/*
 * Copyright 2016 The gRPC Authors
 *
 * 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
 *
 *     http://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 io.grpc.routeguideexample;

import android.content.Context;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.TextUtils;
import android.text.method.ScrollingMovementMethod;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import io.grpc.ManagedChannel;
import io.grpc.ManagedChannelBuilder;
import io.grpc.StatusRuntimeException;
import io.grpc.routeguideexample.RouteGuideGrpc.RouteGuideBlockingStub;
import io.grpc.routeguideexample.RouteGuideGrpc.RouteGuideStub;
import io.grpc.stub.StreamObserver;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.lang.ref.WeakReference;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

public class RouteGuideActivity extends AppCompatActivity {
  private EditText hostEdit;
  private EditText portEdit;
  private Button startRouteGuideButton;
  private Button exitRouteGuideButton;
  private Button getFeatureButton;
  private Button listFeaturesButton;
  private Button recordRouteButton;
  private Button routeChatButton;
  private TextView resultText;
  private ManagedChannel channel;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_routeguide);
    hostEdit = (EditText) findViewById(R.id.host_edit_text);
    portEdit = (EditText) findViewById(R.id.port_edit_text);
    startRouteGuideButton = (Button) findViewById(R.id.start_route_guide_button);
    exitRouteGuideButton = (Button) findViewById(R.id.exit_route_guide_button);
    getFeatureButton = (Button) findViewById(R.id.get_feature_button);
    listFeaturesButton = (Button) findViewById(R.id.list_features_button);
    recordRouteButton = (Button) findViewById(R.id.record_route_button);
    routeChatButton = (Button) findViewById(R.id.route_chat_button);
    resultText = (TextView) findViewById(R.id.result_text);
    resultText.setMovementMethod(new ScrollingMovementMethod());
    disableButtons();
  }

  public void startRouteGuide(View view) {
    String host = hostEdit.getText().toString();
    String portStr = portEdit.getText().toString();
    int port = TextUtils.isEmpty(portStr) ? 0 : Integer.valueOf(portStr);
    ((InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE))
        .hideSoftInputFromWindow(hostEdit.getWindowToken(), 0);
    channel = ManagedChannelBuilder.forAddress(host, port).usePlaintext().build();
    hostEdit.setEnabled(false);
    portEdit.setEnabled(false);
    startRouteGuideButton.setEnabled(false);
    enableButtons();
  }

  public void exitRouteGuide(View view) {
    channel.shutdown();
    disableButtons();
    hostEdit.setEnabled(true);
    portEdit.setEnabled(true);
    startRouteGuideButton.setEnabled(true);
  }

  public void getFeature(View view) {
    setResultText("");
    disableButtons();
    new GrpcTask(new GetFeatureRunnable(), channel, this).execute();
  }

  public void listFeatures(View view) {
    setResultText("");
    disableButtons();
    new GrpcTask(new ListFeaturesRunnable(), channel, this).execute();
  }

  public void recordRoute(View view) {
    setResultText("");
    disableButtons();
    new GrpcTask(new RecordRouteRunnable(), channel, this).execute();
  }

  public void routeChat(View view) {
    setResultText("");
    disableButtons();
    new GrpcTask(new RouteChatRunnable(), channel, this).execute();
  }

  private void setResultText(String text) {
    resultText.setText(text);
  }

  private void disableButtons() {
    getFeatureButton.setEnabled(false);
    listFeaturesButton.setEnabled(false);
    recordRouteButton.setEnabled(false);
    routeChatButton.setEnabled(false);
    exitRouteGuideButton.setEnabled(false);
  }

  private void enableButtons() {
    exitRouteGuideButton.setEnabled(true);
    getFeatureButton.setEnabled(true);
    listFeaturesButton.setEnabled(true);
    recordRouteButton.setEnabled(true);
    routeChatButton.setEnabled(true);
  }

  private static class GrpcTask extends AsyncTask<Void, Void, String> {
    private final GrpcRunnable grpcRunnable;
    private final ManagedChannel channel;
    private final WeakReference<RouteGuideActivity> activityReference;

    GrpcTask(GrpcRunnable grpcRunnable, ManagedChannel channel, RouteGuideActivity activity) {
      this.grpcRunnable = grpcRunnable;
      this.channel = channel;
      this.activityReference = new WeakReference<RouteGuideActivity>(activity);
    }

    @Override
    protected String doInBackground(Void... nothing) {
      try {
        String logs =
            grpcRunnable.run(
                RouteGuideGrpc.newBlockingStub(channel), RouteGuideGrpc.newStub(channel));
        return "Success!\n" + logs;
      } catch (Exception e) {
        StringWriter sw = new StringWriter();
        PrintWriter pw = new PrintWriter(sw);
        e.printStackTrace(pw);
        pw.flush();
        return "Failed... :\n" + sw;
      }
    }

