/*
 * Copyright (c) 2018 Cisco and/or its affiliates.
 *
 * Licensed 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 io.fd.hc2vpp.it.jvpp.benchmark.util;

import com.google.common.io.CharStreams;
import io.fd.vpp.jvpp.JVppRegistry;
import io.fd.vpp.jvpp.JVppRegistryImpl;
import io.fd.vpp.jvpp.dto.JVppReply;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.concurrent.CompletionStage;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Level;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.TearDown;
import org.openjdk.jmh.annotations.Threads;
import org.openjdk.jmh.annotations.Timeout;
import org.openjdk.jmh.annotations.Warmup;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@BenchmarkMode(Mode.AverageTime)
@State(Scope.Thread)
@Fork(1)
@Threads(1)
@Timeout(time = 10)
@Warmup(iterations = 20, time = 2)
@Measurement(iterations = 100, time = 2)
@OutputTimeUnit(TimeUnit.MILLISECONDS)
public abstract class JVppBenchmark {
    private static final Logger LOG = LoggerFactory.getLogger(JVppBenchmark.class);
    private JVppRegistryImpl registry;

    @Setup(Level.Iteration)
    public final void setup() throws Exception {
        startVpp();
        jVppConnect();
        iterationSetup();
    }

    protected void iterationSetup() throws Exception {
        // NOOP
    }

    @TearDown(Level.Iteration)
    public final void tearDown() throws Exception {
        iterationTearDown();
        jVppDisconnect();
        stopVpp();
    }

    protected void iterationTearDown() throws Exception {
        // NOOP
    }

    private void startVpp() throws IOException, InterruptedException {
        LOG.info("Starting VPP ...");
        final String[] cmd = {"/bin/sh", "-c", "sudo service vpp start"};
        exec(cmd);
        LOG.info("VPP started successfully");
    }

    private void stopVpp() throws IOException, InterruptedException {
        LOG.info("Stopping VPP ...");
        final String[] cmd = {"/bin/sh", "-c", "sudo service vpp stop"};
        exec(cmd);

        // Wait to be sure VPP was stopped.
        // Prevents VPP start failure: "vpp.service: Start request repeated too quickly".
        Thread.sleep(1500);
        LOG.info("VPP stopped successfully");

    }

    private static void exec(String[] command) throws IOException, InterruptedException {
        final Process process = Runtime.getRuntime().exec(command);
        process.waitFor();
        if (process.exitValue() != 0) {
            String error_msg = "Failed to execute " + Arrays.toString(command) + ": " +
                CharStreams.toString(new InputStreamReader(process.getErrorStream(), StandardCharsets.UTF_8));
            throw new IllegalStateException(error_msg);
        }
    }

    private void jVppConnect() throws IOException {
        LOG.info("Connecting JVpp ...");
        registry = new JVppRegistryImpl("ACLUpdateBenchmark");
        connect(registry);
        LOG.info("Successfully connected to JVPP");
    }

    /**
     * Connects JVpp plugins.
     * @param registry manages JVpp connection
     */
    protected abstract void connect(final JVppRegistry registry) throws IOException;

    private void jVppDisconnect() throws Exception {
        LOG.info("Disconnecting JVpp...");
        disconnect();
        registry.close();
        LOG.info("Successfully disconnected ...");
    }

    /**
     * Disconnects JVpp plugins.
     */
    protected abstract void disconnect() throws Exception;

    protected static <R extends JVppReply<?>> R invoke(final CompletionStage<R> completionStage)
        throws ExecutionException, InterruptedException {
        return completionStage.toCompletableFuture().get();
    }
}