/*
 * Copyright 2005-2006 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 * THIS FILE WAS MODIFIED BY SUN MICROSYSTEMS, INC.
 */
 


package com.sun.xml.internal.fastinfoset.sax;

import java.io.*;

public class SystemIdResolver {
    
    public SystemIdResolver() {
    }
    
    public static String getAbsoluteURIFromRelative(String localPath) {
        if (localPath == null || localPath.length() == 0) {
            return "";
        }
        
        String absolutePath = localPath;
        if (!isAbsolutePath(localPath)) {
            try {
                absolutePath = getAbsolutePathFromRelativePath(localPath);
            }
            catch (SecurityException se) {
                return "file:" + localPath;
            }
        }
        
        String urlString;
        if (null != absolutePath) {
            urlString = absolutePath.startsWith(File.separator) ?
                ("file://" + absolutePath) :
                ("file:///" + absolutePath);
        }
        else {
            urlString = "file:" + localPath;
        }
        
        return replaceChars(urlString);
    }
    
    private static String getAbsolutePathFromRelativePath(String relativePath) {
        return new File(relativePath).getAbsolutePath();
    }
    
    public static boolean isAbsoluteURI(String systemId) {
        if (systemId == null) {
            return false;
        }
        
        if (isWindowsAbsolutePath(systemId)) {
            return false;
        }
        
        final int fragmentIndex = systemId.indexOf('#');
        final int queryIndex = systemId.indexOf('?');
        final int slashIndex = systemId.indexOf('/');
        final int colonIndex = systemId.indexOf(':');
        
        int index = systemId.length() -1;
        if (fragmentIndex > 0) {
            index = fragmentIndex;
        }
        if (queryIndex > 0 && queryIndex < index) {
            index = queryIndex;
        }
        if (slashIndex > 0 && slashIndex <index) {
            index = slashIndex;
        }
        return (colonIndex > 0) && (colonIndex < index);        
    }
    
    public static boolean isAbsolutePath(String systemId) {
        if(systemId == null)
            return false;
        final File file = new File(systemId);
        return file.isAbsolute();
        
    }
    
    private static boolean isWindowsAbsolutePath(String systemId) {
        if(!isAbsolutePath(systemId))
            return false;
        if (systemId.length() > 2
        && systemId.charAt(1) == ':'
        && Character.isLetter(systemId.charAt(0))
        && (systemId.charAt(2) == '\\' || systemId.charAt(2) == '/'))
            return true;
        else
            return false;
    }
    
    private static String replaceChars(String str) {
        StringBuffer buf = new StringBuffer(str);
        int length = buf.length();
        for (int i = 0; i < length; i++) {
            char currentChar = buf.charAt(i);
            // Replace space with "%20"
            if (currentChar == ' ') {
                buf.setCharAt(i, '%');
                buf.insert(i+1, "20");
                length = length + 2;
                i = i + 2;
            }
            // Replace backslash with forward slash
            else if (currentChar == '\\') {
                buf.setCharAt(i, '/');
            }
        }
        
        return buf.toString();
    }
    
    public static String getAbsoluteURI(String systemId) {
        String absoluteURI = systemId;
        if (isAbsoluteURI(systemId)) {
            if (systemId.startsWith("file:")) {
                String str = systemId.substring(5);
                
                if (str != null && str.startsWith("/")) {
                    if (str.startsWith("///") || !str.startsWith("//")) {
                        int secondColonIndex = systemId.indexOf(':', 5);
                        if (secondColonIndex > 0) {
                            String localPath = systemId.substring(secondColonIndex-1);
                            try {
                                if (!isAbsolutePath(localPath))
                                    absoluteURI = systemId.substring(0, secondColonIndex-1) +
                                    getAbsolutePathFromRelativePath(localPath);
                            }
                            catch (SecurityException se) {
                                return systemId;
                            }
                        }
                    }
                }
                else {
                    return getAbsoluteURIFromRelative(systemId.substring(5));
                }
                
                return replaceChars(absoluteURI);
            }
            else  {
                return systemId;
            }
        }
        else {
            return getAbsoluteURIFromRelative(systemId);
        }
    }
}
