/*
 * 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.internal.batchimport.cache;

import static java.util.Arrays.asList;
import static org.assertj.core.api.Assertions.assertThat;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertNull;
import static org.mockito.Mockito.mock;
import static org.neo4j.configuration.GraphDatabaseSettings.DEFAULT_DATABASE_NAME;
import static org.neo4j.io.pagecache.context.EmptyVersionContextSupplier.EMPTY;

import java.nio.file.Path;
import org.junit.jupiter.api.Test;
import org.neo4j.io.pagecache.PageCache;
import org.neo4j.io.pagecache.context.CursorContextFactory;
import org.neo4j.io.pagecache.tracing.PageCacheTracer;
import org.neo4j.logging.NullLog;

class PageCacheArrayFactoryMonitorTest {
    private final PageCachedNumberArrayFactory factory = new PageCachedNumberArrayFactory(
            mock(PageCache.class),
            new CursorContextFactory(PageCacheTracer.NULL, EMPTY),
            Path.of("storeDir"),
            NullLog.getInstance(),
            DEFAULT_DATABASE_NAME);
    private final PageCacheArrayFactoryMonitor monitor = new PageCacheArrayFactoryMonitor();

    @Test
    void shouldComposeFailureDescriptionForFailedCandidates() {
        // given
        monitor.allocationSuccessful(
                123,
                factory,
                asList(
                        new NumberArrayFactory.AllocationFailure(
                                new OutOfMemoryError("OOM1"), NumberArrayFactories.HEAP),
                        new NumberArrayFactory.AllocationFailure(
                                new OutOfMemoryError("OOM2"), NumberArrayFactories.OFF_HEAP)));

        // when
        String failure = monitor.pageCacheAllocationOrNull();

        // then
        assertThat(failure).contains("OOM1");
        assertThat(failure).contains("OOM2");
    }

    @Test
    void shouldClearFailureStateAfterAccessorCall() {
        // given
        monitor.allocationSuccessful(
                123,
                factory,
                asList(
                        new NumberArrayFactory.AllocationFailure(
                                new OutOfMemoryError("OOM1"), NumberArrayFactories.HEAP),
                        new NumberArrayFactory.AllocationFailure(
                                new OutOfMemoryError("OOM2"), NumberArrayFactories.OFF_HEAP)));

        // when
        String failure = monitor.pageCacheAllocationOrNull();
        String secondCall = monitor.pageCacheAllocationOrNull();

        // then
        assertNotNull(failure);
        assertNull(secondCall);
    }

    @Test
    void shouldReturnNullFailureOnNoFailure() {
        // then
        assertNull(monitor.pageCacheAllocationOrNull());
    }
}