    @Override
    protected void onPostExecute(String result) {
      RouteGuideActivity activity = activityReference.get();
      if (activity == null) {
        return;
      }
      activity.setResultText(result);
      activity.enableButtons();
    }
  }

  private interface GrpcRunnable {
    /** Perform a grpcRunnable and return all the logs. */
    String run(RouteGuideBlockingStub blockingStub, RouteGuideStub asyncStub) throws Exception;
  }

  private static class GetFeatureRunnable implements GrpcRunnable {
    @Override
    public String run(RouteGuideBlockingStub blockingStub, RouteGuideStub asyncStub)
        throws Exception {
      return getFeature(409146138, -746188906, blockingStub);
    }

    /** Blocking unary call example. Calls getFeature and prints the response. */
    private String getFeature(int lat, int lon, RouteGuideBlockingStub blockingStub)
        throws StatusRuntimeException {
      StringBuffer logs = new StringBuffer();
      appendLogs(logs, "*** GetFeature: lat={0} lon={1}", lat, lon);

      Point request = Point.newBuilder().setLatitude(lat).setLongitude(lon).build();

      Feature feature;
      feature = blockingStub.getFeature(request);
      if (RouteGuideUtil.exists(feature)) {
        appendLogs(
            logs,
            "Found feature called \"{0}\" at {1}, {2}",
            feature.getName(),
            RouteGuideUtil.getLatitude(feature.getLocation()),
            RouteGuideUtil.getLongitude(feature.getLocation()));
      } else {
        appendLogs(
            logs,
            "Found no feature at {0}, {1}",
            RouteGuideUtil.getLatitude(feature.getLocation()),
            RouteGuideUtil.getLongitude(feature.getLocation()));
      }
      return logs.toString();
    }
  }

  private static class ListFeaturesRunnable implements GrpcRunnable {
    @Override
    public String run(RouteGuideBlockingStub blockingStub, RouteGuideStub asyncStub)
        throws Exception {
      return listFeatures(400000000, -750000000, 420000000, -730000000, blockingStub);
    }

    /**
     * Blocking server-streaming example. Calls listFeatures with a rectangle of interest. Prints
     * each response feature as it arrives.
     */
    private String listFeatures(
        int lowLat, int lowLon, int hiLat, int hiLon, RouteGuideBlockingStub blockingStub)
        throws StatusRuntimeException {
      StringBuffer logs = new StringBuffer("Result: ");
      appendLogs(
          logs,
          "*** ListFeatures: lowLat={0} lowLon={1} hiLat={2} hiLon={3}",
          lowLat,
          lowLon,
          hiLat,
          hiLon);

      Rectangle request =
          Rectangle.newBuilder()
              .setLo(Point.newBuilder().setLatitude(lowLat).setLongitude(lowLon).build())
              .setHi(Point.newBuilder().setLatitude(hiLat).setLongitude(hiLon).build())
              .build();
      Iterator<Feature> features;
      features = blockingStub.listFeatures(request);

      while (features.hasNext()) {
        Feature feature = features.next();
        appendLogs(logs, feature.toString());
      }
      return logs.toString();
    }
  }

  private static class RecordRouteRunnable implements GrpcRunnable {
    private Throwable failed;

    @Override
    public String run(RouteGuideBlockingStub blockingStub, RouteGuideStub asyncStub)
        throws Exception {
      List<Point> points = new ArrayList<>();
      points.add(Point.newBuilder().setLatitude(407838351).setLongitude(-746143763).build());
      points.add(Point.newBuilder().setLatitude(408122808).setLongitude(-743999179).build());
      points.add(Point.newBuilder().setLatitude(413628156).setLongitude(-749015468).build());
      return recordRoute(points, 5, asyncStub);
    }

    /**
     * Async client-streaming example. Sends {@code numPoints} randomly chosen points from {@code
     * features} with a variable delay in between. Prints the statistics when they are sent from the
     * server.
     */
    private String recordRoute(List<Point> points, int numPoints, RouteGuideStub asyncStub)
        throws InterruptedException, RuntimeException {
      final StringBuffer logs = new StringBuffer();
      appendLogs(logs, "*** RecordRoute");

      final CountDownLatch finishLatch = new CountDownLatch(1);
      StreamObserver<RouteSummary> responseObserver =
          new StreamObserver<RouteSummary>() {
            @Override
            public void onNext(RouteSummary summary) {
              appendLogs(
                  logs,
                  "Finished trip with {0} points. Passed {1} features. "
                      + "Travelled {2} meters. It took {3} seconds.",
                  summary.getPointCount(),
                  summary.getFeatureCount(),
                  summary.getDistance(),
                  summary.getElapsedTime());
            }

