/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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.apache.sling.rewriter.impl;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.rewriter.ProcessorManager;
import org.osgi.framework.Constants;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;

/**
 * This filter activates the rewriter for the output.
 *
 */
@Component(
        service = Filter.class,
        property = {
                Constants.SERVICE_VENDOR + "=The Apache Software Foundation",
                "sling.filter.scope=request",
                "sling.filter.scope=error",
                Constants.SERVICE_RANKING + ":Integer=2500"
        }
)
public class RewriterFilter implements Filter {

    @Reference
    private ProcessorManager pipelineManager;

    /**
     * @see javax.servlet.Filter#init(javax.servlet.FilterConfig)
     */
    @Override
    public void init(FilterConfig config) throws ServletException {
        // nothing to do
    }

    /**
     * @see javax.servlet.Filter#destroy()
     */
    @Override
    public void destroy() {
        // nothing to do
    }

    /**
     * @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
     */
    @Override
    public void doFilter(ServletRequest request,
                         ServletResponse response,
                         FilterChain chain)
    throws IOException, ServletException {
        if ( ! (request instanceof SlingHttpServletRequest)) {
            throw new ServletException("Request is not a Apache Sling HTTP request.");
        }
        final SlingHttpServletRequest slingRequest = (SlingHttpServletRequest) request;
        final SlingHttpServletResponse slingResponse = (SlingHttpServletResponse) response;

        final RewriterResponse rewriterResponse =
                new RewriterResponse(slingRequest, slingResponse, this.pipelineManager);
        boolean errorOccured = true;
        try {
            chain.doFilter(request, rewriterResponse);
            errorOccured = false;
        } finally {
            rewriterResponse.finished(errorOccured);
        }
	}
}