/**
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.airavata.api.server;

import com.google.inject.Guice;
import com.google.inject.Injector;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import org.apache.airavata.api.Airavata;
import org.apache.airavata.api.server.handler.AiravataServerHandler;
import org.apache.airavata.api.server.util.Constants;
import org.apache.airavata.common.exception.ApplicationSettingsException;
import org.apache.airavata.common.utils.IServer;
import org.apache.airavata.common.utils.ServerSettings;
import org.apache.airavata.model.error.AiravataErrorType;
import org.apache.airavata.model.error.AiravataSystemException;
import org.apache.airavata.service.security.interceptor.SecurityModule;
import org.apache.thrift.server.TServer;
import org.apache.thrift.server.TThreadPoolServer;
import org.apache.thrift.transport.TSSLTransportFactory;
import org.apache.thrift.transport.TServerSocket;
import org.apache.thrift.transport.TServerTransport;
import org.apache.thrift.transport.TTransportException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class AiravataAPIServer implements IServer {

    private static final Logger logger = LoggerFactory.getLogger(AiravataAPIServer.class);
    private static final String SERVER_NAME = "Airavata API Server";
    private static final String SERVER_VERSION = "1.0";

    private ServerStatus status;

    private TServer server, TLSServer;

    public AiravataAPIServer() {
        setStatus(ServerStatus.STOPPED);
    }

    public void startAiravataServer(Airavata.Processor<Airavata.Iface> airavataAPIServer)
            throws AiravataSystemException {
        try {
            final String serverHost = ServerSettings.getSetting(Constants.API_SERVER_HOST, null);
            final int serverPort = Integer.parseInt(ServerSettings.getSetting(Constants.API_SERVER_PORT, "8930"));

            if (!ServerSettings.isTLSEnabled()) {
                TServerTransport serverTransport;
                if (serverHost == null) {
                    serverTransport = new TServerSocket(serverPort);
                } else {
                    InetSocketAddress inetSocketAddress = new InetSocketAddress(serverHost, serverPort);
                    serverTransport = new TServerSocket(inetSocketAddress);
                }
                TThreadPoolServer.Args options = new TThreadPoolServer.Args(serverTransport);
                options.minWorkerThreads =
                        Integer.parseInt(ServerSettings.getSetting(Constants.API_SERVER_MIN_THREADS, "50"));
                server = new TThreadPoolServer(options.processor(airavataAPIServer));
                new Thread(() -> {
                            server.serve();
                            setStatus(ServerStatus.STOPPED);
                            logger.info("Airavata API Server Stopped.");
                        })
                        .start();
                new Thread(() -> {
                            while (!server.isServing()) {
                                try {
                                    Thread.sleep(500);
                                } catch (InterruptedException e) {
                                    break;
                                }
                            }
                            if (server.isServing()) {
                                setStatus(ServerStatus.STARTED);
                                logger.info("Starting Airavata API Server on Port " + serverPort);
                                logger.info("Listening to Airavata Clients ....");
                            }
                        })
                        .start();
                logger.info("Started API Server ....");
            } else {
                var TLSParams = new TSSLTransportFactory.TSSLTransportParameters();
                TLSParams.setKeyStore(ServerSettings.getKeyStorePath(), ServerSettings.getKeyStorePassword());
                var TLSServerTransport = TSSLTransportFactory.getServerSocket(
                        serverPort, ServerSettings.getTLSClientTimeout(), InetAddress.getByName(serverHost), TLSParams);
                TThreadPoolServer.Args settings = new TThreadPoolServer.Args(TLSServerTransport);
                settings.minWorkerThreads =
                        Integer.parseInt(ServerSettings.getSetting(Constants.API_SERVER_MIN_THREADS, "50"));
                TLSServer = new TThreadPoolServer(settings.processor(airavataAPIServer));
                new Thread(() -> {
                            TLSServer.serve();
                            setStatus(ServerStatus.STOPPED);
                            logger.info("Airavata API Server over TLS Stopped.");
                        })
                        .start();
                new Thread(() -> {
                            while (!TLSServer.isServing()) {
                                try {
                                    Thread.sleep(500);
                                } catch (InterruptedException e) {
                                    break;
                                }
                            }
                            if (TLSServer.isServing()) {
                                setStatus(ServerStatus.STARTED);
                            }
                        })
                        .start();
                logger.info("API server started over TLS on Port: " + serverPort + " ...");
            }

        } catch (TTransportException | ApplicationSettingsException | UnknownHostException e) {
            logger.error("Failed to start API server ...", e);
            setStatus(ServerStatus.FAILED);
            throw new AiravataSystemException(AiravataErrorType.INTERNAL_ERROR);
        }
    }

    public static void main(String[] args) {
        try {
            AiravataAPIServer server = new AiravataAPIServer();
            server.start();
        } catch (Exception e) {
            logger.error("Error while initializing Airavata API server", e);
        }
    }

    @Override
    public void start() throws Exception {
        setStatus(ServerStatus.STARTING);
        // Obtain a AiravataServerHandl
        // er object from Guice which is wrapped with interception logic.
        Injector injector = Guice.createInjector(new SecurityModule());
        Airavata.Processor<Airavata.Iface> airavataAPIServer =
                new Airavata.Processor<Airavata.Iface>(injector.getInstance(AiravataServerHandler.class));
        startAiravataServer(airavataAPIServer);
    }

    @Override
    public void stop() throws Exception {
        if ((!ServerSettings.isTLSEnabled()) && server.isServing()) {
            setStatus(ServerStatus.STOPING);
            server.stop();
        }
        // stop the Airavata API server hosted over TLS.
        if ((ServerSettings.isTLSEnabled()) && TLSServer.isServing()) {
            TLSServer.stop();
        }
    }

    @Override
    public void restart() throws Exception {
        stop();
        start();
    }

    @Override
    public void configure() throws Exception {
        // TODO Auto-generated method stub

    }

    @Override
    public ServerStatus getStatus() throws Exception {
        return status;
    }

    private void setStatus(ServerStatus stat) {
        status = stat;
        status.updateTime();
    }

    @Override
    public String getName() {
        return SERVER_NAME;
    }

    @Override
    public String getVersion() {
        return SERVER_VERSION;
    }
}
