//SERVER

import java.io.IOException;
import java.net.BindException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.LinkedList;

public class Server extends Thread{

    public static LinkedList <Korisnik> korisnici = new LinkedList <Korisnik>();
    public static LinkedList <ServerNit> niti = new LinkedList <ServerNit>();
    public static void main(String[] args) {

        int port = 10000;
        ServerSocket serverSoket = null;
        Socket soketZaKomunikaciju = null;
        try {
            serverSoket = new ServerSocket(port);

            while(true){
                System.out.println("Cekam na konekciju...");
                soketZaKomunikaciju = serverSoket.accept();
                System.out.println("Konekcija je uspostavljena");
                ServerNit klijent = new ServerNit(soketZaKomunikaciju);
                niti.add(klijent);
                klijent.start();
            }
        }catch (BindException e){
            System.out.println("Port je zauzet.");
        }
        catch (IOException e) {
            e.printStackTrace();
        }

    }

}

//KLIJENT

import java.io.BufferedReader;
import java.io.DataOutput;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.io.RandomAccessFile;
import java.net.Socket;
import java.net.UnknownHostException;

import org.omg.CORBA.portable.InputStream;

public class Klijent implements Runnable{

    static Socket soketZaKomunikaciju= null;
    static BufferedReader inputSaKonzole = null;
    static BufferedReader input = null;
    static PrintStream output = null;
    static   InputStream inbyte= null;

    public static void main(String[] args) {

        try {
            soketZaKomunikaciju=new Socket("localhost",10000);
            inputSaKonzole = new BufferedReader(new InputStreamReader(System.in));
            input = new BufferedReader(new InputStreamReader(soketZaKomunikaciju.getInputStream()));
            output = new PrintStream(soketZaKomunikaciju.getOutputStream());

            new Thread(new Klijent()).start();
            String str;
            while(true){
                str = input.readLine();
                System.out.println(str);

                if(str.startsWith("Dovidjenja"))
                    break;
            }

            soketZaKomunikaciju.close();
        } catch (UnknownHostException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            System.out.println("SERVER PAO!");
        }

    }

    @Override
    public void run() {

        try {
            String poruka;

            while(true){
                poruka = inputSaKonzole.readLine();
                output.println(poruka);
                if(poruka.equals("quit")){
                    break;
                }
            }

        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

}

//SERVERNIT

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.DataOutput;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.io.RandomAccessFile;
import java.net.Socket;
import java.util.Random;

import org.omg.CORBA.portable.InputStream;

public class ServerNit extends Thread{

    Socket soketNit = null;
    String username = null;
    String password = null;
    static int procitaniBajtovi=0;
    public static byte[] niz = new byte[1024];

    public ServerNit(Socket soket) {
        soketNit=soket;
    }

    @Override
    public void run() {
        try {
            while (true) {
                PrintStream out = new PrintStream(soketNit.getOutputStream());
                BufferedReader in = new BufferedReader(new InputStreamReader(soketNit.getInputStream()));
                OutputStream outbyte = soketNit.getOutputStream();

                out.println("Izaberite opciju: \n1. Upload fajlova\n2. Download fajlova\nZa prekid komunikacije ukucajte quit");
                out.flush();
                String opcija=in.readLine();
                if (opcija.equals("1")) {
                    boolean z = false;
                    boolean pom = false;
                    boolean x = false;
                    String karakteri = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
                    while (x == false) {
                        out.println("Da li zelite da se registrujete? Da/Ne");
                        out.flush();
                        String izbor=in.readLine();
                        if (izbor.equals("Da")) {
                            out.println("Unesite korisnicko ime: ");
                            out.flush();
                            username = in.readLine();
                            out.println("Unesite lozinku: ");
                            out.flush();
                            password = in.readLine();
                            for (int i = 0; i < Server.korisnici.size(); i++) {
                                if (Server.korisnici.get(i).username.equals(username)) {
                                    out.println("Vec ste registrovani!");
                                    out.flush();
                                    pom = true;
                                    break;
                                }
                            }
                            if (pom == false) {
                                Korisnik korisnik = new Korisnik(username, password);
                                Server.korisnici.add(korisnik);
                                x = true;
                            }

