content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 org.apache.beam.sdk.extensions.ordered;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.util.List;
  import java.util.Objects;
  import javax.annotation.Nullable;
  import org.apache.beam.sdk.coders.BooleanCoder;
  import org.apache.beam.sdk.coders.Coder;
  import org.apache.beam.sdk.coders.NullableCoder;
  import org.apache.beam.sdk.coders.VarIntCoder;
  import org.apache.beam.sdk.coders.VarLongCoder;
  import org.apache.beam.sdk.extensions.ordered.ContiguousSequenceRange.ContiguousSequenceRangeCoder;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableList;
  import org.checkerframework.checker.initialization.qual.Initialized;
  
  /**
   * Class used to store the status of processing for a particular key.
   *
   * @param <KeyT>
   */
  class ProcessingState<KeyT> {
  
    @Nullable private Long lastOutputSequence;
    @Nullable private Long latestBufferedSequence;
    @Nullable private Long earliestBufferedSequence;
    private long bufferedEventCount;
  
    private boolean lastEventReceived;
  
    private long eventsReceived;
  
    private long duplicates;
  
    private long resultCount;
  
    @Nullable private ContiguousSequenceRange lastCompleteGlobalSequence;
  
    private KeyT key;
  
    public ProcessingState(KeyT key) {
      this.key = key;
      this.bufferedEventCount = 0;
      this.lastOutputSequence = null;
      this.earliestBufferedSequence = null;
      this.latestBufferedSequence = null;
      this.lastCompleteGlobalSequence = null;
    }
  
    /**
     * Only to be used by the coder.
     *
     * @param key
     * @param lastOutputSequence
     * @param earliestBufferedSequence
     * @param latestBufferedSequence
     * @param bufferedEventCount
     */
    ProcessingState(
        KeyT key,
        @Nullable Long lastOutputSequence,
        @Nullable Long earliestBufferedSequence,
        @Nullable Long latestBufferedSequence,
        long bufferedEventCount,
        long eventsReceived,
        long duplicates,
        long resultCount,
        boolean lastEventReceived) {
      this(key);
      this.lastOutputSequence = lastOutputSequence;
      this.earliestBufferedSequence = earliestBufferedSequence;
      this.latestBufferedSequence = latestBufferedSequence;
      this.bufferedEventCount = bufferedEventCount;
      this.eventsReceived = eventsReceived;
      this.duplicates = duplicates;
      this.resultCount = resultCount;
      this.lastEventReceived = lastEventReceived;
    }
  
    @Nullable
    public Long getLastOutputSequence() {
      return lastOutputSequence;
    }
  
    @Nullable
    public Long getLatestBufferedSequence() {
      return latestBufferedSequence;
    }
  
    @Nullable
    public Long getEarliestBufferedSequence() {
      return earliestBufferedSequence;
    }
  
    public long getBufferedEventCount() {
      return bufferedEventCount;
    }
  
    public long getEventsReceived() {
      return eventsReceived;
    }
  
    public boolean isLastEventReceived() {
      return lastEventReceived;
    }
  
    public long getResultCount() {
      return resultCount;
    }
  
    public long getDuplicates() {
      return duplicates;
    }
  
    public KeyT getKey() {
      return key;
    }
  
    public @Nullable ContiguousSequenceRange getLastContiguousRange() {
      return lastCompleteGlobalSequence;
    }
  
    public void setLastCompleteGlobalSequence(
        @Nullable ContiguousSequenceRange lastCompleteGlobalSequence) {
      this.lastCompleteGlobalSequence = lastCompleteGlobalSequence;
    }
  
    /**
     * Current event matched the sequence and was processed.
     *
     * @param sequence
     * @param lastEvent
     */
    public void eventAccepted(long sequence, boolean lastEvent) {
      this.lastOutputSequence = sequence;
      setLastEventReceived(lastEvent);
    }
  
    private void setLastEventReceived(boolean lastEvent) {
      // Only one last event can be received.
      this.lastEventReceived = this.lastEventReceived ? true : lastEvent;
    }
  
