/*
 * Copyright (c) 2015, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
 *
 * WSO2 Inc. licenses this file to you 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.wso2.carbon.dynamic.client.web;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonObject;

import javax.ws.rs.Produces;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.MessageBodyWriter;
import javax.ws.rs.ext.Provider;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;

@Provider
@Produces(MediaType.APPLICATION_JSON)
public class FaultMessageBodyWriter implements MessageBodyWriter<FaultResponse> {

    private static final String UTF_8 = "UTF-8";

    @Override
    public boolean isWriteable(Class<?> aClass, Type type, Annotation[] annotations, MediaType mediaType) {
        return (FaultResponse.class == type);
    }

    @Override
    public long getSize(FaultResponse faultResponse, Class<?> aClass, Type type, Annotation[] annotations,
                        MediaType mediaType) {
        return -1;
    }

    @Override
    public void writeTo(FaultResponse faultResponse, Class<?> aClass, Type type, Annotation[] annotations,
                        MediaType mediaType, MultivaluedMap<String, Object> stringObjectMultivaluedMap,
                        OutputStream outputStream) throws IOException, WebApplicationException {
        try (OutputStreamWriter writer = new OutputStreamWriter(outputStream, UTF_8)) {
            JsonObject response = new JsonObject();
            response.addProperty("error", faultResponse.getCode().getValue());
            response.addProperty("error_description", faultResponse.getDescription());
            getGson().toJson(response, type, writer);
        }
    }

    private Gson getGson() {
        GsonBuilder gsonBuilder = new GsonBuilder();
        return gsonBuilder.create();
    }

}
