/*
  http-realm - 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.realm;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * Eine einfache Implementierung der Schnittstelle Realm, die 
 * Benutzerinformationen aus einer Datei liest. Die Datei ist dabei 
 * wie folgt aufgebaut.
 * 
 * test=test,testRolle
 * ulrich=ulrich,testRolle,andereRolle
 * 
 * Der erste Eintrag nach dem Gleichheitszeichen ist das Passwort, die restlichen 
 * Eintrage sind Rollen.
 * 
 * @author Ulrich Hilger
 * @version 1, 03.06.2021
 */
public class SimpleRealm implements Realm {
  
  private static final Logger logger = Logger.getLogger(SimpleRealm.class.getName());
  
  public static final String LIST_INDICATOR = "=";
  public static final String ROLE_SEPARATOR = ",";
  public static final String COMMENT_INDICATOR = "#";
  
  private String name;
  private final Map<String, User> users;
  private final Map<String, List> userRoles;
  
  public SimpleRealm() {
    users = new HashMap<>();
    userRoles = new HashMap<>();
  }

  public void setName(String name) {
    this.name = name;
  }
  
  public void readFromFile(File file) throws IOException {
    BufferedReader r = new BufferedReader(new FileReader(file));
    String line = r.readLine();
    while(line != null) {
      parse(line);
      line = r.readLine();
    }
    r.close();
  }
  
  private void parse(String line) {
    if(!line.startsWith(COMMENT_INDICATOR)) {
      String[] teile = line.split(LIST_INDICATOR);
      String[] rollen = teile[1].split(ROLE_SEPARATOR);
      String userId = teile[0];
      User user = new User();
      user.setName(userId);
      user.setPassword(rollen[0]);
      try {
        Encoder encoder = new Encoder();
        String hex = encoder.bytesToHex(encoder.encode(rollen[0]));
        logger.fine(hex);
      } catch (NoSuchAlgorithmException ex) {
        logger.log(Level.SEVERE, null, ex);
      }
      ArrayList rollenListe = new ArrayList(); 
      for(int i = 1; i < rollen.length; i++) {
        rollenListe.add(rollen[i]);
      }
      users.put(userId, user);
      userRoles.put(userId, rollenListe);
    }
  }
  
  /* ------------ Realm implementation -------------- */

  @Override
  public boolean isValid(String userId, String kennwort) {
    Object o = users.get(userId);
    if(o instanceof User) {
      User user = (User) o;
      return user.getPassword().equals(kennwort);
    } else {
      return false;
    }
  }

  @Override
  public boolean hasRole(String userId, String rollenId) {
    Object o = userRoles.get(userId);
    if(o instanceof List) {
      List roles = (List) o;
      return roles.contains(rollenId);
    } else {
      return false;
    }
  }

  @Override
  public String getName() {
    return name;
  }
  
}