    /**
     * New event added to the buffer.
     *
     * @param sequenceNumber of the event
     * @param isLastEvent
     */
    void eventBuffered(long sequenceNumber, boolean isLastEvent) {
      bufferedEventCount++;
      latestBufferedSequence =
          Math.max(
              sequenceNumber,
              latestBufferedSequence == null ? Long.MIN_VALUE : latestBufferedSequence);
      earliestBufferedSequence =
          Math.min(
              sequenceNumber,
              earliestBufferedSequence == null ? Long.MAX_VALUE : earliestBufferedSequence);
  
      setLastEventReceived(isLastEvent);
    }
  
    /**
     * An event was processed and removed from the buffer.
     *
     * @param sequence of the processed event
     */
    public void processedBufferedEvent(long sequence) {
      bufferedEventCount--;
      lastOutputSequence = sequence;
  
      if (bufferedEventCount == 0) {
        earliestBufferedSequence = latestBufferedSequence = null;
      } else {
        // We don't know for sure that it's the earliest record yet, but OrderedEventProcessor will
        // read the next
        // buffered event and call foundSequenceGap() and adjust this value.
        earliestBufferedSequence = sequence + 1;
      }
    }
  
    /**
     * A set of records was pulled from the buffer, but it turned out that the element is not
     * sequential.
     *
     * @param newEarliestSequence
     */
    public void foundSequenceGap(long newEarliestSequence) {
      earliestBufferedSequence = newEarliestSequence;
    }
  
    @Override
    public boolean equals(@Nullable @Initialized Object o) {
      if (this == o) {
        return true;
      }
      if (!(o instanceof ProcessingState)) {
        return false;
      }
      ProcessingState<?> that = (ProcessingState<?>) o;
      return bufferedEventCount == that.bufferedEventCount
          && lastEventReceived == that.lastEventReceived
          && eventsReceived == that.eventsReceived
          && duplicates == that.duplicates
          && Objects.equals(lastOutputSequence, that.lastOutputSequence)
          && Objects.equals(latestBufferedSequence, that.latestBufferedSequence)
          && Objects.equals(earliestBufferedSequence, that.earliestBufferedSequence)
          && Objects.equals(key, that.key)
          && resultCount == that.resultCount;
    }
  
    @Override
    public int hashCode() {
      return Objects.hash(
          lastOutputSequence,
          latestBufferedSequence,
          earliestBufferedSequence,
          bufferedEventCount,
          lastEventReceived,
          eventsReceived,
          duplicates,
          resultCount,
          key);
    }
  
    @Override
    public String toString() {
      return "ProcessingState{"
          + "lastOutputSequence="
          + lastOutputSequence
          + ", latestBufferedSequence="
          + latestBufferedSequence
          + ", earliestBufferedSequence="
          + earliestBufferedSequence
          + ", bufferedEventCount="
          + bufferedEventCount
          + ", lastEventReceived="
          + lastEventReceived
          + ", eventsReceived="
          + eventsReceived
          + ", duplicates="
          + duplicates
          + ", resultCount="
          + resultCount
          + ", lastCompleteGlobalSequence="
          + lastCompleteGlobalSequence
          + ", key="
          + key
          + '}';
    }
  
    public boolean isProcessingCompleted() {
      return lastEventReceived && bufferedEventCount == 0;
    }
  
    public void eventReceived() {
      eventsReceived++;
    }
  
    public boolean isNextEvent(long sequence) {
      return lastOutputSequence != null && sequence == lastOutputSequence + 1;
    }
  
    public boolean hasAlreadyBeenProcessed(long currentSequence) {
      boolean result = lastOutputSequence != null && lastOutputSequence >= currentSequence;
      if (result) {
        duplicates++;
      }
      return result;
    }
  
    public boolean checkForDuplicateBatchedEvent(long currentSequence) {
      boolean result = lastOutputSequence != null && lastOutputSequence == currentSequence;
      if (result) {
        duplicates++;
        if (--bufferedEventCount == 0) {
          earliestBufferedSequence = latestBufferedSequence = null;
        }
      }
      return result;
    }
  
    public boolean readyToProcessBufferedEvents() {
      return earliestBufferedSequence != null
          && lastOutputSequence != null
          && earliestBufferedSequence == lastOutputSequence + 1;
    }
  
    public void resultProduced() {
      resultCount++;
    }
  
    public long resultsProducedInBundle(long numberOfResultsBeforeBundleStart) {
      return resultCount - numberOfResultsBeforeBundleStart;
    }
  
