/*
 * 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.test.classloading.jar;

import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.api.common.io.InputFormat;
import org.apache.flink.api.common.io.statistics.BaseStatistics;
import org.apache.flink.api.common.typeinfo.BasicTypeInfo;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.api.java.typeutils.ResultTypeQueryable;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.core.io.InputSplit;
import org.apache.flink.core.io.InputSplitAssigner;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.sink.v2.DiscardingSink;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/** Test class used by the {@link org.apache.flink.test.classloading.ClassLoaderITCase}. */
@SuppressWarnings("serial")
public class CustomInputSplitProgram {

    public static void main(String[] args) throws Exception {

        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        DataStream<Integer> data = env.createInput(new CustomInputFormat());

        data.map(
                        new MapFunction<Integer, Tuple2<Integer, Double>>() {
                            @Override
                            public Tuple2<Integer, Double> map(Integer value) {
                                return new Tuple2<Integer, Double>(value, value * 0.5);
                            }
                        })
                .sinkTo(new DiscardingSink<>());

        env.execute();
    }

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

    private static final class CustomInputFormat
            implements InputFormat<Integer, CustomInputSplit>, ResultTypeQueryable<Integer> {

        private static final long serialVersionUID = 1L;

        private Integer value;

        @Override
        public void configure(Configuration parameters) {}

        @Override
        public BaseStatistics getStatistics(BaseStatistics cachedStatistics) {
            return null;
        }

        @Override
        public CustomInputSplit[] createInputSplits(int minNumSplits) {
            CustomInputSplit[] splits = new CustomInputSplit[minNumSplits];
            for (int i = 0; i < minNumSplits; i++) {
                splits[i] = new CustomInputSplit(i);
            }
            return splits;
        }

        @Override
        public InputSplitAssigner getInputSplitAssigner(CustomInputSplit[] inputSplits) {
            return new CustomSplitAssigner(inputSplits);
        }

        @Override
        public void open(CustomInputSplit split) {
            this.value = split.getSplitNumber();
        }

        @Override
        public boolean reachedEnd() {
            return this.value == null;
        }

        @Override
        public Integer nextRecord(Integer reuse) {
            Integer val = this.value;
            this.value = null;
            return val;
        }

        @Override
        public void close() {}

        @Override
        public TypeInformation<Integer> getProducedType() {
            return BasicTypeInfo.INT_TYPE_INFO;
        }
    }

    private static final class CustomInputSplit implements InputSplit {

        private static final long serialVersionUID = 1L;

        private final int splitNumber;

        public CustomInputSplit(int splitNumber) {
            this.splitNumber = splitNumber;
        }

        @Override
        public int getSplitNumber() {
            return this.splitNumber;
        }
    }

    private static final class CustomSplitAssigner implements InputSplitAssigner {

        private final List<CustomInputSplit> remainingSplits;

        public CustomSplitAssigner(CustomInputSplit[] splits) {
            this.remainingSplits = new ArrayList<CustomInputSplit>(Arrays.asList(splits));
        }

        @Override
        public InputSplit getNextInputSplit(String host, int taskId) {
            synchronized (this) {
                int size = remainingSplits.size();
                if (size > 0) {
                    return remainingSplits.remove(size - 1);
                } else {
                    return null;
                }
            }
        }

        @Override
        public void returnInputSplit(List<InputSplit> splits, int taskId) {
            synchronized (this) {
                for (InputSplit split : splits) {
                    remainingSplits.add((CustomInputSplit) split);
                }
            }
        }
    }
}
