/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you under the Educational
    * Community License, Version 2.0 (the "License"); you may not use this file
    * except in compliance with the License. You may obtain a copy of the License
   * at:
   *
   *   http://opensource.org/licenses/ecl2.txt
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
   * License for the specific language governing permissions and limitations under
   * the License.
   *
   */
  package org.opencastproject.external.util;
  
  import static org.opencastproject.index.service.util.JSONUtils.safeString;
  
  import org.opencastproject.security.api.AccessControlEntry;
  import org.opencastproject.security.api.AccessControlList;
  
  import com.google.gson.JsonArray;
  import com.google.gson.JsonObject;
  
  import org.apache.commons.lang3.StringUtils;
  import org.json.simple.JSONArray;
  import org.json.simple.JSONObject;
  import org.json.simple.parser.JSONParser;
  import org.json.simple.parser.ParseException;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.ListIterator;
  
  public final class AclUtils {
    private static final String ACTION_JSON_KEY = "action";
    private static final String ALLOW_JSON_KEY = "allow";
    private static final String ROLE_JSON_KEY = "role";
  
    private AclUtils() {
    }
  
    /**
     * De-serialize an JSON into an {@link AccessControlList}.
     *
     * @param json
     *          The {@link AccessControlList} to serialize.
     * @param assumeAllow
     *          Assume that all entries are allows.
     * @return An {@link AccessControlList} representation of the Json
     * @throws IllegalArgumentException
     *           Thrown if essential parts of an access control element is missing.
     * @throws ParseException
     *           Thrown if unable to parse the json value of the acl.
     */
    public static AccessControlList deserializeJsonToAcl(String json, boolean assumeAllow)
            throws IllegalArgumentException, ParseException {
      JSONParser parser = new JSONParser();
      JSONArray aclJson = (JSONArray) parser.parse(json);
      @SuppressWarnings("unchecked")
      ListIterator<Object> iterator = aclJson.listIterator();
      JSONObject aceJson;
      List<AccessControlEntry> entries = new ArrayList<AccessControlEntry>();
      while (iterator.hasNext()) {
        aceJson = (JSONObject) iterator.next();
        String action = aceJson.get(ACTION_JSON_KEY) != null ? aceJson.get(ACTION_JSON_KEY).toString() : "";
        String allow;
        if (assumeAllow) {
          allow = "true";
        } else {
          allow = aceJson.get(ALLOW_JSON_KEY) != null ? aceJson.get(ALLOW_JSON_KEY).toString() : "";
        }
        String role = aceJson.get(ROLE_JSON_KEY) != null ? aceJson.get(ROLE_JSON_KEY).toString() : "";
        if (StringUtils.trimToNull(action) != null && StringUtils.trimToNull(allow) != null
                && StringUtils.trimToNull(role) != null) {
          AccessControlEntry ace = new AccessControlEntry(role, action, Boolean.parseBoolean(allow));
          entries.add(ace);
        } else {
          throw new IllegalArgumentException(
                  String.format(
                          "One of the access control elements is missing a property. The action was '%s', allow was '%s' and the role was '%s'",
                          action, allow, role));
        }
      }
      return new AccessControlList(entries);
    }
  
    /**
     * Serialize an {@link AccessControlList} into json.
     *
     * @param acl
     *          The {@link AccessControlList} to serialize.
     * @return A {@link JsonArray} representation of the {@link AccessControlList}
    */
   public static JsonArray serializeAclToJson(AccessControlList acl) {
     JsonArray entries = new JsonArray();
     for (AccessControlEntry ace : acl.getEntries()) {
       JsonObject entry = new JsonObject();
       entry.addProperty(ALLOW_JSON_KEY, ace.isAllow());
       entry.addProperty(ACTION_JSON_KEY, safeString(ace.getAction()));
       entry.addProperty(ROLE_JSON_KEY, safeString(ace.getRole()));
       entries.add(entry);
     }
     return entries;
   }
 }