/*
    * 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.util;
  
  import static java.lang.String.format;
  import static org.opencastproject.util.data.Option.none;
  import static org.opencastproject.util.data.Option.some;
  import static org.opencastproject.util.data.functions.Misc.cast;
  import static org.opencastproject.util.data.functions.Misc.chuck;
  
  import org.opencastproject.util.data.Function;
  import org.opencastproject.util.data.Option;
  
  import org.json.simple.parser.JSONParser;
  import org.json.simple.parser.ParseException;
  
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  /** Accessor for JSON objects aka maps. */
  // todo -- think about using specialized Exception (JsonExcpetion ?); handle parse exception in jsonObj(String)
  public final class JsonObj {
    private final Map json;
  
    /** Create a wrapper for a map. */
    public JsonObj(Map json) {
      this.json = json;
    }
  
    /** Constructor function. */
    public static JsonObj jsonObj(Map json) {
      return new JsonObj(json);
    }
  
    /** Create a JsonObj from a JSON string. */
    public static JsonObj jsonObj(String json) {
      return new JsonObj(parse(json));
    }
  
    /** {@link #jsonObj(java.util.Map)} as a function. */
    public static final Function<Map, JsonObj> jsonObj = new Function<Map, JsonObj>() {
      @Override
      public JsonObj apply(Map json) {
        return jsonObj(json);
      }
    };
  
    private static Map parse(String json) {
      try {
        return (Map) new JSONParser().parse(json);
      } catch (ParseException e) {
        return chuck(e);
      }
    }
  
    public Set keySet() {
      return json.keySet();
    }
  
    public JsonVal val(String key) {
      return new JsonVal(get(Object.class, key));
    }
  
    public JsonObj obj(String key) {
      return jsonObj(get(Map.class, key));
    }
  
    public JsonArr arr(String key) {
      return new JsonArr(get(List.class, key));
    }
  
    public boolean has(String key) {
      return json.containsKey(key);
    }
  
    /**
     * Get mandatory value of type <code>ev</code>.
     *
     * @return the requested value if it exists and has the required type
    * @deprecated
    */
   public <A> A get(Class<A> ev, String key) {
     final Object v = json.get(key);
     if (v != null) {
       try {
         return cast(v, ev);
       } catch (ClassCastException e) {
         throw new RuntimeException(format("Key %s has not required type %s but %s", key, ev.getName(), v.getClass()
                 .getName()));
       }
     } else {
       throw new RuntimeException(format("Key %s does not exist", key));
     }
   }
 
   /**
    * Get optional value of type <code>ev</code>.
    *
    * @return some if the value exists and has the required type, none otherwise
    * @deprecated
    */
   public <A> Option<A> opt(Class<A> ev, String key) {
     final Object v = json.get(key);
     if (v != null) {
       try {
         return some(cast(v, ev));
       } catch (ClassCastException e) {
         return none();
       }
     } else {
       return none();
     }
   }
 
   /**
    * Get mandatory JSON object.
    *
    * @deprecated
    */
   public JsonObj getObj(String key) {
     return jsonObj(get(Map.class, key));
   }
 
   /**
    * Get an optional JSON object.
    *
    * @deprecated
    */
   public Option<JsonObj> optObj(String key) {
     return opt(Map.class, key).map(jsonObj);
   }
 }