/*
 * 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.maven.surefire.junitcore;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;

import org.apache.maven.surefire.api.util.internal.DaemonThreadFactory;
import org.junit.runner.Computer;
import org.junit.runner.Runner;
import org.junit.runners.ParentRunner;
import org.junit.runners.Suite;
import org.junit.runners.model.InitializationError;
import org.junit.runners.model.RunnerBuilder;
import org.junit.runners.model.RunnerScheduler;

/**
 * Since SUREFIRE 2.18 this class is deprecated.
 * Please use {@link org.apache.maven.surefire.junitcore.pc.ParallelComputerBuilder} instead.
 *
 * @author Kristian Rosenvold
 */
@Deprecated
public class ConfigurableParallelComputer extends Computer {
    private static final ThreadFactory DAEMON_THREAD_FACTORY = DaemonThreadFactory.newDaemonThreadFactory();

    private final boolean fClasses;

    private final boolean fMethods;

    private final boolean fixedPool;

    private final ExecutorService fService;

    private final List<AsynchronousRunner> nonBlockers = Collections.synchronizedList(new ArrayList<>());

    public ConfigurableParallelComputer() {
        this(true, true, Executors.newCachedThreadPool(DAEMON_THREAD_FACTORY), false);
    }

    public ConfigurableParallelComputer(boolean fClasses, boolean fMethods) {
        this(fClasses, fMethods, Executors.newCachedThreadPool(DAEMON_THREAD_FACTORY), false);
    }

    public ConfigurableParallelComputer(boolean fClasses, boolean fMethods, Integer numberOfThreads, boolean perCore) {
        this(
                fClasses,
                fMethods,
                Executors.newFixedThreadPool(
                        numberOfThreads * (perCore ? Runtime.getRuntime().availableProcessors() : 1),
                        DAEMON_THREAD_FACTORY),
                true);
    }

    private ConfigurableParallelComputer(
            boolean fClasses, boolean fMethods, ExecutorService executorService, boolean fixedPool) {
        this.fClasses = fClasses;
        this.fMethods = fMethods;
        fService = executorService;
        this.fixedPool = fixedPool;
    }

    @SuppressWarnings({"UnusedDeclaration"})
    public void close() throws ExecutionException {
        for (AsynchronousRunner nonBlocker : nonBlockers) {
            nonBlocker.waitForCompletion();
        }

        fService.shutdown();
        try {
            if (!fService.awaitTermination(10, java.util.concurrent.TimeUnit.SECONDS)) {
                throw new RuntimeException("Executor did not shut down within timeout");
            }
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
    }

    private Runner parallelize(Runner runner, RunnerScheduler runnerInterceptor) {
        if (runner instanceof ParentRunner<?>) {
            ((ParentRunner<?>) runner).setScheduler(runnerInterceptor);
        }
        return runner;
    }

    private RunnerScheduler getMethodInterceptor() {
        if (fClasses && fMethods) {
            final AsynchronousRunner blockingAsynchronousRunner = new AsynchronousRunner(fService);
            nonBlockers.add(blockingAsynchronousRunner);
            return blockingAsynchronousRunner;
        }
        return fMethods ? new AsynchronousRunner(fService) : new SynchronousRunner();
    }

    private RunnerScheduler getClassInterceptor() {
        if (fClasses) {
            return fMethods ? new SynchronousRunner() : new AsynchronousRunner(fService);
        }
        return new SynchronousRunner();
    }

    @Override
    public Runner getSuite(RunnerBuilder builder, java.lang.Class<?>[] classes) throws InitializationError {
        Runner suite = super.getSuite(builder, classes);
        return fClasses ? parallelize(suite, getClassInterceptor()) : suite;
    }

    @Override
    protected Runner getRunner(RunnerBuilder builder, Class<?> testClass) throws Throwable {
        Runner runner = super.getRunner(builder, testClass);
        return fMethods && !isTestSuite(testClass) ? parallelize(runner, getMethodInterceptor()) : runner;
    }

    private boolean isTestSuite(Class<?> testClass) {
        // Todo: Find out how/if this is enough
        final Suite.SuiteClasses annotation = testClass.getAnnotation(Suite.SuiteClasses.class);
        return (annotation != null);
    }

    @Override
    public String toString() {
        return "ConfigurableParallelComputer{" + "classes=" + fClasses + ", methods=" + fMethods + ", fixedPool="
                + fixedPool + '}';
    }
}
