package src;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.net.DatagramSocket;
import java.net.InetAddress;

public class Server implements Runnable
{

    public static String leader = "";
    public static boolean isLeader = false;
    public static ServerSocket serverSocket = null; // Sempre que for o leader vai ter valor definido
    public static ArrayList<String> IP_LIST = new ArrayList<>();
    public static int PORT = 4000;
    public static boolean IN_SELECTION = false;

    public Server()
    {
        System.out.println("Exec 1");
        Thread t = new Thread(this);
        t.start();
    }

    @Override
    public void run()
    {
        Server.IP_LIST.add("10.3.15.17");
        Server.IP_LIST.add("10.3.15.18");
        Server.IP_LIST.add("10.3.15.19");

        String candidateLeader = "";
        while (true)
        {
            try
            {
                if (Server.isLeader())
                {
                    System.out.println("--------------------------------");

                    try (final DatagramSocket socket = new DatagramSocket())
                    {
                        socket.connect(InetAddress.getByName("8.8.8.8"), 10002);
                        String ip = socket.getLocalAddress().getHostAddress();

                        System.out.println("I am the leader - " + ip);
                    }

                    Thread.sleep(5 * 1000);

                } else if (Server.pingLeader())
                {
                    System.out.println("------------------------------------");
                    System.out.println("I am not the leader, but ping to leader responded");
                    System.out.println("The leader is: " + Server.leader);

                    System.out.println("Wait 10 seconds");
                    Thread.sleep(10 * 1000);
                } else
                {
                    System.out.println("----------------------------------");
                    System.out.println("There is no leader. Initializing election.");

                    if (!Server.IN_SELECTION)
                    {
                        candidateLeader = Server.selectLeader();

                        System.out.println("Leader returned - " + candidateLeader);

                        if (candidateLeader.isEmpty())
                        {
                            System.out.println("Assuming leadership...");
                            Server.takeLeadership();
                        } else
                        {
                            System.out.println("Defining candidate leader...");
                            Server.defineLider(candidateLeader);
                        }
                    }
                }
            } catch (Exception e)
            {
                try
                {
                    Server.resetLeader();
                } catch (IOException ex)
                {
                    Logger.getLogger(Server.class.getName()).log(Level.SEVERE, null, ex);
                }
                e.printStackTrace();
            }
        }
    }

    public static boolean hasLeader()
    {
        return Server.leader != null;
    }

    public static boolean isLeader()
    {
        return Server.isLeader;
    }

    public static void resetLeader() throws IOException
    {
        Server.isLeader = false;

        Server.leader = null;
    }

    public static String getHighestIp(ArrayList<String> vet)
    {

        String leaderIP = "";
        int comparator = 0;

        for (String string : vet)
        {
            String[] split = string.split("\\.");

            if (Integer.parseInt(split[3]) > comparator)
            {
                comparator = Integer.parseInt(split[3]);
                leaderIP = string;
            }
        }

        return leaderIP;
    }

    public static String selectLeader() throws IOException
    {

        String leader = "";
        Server.IN_SELECTION = true;
        ArrayList<String> vetInterno = Server.clone(Server.IP_LIST);

        for (int i = 0; i < vetInterno.size(); i++)
        {

            String highestIp = Server.getHighestIp(vetInterno);
            System.out.println("Tryng pinging - " + highestIp);

            try
            {
                Socket socket = new Socket();
                socket.connect(new InetSocketAddress(highestIp, Server.PORT), 10 * 1000);

                ObjectOutputStream saida = new ObjectOutputStream(socket.getOutputStream());
                ObjectInputStream entrada = new ObjectInputStream(socket.getInputStream());

                saida.flush();
                saida.writeObject("pinging...");

                leader = highestIp;
                break;
            } catch (Exception e)
            {
                System.out.println("Did not respond...");
                vetInterno.remove(vetInterno.indexOf(highestIp));
                continue;
            }

        }

        Server.IN_SELECTION = false;
        return leader;
    }

    public static ArrayList<String> clone(ArrayList<String> list)
    {
        ArrayList<String> clone = new ArrayList<String>(list.size());
        for (int i = 0; i < list.size(); i++)
        {
            clone.add(list.get(i));
        }
        return clone;
    }

    public static boolean defineLider(String s) throws IOException
    {
        Server.resetLeader();
        Server.leader = s;
        return true;
    }

    public static boolean takeLeadership() throws IOException
    {

        Server.isLeader = true;

        return true;
    }

    public static boolean pingLeader()
    {

        if (Server.leader.isEmpty())
        {
            return false;
        }

        boolean ping = false;
        System.out.println("Pinging leader...");
        try
        {
            Socket socket = new Socket();
            socket.connect(new InetSocketAddress(Server.leader, Server.PORT), 10 * 1000);

            ObjectOutputStream saida = new ObjectOutputStream(socket.getOutputStream());
            ObjectInputStream entrada = new ObjectInputStream(socket.getInputStream());

            saida.flush();
            saida.writeObject("pinging...");

            ping = true;

        } catch (Exception e)
        {
            System.out.println("Leader did not respond...");

        }

        return ping;
    }

    public static void main(String[] args) throws IOException, ClassNotFoundException
    {
        new Server();
    }
}