
			appendStyleSheetURL(pageProlog, styleSheet);
			
			pageProlog.append("<body text=\"#000000\" bgcolor=\""); //$NON-NLS-1$
			appendColor(pageProlog, bgRGB);
			pageProlog.append("\">"); //$NON-NLS-1$
			
			buffer.insert(position,  pageProlog.toString());
		}
	}
	
	private static void appendStyleSheetURL(StringBuffer buffer, String styleSheet) {
		if (styleSheet == null)
			return;
		
		buffer.append("<head><style CHARSET=\"ISO-8859-1\" TYPE=\"text/css\">"); //$NON-NLS-1$
		buffer.append(styleSheet);
		buffer.append("</style></head>"); //$NON-NLS-1$
	}

	private static void appendColor(StringBuffer buffer, RGB rgb) {
		buffer.append('#');
		buffer.append(Integer.toHexString(rgb.red));
		buffer.append(Integer.toHexString(rgb.green));
		buffer.append(Integer.toHexString(rgb.blue));
	}

	public static void insertPageProlog(StringBuffer buffer, int position) {
		insertPageProlog(buffer, position, getBgColor()); //$NON-NLS-1$
	}

	private static RGB getBgColor() {
		if (BG_COLOR_RGB != null)
			return BG_COLOR_RGB;
		return new RGB(255, 255, 225); // RGB value of info bg color on
											// WindowsXP
	}

	public static void addPageProlog(StringBuffer buffer) {
		insertPageProlog(buffer, buffer.length());
	}

	public static void addPageEpilog(StringBuffer buffer) {
		buffer.append("</font></body></html>"); //$NON-NLS-1$
	}

	public static void startBulletList(StringBuffer buffer) {
		buffer.append("<ul>"); //$NON-NLS-1$
	}

	public static void endBulletList(StringBuffer buffer) {
		buffer.append("</ul>"); //$NON-NLS-1$
	}

	public static void addBullet(StringBuffer buffer, String bullet) {
		if (bullet != null) {
			buffer.append("<li>"); //$NON-NLS-1$
			buffer.append(bullet);
			buffer.append("</li>"); //$NON-NLS-1$
		}
	}

	public static void addSmallHeader(StringBuffer buffer, String header) {
		if (header != null) {
			buffer.append("<h5>"); //$NON-NLS-1$
			buffer.append(header);
			buffer.append("</h5>"); //$NON-NLS-1$
		}
	}

	public static void addParagraph(StringBuffer buffer, String paragraph) {
		if (paragraph != null) {
			buffer.append("<p>"); //$NON-NLS-1$
			buffer.append(paragraph);
		}
	}

	public static void addParagraph(StringBuffer buffer, Reader paragraphReader) {
		if (paragraphReader != null) addParagraph(buffer, read(paragraphReader));
	}
}