content: /*
   * Copyright © 2017-2023 WireGuard LLC. All Rights Reserved.
   * SPDX-License-Identifier: Apache-2.0
   */
  
  package org.amnezia.awg.backend;
  
  import android.os.SystemClock;
  
  import org.amnezia.awg.crypto.Key;
  import org.amnezia.awg.util.NonNullForAll;
  
  import java.util.HashMap;
  import java.util.Map;
  
  import androidx.annotation.Nullable;
  
  /**
   * Class representing transfer statistics for a {@link Tunnel} instance.
   */
  @NonNullForAll
  public class Statistics {
      public record PeerStats(long rxBytes, long txBytes, long latestHandshakeEpochMillis) { }
      private final Map<Key, PeerStats> stats = new HashMap<>();
      private long lastTouched = SystemClock.elapsedRealtime();
  
      Statistics() {
      }
  
      /**
       * Add a peer and its current stats to the internal map.
       *
       * @param key               An AmneziaWG public key bound to a particular peer
       * @param rxBytes           The received traffic for the {@link org.amnezia.config.Peer} referenced by
       *                          the provided {@link Key}. This value is in bytes
       * @param txBytes           The transmitted traffic for the {@link org.amnezia.config.Peer} referenced by
       *                          the provided {@link Key}. This value is in bytes.
       * @param latestHandshake   The timestamp of the latest handshake for the {@link org.amnezia.config.Peer}
       *                          referenced by the provided {@link Key}. The value is in epoch milliseconds.
       */
      void add(final Key key, final long rxBytes, final long txBytes, final long latestHandshake) {
          stats.put(key, new PeerStats(rxBytes, txBytes, latestHandshake));
          lastTouched = SystemClock.elapsedRealtime();
      }
  
      /**
       * Check if the statistics are stale, indicating the need for the {@link Backend} to update them.
       *
       * @return boolean indicating if the current statistics instance has stale values.
       */
      public boolean isStale() {
          return SystemClock.elapsedRealtime() - lastTouched > 900;
      }
  
      /**
       * Get the statistics for the {@link org.amnezia.config.Peer} referenced by the provided {@link Key}
       *
       * @param peer A {@link Key} representing a {@link org.amnezia.config.Peer}.
       * @return a {@link PeerStats} representing various statistics about this peer.
       */
      @Nullable
      public PeerStats peer(final Key peer) {
          return stats.get(peer);
      }
  
      /**
       * Get the list of peers being tracked by this instance.
       *
       * @return An array of {@link Key} instances representing AmneziaWG
       * {@link org.amnezia.config.Peer}s
       */
      public Key[] peers() {
          return stats.keySet().toArray(new Key[0]);
      }
  
      /**
       * Get the total received traffic by all the peers being tracked by this instance
       *
       * @return a long representing the number of bytes received by the peers being tracked.
       */
      public long totalRx() {
          long rx = 0;
          for (final PeerStats val : stats.values()) {
              rx += val.rxBytes;
          }
          return rx;
      }
  
      /**
       * Get the total transmitted traffic by all the peers being tracked by this instance
       *
       * @return a long representing the number of bytes transmitted by the peers being tracked.
       */
      public long totalTx() {
          long tx = 0;
          for (final PeerStats val : stats.values()) {
              tx += val.txBytes;
          }
          return tx;
      }
  }
  