import java.io.*;
import java.net.*;
import java.security.KeyStore;
import javax.net.*;
import javax.net.ssl.*;
import javax.security.cert.X509Certificate;
import java.util.HashMap;

public class server implements Runnable {
    private ServerSocket serverSocket = null;
    private static int numConnectedClients = 0;

    public server(ServerSocket ss) throws IOException {
        serverSocket = ss;
        newListener();
    }

    public String[] getGroupPrivilege(String subject){
        String group = "";
        String privilege = "";
        String[] result = new String[2];
        for(int i = 0; i < subject.length()-2; i++){
            if(subject.charAt(i)== 'O' && subject.charAt(i+1) == 'U' && subject.charAt(i+2) == '='){
                while(subject.charAt(i+3) != ','){
                    group+= subject.charAt(i+3);
                    i++;
                }
                break;
            }
        }
        for(int i = 0; i < subject.length()-2; i++){
            if(subject.charAt(i)== 'O' && subject.charAt(i+1) == '='){
                while(subject.charAt(i+2) != ','){
                    privilege+= subject.charAt(i+2);
                    i++;
                }
                break;
            }
        }
        result[0] = group;
        result[1]= privilege;
        return result;
    }

    public HashMap read(String username) throws FileNotFoundException, IOException{
        BufferedReader br = new BufferedReader(new FileReader("file.txt"));
        HashMap<String, String> passwords = new HashMap<String, String>();
        try {
            String line = br.readLine();

            while (line != null) {
                String[] user = line.split(" ", 0);
                passwords.put(user[0], user[1]);
                line = br.readLine();
            }
                return passwords;
            } finally {
                br.close();
            }
    }
    public String getGroup(String username) throws FileNotFoundException, IOException{
        BufferedReader br = new BufferedReader(new FileReader("file.txt"));
        try {
            String line = br.readLine();

            while (line != null) {
                String[] user = line.split(" ", 0);
                System.out.println(user[0]);
                if(user[0].equals(username)){
                    return user[1];
                }
                line = br.readLine();
            }
                return "-1";
            } finally {
                br.close();
            }
    }
    public String getName(String subject){
        String name = "";
        for(int i = 0; i < subject.length()-2; i++){
            if(subject.charAt(i)== 'C' && subject.charAt(i+1) == 'N' && subject.charAt(i+2) == '=' && subject.charAt(i+3) == '"'){
                while(subject.charAt(i+4) != '"'){
                    name+= subject.charAt(i+4);
                    i++;
                }
                break;
            }
        }
        return name;
    }
    public Boolean isAssociated(String name, String patient) throws FileNotFoundException, IOException{
        String file = patient+"/file.txt";

        BufferedReader br = new BufferedReader(new FileReader(file));
        try {
            String line = br.readLine();

            while (line != null) {
                if(line.equals(name)){
                    return true;
                }
                line = br.readLine();
            }
                return false;
            } finally {
                br.close();
            }
    }

    public Boolean getPass(String action, String subject, String patient) throws FileNotFoundException, IOException{
        String[] groupPrivilege = getGroupPrivilege(subject);
        switch(groupPrivilege[1]){

            case "government":
            if(action.equals("delete")){
                return true;
            }
            break;

            case "doctor":
            if(action.equals("read")){
                if(groupPrivilege[0].equals(getGroup(patient))){
                    return true;
                }
                return false;
            }
            if(action.equals("write"))
            break;

            case "nurse":
            return false;

        }
        return false;
    }
    public void run() {
        try {
            SSLSocket socket=(SSLSocket)serverSocket.accept();
            newListener();
            SSLSession session = socket.getSession();
            X509Certificate cert = (X509Certificate)session.getPeerCertificateChain()[0];
            String subject = cert.getSubjectDN().getName();
            String issuer = cert.getIssuerDN().getName();
            int serial = cert.getSerialNumber().intValue();
    	    numConnectedClients++;
            System.out.println("client connected");
            System.out.println("client name (cert subject DN field): " + subject);
            System.out.println("client name (cert issuer DN field): " + issuer);
            System.out.println(serial);
            System.out.println(numConnectedClients + " concurrent connection(s)\n");
            HashMap läs = read("ss");
            System.out.println(läs.get("rrrrr"));
            PrintWriter out = null;
            BufferedReader in = null;
            out = new PrintWriter(socket.getOutputStream(), true);
            in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            String[] res = getGroupPrivilege(subject);
            Boolean name =isAssociated(getName(subject), "1");
            System.out.println(name);
            String clientMsg = null;
            String action = in.readLine();
            String patient = in.readLine();
            String doc = in.readLine();
            while ((clientMsg = in.readLine()) != null) {
			    String rev = new StringBuilder(clientMsg).reverse().toString();
				out.println(rev);
				out.flush();
			}
			in.close();
			out.close();
			socket.close();
    	    numConnectedClients--;
            System.out.println("client disconnected");
            System.out.println(numConnectedClients + " concurrent connection(s)\n");
		} catch (IOException e) {
            System.out.println("Client died: " + e.getMessage());
            e.printStackTrace();
            return;
        }
    }

    private void newListener() { (new Thread(this)).start(); } // calls run()

    public static void main(String args[]) {
        System.out.println("\nServer Started\n");
        int port = -1;
        if (args.length >= 1) {
            port = Integer.parseInt(args[0]);
        }
        String type = "TLS";
        try {
            ServerSocketFactory ssf = getServerSocketFactory(type);
            ServerSocket ss = ssf.createServerSocket(port);
            ((SSLServerSocket)ss).setNeedClientAuth(true); // enables client authentication
            new server(ss);
        } catch (IOException e) {
            System.out.println("Unable to start Server: " + e.getMessage());
            e.printStackTrace();
        }
    }

    private static ServerSocketFactory getServerSocketFactory(String type) {
        if (type.equals("TLS")) {
            SSLServerSocketFactory ssf = null;
            try { // set up key manager to perform server authentication
                SSLContext ctx = SSLContext.getInstance("TLS");
                KeyManagerFactory kmf = KeyManagerFactory.getInstance("SunX509");
                TrustManagerFactory tmf = TrustManagerFactory.getInstance("SunX509");
                KeyStore ks = KeyStore.getInstance("JKS");
				KeyStore ts = KeyStore.getInstance("JKS");
                char[] password = "password".toCharArray();

                ks.load(new FileInputStream("serverkeystore"), password);  // keystore password (storepass)
                ts.load(new FileInputStream("servertruststore"), password); // truststore password (storepass)
                kmf.init(ks, password); // certificate password (keypass)
                tmf.init(ts);  // possible to use keystore as truststore here
                ctx.init(kmf.getKeyManagers(), tmf.getTrustManagers(), null);
                ssf = ctx.getServerSocketFactory();
                return ssf;
            } catch (Exception e) {
                e.printStackTrace();
            }
        } else {
            return ServerSocketFactory.getDefault();
        }
        return null;
    }
}