/*
    * DavMail POP/IMAP/SMTP/CalDav/LDAP Exchange Gateway
    * Copyright (C) 2010  Mickael Guessant
    *
    * This program is free software; you can redistribute it and/or
    * modify it under the terms of the GNU General Public License
    * as published by the Free Software Foundation; either version 2
    * of the License, or (at your option) any later version.
    *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
   */
  
  package davmail.exchange.graph;
  
  import davmail.http.HttpClientAdapter;
  import davmail.util.IOUtil;
  import org.apache.http.Header;
  import org.apache.http.HttpEntity;
  import org.apache.http.HttpResponse;
  import org.apache.http.client.ResponseHandler;
  import org.codehaus.jettison.json.JSONException;
  import org.codehaus.jettison.json.JSONObject;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.nio.charset.StandardCharsets;
  import java.util.zip.GZIPInputStream;
  
  /**
   * Generic Json response handler for graph API calls
   */
  public class JsonResponseHandler implements ResponseHandler<JSONObject> {
      @Override
      public JSONObject handleResponse(HttpResponse response) throws IOException {
          JSONObject jsonResponse = null;
          Header contentTypeHeader = response.getFirstHeader("Content-Type");
          if (contentTypeHeader != null && contentTypeHeader.getValue().startsWith("application/json")) {
              try {
                  jsonResponse = new JSONObject(new String(readResponse(response), StandardCharsets.UTF_8));
              } catch (JSONException e) {
                  throw new IOException(e.getMessage(), e);
              }
          } else {
              HttpEntity httpEntity = response.getEntity();
              if (httpEntity != null) {
                  try {
                      return new JSONObject().put("response", new String(readResponse(response), StandardCharsets.UTF_8));
                  } catch (JSONException e) {
                      throw new IOException("Invalid response content");
                  }
              }
          }
          // check http error code
          if (response.getStatusLine().getStatusCode() >= 400) {
              String errorMessage = null;
              if (jsonResponse != null && jsonResponse.optJSONObject("error") != null) {
                  try {
                      JSONObject jsonError = jsonResponse.getJSONObject("error");
                      errorMessage = jsonError.optString("code") + " " + jsonError.optString("message");
                  } catch (JSONException e) {
                      // ignore
                  }
              }
              if (errorMessage == null) {
                  errorMessage = response.getStatusLine().getReasonPhrase();
              }
              throw new IOException(errorMessage);
          }
          return jsonResponse;
      }
  
      protected byte[] readResponse(HttpResponse response) throws IOException {
          byte[] content;
          try (InputStream inputStream = response.getEntity().getContent()) {
              if (HttpClientAdapter.isGzipEncoded(response)) {
                  content = IOUtil.readFully(new GZIPInputStream(inputStream));
              } else {
                  content = IOUtil.readFully(inputStream);
              }
          }
          return content;
      }
  }