/*
 * 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.flink.cep.nfa.sharedbuffer;

import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.api.common.typeutils.base.IntSerializer;
import org.apache.flink.api.common.typeutils.base.LongSerializer;
import org.apache.flink.api.common.typeutils.base.TypeSerializerSingleton;
import org.apache.flink.core.memory.DataInputView;
import org.apache.flink.core.memory.DataOutputView;

import java.io.IOException;
import java.util.Comparator;
import java.util.Objects;

/**
 * Composite key for events in {@link SharedBuffer}.
 */
public class EventId implements Comparable<EventId> {
	private final int id;
	private final long timestamp;

	public EventId(int id, long timestamp) {
		this.id = id;
		this.timestamp = timestamp;
	}

	public int getId() {
		return id;
	}

	public long getTimestamp() {
		return timestamp;
	}

	public static final Comparator<EventId> COMPARATOR = Comparator.comparingLong(EventId::getTimestamp)
		.thenComparingInt(EventId::getId);

	@Override
	public boolean equals(Object o) {
		if (this == o) {
			return true;
		}
		if (o == null || getClass() != o.getClass()) {
			return false;
		}
		EventId eventId = (EventId) o;
		return id == eventId.id &&
			timestamp == eventId.timestamp;
	}

	@Override
	public int hashCode() {
		return Objects.hash(id, timestamp);
	}

	@Override
	public String toString() {
		return "EventId{" +
			"id=" + id +
			", timestamp=" + timestamp +
			'}';
	}

	@Override
	public int compareTo(EventId o) {
		return COMPARATOR.compare(this, o);
	}

	/** {@link TypeSerializer} for {@link EventId}. */
	public static class EventIdSerializer extends TypeSerializerSingleton<EventId> {

		private static final long serialVersionUID = -5685733582601394497L;

		private EventIdSerializer() {
		}

		public static final EventIdSerializer INSTANCE = new EventIdSerializer();

		@Override
		public boolean isImmutableType() {
			return true;
		}

		@Override
		public EventId createInstance() {
			return null;
		}

		@Override
		public EventId copy(EventId from) {
			return new EventId(from.id, from.timestamp);
		}

		@Override
		public EventId copy(EventId from, EventId reuse) {
			return copy(from);
		}

		@Override
		public int getLength() {
			return 2 * LongSerializer.INSTANCE.getLength();
		}

		@Override
		public void serialize(EventId record, DataOutputView target) throws IOException {
			IntSerializer.INSTANCE.serialize(record.id, target);
			LongSerializer.INSTANCE.serialize(record.timestamp, target);
		}

		@Override
		public EventId deserialize(DataInputView source) throws IOException {
			int id = IntSerializer.INSTANCE.deserialize(source);
			long timestamp = LongSerializer.INSTANCE.deserialize(source);

			return new EventId(id, timestamp);
		}

		@Override
		public EventId deserialize(EventId reuse, DataInputView source) throws IOException {
			return deserialize(source);
		}

		@Override
		public void copy(DataInputView source, DataOutputView target) throws IOException {
			IntSerializer.INSTANCE.copy(source, target);
			LongSerializer.INSTANCE.copy(source, target);
		}

		@Override
		public boolean canEqual(Object obj) {
			return obj.getClass().equals(EventIdSerializer.class);
		}
	}
}