/**
 * @license Copyright Google Inc.
 * <p>
 * Licensed 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
 * <p>
 * https://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * 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.
 */
public class Execute {
  // [START apps_script_api_execute]

  /**
   * Create a HttpRequestInitializer from the given one, except set
   * the HTTP read timeout to be longer than the default (to allow
   * called scripts time to execute).
   *
   * @param {HttpRequestInitializer} requestInitializer the initializer
   *                                 to copy and adjust; typically a Credential object.
   * @return an initializer with an extended read timeout.
   */
  private static HttpRequestInitializer setHttpTimeout(
      final HttpRequestInitializer requestInitializer) {
    return new HttpRequestInitializer() {
      @Override
      public void initialize(HttpRequest httpRequest) throws IOException {
        requestInitializer.initialize(httpRequest);
        // This allows the API to call (and avoid timing out on)
        // functions that take up to 6 minutes to complete (the maximum
        // allowed script run time), plus a little overhead.
        httpRequest.setReadTimeout(380000);
      }
    };
  }

  /**
   * Build and return an authorized Script client service.
   *
   * @param {Credential} credential an authorized Credential object
   * @return an authorized Script client service
   */
  public static Script getScriptService() throws IOException {
    Credential credential = authorize();
    return new Script.Builder(
        HTTP_TRANSPORT, JSON_FACTORY, setHttpTimeout(credential))
        .setApplicationName(APPLICATION_NAME)
        .build();
  }

  /**
   * Interpret an error response returned by the API and return a String
   * summary.
   *
   * @param {Operation} op the Operation returning an error response
   * @return summary of error response, or null if Operation returned no
   * error
   */
  public static String getScriptError(Operation op) {
    if (op.getError() == null) {
      return null;
    }

    // Extract the first (and only) set of error details and cast as a Map.
    // The values of this map are the script's 'errorMessage' and
    // 'errorType', and an array of stack trace elements (which also need to
    // be cast as Maps).
    Map<String, Object> detail = op.getError().getDetails().get(0);
    List<Map<String, Object>> stacktrace =
        (List<Map<String, Object>>) detail.get("scriptStackTraceElements");

    java.lang.StringBuilder sb =
        new StringBuilder("\nScript error message: ");
    sb.append(detail.get("errorMessage"));
    sb.append("\nScript error type: ");
    sb.append(detail.get("errorType"));

    if (stacktrace != null) {
      // There may not be a stacktrace if the script didn't start
      // executing.
      sb.append("\nScript error stacktrace:");
      for (Map<String, Object> elem : stacktrace) {
        sb.append("\n  ");
        sb.append(elem.get("function"));
        sb.append(":");
        sb.append(elem.get("lineNumber"));
      }
    }
    sb.append("\n");
    return sb.toString();
  }

  public static void main(String[] args) throws IOException {
    // ID of the script to call. Acquire this from the Apps Script editor,
    // under Publish > Deploy as API executable.
    String scriptId = "ENTER_YOUR_SCRIPT_ID_HERE";
    Script service = getScriptService();

    // Create an execution request object.
    ExecutionRequest request = new ExecutionRequest()
        .setFunction("getFoldersUnderRoot");

    try {
      // Make the API request.
      Operation op =
          service.scripts().run(scriptId, request).execute();

      // Print results of request.
      if (op.getError() != null) {
        // The API executed, but the script returned an error.
        System.out.println(getScriptError(op));
      } else {
        // The result provided by the API needs to be cast into
        // the correct type, based upon what types the Apps
        // Script function returns. Here, the function returns
        // an Apps Script Object with String keys and values,
        // so must be cast into a Java Map (folderSet).
        Map<String, String> folderSet =
            (Map<String, String>) (op.getResponse().get("result"));
        if (folderSet.size() == 0) {
          System.out.println("No folders returned!");
        } else {
          System.out.println("Folders under your root folder:");
          for (String id : folderSet.keySet()) {
            System.out.printf(
                "\t%s (%s)\n", folderSet.get(id), id);
          }
        }
      }
    } catch (GoogleJsonResponseException e) {
      // The API encountered a problem before the script was called.
      e.printStackTrace(System.out);
    }
  }
  // [END apps_script_api_execute]
}