/*
 * 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.eclipse.aether.named.hazelcast;

import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.TimeUnit;

import com.hazelcast.core.HazelcastInstance;
import com.hazelcast.cp.ISemaphore;
import org.eclipse.aether.named.NamedLock;
import org.eclipse.aether.named.NamedLockKey;
import org.eclipse.aether.named.support.AdaptedSemaphoreNamedLock;
import org.eclipse.aether.named.support.AdaptedSemaphoreNamedLock.AdaptedSemaphore;
import org.eclipse.aether.named.support.NamedLockFactorySupport;

import static java.util.Objects.requireNonNull;

/**
 * Factory of {@link AdaptedSemaphoreNamedLock} instances, using adapted Hazelcast {@link ISemaphore}. It delegates
 * most the work to {@link HazelcastSemaphoreProvider} and this class just adapts the returned semaphore to named lock
 * and caches {@link ISemaphore} instances, as recommended by Hazelcast.
 */
public class HazelcastSemaphoreNamedLockFactory extends NamedLockFactorySupport {
    protected final HazelcastInstance hazelcastInstance;

    protected final boolean manageHazelcast;

    private final HazelcastSemaphoreProvider hazelcastSemaphoreProvider;

    private final ConcurrentMap<NamedLockKey, ISemaphore> semaphores;

    public HazelcastSemaphoreNamedLockFactory(
            final HazelcastInstance hazelcastInstance,
            final boolean manageHazelcast,
            final HazelcastSemaphoreProvider hazelcastSemaphoreProvider) {
        this.hazelcastInstance = requireNonNull(hazelcastInstance);
        this.manageHazelcast = manageHazelcast;
        this.hazelcastSemaphoreProvider = requireNonNull(hazelcastSemaphoreProvider);
        this.semaphores = new ConcurrentHashMap<>();
    }

    @Override
    protected AdaptedSemaphoreNamedLock createLock(final NamedLockKey key) {
        ISemaphore semaphore = semaphores.computeIfAbsent(
                key, k -> hazelcastSemaphoreProvider.acquireSemaphore(hazelcastInstance, key));
        return new AdaptedSemaphoreNamedLock(key, this, new HazelcastSemaphore(semaphore));
    }

    @Override
    protected void destroyLock(final NamedLock namedLock) {
        if (namedLock instanceof AdaptedSemaphoreNamedLock) {
            final NamedLockKey key = namedLock.key();
            hazelcastSemaphoreProvider.releaseSemaphore(hazelcastInstance, key, semaphores.remove(key));
        }
    }

    @Override
    protected void doShutdown() {
        if (manageHazelcast) {
            hazelcastInstance.shutdown();
        }
    }

    private static final class HazelcastSemaphore implements AdaptedSemaphore {
        private final ISemaphore semaphore;

        private HazelcastSemaphore(final ISemaphore semaphore) {
            this.semaphore = semaphore;
        }

        @Override
        public boolean tryAcquire(final int perms, final long time, final TimeUnit unit) throws InterruptedException {
            return semaphore.tryAcquire(perms, time, unit);
        }

        @Override
        public void release(final int perms) {
            semaphore.release(perms);
        }
    }
}
