/*
 * 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.wicket.protocol.ws.api;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.time.Instant;
import javax.servlet.http.Cookie;
import org.apache.wicket.request.Response;
import org.apache.wicket.request.http.WebResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A {@link Response} used to cache the written data to the web socket client
 * when Wicket thread locals are available.
 *
 * When the thread locals are not available then you can write directly to the {@link IWebSocketConnection}
 * taken from {@link org.apache.wicket.protocol.ws.api.registry.IWebSocketConnectionRegistry}.
 * In this case the response wont be cached.
 *
 * @since 6.0
 */
public class WebSocketResponse extends WebResponse
{
        private static final Logger LOG = LoggerFactory.getLogger(WebSocketResponse.class);
        
        private final IWebSocketConnection connection;

        private StringBuilder text;

        private ByteArrayOutputStream binary;

        private boolean isRedirect = false;

        private final boolean asynchronous;

        private final long timeout;

        public WebSocketResponse(final IWebSocketConnection conn)
        {
                this(conn, false, -1);
        }

        public WebSocketResponse(final IWebSocketConnection conn, boolean asynchronous, long timeout)
        {
                this.connection = conn;
                this.asynchronous = asynchronous;
                this.timeout = timeout;
        }

        @Override
        public void write(CharSequence sequence)
        {
                if (text == null)
                {
                        text = new StringBuilder();
                }
                text.append(sequence);
        }

        @Override
        public void write(byte[] array)
        {
                write(array, 0, array.length);
        }

        @Override
        public void write(byte[] array, int offset, int length)
        {
                if (binary == null)
                {
                        binary = new ByteArrayOutputStream();
                }
                binary.write(array, offset, length);
        }

        @Override
        public void close()
        {
                if (connection.isOpen())
                {
                        try
                        {
                                if (text != null)
                                {
                                        if (asynchronous)
                                        {
                                                connection.sendMessageAsync(text.toString(), timeout);
                                        }
                                        else
                                        {
                                                connection.sendMessage(text.toString());
                                        }
                                        text = null;
                                }
                                else if (binary != null)
                                {
                                        byte[] bytes = binary.toByteArray();
                                        if (asynchronous)
                                        {
                       connection.sendMessageAsync(bytes, 0, bytes.length, timeout);
                                        }
                                        else
                                        {
                                                connection.sendMessage(bytes, 0, bytes.length);
                                        }
                                        binary.close();
                                        binary = null;
                                }

                        } catch (IOException iox)
                        {
                                LOG.error("An error occurred while writing response to WebSocket client.", iox);
                        }
                }
                super.close();
        }

        @Override
        public void reset()
        {
                text = null;
                if (binary != null)
                {
                        try
                        {
                                binary.close();
                        } catch (IOException iox)
                        {
                                LOG.error("An error occurred while resetting the binary content", iox);
                        }
                        binary = null;
                }
                isRedirect = false;
                super.reset();
        }

        @Override
        public String encodeURL(CharSequence url)
        {
                return url.toString();
        }

        @Override
        public final IWebSocketConnection getContainerResponse()
        {
                return connection;
        }

        @Override
        public void addCookie(Cookie cookie)
        {
                throw new UnsupportedOperationException();
        }

        @Override
        public void clearCookie(Cookie cookie)
        {
                throw new UnsupportedOperationException();
        }

        @Override
        public boolean isHeaderSupported() {
                return false;
        }
        
        @Override
        public void setHeader(String name, String value)
        {
                throw new UnsupportedOperationException();
        }

        @Override
        public void addHeader(String name, String value)
        {
                throw new UnsupportedOperationException();
        }

        @Override
        public void setDateHeader(String name, Instant date)
        {
                throw new UnsupportedOperationException();
        }

        @Override
        public void setContentLength(long length)
        {
                throw new UnsupportedOperationException();
        }

        @Override
        public void setContentType(String mimeType)
        {
                throw new UnsupportedOperationException();
        }

        @Override
        public void setStatus(int sc)
        {
                throw new UnsupportedOperationException();
        }

        @Override
        public void sendError(int sc, String msg)
        {
                LOG.warn("An HTTP error response in WebSocket communication would not be processed by the browser! " +
                                "If you need to send the error code and message to the client then configure custom WebSocketResponse " +
                                "via WebSocketSettings#newWebSocketResponse() factory method and override #sendError() method to write " +
                                "them in an appropriate format for your application. " +
                                "The ignored error code is '{}' and the message: '{}'.", sc, msg);
        }

        @Override
        public String encodeRedirectURL(CharSequence url)
        {
                return url.toString();
        }

        @Override
        public void sendRedirect(String url)
        {
                isRedirect = true;
                url = encodeRedirectURL(url);

                String ajaxRedirect = "<ajax-response><redirect><![CDATA[" + url + "]]></redirect></ajax-response>";
                write(ajaxRedirect);
        }

        @Override
        public boolean isRedirect()
        {
                return isRedirect;
        }

        @Override
        public void flush()
        {
        }
}