/*
 * 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.streaming.util;

import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.java.functions.KeySelector;
import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
import org.apache.flink.streaming.api.operators.Output;
import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.ConcurrentLinkedQueue;

/** Simple test context for stream operators. */
public class MockContext<IN, OUT> {

    private List<OUT> outputs;

    private MockOutput<OUT> output;

    public MockContext(Collection<IN> inputs) {
        if (inputs.isEmpty()) {
            throw new RuntimeException("Inputs must not be empty");
        }

        outputs = new ArrayList<OUT>();
        output = new MockOutput<OUT>(outputs);
    }

    public List<OUT> getOutputs() {
        return outputs;
    }

    public Output<StreamRecord<OUT>> getOutput() {
        return output;
    }

    public static <IN, OUT> List<OUT> createAndExecute(
            OneInputStreamOperator<IN, OUT> operator, List<IN> inputs) throws Exception {
        return createAndExecuteForKeyedStream(operator, inputs, null, null);
    }

    public static <IN, OUT, KEY> List<OUT> createAndExecuteForKeyedStream(
            OneInputStreamOperator<IN, OUT> operator,
            List<IN> inputs,
            KeySelector<IN, KEY> keySelector,
            TypeInformation<KEY> keyType)
            throws Exception {

        OneInputStreamOperatorTestHarness<IN, OUT> testHarness =
                new KeyedOneInputStreamOperatorTestHarness<>(operator, keySelector, keyType);

        testHarness.setup();
        testHarness.open();

        operator.open();

        for (IN in : inputs) {
            testHarness.processElement(new StreamRecord<>(in));
        }

        testHarness.close();

        ConcurrentLinkedQueue<Object> output = testHarness.getOutput();

        List<OUT> result = new ArrayList<>();

        for (Object o : output) {
            if (o instanceof StreamRecord) {
                result.add((OUT) ((StreamRecord) o).getValue());
            }
        }

        return result;
    }
}
