package io.happycoding;

import java.net.URL;
import org.eclipse.jetty.annotations.AnnotationConfiguration;
import org.eclipse.jetty.server.Handler;
import org.eclipse.jetty.server.handler.DefaultHandler;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.servlet.DefaultServlet;
import org.eclipse.jetty.webapp.Configuration;
import org.eclipse.jetty.webapp.WebAppContext;
import org.eclipse.jetty.webapp.WebInfConfiguration;

/**
 * Starts up the server, including a DefaultServlet that handles static files,
 * and any servlet classes annotated with the @WebServlet annotation.
 */
public class ServerMain {

  public static void main(String[] args) throws Exception {

    // Create a server that listens on port 8080.
    Server server = new Server(8080);
    WebAppContext webAppContext = new WebAppContext();
    server.setHandler(webAppContext);

    // Load static content from inside the jar file.
    URL webAppDir =
        ServerMain.class.getClassLoader().getResource("META-INF/resources");
    webAppContext.setResourceBase(webAppDir.toURI().toString());

    // Enable annotations so the server sees classes annotated with @WebServlet.
    webAppContext.setConfigurations(new Configuration[]{
      new AnnotationConfiguration(),
      new WebInfConfiguration(),
    });

    // Look for annotations in the classes directory (dev server) and in the
    // jar file (live server)
    webAppContext.setAttribute(
        "org.eclipse.jetty.server.webapp.ContainerIncludeJarPattern",
        ".*/target/classes/|.*\\.jar");

    // Handle static resources, e.g. html files.
    webAppContext.addServlet(DefaultServlet.class, "/");

    // Start the server! 🚀
    server.start();
    System.out.println("Server started!");

    // Keep the main thread alive while the server is running.
    server.join();
  }
}

package io.happycoding.servlets;

import java.io.IOException;

import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.google.cloud.datastore.Datastore;
import com.google.cloud.datastore.DatastoreOptions;
import com.google.cloud.datastore.Entity;
import com.google.cloud.datastore.FullEntity;
import com.google.cloud.datastore.KeyFactory;
import com.google.cloud.datastore.Query;
import com.google.cloud.datastore.QueryResults;
import com.google.cloud.datastore.StructuredQuery.OrderBy;

@WebServlet("/message")
public class MessageServlet extends HttpServlet {

  @Override
  public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws IOException {

    response.setContentType("text/html;");
    response.getWriter().println("<h1>Shoutbox</h1>");
    response.getWriter().println("<ul>");

    Datastore datastore = DatastoreOptions.getDefaultInstance().getService();

    Query<Entity> query = Query.newEntityQueryBuilder()
      .setKind("Message")
      .setOrderBy(OrderBy.desc("timestamp"))
      .build();
    QueryResults<Entity> results = datastore.run(query);

    while (results.hasNext()) {
      Entity entity = results.next();
      String message = entity.getString("text");
      response.getWriter().println("<li>" + message + "</li>");
    }

    response.getWriter().println("</ul>");
    response.getWriter().println("<p><a href=\"/\">Back</a></p>");
  }

  @Override
  public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {

    String text = request.getParameter("message");

    Datastore datastore = DatastoreOptions.getDefaultInstance().getService();
    KeyFactory keyFactory = datastore.newKeyFactory().setKind("Message");
    FullEntity messageEntity = Entity.newBuilder(keyFactory.newKey())
      .set("text", text)
      .set("timestamp", System.currentTimeMillis())
      .build();
    datastore.put(messageEntity);

    // Redirect to /message.
    // The request will be routed to the doGet() function above.
    response.sendRedirect("/message");
  }
}