/*
 * 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.connector.file.src.assigners;

import org.apache.flink.annotation.PublicEvolving;
import org.apache.flink.connector.file.src.FileSourceSplit;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Optional;

/**
 * The {@code SimpleSplitAssigner} hands out splits in a random order, without any consideration for
 * order or locality.
 */
@PublicEvolving
public class SimpleSplitAssigner implements FileSplitAssigner {

    private final ArrayList<FileSourceSplit> splits;

    public SimpleSplitAssigner(Collection<FileSourceSplit> splits) {
        this.splits = new ArrayList<>(splits);
    }

    // ------------------------------------------------------------------------

    @Override
    public Optional<FileSourceSplit> getNext(String hostname) {
        final int size = splits.size();
        return size == 0 ? Optional.empty() : Optional.of(splits.remove(size - 1));
    }

    @Override
    public void addSplits(Collection<FileSourceSplit> newSplits) {
        splits.addAll(newSplits);
    }

    @Override
    public Collection<FileSourceSplit> remainingSplits() {
        return splits;
    }

    // ------------------------------------------------------------------------

    @Override
    public String toString() {
        return "SimpleSplitAssigner " + splits;
    }
}
