package com.gcmdemoapp;

import java.io.IOException;
import java.util.List;

import javax.annotation.Nullable;
import javax.inject.Named;
import javax.persistence.EntityManager;
import javax.persistence.Query;

import com.google.android.gcm.server.Constants;
import com.google.android.gcm.server.Message;
import com.google.android.gcm.server.Result;
import com.google.android.gcm.server.Sender;
import com.google.api.server.spi.config.Api;
import com.google.api.server.spi.config.ApiMethod;
import com.google.api.server.spi.config.ApiNamespace;
import com.google.api.server.spi.response.CollectionResponse;
import com.google.appengine.api.datastore.Cursor;
import com.google.appengine.datanucleus.query.JPACursorHelper;


/**
 * A simple Cloud Endpoint that receives notifications from a web client
 * (<server url>/index.html), and broadcasts them to all of the devices that
 * were registered with this application (via DeviceInfoEndpoint).
 * 
 * In order for this sample to work, you have to populate the API_KEY field with
 * your key for server apps. You can obtain this key from the API console
 * (https://code.google.com/apis/console). You'll first have to create a project
 * and enable the Google Cloud Messaging Service for it, as described in the
 * javadoc for GCMIntentService.java (in your Android project).
 * 
 * After creating the project in the API console, browse to the "API Access"
 * section, and select the option to "Create a New Server Key". The generated
 * key is what you'll enter into the API_KEY field.
 * 
 * See the documentation at
 * http://developers.google.com/eclipse/docs/cloud_endpoints for more
 * information.
 * 
 * NOTE: This endpoint does not use any form of authorization or authentication!
 * If this app is deployed, anyone can access this endpoint! If you'd like to
 * add authentication, take a look at the documentation.
 */
@Api(name = "messageEndpoint", namespace = @ApiNamespace(ownerDomain = "gcmdemoapp.com", ownerName = "gcmdemoapp.com", packagePath=""))
// NO AUTHENTICATION; OPEN ENDPOINT!
public class MessageEndpoint {

  /*
   * TODO: Fill this in with the server key that you've obtained from the API
   * Console (https://code.google.com/apis/console). This is required for using
   * Google Cloud Messaging from your AppEngine application even if you are
   * using a App Engine's local development server.
   */
  private static final String API_KEY = "AIzaSyAMj1FWqKoO8UubDjAKcjA_6cl72jIwKCA";

  private static final DeviceInfoEndpoint endpoint = new DeviceInfoEndpoint();
  
  /**
   * This function returns a list of messages starting with the newest message
   * first and in descending order from there
   * 
   * @param cursorString 
   *          for paging, empty for the first request, subsequent requests can
   *          use the returned information from an earlier request to fill this
   *          parameter
   * @param limit
   *          number of results returned for this query
   * @return
   *          A collection of MessageData items
   */
  @SuppressWarnings({ "unchecked", "unused" })
  @ApiMethod(name = "listMessages")
  public CollectionResponse<MessageData> listMessages(
      @Nullable @Named("cursor") String cursorString,
      @Nullable @Named("limit") Integer limit) {

    EntityManager mgr = null;  
    Cursor cursor = null;
    List<MessageData> execute = null;
    
    try {
      mgr = getEntityManager();
      // query for messages, newest message first
      Query query = mgr
          .createQuery("select from MessageData as MessageData order by timestamp desc");
      if (cursorString != null && cursorString != "") {
        cursor = Cursor.fromWebSafeString(cursorString);
        query.setHint(JPACursorHelper.CURSOR_HINT, cursor);
      }

      if (limit != null) {
        query.setFirstResult(0);
        query.setMaxResults(limit);
      }

      execute = (List<MessageData>) query.getResultList();
      cursor = JPACursorHelper.getCursor(execute);
      if (cursor != null)
        cursorString = cursor.toWebSafeString();

      // Tight loop for fetching all entities from datastore and accomodate
      // for lazy fetch.
      for (MessageData obj : execute) {
        ;
      }
    } finally {
      mgr.close();
    }

    return CollectionResponse.<MessageData> builder().setItems(execute)
        .setNextPageToken(cursorString).build();
  }
  
  /**
   * This accepts a message and persists it in the AppEngine datastore, it 
   * will also broadcast the message to upto 10 registered android devices
   * via Google Cloud Messaging
   *  
   * @param message
   *            the entity to be inserted.
   * @return 
   * @throws IOException
   */
  @ApiMethod(name = "sendMessage")
  public void sendMessage(@Named("message") String message)
      throws IOException {
    Sender sender = new Sender(API_KEY);
    // create a MessageData entity with a timestamp of when it was
    // received, and persist it
    MessageData messageObj = new MessageData();
    messageObj.setMessage(message);
    messageObj.setTimestamp(System.currentTimeMillis());
    EntityManager mgr = getEntityManager();
    try {
      mgr.persist(messageObj);
    } finally {
      mgr.close();
    }
    // ping a max of 10 registered devices
    CollectionResponse<DeviceInfo> response = endpoint.listDeviceInfo(null,
        1000);
    for (DeviceInfo deviceInfo : response.getItems()) {
      doSendViaGcm(message, sender, deviceInfo);
    }
  }

  /**
   * Sends the message using the Sender object to the registered device.
   * 
   * @param message
   *            the message to be sent in the GCM ping to the device.
   * @param sender
   *            the Sender object to be used for ping,
   * @param deviceInfo
   *            the registration id of the device.
   * @return Result the result of the ping.
   */
  private static Result doSendViaGcm(String message, Sender sender,
      DeviceInfo deviceInfo) throws IOException {
    // Trim message if needed.
    if (message.length() > 1000) {
      message = message.substring(0, 1000) + "[...]";
    }

    // This message object is a Google Cloud Messaging object, it is NOT 
    // related to the MessageData class
    Message msg = new Message.Builder().addData("message", message).build();
    Result result = sender.send(msg, deviceInfo.getDeviceRegistrationID(),
        5);
    if (result.getMessageId() != null) {
      String canonicalRegId = result.getCanonicalRegistrationId();
      if (canonicalRegId != null) {
        endpoint.removeDeviceInfo(deviceInfo.getDeviceRegistrationID());
        deviceInfo.setDeviceRegistrationID(canonicalRegId);
        endpoint.insertDeviceInfo(deviceInfo);
      }
    } else {
      String error = result.getErrorCodeName();
      if (error.equals(Constants.ERROR_NOT_REGISTERED)) {
        endpoint.removeDeviceInfo(deviceInfo.getDeviceRegistrationID());
      }
    }

    return result;
  }
  
  private static EntityManager getEntityManager() {
    return EMF.get().createEntityManager();
  }
}

@@ -5232,16 +5232,17 @@
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@@ -5340,17 +5340,16 @@
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Update MessageEndpoint.java