/*******************************************************************************
 * Copyright (c) 2016 Association for Decentralized Information Management
 * in Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     THTH ry - initial API and implementation
 *******************************************************************************/
package org.simantics.debug.browser.utils;

public class Escapes {

    public static String html(String s) {
        if (!containsAnyOf(s, HTML_CHARS_TO_ESCAPE))
            return s;
        return batchReplace(s, HTML_CHARS_TO_ESCAPE, HTML_CHAR_REPLACEMENTS);
    }

    private static final char[] HTML_CHARS_TO_ESCAPE = { '&', '<', '>', '\n' };
    private static final String[] HTML_CHAR_REPLACEMENTS = { "&amp;", "&lt;", "&gt;", "<br/>" };

    private static boolean containsAnyOf(String s, char[] chars) {
        int l = s.length();
        for (int i = 0; i < l; ++i) {
            char p = s.charAt(i);
            for (char ch : chars)
                if (p == ch)
                    return true;
        }
        return false;
    }

    private static String batchReplace(String s, char[] charsToReplace, String[] replacements) {
        int l = s.length();
        int rl = charsToReplace.length;
        StringBuilder sb = new StringBuilder(l*2);
        nextChar:
            for (int i = 0; i < l; ++i) {
                char p = s.charAt(i);
                for (int j = 0; j < rl; ++j) {
                    if (p == charsToReplace[j]) {
                        sb.append(replacements[j]);
                        continue nextChar;
                    }
                }
                sb.append(p);
            }
        return sb.toString();
    }

    public static void main(String[] args) {
        System.out.println(html("><&\nfoobar\n<>"));
    }

}