/*
    * 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.eclipse.aether.transport.http.RFC9457;
  
  import java.io.IOException;
  import java.nio.charset.StandardCharsets;
  
  import org.apache.http.Header;
  import org.apache.http.HttpHeaders;
  import org.apache.http.client.methods.CloseableHttpResponse;
  import org.apache.http.util.EntityUtils;
  
  public class RFC9457Reporter {
      public static final RFC9457Reporter INSTANCE = new RFC9457Reporter();
  
      public boolean isRFC9457Message(CloseableHttpResponse response) {
          Header[] headers = response.getHeaders(HttpHeaders.CONTENT_TYPE);
          if (headers.length > 0) {
              String contentType = headers[0].getValue();
              return hasRFC9457ContentType(contentType);
          }
          return false;
      }
  
      public void generateException(CloseableHttpResponse response) throws HttpRFC9457Exception {
          int statusCode = getStatusCode(response);
          String reasonPhrase = getReasonPhrase(response);
  
          String body;
          try {
              body = getBody(response);
          } catch (IOException ignore) {
              // No body found but it is representing a RFC 9457 message due to the content type.
              throw new HttpRFC9457Exception(statusCode, reasonPhrase, RFC9457Payload.INSTANCE);
          }
  
          if (body != null && !body.isEmpty()) {
              RFC9457Payload rfc9457Payload = RFC9457Parser.parse(body);
              throw new HttpRFC9457Exception(statusCode, reasonPhrase, rfc9457Payload);
          }
          throw new HttpRFC9457Exception(statusCode, reasonPhrase, RFC9457Payload.INSTANCE);
      }
  
      private String getBody(final CloseableHttpResponse response) throws IOException {
          return EntityUtils.toString(response.getEntity(), StandardCharsets.UTF_8);
      }
  
      private int getStatusCode(final CloseableHttpResponse response) {
          return response.getStatusLine().getStatusCode();
      }
  
      private String getReasonPhrase(final CloseableHttpResponse response) {
          String reasonPhrase = response.getStatusLine().getReasonPhrase();
          if (reasonPhrase == null || reasonPhrase.isEmpty()) {
              return "";
          }
          int statusCode = getStatusCode(response);
          return reasonPhrase + " (" + statusCode + ")";
      }
  
      private boolean hasRFC9457ContentType(String contentType) {
          return "application/problem+json".equals(contentType);
      }
  }