/*
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:  
 *       "This product includes software developed by the 
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written 
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
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 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * [Additional notices, if required by prior licensing conditions]
 *
 */ 

package org.apache.tomcat.util.http;

import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Locale;
import java.util.StringTokenizer;
import java.util.Vector;

/**
 * Util to process the "Accept-Language" header. Used by facade to implement
 * getLocale() and by StaticInterceptor.
 *
 * Not optimized - it's very slow.
 * 
 * @author James Duncan Davidson [duncan@eng.sun.com]
 * @author James Todd [gonzo@eng.sun.com]
 * @author Jason Hunter [jch@eng.sun.com]
 * @author Harish Prabandham
 * @author costin@eng.sun.com
 */
public class AcceptLanguage {

    public static Locale getLocale(String acceptLanguage) {
	if( acceptLanguage == null ) return Locale.getDefault();

        Hashtable languages = new Hashtable();
        Vector quality=new Vector();
        processAcceptLanguage(acceptLanguage, languages,quality);

        if (languages.size() == 0) return Locale.getDefault();

        Vector l = new Vector();
        extractLocales( languages,quality, l);

        return (Locale)l.elementAt(0);
    }

    public static Enumeration getLocales(String acceptLanguage) {
    	// Short circuit with an empty enumeration if null header
        if (acceptLanguage == null) {
            Vector v = new Vector();
            v.addElement(Locale.getDefault());
            return v.elements();
        }
	
        Hashtable languages = new Hashtable();
        Vector quality=new Vector();
    	processAcceptLanguage(acceptLanguage, languages , quality);

        if (languages.size() == 0) {
            Vector v = new Vector();
            v.addElement(Locale.getDefault());
            return v.elements();
        }
    	Vector l = new Vector();
    	extractLocales( languages, quality , l);
    	return l.elements();
    }

    private static void processAcceptLanguage( String acceptLanguage,
					      Hashtable languages, Vector q)
    {
        StringTokenizer languageTokenizer =
            new StringTokenizer(acceptLanguage, ",");

        while (languageTokenizer.hasMoreTokens()) {
            String language = languageTokenizer.nextToken().trim();
            int qValueIndex = language.indexOf(';');
            int qIndex = language.indexOf('q');
            int equalIndex = language.indexOf('=');
            Double qValue = new Double(1);

            if (qValueIndex > -1 &&
                    qValueIndex < qIndex &&
                    qIndex < equalIndex) {
    	        String qValueStr = language.substring(qValueIndex + 1);
                language = language.substring(0, qValueIndex);
                qValueStr = qValueStr.trim().toLowerCase();
                qValueIndex = qValueStr.indexOf('=');
                qValue = new Double(0);
                if (qValueStr.startsWith("q") &&
                    qValueIndex > -1) {
                    qValueStr = qValueStr.substring(qValueIndex + 1);
                    try {
                        qValue = new Double(qValueStr.trim());
                    } catch (NumberFormatException nfe) {
                    }
                }
            }

            // XXX
            // may need to handle "*" at some point in time

            if (! language.equals("*")) {
                String key = qValue.toString();
                Vector v;
                if (languages.containsKey(key)) {
                    v = (Vector)languages.get(key) ;
                } else {
                    v= new Vector();
                    q.addElement(qValue);
                }
                v.addElement(language);
                languages.put(key, v);
            }
        }
    }

    private static void extractLocales(Hashtable languages, Vector q,Vector l)
    {
        // XXX We will need to order by q value Vector in the Future ?
        Enumeration e = q.elements();
        while (e.hasMoreElements()) {
            Vector v =
                (Vector)languages.get(((Double)e.nextElement()).toString());
            Enumeration le = v.elements();
            while (le.hasMoreElements()) {
    	        String language = (String)le.nextElement();
	        	String country = "";
        		int countryIndex = language.indexOf("-");
                if (countryIndex > -1) {
                    country = language.substring(countryIndex + 1).trim();
                    language = language.substring(0, countryIndex).trim();
                }
                l.addElement(new Locale(language, country));
            }
        }
    }


}
