/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.consistency.checker;

import static java.lang.Math.toIntExact;

import java.util.Arrays;
import java.util.concurrent.atomic.AtomicLong;
import org.neo4j.internal.batchimport.cache.IntArray;
import org.neo4j.internal.batchimport.cache.NumberArrayFactories;
import org.neo4j.memory.MemoryTracker;

/**
 * Basically a dynamically growing int[] to store label ids in. Should only be used to store the dynamic node labels, not all the inlined
 * label ids too since it prioritizes simplicity over space efficiency.
 */
class DynamicNodeLabelsCache implements AutoCloseable {
    private final IntArray cache;
    private final AtomicLong nextIndex = new AtomicLong();

    DynamicNodeLabelsCache(MemoryTracker memoryTracker) {
        cache = NumberArrayFactories.OFF_HEAP.newDynamicIntArray(100_000, 0, memoryTracker);
    }

    long put(long[] labels) {
        final long index = nextIndex.getAndAdd(labels.length + 1);
        cache.set(index, labels.length);
        for (int i = 0; i < labels.length; i++) {
            cache.set(index + 1 + i, toIntExact(labels[i]));
        }
        return index;
    }

    long[] get(long index, long[] into) {
        int count = cache.get(index);
        if (count > into.length) {
            into = Arrays.copyOf(into, count);
        }
        for (int i = 0; i < count; i++) {
            into[i] = cache.get(index + 1 + i);
        }
        if (count < into.length) {
            // -1 terminate it
            into[count] = -1;
        }
        return into;
    }

    void clear() {
        cache.clear();
        nextIndex.set(0);
    }

    @Override
    public void close() {
        cache.close();
    }
}
