/*
    * 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.maven.index.reader;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.HttpURLConnection;
  import java.net.URI;
  import java.net.http.HttpClient;
  import java.net.http.HttpRequest;
  import java.net.http.HttpResponse;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * A trivial HTTP {@link ResourceHandler} that uses {@link URI} to fetch remote content. This implementation does not
   * handle any advanced cases, like redirects, authentication, etc.
   */
  public class HttpResourceHandler implements ResourceHandler {
      private final HttpClient client =
              HttpClient.newBuilder().followRedirects(HttpClient.Redirect.NEVER).build();
      private final URI root;
  
      public HttpResourceHandler(final URI root) {
          this.root = requireNonNull(root);
      }
  
      @Override
      public Resource locate(final String name) {
          return new HttpResource(name);
      }
  
      private class HttpResource implements Resource {
          private final String name;
  
          private HttpResource(final String name) {
              this.name = name;
          }
  
          @Override
          public InputStream read() throws IOException {
              HttpRequest request =
                      HttpRequest.newBuilder().uri(root.resolve(name)).GET().build();
              try {
                  HttpResponse<InputStream> response = client.send(request, HttpResponse.BodyHandlers.ofInputStream());
                  if (response.statusCode() == HttpURLConnection.HTTP_OK) {
                      return response.body();
                  } else {
                      throw new IOException("Unexpected response: " + response);
                  }
              } catch (InterruptedException e) {
                  Thread.currentThread().interrupt();
                  throw new IOException(e);
              }
          }
      }
  }