/*
  http-auth - Authentication Extensions to jdk.httpserver
  Copyright (C) 2021  Ulrich Hilger

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU Affero General Public License as
  published by the Free Software Foundation, either version 3 of the
  License, or (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License
  along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
package de.uhilger.httpserver.auth.handler;

import com.sun.net.httpserver.Authenticator;
import com.sun.net.httpserver.Headers;
import com.sun.net.httpserver.HttpContext;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import de.uhilger.httpserver.auth.TokenAuthenticator;
import de.uhilger.httpserver.auth.realm.User;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

/**
 *
 * @author Ulrich Hilger
 * @version 1, 30.05.2021
 */
public abstract class LoginHandler implements HttpHandler {
  
  /* Der Logger fuer diesen JWTLoginHandler */
  //private static final Logger logger = Logger.getLogger(LoginHandler.class.getName());
  
  public static final String ATTR_AUTHENTICATOR = "authenticator";
  
  
  //protected String ctx;

  /**
   * Wenn einfach ein HTML-Formular hierhin geschickt wird, das wie
   * bei Java die Formular-Eingabefelder 'j_username' und 'j_password'
   * enthaelt, kommt im Body folgendes an:
   * j_username=name&amp;j_password=password
   *
   * body koennte auch einen JSON-Ausdruck enthalten wie z.B.
   * {"name": "fred", "password": "secret"}
   *
   * Das ist hier noch nicht implementiert
   *
   * @param exchange
   * @throws IOException
   */
  @Override
  public void handle(HttpExchange exchange) throws IOException {
    User nutzer = getUser(exchange);
    HttpContext context = exchange.getHttpContext();
    Object o = context.getAttributes().get(ATTR_AUTHENTICATOR);
    if (o instanceof TokenAuthenticator) {
      TokenAuthenticator auth = (TokenAuthenticator) o;
      String token = auth.anmelden(nutzer.getName(), nutzer.getPassword());
      if (token != null) {
        loginResponse(exchange, auth, token);
      } else {
        // Nutzer und Kennwort passen nicht
      }
    } else {
      // interner Fehler: Kein passender Authenticator
    }
  }
  
  protected void setAuthenticatedHeader(HttpExchange exchange, Authenticator auth, String token) {
    if(auth instanceof TokenAuthenticator) {
      TokenAuthenticator tAuth = (TokenAuthenticator) auth;
      // angemeldet, Token als Antwort zurueckgeben
      Headers respHeaders = exchange.getResponseHeaders();
      // JWT=[cookie-inhalt]; Expires=Thu, 21 Oct 2021 07:28:00 GMT; Secure; HttpOnly
      SimpleDateFormat f = 
              new SimpleDateFormat(TokenAuthenticator.HEADER_DATE_PATTERN, Locale.US);
      Date exp = Date.from(new Date().toInstant().plusSeconds(TokenAuthenticator.TOKEN_EXPIRATION));
      respHeaders.add(TokenAuthenticator.SET_COOKIE_HEADER, 
              tAuth.cookieBilden(TokenAuthenticator.JWT_INDICATOR, token, exp));
    }
  }
  
  protected abstract void loginResponse(HttpExchange exchange, Authenticator auth, String token) throws IOException;
  
  protected abstract User getUser(HttpExchange exchange) throws IOException;

  /*
  protected String bodyLesen(HttpExchange exchange) throws IOException {
    StringBuilder sb = new StringBuilder();
    InputStream is = exchange.getRequestBody();
    BufferedReader in = new BufferedReader(new InputStreamReader(is));
    String line = in.readLine();
    while (line != null) {
      sb.append(line);
      line = in.readLine();
    }
    return sb.toString();
  }
  */
  
}