/*
    * ====================================================================
    * 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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  
  package org.apache.hc.core5.http.impl.io;
  
  import java.io.IOException;
  import java.io.OutputStream;
  import java.util.Iterator;
  
  import org.apache.hc.core5.http.FormattedHeader;
  import org.apache.hc.core5.http.Header;
  import org.apache.hc.core5.http.HttpException;
  import org.apache.hc.core5.http.HttpMessage;
  import org.apache.hc.core5.http.io.HttpMessageWriter;
  import org.apache.hc.core5.http.io.SessionOutputBuffer;
  import org.apache.hc.core5.http.message.BasicLineFormatter;
  import org.apache.hc.core5.http.message.LineFormatter;
  import org.apache.hc.core5.util.Args;
  import org.apache.hc.core5.util.CharArrayBuffer;
  
  /**
   * Abstract base class for HTTP message writers that serialize output to
   * an instance of {@link org.apache.hc.core5.http.io.SessionOutputBuffer}.
   *
   * @since 4.0
   */
  public abstract class AbstractMessageWriter<T extends HttpMessage> implements HttpMessageWriter<T> {
  
      private final CharArrayBuffer lineBuf;
      private final LineFormatter lineFormatter;
  
      /**
       * Creates an instance of AbstractMessageWriter.
       *
       * @param formatter the line formatter If {@code null} {@link BasicLineFormatter#INSTANCE}
       *   will be used.
       *
       * @since 4.3
       */
      public AbstractMessageWriter(final LineFormatter formatter) {
          super();
          this.lineFormatter = formatter != null ? formatter : BasicLineFormatter.INSTANCE;
          this.lineBuf = new CharArrayBuffer(128);
      }
  
      LineFormatter getLineFormatter() {
          return this.lineFormatter;
      }
  
      /**
       * Subclasses must override this method to write out the first header line
       * based on the {@link HttpMessage} passed as a parameter.
       *
       * @param message the message whose first line is to be written out.
       * @param lineBuf line buffer
       * @throws IOException in case of an I/O error.
       */
      protected abstract void writeHeadLine(T message, CharArrayBuffer lineBuf) throws IOException;
  
      @Override
      public void write(final T message, final SessionOutputBuffer buffer, final OutputStream outputStream) throws IOException, HttpException {
          Args.notNull(message, "HTTP message");
          Args.notNull(buffer, "Session output buffer");
          Args.notNull(outputStream, "Output stream");
          writeHeadLine(message, this.lineBuf);
          buffer.writeLine(this.lineBuf, outputStream);
          for (final Iterator<Header> it = message.headerIterator(); it.hasNext(); ) {
              final Header header = it.next();
              if (header instanceof FormattedHeader) {
                  final CharArrayBuffer chbuffer = ((FormattedHeader) header).getBuffer();
                  buffer.writeLine(chbuffer, outputStream);
              } else {
                  this.lineBuf.clear();
                  lineFormatter.formatHeader(this.lineBuf, header);
                  buffer.writeLine(this.lineBuf, outputStream);
             }
         }
         this.lineBuf.clear();
         buffer.writeLine(this.lineBuf, outputStream);
     }
 
 }