/*
 * Copyright DataStax, Inc.
 *
 * 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 com.datastax.dse.driver.internal.core.tracker;

import com.datastax.oss.driver.api.core.config.DriverExecutionProfile;
import com.datastax.oss.driver.api.core.metadata.Node;
import com.datastax.oss.driver.api.core.session.Request;
import com.datastax.oss.driver.api.core.session.Session;
import com.datastax.oss.driver.api.core.tracker.RequestTracker;
import edu.umd.cs.findbugs.annotations.NonNull;
import edu.umd.cs.findbugs.annotations.Nullable;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

Combines multiple request trackers into a single one.
The default context always wraps any user-provided tracker into this, in case other internal
components need to add their own trackers later (see InternalDriverContext.buildRequestTracker).
We also use it to catch and log any unexpected exception thrown by a tracker.
/**
 * Combines multiple request trackers into a single one.
 *
 * <p>The default context always wraps any user-provided tracker into this, in case other internal
 * components need to add their own trackers later (see InternalDriverContext.buildRequestTracker).
 *
 * <p>We also use it to catch and log any unexpected exception thrown by a tracker.
 */
public class MultiplexingRequestTracker implements RequestTracker {

  private static final Logger LOG = LoggerFactory.getLogger(MultiplexingRequestTracker.class);

  private final List<RequestTracker> trackers = new CopyOnWriteArrayList<>();

  public void register(RequestTracker tracker) {
    trackers.add(tracker);
  }

  @Override
  public void onSuccess(
      @NonNull Request request,
      long latencyNanos,
      @NonNull DriverExecutionProfile executionProfile,
      @NonNull Node node,
      @NonNull String logPrefix) {
    for (RequestTracker tracker : trackers) {
      try {
        tracker.onSuccess(request, latencyNanos, executionProfile, node, logPrefix);
      } catch (Throwable t) {
        LOG.error("[{}] Unexpected error while invoking request tracker", logPrefix, t);
      }
    }
  }

  @Override
  public void onError(
      @NonNull Request request,
      @NonNull Throwable error,
      long latencyNanos,
      @NonNull DriverExecutionProfile executionProfile,
      @Nullable Node node,
      @NonNull String logPrefix) {
    for (RequestTracker tracker : trackers) {
      try {
        tracker.onError(request, error, latencyNanos, executionProfile, node, logPrefix);
      } catch (Throwable t) {
        LOG.error("[{}] Unexpected error while invoking request tracker", logPrefix, t);
      }
    }
  }

  @Override
  public void onNodeSuccess(
      @NonNull Request request,
      long latencyNanos,
      @NonNull DriverExecutionProfile executionProfile,
      @NonNull Node node,
      @NonNull String logPrefix) {
    for (RequestTracker tracker : trackers) {
      try {
        tracker.onNodeSuccess(request, latencyNanos, executionProfile, node, logPrefix);
      } catch (Throwable t) {
        LOG.error("[{}] Unexpected error while invoking request tracker", logPrefix, t);
      }
    }
  }

  @Override
  public void onNodeError(
      @NonNull Request request,
      @NonNull Throwable error,
      long latencyNanos,
      @NonNull DriverExecutionProfile executionProfile,
      @NonNull Node node,
      @NonNull String logPrefix) {
    for (RequestTracker tracker : trackers) {
      try {
        tracker.onNodeError(request, error, latencyNanos, executionProfile, node, logPrefix);
      } catch (Throwable t) {
        LOG.error("[{}] Unexpected error while invoking request tracker", logPrefix, t);
      }
    }
  }

  @Override
  public void onSessionReady(@NonNull Session session) {
    for (RequestTracker tracker : trackers) {
      try {
        tracker.onSessionReady(session);
      } catch (Throwable t) {
        LOG.error("[{}] Unexpected error while invoking request tracker", session.getName(), t);
      }
    }
  }

  @Override
  public void close() throws Exception {
    Exception toThrow = null;
    for (RequestTracker tracker : trackers) {
      try {
        tracker.close();
      } catch (Exception e) {
        if (toThrow == null) {
          toThrow = e;
        } else {
          toThrow.addSuppressed(e);
        }
      }
    }
    if (toThrow != null) {
      throw toThrow;
    }
  }
}