package davidhorak.authentication;

import davidhorak.Config;

import java.io.*;
import java.util.ArrayList;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Trida pro prihlasovani uzivatele
 */
public class Authenticator {
    private static ThreadLocal<Authenticator> instance = new ThreadLocal<>();

    public static Authenticator getInstance() {
        if(instance.get() == null){
            instance.set(new Authenticator());
        }

        return instance.get();
    }

    private String USER_FILE_URL = Config.getInstance().getUserFileUrl();
    private ArrayList<User> users = new ArrayList<>();
    private User currentUser = null;

    /**
     * Vrati aktualne prihlaseneho uzivatele
     */
    public User getCurrentUser() {
        return currentUser;
    }

    private Authenticator(){ }

    /**
     * Nacte uzivatele ze souboru
     * @throws IOException
     */
    public void load() throws IOException {
        FileInputStream file = new FileInputStream(USER_FILE_URL);
        BufferedReader reader = new BufferedReader(new InputStreamReader(file));

        String line;
        while((line = reader.readLine()) != null){
            Pattern p = Pattern.compile("^(\\w+):(\\w+)$");
            Matcher matcher = p.matcher(line);

            if(matcher.find()){
                String name = matcher.group(1);
                String password = matcher.group(2);

                users.add(new User(name, password));
            }
        }

        reader.close();
        file.close();
    }

    /**
     * Zapta se uzivatele na jmeno a heslo.
     * Pokud se data shoduji prihlasi uzivatele, pokud ne zeptase uzivatele znovu
     * @param inputStream InputStream ze socketu pro pro komunikaci s klientem
     * @param outputStream OutputStream ze socketu pro pro komunikaci s klientem
     * @throws IOException
     */
    public void authenticate(InputStream inputStream, OutputStream outputStream) throws IOException{
        PrintWriter writer = new PrintWriter(new OutputStreamWriter(outputStream), true);
        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));

        while(currentUser == null){
            writer.println("Jmeno: ");
            String name = reader.readLine();

            writer.println("Heslo: ");
            String password = reader.readLine();

            for(User user : users){
                if(user.match(name, password)){
                    currentUser = user;
                    writer.println("Uspesne prihlasen");
                    return;
                }
            }

            writer.println("Nespravne jmeno nebo heslo");
        }
    }
}