    public void updateGlobalSequenceDetails(ContiguousSequenceRange updated) {
      if (thereAreGloballySequencedEventsToBeProcessed()) {
        // We don't update the timer if we can already process events in the onTimer batch.
        // Otherwise, it's possible that we will be pushing the timer to later timestamps
        // without a chance to run and produce output.
        return;
      }
      this.lastCompleteGlobalSequence = updated;
    }
  
    public boolean thereAreGloballySequencedEventsToBeProcessed() {
      return bufferedEventCount > 0
          && lastCompleteGlobalSequence != null
          && earliestBufferedSequence != null
          && earliestBufferedSequence < lastCompleteGlobalSequence.getEnd();
    }
  
    /**
     * Coder for the processing status.
     *
     * @param <KeyT>
     */
    static class ProcessingStateCoder<KeyT> extends Coder<ProcessingState<KeyT>> {
  
      private static final NullableCoder<Long> NULLABLE_LONG_CODER =
          NullableCoder.of(VarLongCoder.of());
      private static final Coder<Long> LONG_CODER = VarLongCoder.of();
      private static final VarIntCoder INTEGER_CODER = VarIntCoder.of();
      private static final BooleanCoder BOOLEAN_CODER = BooleanCoder.of();
  
      private static final NullableCoder<ContiguousSequenceRange> SEQUENCE_AND_TIMESTAMP_CODER =
          NullableCoder.of(ContiguousSequenceRangeCoder.of());
  
      private Coder<KeyT> keyCoder;
  
      private ProcessingStateCoder(Coder<KeyT> keyCoder) {
        this.keyCoder = keyCoder;
      }
  
      public static <KeyT> ProcessingStateCoder<KeyT> of(Coder<KeyT> keyCoder) {
        return new ProcessingStateCoder<>(keyCoder);
      }
  
      @Override
      public void encode(ProcessingState<KeyT> value, OutputStream outStream) throws IOException {
        NULLABLE_LONG_CODER.encode(value.getLastOutputSequence(), outStream);
        NULLABLE_LONG_CODER.encode(value.getEarliestBufferedSequence(), outStream);
        NULLABLE_LONG_CODER.encode(value.getLatestBufferedSequence(), outStream);
        LONG_CODER.encode(value.getBufferedEventCount(), outStream);
        LONG_CODER.encode(value.getEventsReceived(), outStream);
        LONG_CODER.encode(value.getDuplicates(), outStream);
        LONG_CODER.encode(value.getResultCount(), outStream);
        BOOLEAN_CODER.encode(value.isLastEventReceived(), outStream);
        keyCoder.encode(value.getKey(), outStream);
        SEQUENCE_AND_TIMESTAMP_CODER.encode(value.getLastContiguousRange(), outStream);
      }
  
      @Override
      public ProcessingState<KeyT> decode(InputStream inStream) throws IOException {
        Long lastOutputSequence = NULLABLE_LONG_CODER.decode(inStream);
        Long earliestBufferedSequence = NULLABLE_LONG_CODER.decode(inStream);
        Long latestBufferedSequence = NULLABLE_LONG_CODER.decode(inStream);
        int bufferedRecordCount = INTEGER_CODER.decode(inStream);
        long recordsReceivedCount = LONG_CODER.decode(inStream);
        long duplicates = LONG_CODER.decode(inStream);
        long resultCount = LONG_CODER.decode(inStream);
        boolean isLastEventReceived = BOOLEAN_CODER.decode(inStream);
        KeyT key = keyCoder.decode(inStream);
        ContiguousSequenceRange lastCompleteGlobalSequence =
            SEQUENCE_AND_TIMESTAMP_CODER.decode(inStream);
  
        ProcessingState<KeyT> result =
            new ProcessingState<>(
                key,
                lastOutputSequence,
                earliestBufferedSequence,
                latestBufferedSequence,
                bufferedRecordCount,
                recordsReceivedCount,
                duplicates,
                resultCount,
                isLastEventReceived);
        result.setLastCompleteGlobalSequence(lastCompleteGlobalSequence);
  
        return result;
      }
  
      @Override
      public List<? extends Coder<?>> getCoderArguments() {
        return ImmutableList.of();
      }
  
      @Override
      public void verifyDeterministic() {}
    }
  }
  