/*
 * Copyright 2012 - 2020 Anton Tananaev (anton@traccar.org)
 *
 * 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 org.traccar;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.traccar.config.Keys;

import java.io.File;
import java.io.IOException;
import java.net.BindException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLDecoder;
import java.nio.charset.StandardCharsets;
import java.util.Enumeration;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

public class ServerManager {

    private static final Logger LOGGER = LoggerFactory.getLogger(ServerManager.class);

    private final List<TrackerServer> serverList = new LinkedList<>();
    private final Map<String, BaseProtocol> protocolList = new ConcurrentHashMap<>();

    private void loadPackage(String packageName) throws IOException, URISyntaxException, ReflectiveOperationException {

        List<String> names = new LinkedList<>();
        String packagePath = packageName.replace('.', '/');
        URL packageUrl = getClass().getClassLoader().getResource(packagePath);

        if (packageUrl.getProtocol().equals("jar")) {
            String jarFileName = URLDecoder.decode(packageUrl.getFile(), StandardCharsets.UTF_8.name());
            try (JarFile jf = new JarFile(jarFileName.substring(5, jarFileName.indexOf("!")))) {
                Enumeration<JarEntry> jarEntries = jf.entries();
                while (jarEntries.hasMoreElements()) {
                    String entryName = jarEntries.nextElement().getName();
                    if (entryName.startsWith(packagePath) && entryName.length() > packagePath.length() + 5) {
                        names.add(entryName.substring(packagePath.length() + 1, entryName.lastIndexOf('.')));
                    }
                }
            }
        } else {
            File folder = new File(new URI(packageUrl.toString()));
            File[] files = folder.listFiles();
            if (files != null) {
                for (File actual: files) {
                    String entryName = actual.getName();
                    names.add(entryName.substring(0, entryName.lastIndexOf('.')));
                }
            }
        }

        for (String name : names) {
            Class<?> protocolClass = Class.forName(packageName + '.' + name);
            if (BaseProtocol.class.isAssignableFrom(protocolClass) && Context.getConfig().hasKey(
                    Keys.PROTOCOL_PORT.withPrefix(BaseProtocol.nameFromClass(protocolClass)))) {
                BaseProtocol protocol = (BaseProtocol) protocolClass.getDeclaredConstructor().newInstance();
                serverList.addAll(protocol.getServerList());
                protocolList.put(protocol.getName(), protocol);
            }
        }
    }

    public ServerManager() throws IOException, URISyntaxException, ReflectiveOperationException {
        loadPackage("org.traccar.protocol");
    }

    public BaseProtocol getProtocol(String name) {
        return protocolList.get(name);
    }

    public void start() throws Exception {
        for (TrackerServer server: serverList) {
            try {
                server.start();
            } catch (BindException e) {
                LOGGER.warn("Port {} is disabled due to conflict", server.getPort());
            }
        }
    }

    public void stop() {
        for (TrackerServer server: serverList) {
            server.stop();
        }
        GlobalTimer.release();
    }

}