            @Override
            public void onError(Throwable t) {
              failed = t;
              finishLatch.countDown();
            }

            @Override
            public void onCompleted() {
              appendLogs(logs, "Finished RecordRoute");
              finishLatch.countDown();
            }
          };

      StreamObserver<Point> requestObserver = asyncStub.recordRoute(responseObserver);
      try {
        // Send numPoints points randomly selected from the points list.
        Random rand = new Random();
        for (int i = 0; i < numPoints; ++i) {
          int index = rand.nextInt(points.size());
          Point point = points.get(index);
          appendLogs(
              logs,
              "Visiting point {0}, {1}",
              RouteGuideUtil.getLatitude(point),
              RouteGuideUtil.getLongitude(point));
          requestObserver.onNext(point);
          // Sleep for a bit before sending the next one.
          Thread.sleep(rand.nextInt(1000) + 500);
          if (finishLatch.getCount() == 0) {
            // RPC completed or errored before we finished sending.
            // Sending further requests won't error, but they will just be thrown away.
            break;
          }
        }
      } catch (RuntimeException e) {
        // Cancel RPC
        requestObserver.onError(e);
        throw e;
      }
      // Mark the end of requests
      requestObserver.onCompleted();

      // Receiving happens asynchronously
      if (!finishLatch.await(1, TimeUnit.MINUTES)) {
        throw new RuntimeException(
            "Could not finish rpc within 1 minute, the server is likely down");
      }

      if (failed != null) {
        throw new RuntimeException(failed);
      }
      return logs.toString();
    }
  }

  private static class RouteChatRunnable implements GrpcRunnable {
    private Throwable failed;

    @Override
    public String run(RouteGuideBlockingStub blockingStub, RouteGuideStub asyncStub)
        throws Exception {
      return routeChat(asyncStub);
    }

    /**
     * Bi-directional example, which can only be asynchronous. Send some chat messages, and print
     * any chat messages that are sent from the server.
     */
    private String routeChat(RouteGuideStub asyncStub)
        throws InterruptedException, RuntimeException {
      final StringBuffer logs = new StringBuffer();
      appendLogs(logs, "*** RouteChat");
      final CountDownLatch finishLatch = new CountDownLatch(1);
      StreamObserver<RouteNote> requestObserver =
          asyncStub.routeChat(
              new StreamObserver<RouteNote>() {
                @Override
                public void onNext(RouteNote note) {
                  appendLogs(
                      logs,
                      "Got message \"{0}\" at {1}, {2}",
                      note.getMessage(),
                      note.getLocation().getLatitude(),
                      note.getLocation().getLongitude());
                }

                @Override
                public void onError(Throwable t) {
                  failed = t;
                  finishLatch.countDown();
                }

                @Override
                public void onCompleted() {
                  appendLogs(logs, "Finished RouteChat");
                  finishLatch.countDown();
                }
              });

      try {
        RouteNote[] requests = {
          newNote("First message", 0, 0),
          newNote("Second message", 0, 1),
          newNote("Third message", 1, 0),
          newNote("Fourth message", 1, 1)
        };

        for (RouteNote request : requests) {
          appendLogs(
              logs,
              "Sending message \"{0}\" at {1}, {2}",
              request.getMessage(),
              request.getLocation().getLatitude(),
              request.getLocation().getLongitude());
          requestObserver.onNext(request);
        }
      } catch (RuntimeException e) {
        // Cancel RPC
        requestObserver.onError(e);
        throw e;
      }
      // Mark the end of requests
      requestObserver.onCompleted();

      // Receiving happens asynchronously
      if (!finishLatch.await(1, TimeUnit.MINUTES)) {
        throw new RuntimeException(
            "Could not finish rpc within 1 minute, the server is likely down");
      }

      if (failed != null) {
        throw new RuntimeException(failed);
      }

      return logs.toString();
    }
  }

  private static void appendLogs(StringBuffer logs, String msg, Object... params) {
    if (params.length > 0) {
      logs.append(MessageFormat.format(msg, params));
    } else {
      logs.append(msg);
    }
    logs.append("\n");
  }

  private static RouteNote newNote(String message, int lat, int lon) {
    return RouteNote.newBuilder()
        .setMessage(message)
        .setLocation(Point.newBuilder().setLatitude(lat).setLongitude(lon).build())
        .build();
  }
}