package de.frankfiedler.cms.client.transformer;

/**
 * The default transformer used by makeYourNet. Does some really basic
 * conversion.
 */
public class DefaultTransformer implements Transformer {

	public String getAsciiFromHtml(String html) {

		// System.out.println("html ascii before:"+html);

		// cut off all whitespace except space
		String result = html.replaceAll("[\\x00-\\x1F]", "");

		// cut off space before <br>
		result = result.replaceAll(" +<br ?/? ?>", "<br>");

		// cut off &nbsp; before <br>
		result = result.replaceAll("(&nbsp;)+<br ?/? ?>", "<br>");

		// reduce all repeated space to one
		result = result.replaceAll("\\s+", " ");

		// replace every appearence of <br> with newline
		result = result.replaceAll("<br ?/? ?>", "\n");

		// replace all &nbsp; with space
		result = result.replaceAll("&nbsp;", " ");

		// special letters
		result = result.replaceAll("&quot;", "\"");
		result = result.replaceAll("&auml;", "\u00e4");
		result = result.replaceAll("&Auml;", "\u00c4");
		result = result.replaceAll("&uuml;", "\u00fc");
		result = result.replaceAll("&Uuml;", "\u00dc");
		result = result.replaceAll("&ouml;", "\u00f6");
		result = result.replaceAll("&Ouml;", "\u00d6");
		result = result.replaceAll("&szlig;", "\u00df");// \u00df
		result = result.replaceAll("&euro;", "\u20ac"); // \u0080

		// System.out.println("html ascii after:"+html);

		return result;
	}

	public String getHtmlFromAscii(String ascii) {

		// System.out.println("ascii ->html before: " + ascii);
		
		// Quotations are replaced only outside tags, to leave the user with the
		// possibility to enter html
		String result = replaceQuotsOutsideTags(ascii);
		
		// newline is replaced by <br> plus newline
		// (The newline is for readability)
		// ascii=ascii.replaceAll("\"", "quot");
		result = result.replaceAll("\\n", "<br>\n");

		// Replace <br> after a newline with &nbsp;<br>
		// So it is not surpressed by the browser
		result = result.replaceAll("\\n<br>", "\n&nbsp;<br>");

		// Replace tabs with 6 &nbsp;
		result = result.replaceAll("\\t", "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;");

		// Replace 2 spaces by 2 &nbsp;
		result = result.replaceAll(" {2}", "&nbsp;&nbsp;");

		// special letters

		result = result.replaceAll("\u00e4", "&auml;");
		result = result.replaceAll("\u00c4", "&Auml;");
		result = result.replaceAll("\u00fc", "&uuml;");
		result = result.replaceAll("\u00dc", "&Uuml;");
		result = result.replaceAll("\u00f6", "&ouml;");
		result = result.replaceAll("\u00d6", "&Ouml;");
		result = result.replaceAll("\u00df", "&szlig;"); // \u00df
		result = result.replaceAll("\u20ac", "&euro;"); // \u0080

		// System.out.println("ascii -> html after: " + ascii);

		return result;
	}

	/**
	 * An algorithm to replace the double quotes with &quot; but not
	 * inside html tags
	 * 
	 * @param s the text to process
	 * @return the result
	 */
	private String replaceQuotsOutsideTags(String s) {
		StringBuilder r = new StringBuilder();
		String m = s;
		while (m.indexOf("<") != -1) {
			// There is at least one <
			int p = m.indexOf("<");
			r.append(replaceQuotes(m.substring(0, p))); // add the part before < to
																									// result
			m = m.substring(p); // cut off the part before <
			p = m.indexOf(">");
			if (p != -1) {
				// There is a closing >
				r.append(m.substring(0, p)); // add part inside <> without change to
																			// result
				m = m.substring(p); // cut off the processed part
			} else {
				// There is no closing >, so we assume that it is not valid html and
				// replace the quots
				r.append(replaceQuotes(m));
				m = "";
			}

		}
		// add rest
		r.append(replaceQuotes(m));
		return r.toString();
	}

	protected String replaceQuotes(String string) {
		String result = string.replaceAll("\"", "&quot;");
		return result;
	}

}