/* ====================================================================
 * Copyright (c) 2006 J.T. Beetstra
 *
 * Permission is hereby granted, free of charge, to any person obtaining 
 * a copy of this software and associated documentation files (the 
 * "Software"), to deal in the Software without restriction, including 
 * without limitation the rights to use, copy, modify, merge, publish, 
 * distribute, sublicense, and/or sell copies of the Software, and to 
 * permit persons to whom the Software is furnished to do so, subject to 
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be 
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 * ====================================================================
 */

package com.beetstra.jutf7;

import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;

/**
 * <p>
 * Charset service-provider class used for both variants of the UTF-7 charset
 * and the modified-UTF-7 charset.
 * </p>
 * 
 * @author Jaap Beetstra
 */
public class CharsetProvider extends java.nio.charset.spi.CharsetProvider {
    private static final String UTF7_NAME = "UTF-7";
    private static final String UTF7_O_NAME = "X-UTF-7-OPTIONAL";
    private static final String UTF7_M_NAME = "X-MODIFIED-UTF-7";
    private static final String[] UTF7_ALIASES = new String[] {
            "UNICODE-1-1-UTF-7", "CSUNICODE11UTF7", "X-RFC2152", "X-RFC-2152"
    };
    private static final String[] UTF7_O_ALIASES = new String[] {
            "X-RFC2152-OPTIONAL", "X-RFC-2152-OPTIONAL"
    };
    private static final String[] UTF7_M_ALIASES = new String[] {
            "X-IMAP-MODIFIED-UTF-7", "X-IMAP4-MODIFIED-UTF7", "X-IMAP4-MODIFIED-UTF-7",
            "X-RFC3501", "X-RFC-3501"
    };
    private Charset utf7charset = new UTF7Charset(UTF7_NAME, UTF7_ALIASES, false);
    private Charset utf7oCharset = new UTF7Charset(UTF7_O_NAME, UTF7_O_ALIASES, true);
    private Charset imap4charset = new ModifiedUTF7Charset(UTF7_M_NAME, UTF7_M_ALIASES);
    private List charsets;

    public CharsetProvider() {
        charsets = Arrays.asList(new Object[] {
                utf7charset, imap4charset, utf7oCharset
        });
    }

    /**
     * {@inheritDoc}
     */
    public Charset charsetForName(String charsetName) {
        charsetName = charsetName.toUpperCase();
        for (Iterator iter = charsets.iterator(); iter.hasNext();) {
            Charset charset = (Charset)iter.next();
            if (charset.name().equals(charsetName))
                return charset;
        }
        for (Iterator iter = charsets.iterator(); iter.hasNext();) {
            Charset charset = (Charset)iter.next();
            if (charset.aliases().contains(charsetName))
                return charset;
        }
        return null;
    }

    /**
     * {@inheritDoc}
     */
    public Iterator charsets() {
        return charsets.iterator();
    }
}