// Copyright 2020 Google LLC. All rights reserved.

package com.google.video.widevine.jts.providers;

import com.google.chrome.widevine.contentpartners.v1beta1.PublishedDevices;
import com.google.chrome.widevine.contentpartners.v1beta1.PublishedDevicesRequest;
import com.google.chrome.widevine.contentpartners.v1beta1.PublishedDevicesServiceGrpc;
import com.google.inject.Inject;
import com.google.protobuf.TextFormat;
import com.google.video.widevine.jts.httpclient.Credentials;
import com.google.video.widevine.jts.interfaces.DeviceCertificate;
import com.google.video.widevine.sdk.wvpl.WvPLBaseEnvironment;
import com.google.video.widevine.sdk.wvpl.WvPLStatusException;
import io.grpc.ManagedChannel;
import io.grpc.Metadata;
import io.grpc.netty.NettyChannelBuilder;
import io.grpc.stub.MetadataUtils;
import java.io.IOException;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * Provides the latest {@code PublishedDevices} data from the Widevine Published Devices Service.
 *
 * This implementation uses the Widevine Published Devices API, and support a gRPC method for
 * retrieving PublishedDevices with an embedded Published Devices list.
 */
public class PublishedDevicesProvider implements DeviceCertificate {
  private static final Logger logger = Logger.getLogger(PublishedDevicesProvider.class.getName());
  private WvPLBaseEnvironment<?> environment = null;
  private String apiServicePath = null;
  private Credentials credentials = null;

  /**
   * PublishedDevicesProvider constructor.
   *
   * @param environment A WvPLBaseEnvironment object initialized with a Service Certificate.
   * @param serviceAccountPath Path to a GCP Service Account json file, used in OAUTH.
   * @param apiServicePath Path to a Widevine Published Devices API service.
   * @throws IOException upon failure creating OAUTH credentials.
   */
  @Inject
  public PublishedDevicesProvider(
      WvPLBaseEnvironment<?> environment, String serviceAccountPath, String apiServicePath)
      throws IOException {
    this.environment = environment;
    this.apiServicePath = apiServicePath;
    credentials = new Credentials(serviceAccountPath);
  }

  /**
   * Get the latest {@code PublishedDevices} from the Widevine Published Devices Service.
   *
   * @return The latest {@code PublishedDevices} data.
   * @throws InterruptedException upon RPC failure.
   * @throws WvPLStatusException upon WvPLBaseEnvironment errors.
   */
  @Override
  public PublishedDevices getPublishedDevices() throws InterruptedException, WvPLStatusException{
    ManagedChannel channel = null;
    PublishedDevices devicesResponse = null;

    logger.log(Level.INFO, "Getting PublishedDevices...");
    try {
      channel = createRpcChannel(apiServicePath);
      Metadata metadata = new Metadata();
      String token = "Bearer " + credentials.getAccessToken();
      metadata.put(Metadata.Key.of("authorization", Metadata.ASCII_STRING_MARSHALLER), token);
      PublishedDevicesServiceGrpc.PublishedDevicesServiceBlockingStub blockingStub =
          PublishedDevicesServiceGrpc.newBlockingStub(channel)
              .withInterceptors(MetadataUtils.newAttachHeadersInterceptor(metadata));
      devicesResponse = blockingStub.getPublishedDevices(PublishedDevicesRequest.parseFrom(
          environment.generateDeviceStatusListRequest()));
      logger.log(Level.INFO, "GRPC Call to PublishedDevicesService.GetSignedList returned:\n %s"
          + TextFormat.printer().printToString(devicesResponse));
    } catch (IOException e) {
      logger.log(Level.INFO, "IOException encountered trying to retrieve the signed list: " + e);
    } finally {
      if (channel != null) {
        channel.shutdown();
        channel.awaitTermination(1, TimeUnit.SECONDS);
      }
    }
    return devicesResponse;
  }

  private static ManagedChannel createRpcChannel(String host) {
    return NettyChannelBuilder.forTarget(host).build();
  }
}