/*
 * 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 java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.apache.flink.api.common.ExecutionConfig;
import org.apache.flink.api.common.accumulators.Accumulator;
import org.apache.flink.api.common.functions.RichFunction;
import org.apache.flink.api.common.functions.RuntimeContext;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.runtime.operators.testutils.MockEnvironment;
import org.apache.flink.runtime.operators.testutils.MockInputSplitProvider;
import org.apache.flink.streaming.api.functions.source.SourceFunction;
import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
import org.apache.flink.streaming.api.operators.StreamingRuntimeContext;

import static org.mockito.Mockito.*;

public class SourceFunctionUtil {

	public static <T extends Serializable> List<T> runSourceFunction(SourceFunction<T> sourceFunction) throws Exception {
		final List<T> outputs = new ArrayList<T>();

		if (sourceFunction instanceof RichFunction) {

			AbstractStreamOperator<?> operator = mock(AbstractStreamOperator.class);
			when(operator.getExecutionConfig()).thenReturn(new ExecutionConfig());

			RuntimeContext runtimeContext =  new StreamingRuntimeContext(
					operator,
					new MockEnvironment("MockTask", 3 * 1024 * 1024, new MockInputSplitProvider(), 1024),
					new HashMap<String, Accumulator<?, ?>>());

			((RichFunction) sourceFunction).setRuntimeContext(runtimeContext);

			((RichFunction) sourceFunction).open(new Configuration());
		}
		try {
			SourceFunction.SourceContext<T> ctx = new CollectingSourceContext<T>(new Object(), outputs);
			sourceFunction.run(ctx);
		} catch (Exception e) {
			throw new RuntimeException("Cannot invoke source.", e);
		}
		return outputs;
	}
}