/*******************************************************************************
 * Copyright (c) 2012-2016 Codenvy, S.A.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.everrest.core.servlet;

import org.everrest.core.ContainerResponseWriter;
import org.everrest.core.GenericContainerResponse;
import org.everrest.core.impl.header.HeaderHelper;

import javax.servlet.http.HttpServletResponse;
import javax.ws.rs.ext.MessageBodyWriter;
import java.io.IOException;
import java.io.OutputStream;
import java.util.List;
import java.util.Map;

public class ServletContainerResponseWriter implements ContainerResponseWriter {
    /** See {@link HttpServletResponse}. */
    private final HttpServletResponse servletResponse;

    /**
     * @param response
     *         HttpServletResponse
     */
    public ServletContainerResponseWriter(HttpServletResponse response) {
        this.servletResponse = response;
    }


    @Override
    @SuppressWarnings({"unchecked"})
    public void writeBody(GenericContainerResponse response, MessageBodyWriter entityWriter) throws IOException {
        if (servletResponse.isCommitted()) {
            return;
        }
        Object entity = response.getEntity();
        if (entity != null) {
            OutputStream out = servletResponse.getOutputStream();
            entityWriter.writeTo(entity, entity.getClass(), response.getEntityType(), null, response.getContentType(),
                                 response.getHttpHeaders(), out);
            out.flush();
        }
    }

    @Override
    public void writeHeaders(GenericContainerResponse response) throws IOException {
        if (servletResponse.isCommitted()) {
            return;
        }

        servletResponse.setStatus(response.getStatus());

        if (response.getHttpHeaders() != null) {
            // content-type and content-length should be preset in headers
            for (Map.Entry<String, List<Object>> e : response.getHttpHeaders().entrySet()) {
                String name = e.getKey();
                for (Object o : e.getValue()) {
                    String value;
                    if (o != null && (value = HeaderHelper.getHeaderAsString(o)) != null) {
                        servletResponse.addHeader(name, value);
                    }
                }
            }
        }
    }
}