                        } else if (izbor.equals("Ne")) {
                            out.println("Ako zelite da nastavite sa upload-om, molimo Vas da se prijavite");
                            out.flush();
                            out.println("Unesite korisnicko ime: ");
                            out.flush();
                            username = in.readLine();
                            out.println("Unesite lozinku: ");
                            out.flush();
                            password = in.readLine();
                            for (int i = 0; i < Server.korisnici.size(); i++) {
                                if (Server.korisnici.get(i).username.equals(username)
                                        && Server.korisnici.get(i).password.equals(password)) {
                                    out.println("Uspesno ste se prijavili!");
                                    out.flush();
                                    pom = true;
                                    x = true;
                                    break;
                                }
                            }
                            if (pom == false) {
                                out.println("Neuspesno prijavljivanje!");
                            }

                        } else {
                            out.println("Greska!! Unesite Da ili Ne!");
                        }
                    }

                    while (z == false) {
                        out.println("Mozete uneti najvise 500 karaktera");
                        out.flush();
                        String tekst=in.readLine();
                        if (tekst.length() > 500) {
                            out.println("Greska! Uneli ste vise od 500 karaktera!");
                        } else {
                            out.println("Unesite naziv fajla: ");
                            out.flush();
                            String naziv = in.readLine();
                            String id = "";
                            Random r = new Random();
                            for (int i = 0; i < 10; i++) {
                                id = id + karakteri.charAt(r.nextInt(karakteri.length()));
                            }
                            out.println("Kod za upload-ovani fajl je " + id);
                            out.flush();
                            for (int i = 0; i < Server.korisnici.size(); i++) {
                                if (Server.korisnici.get(i).username.equals(username)) {
                                    Fajl f = new Fajl(id);
                                    f.fajl = new File(naziv);
                                    RandomAccessFile raf = new RandomAccessFile(f.fajl, "rw");
                                    raf.writeUTF(tekst);
                                    raf.close();
                                    Server.korisnici.get(i).fajlovi.add(f);
                                }
                            }
                            out.println("Da li zelite da vidite koje ste fajlove upload-ovali? Da/Ne");
                            out.flush();
                            String izbor2=in.readLine();
                            if (izbor2.equals("Da")) {
                                for (int i = 0; i < Server.korisnici.size(); i++) {
                                    if (Server.korisnici.get(i).username.equals(username)) {
                                        for (int j = 0; j < Server.korisnici.get(i).fajlovi.size(); j++) {
                                            out.println("Kod za fajl: " + Server.korisnici.get(i).fajlovi.get(j).id + " Naziv fajla: "
                                                    + Server.korisnici.get(i).fajlovi.get(j).fajl.getName()+"\n");
                                        }
                                    }
                                }
                            }
                            z = true;
                        }
                    }
                } else if (opcija.equals("2")) {
                    out.println("Unesite kod za fajl koji zelite da download-ujete");
                    out.flush();
                    String kod=in.readLine();
                    boolean y = false;
                    for (int i = 0; i < Server.korisnici.size(); i++) {
                        for (int j = 0; j < Server.korisnici.get(i).fajlovi.size(); j++) {
                            if (Server.korisnici.get(i).fajlovi.get(j).id.equals(kod)) {
                                RandomAccessFile citanje = new RandomAccessFile(Server.korisnici.get(i).fajlovi.get(j).fajl, "rw");
                                RandomAccessFile download= new RandomAccessFile(Server.korisnici.get(i).fajlovi.get(j).fajl.getName(), "rw");
                                while(true){
                                    procitaniBajtovi = citanje.read(niz);
                                    if(procitaniBajtovi == -1){
                                        break;
                                    }
                                    out.println("Sadrzaj fajla: ");
                                    out.flush();
                                    outbyte.write(niz,0,procitaniBajtovi);
                                    download.write(niz,0,procitaniBajtovi);
                                    out.println("\n");
                                }
                                citanje.close();
                                download.close();
                                y = true;
                                break;
                            }
                        }
                    }
                    if (y == false) {
                        out.println("Ne postoji fajl sa unetim kodom");
                    }
                } else {
                    out.println("Morate izabrati 1 ili 2!");
                }
            }


        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}

//KORISNIK

import java.io.File;
import java.util.LinkedList;

public class Korisnik {

    public String username;
    public String password;
    public LinkedList <Fajl> fajlovi = new LinkedList <Fajl>();

    public Korisnik(String ime, String lozinka){
        username = ime;
        password = lozinka;

    }
}

//FAJL

import java.io.File;

public class Fajl {

    public String id;
    public File fajl;

    public Fajl(String id){
        this.id=id;
    }

}