/*
    * Copyright (c) 2001-2017, Zoltan Farkas All Rights Reserved.
    *
    * This library is free software; you can redistribute it and/or
    * modify it under the terms of the GNU Lesser General Public
    * License as published by the Free Software Foundation; either
    * version 2.1 of the License, or (at your option) any later version.
    *
    * This library 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 General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
   *
   * Additionally licensed with:
   *
   * Licensed under the Apache 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://www.apache.org/licenses/LICENSE-2.0
   *
   * 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.spf4j.base;
  
  import com.fasterxml.jackson.core.JsonFactory;
  import com.fasterxml.jackson.core.JsonGenerator;
  import com.fasterxml.jackson.core.JsonParser;
  import com.fasterxml.jackson.databind.JsonSerializer;
  import com.fasterxml.jackson.databind.Module;
  import com.fasterxml.jackson.databind.ObjectMapper;
  import com.fasterxml.jackson.databind.SerializationFeature;
  import com.fasterxml.jackson.databind.SerializerProvider;
  import com.fasterxml.jackson.databind.module.SimpleModule;
  import java.io.IOException;
  import java.util.ServiceLoader;
  
  /**
   * @author Zoltan Farkas
   */
  public final class Json {
  
    public static final JsonFactory FACTORY = new JsonFactory();
  
    public static final ObjectMapper MAPPER = new ObjectMapper(FACTORY);
  
    private Json() { }
  
    static {
      FACTORY.disable(JsonParser.Feature.AUTO_CLOSE_SOURCE);
      SimpleModule module = new SimpleModule("spf4j");
      loadServices(module);
      module.addSerializer(JsonWriteable.class, jsonWritableSerializer());
      MAPPER.registerModule(module);
      ServiceLoader<Module> loader = ServiceLoader.load(Module.class);
      for (Module mod : loader) {
        MAPPER.registerModule(mod);
      }
      MAPPER.disable(SerializationFeature.FLUSH_AFTER_WRITE_VALUE);
      FACTORY.setCodec(MAPPER);
    }
  
    private static void loadServices(final SimpleModule module) {
      ServiceLoader<JsonSerializer> loader = ServiceLoader.load(JsonSerializer.class);
      for (JsonSerializer ser : loader) {
        module.addSerializer(ser);
      }
    }
  
    public static JsonSerializer<JsonWriteable> jsonWritableSerializer() {
      return new JsonSerializer<JsonWriteable>() {
        @Override
        public void serialize(final JsonWriteable value, final JsonGenerator jgen, final SerializerProvider provider)
                throws IOException {
          Object outputTarget = jgen.getOutputTarget();
          if (outputTarget instanceof Appendable) {
            jgen.flush();
            if (jgen.getOutputContext().getCurrentName() != null) {
              ((Appendable) outputTarget).append(':');
            }
            value.writeJsonTo((Appendable) outputTarget);
            return;
          }
          StringBuilder json = new StringBuilder(32);
          value.writeJsonTo(json);
          jgen.writeRawValue(json.toString());
        }
      };
    }
  
    public static JsonSerializer<Object> toStringJsonWritableSerializer() {
     return new JsonSerializer<Object>() {
       @Override
       public void serialize(final Object value, final JsonGenerator jgen, final SerializerProvider provider)
               throws IOException {
         jgen.writeString(value.toString());
       }
     };
   }
 
 
 }