// Copyright 2019 Google LLC
//
// 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
//
//     https://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 com.google.sps.servlets;


import com.google.appengine.api.datastore.DatastoreService;
import com.google.appengine.api.datastore.DatastoreServiceFactory;
import com.google.appengine.api.datastore.Key;
import com.google.appengine.api.datastore.KeyFactory;
import java.io.IOException;
import java.util.logging.Logger;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/delete-event")
public class DeleteEventServlet extends HttpServlet {

  private static final Logger LOGGER = Logger.getLogger(DeleteEventServlet.class.getName());

  @Override
  public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
    String userToken = request.getParameter("userToken");
    String eventKeyString = request.getParameter("event");
    Key keyRequested = KeyFactory.stringToKey(eventKeyString);

    DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();
    datastore.delete(keyRequested);

    // Redirect back to the my-events HTML page.
    response.sendRedirect("/my-events.html");
  }
}

Add delete event servlet