/**
 * 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.hadoop.hdfs.server.datanode.web;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.HttpRequest;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hdfs.server.datanode.web.webhdfs.WebHdfsHandler;

import java.io.IOException;
import java.net.InetSocketAddress;

import static org.apache.hadoop.hdfs.server.datanode.web.webhdfs.WebHdfsHandler.WEBHDFS_PREFIX;

class URLDispatcher extends SimpleChannelInboundHandler<HttpRequest> {
  private final InetSocketAddress proxyHost;
  private final Configuration conf;
  private final Configuration confForCreate;

  URLDispatcher(InetSocketAddress proxyHost, Configuration conf,
                Configuration confForCreate) {
    this.proxyHost = proxyHost;
    this.conf = conf;
    this.confForCreate = confForCreate;
  }

  @Override
  protected void channelRead0(ChannelHandlerContext ctx, HttpRequest req)
    throws Exception {
    String uri = req.getUri();
    ChannelPipeline p = ctx.pipeline();
    if (uri.startsWith(WEBHDFS_PREFIX)) {
      WebHdfsHandler h = new WebHdfsHandler(conf, confForCreate);
      p.replace(this, WebHdfsHandler.class.getSimpleName(), h);
      h.channelRead0(ctx, req);
    } else {
      SimpleHttpProxyHandler h = new SimpleHttpProxyHandler(proxyHost);
      p.replace(this, SimpleHttpProxyHandler.class.getSimpleName(), h);
      h.channelRead0(ctx, req);
    }
  }
}