package org.opendaylight.controller.sal.rest.impl;

import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;

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.core.Response;
import javax.ws.rs.ext.MessageBodyWriter;
import javax.ws.rs.ext.Provider;

import org.opendaylight.controller.sal.rest.api.Draft01;
import org.opendaylight.controller.sal.rest.api.Draft02;
import org.opendaylight.controller.sal.rest.api.RestconfService;
import org.opendaylight.controller.sal.restconf.impl.StructuredData;
import org.opendaylight.yangtools.yang.data.api.CompositeNode;
import org.opendaylight.yangtools.yang.model.api.DataNodeContainer;

import com.google.gson.stream.JsonWriter;

@Provider
@Produces({ Draft01.MediaTypes.DATA + RestconfService.JSON, Draft02.MediaTypes.DATA + RestconfService.JSON,
        MediaType.APPLICATION_JSON })
public enum StructuredDataToJsonProvider implements MessageBodyWriter<StructuredData> {
    INSTANCE;

    @Override
    public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
        return true;
    }

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

    @Override
    public void writeTo(StructuredData t, Class<?> type, Type genericType, Annotation[] annotations,
            MediaType mediaType, MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream)
            throws IOException, WebApplicationException {
        CompositeNode data = t.getData();
        if (data == null) {
            throw new WebApplicationException(Response.status(Response.Status.NOT_FOUND).build());
        }

        JsonWriter writer = new JsonWriter(new OutputStreamWriter(entityStream, "UTF-8"));
        writer.setIndent("    ");
        JsonMapper jsonMapper = new JsonMapper();
        jsonMapper.write(writer, data, (DataNodeContainer) t.getSchema());
        writer.flush();
    }

}