/*
 * ConnectBot: simple, powerful, open-source SSH client for Android
 * Copyright 2007 Kenny Root, Jeffrey Sharkey
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package ch.ethz.ssh2.compression;

import java.util.Vector;

/**
 * @author Kenny Root
 *
 */
public class CompressionFactory {
    static class CompressorEntry {
        String type;
        String compressorClass;

        public CompressorEntry(String type, String compressorClass) {
            this.type = type;
            this.compressorClass = compressorClass;
        }
    }

    static Vector<CompressorEntry> compressors = new Vector<CompressorEntry>();

    static {
        /* Higher Priority First */
        compressors.addElement(new CompressorEntry("zlib", "ch.ethz.ssh2.compression.Zlib"));
        compressors.addElement(new CompressorEntry("zlib@openssh.com", "ch.ethz.ssh2.compression.ZlibOpenSSH"));
        compressors.addElement(new CompressorEntry("none", ""));
    }

    public static String[] getDefaultCompressorList() {
        String list[] = new String[compressors.size()];

        for (int i = 0; i < compressors.size(); i++) {
            CompressorEntry ce = compressors.elementAt(i);
            list[i] = new String(ce.type);
        }

        return list;
    }

    public static void checkCompressorList(String[] compressorCandidates) {
        for (int i = 0; i < compressorCandidates.length; i++)
            getEntry(compressorCandidates[i]);
    }

    public static Compressor createCompressor(String type) {
        try {
            CompressorEntry ce = getEntry(type);

            if ("".equals(ce.compressorClass))
                return null;

            Class<?> cc = Class.forName(ce.compressorClass);
            Compressor cmp = (Compressor) cc.newInstance();
            return cmp;
        }
        catch (Exception e) {
            throw new IllegalArgumentException("Cannot instantiate " + type);
        }
    }

    private static CompressorEntry getEntry(String type) {
        for (int i = 0; i < compressors.size(); i++) {
            CompressorEntry ce = compressors.elementAt(i);

            if (ce.type.equals(type))
                return ce;
        }

        throw new IllegalArgumentException("Unkown algorithm " + type);
    }
}