/*
 * 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.kernel.impl.api.index;

import java.io.UncheckedIOException;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.neo4j.exceptions.UnderlyingStorageException;
import org.neo4j.internal.schema.IndexDescriptor;
import org.neo4j.io.pagecache.context.CursorContext;
import org.neo4j.kernel.api.exceptions.index.IndexEntryConflictException;
import org.neo4j.kernel.api.index.IndexUpdater;
import org.neo4j.kernel.impl.store.IndexFailureRecord;
import org.neo4j.kernel.impl.store.MultipleUnderlyingStorageExceptions;

/**
 * Holds currently open index updaters that are created dynamically when requested for any existing index in
 * the given indexMap.
 *
 * Also provides a close method for closing and removing any remaining open index updaters.
 *
 * All updaters retrieved from this map must be either closed manually or handle duplicate calls to close
 * or must all be closed indirectly by calling close on this updater map.
 */
class IndexUpdaterMap implements AutoCloseable {
    private final IndexUpdateMode indexUpdateMode;
    private final IndexMap indexMap;
    private final boolean parallel;
    private final Map<IndexDescriptor, IndexUpdater> updaterMap;

    IndexUpdaterMap(IndexMap indexMap, IndexUpdateMode indexUpdateMode, boolean parallel) {
        this.indexUpdateMode = indexUpdateMode;
        this.indexMap = indexMap;
        this.parallel = parallel;
        this.updaterMap = new HashMap<>();
    }

    IndexUpdater getUpdater(IndexDescriptor descriptor, CursorContext cursorContext) {
        IndexUpdater updater = updaterMap.get(descriptor);
        if (null == updater) {
            IndexProxy indexProxy = indexMap.getIndexProxy(descriptor);
            if (null != indexProxy) {
                updater = indexProxy.newUpdater(indexUpdateMode, cursorContext, parallel);
                updaterMap.put(descriptor, updater);
            }
        }
        return updater;
    }

    @Override
    public void close() throws UnderlyingStorageException {
        Set<IndexFailureRecord> exceptions = null;

        for (Map.Entry<IndexDescriptor, IndexUpdater> updaterEntry : updaterMap.entrySet()) {
            IndexUpdater updater = updaterEntry.getValue();
            try {
                updater.close();
            } catch (UncheckedIOException | IndexEntryConflictException e) {
                if (null == exceptions) {
                    exceptions = new HashSet<>();
                }
                exceptions.add(new IndexFailureRecord(updaterEntry.getKey(), new UnderlyingStorageException(e)));
            }
        }

        clear();

        if (null != exceptions) {
            throw new MultipleUnderlyingStorageExceptions(exceptions);
        }
    }

    public void clear() {
        updaterMap.clear();
    }

    public boolean isEmpty() {
        return updaterMap.isEmpty();
    }

    public int size() {
        return updaterMap.size();
    }
}
