/*
 * 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.runtime.query;

import org.apache.flink.api.common.JobID;
import org.apache.flink.runtime.execution.SuppressRestartsException;
import org.apache.flink.runtime.executiongraph.ExecutionJobVertex;
import org.apache.flink.runtime.jobgraph.JobVertexID;
import org.apache.flink.runtime.state.KeyGroupRange;
import org.apache.flink.runtime.state.internal.InternalKvState;
import org.apache.flink.util.Preconditions;

import java.util.HashMap;
import java.util.Map;

/**
 * Simple registry, which maps {@link InternalKvState} registration notifications to
 * {@link KvStateLocation} instances.
 */
public class KvStateLocationRegistry {

	/** JobID this coordinator belongs to. */
	private final JobID jobId;

	/** Job vertices for determining parallelism per key. */
	private final Map<JobVertexID, ExecutionJobVertex> jobVertices;

	/**
	 * Location info keyed by registration name. The name needs to be unique
	 * per JobID, i.e. two operators cannot register KvState with the same
	 * name.
	 */
	private final Map<String, KvStateLocation> lookupTable = new HashMap<>();

	/**
	 * Creates the registry for the job.
	 *
	 * @param jobId       JobID this coordinator belongs to.
	 * @param jobVertices Job vertices map of all vertices of this job.
	 */
	public KvStateLocationRegistry(JobID jobId, Map<JobVertexID, ExecutionJobVertex> jobVertices) {
		this.jobId = Preconditions.checkNotNull(jobId, "JobID");
		this.jobVertices = Preconditions.checkNotNull(jobVertices, "Job vertices");
	}

	/**
	 * Returns the {@link KvStateLocation} for the registered KvState instance
	 * or <code>null</code> if no location information is available.
	 *
	 * @param registrationName Name under which the KvState instance is registered.
	 * @return Location information or <code>null</code>.
	 */
	public KvStateLocation getKvStateLocation(String registrationName) {
		return lookupTable.get(registrationName);
	}

	/**
	 * Notifies the registry about a registered KvState instance.
	 *
	 * @param jobVertexId JobVertexID the KvState instance belongs to
	 * @param keyGroupRange Key group range the KvState instance belongs to
	 * @param registrationName Name under which the KvState has been registered
	 * @param kvStateId ID of the registered KvState instance
	 * @param kvStateServerAddress Server address where to find the KvState instance
	 *
	 * @throws IllegalArgumentException If JobVertexID does not belong to job
	 * @throws IllegalArgumentException If state has been registered with same
	 * name by another operator.
	 * @throws IndexOutOfBoundsException If key group index is out of bounds.
	 */
	public void notifyKvStateRegistered(
			JobVertexID jobVertexId,
			KeyGroupRange keyGroupRange,
			String registrationName,
			KvStateID kvStateId,
			KvStateServerAddress kvStateServerAddress) {

		KvStateLocation location = lookupTable.get(registrationName);

		if (location == null) {
			// First registration for this operator, create the location info
			ExecutionJobVertex vertex = jobVertices.get(jobVertexId);

			if (vertex != null) {
				int parallelism = vertex.getMaxParallelism();
				location = new KvStateLocation(jobId, jobVertexId, parallelism, registrationName);
				lookupTable.put(registrationName, location);
			} else {
				throw new IllegalArgumentException("Unknown JobVertexID " + jobVertexId);
			}
		}

		// Duplicated name if vertex IDs don't match
		if (!location.getJobVertexId().equals(jobVertexId)) {
			IllegalStateException duplicate = new IllegalStateException(
					"Registration name clash. KvState with name '" + registrationName +
							"' has already been registered by another operator (" +
							location.getJobVertexId() + ").");

			ExecutionJobVertex vertex = jobVertices.get(jobVertexId);
			if (vertex != null) {
				vertex.fail(new SuppressRestartsException(duplicate));
			}

			throw duplicate;
		}
		location.registerKvState(keyGroupRange, kvStateId, kvStateServerAddress);
	}

	/**
	 * Notifies the registry about an unregistered KvState instance.
	 *
	 * @param jobVertexId JobVertexID the KvState instance belongs to
	 * @param keyGroupRange Key group index the KvState instance belongs to
	 * @param registrationName Name under which the KvState has been registered
	 * @throws IllegalArgumentException If another operator registered the state instance
	 * @throws IllegalArgumentException If the registration name is not known
	 */
	public void notifyKvStateUnregistered(
			JobVertexID jobVertexId,
			KeyGroupRange keyGroupRange,
			String registrationName) {

		KvStateLocation location = lookupTable.get(registrationName);

		if (location != null) {
			// Duplicate name if vertex IDs don't match
			if (!location.getJobVertexId().equals(jobVertexId)) {
				throw new IllegalArgumentException("Another operator (" +
						location.getJobVertexId() + ") registered the KvState " +
						"under '" + registrationName + "'.");
			}

			location.unregisterKvState(keyGroupRange);

			if (location.getNumRegisteredKeyGroups() == 0) {
				lookupTable.remove(registrationName);
			}
		} else {
			throw new IllegalArgumentException("Unknown registration name '" +
					registrationName + "'. " + "Probably registration/unregistration race.");
		}
	}

}