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/*
 * Copyright 2013 Jeanfrancois Arcand
 *
 * 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.atmosphere.cpr;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;

/**
 * An {@link AsyncIOWriter} that delegates the write operation to it's {@link AsyncIOInterceptor}. If no
 * AsyncIOInterceptor are specified, this class does nothing and the response's will never get written.
 *
 * @author Jeanfrancois Arcand
 */
public class AtmosphereInterceptorWriter extends AsyncIOWriterAdapter {

    private static final Logger logger = LoggerFactory.getLogger(AtmosphereInterceptorWriter.class);
    private final AtmosphereResponse response;

    private final ArrayList filters = new ArrayList();

    public AtmosphereInterceptorWriter(AtmosphereResponse response) {
        this.response = response;
    }

    @Override
    public AsyncIOWriter redirect(String location) throws IOException {
        response.sendRedirect(location);
        return this;
    }

    @Override
    public AsyncIOWriter writeError(int errorCode, String message) throws IOException {
        response.sendError(errorCode);
        return this;
    }

    @Override
    public AsyncIOWriter write(String data) throws IOException {
        return write(data.getBytes(response.getCharacterEncoding()));
    }

    @Override
    public AsyncIOWriter write(byte[] data) throws IOException {
        return write(data, 0, data.length);
    }

    @Override
    public AsyncIOWriter write(byte[] data, int offset, int length) throws IOException {
        for (AsyncIOInterceptor i : filters) {
            i.prePayload(response, data, offset, length);
        }

        byte[] responseDraft = new byte[length];
        System.arraycopy(data, offset, responseDraft, 0, length);
        for (AsyncIOInterceptor i : filters) {
            responseDraft = i.transformPayload(responseDraft, data);
        }
        response.write(responseDraft);

        ArrayList reversedFilters = (ArrayList)filters.clone();
        Collections.reverse(reversedFilters);
        for (AsyncIOInterceptor i : reversedFilters) {
            i.postPayload(response, data, offset, length);
        }

        return this;
    }

    @Override
    public void close() throws IOException {
        response.closeStreamOrWriter();
    }

    @Override
    public AsyncIOWriter flush() throws IOException {
        response.flushBuffer();
        return this;
    }

    public AtmosphereInterceptorWriter interceptor(AsyncIOInterceptor filter) {
        filters.add(filter);
        return this;
    }
}