/*
 * 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.
 */

/*
 * 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.dubbo.remoting.etcd.jetcd;

import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.utils.ReflectUtils;
import org.apache.dubbo.remoting.etcd.ChildListener;

import com.google.protobuf.ByteString;
import io.etcd.jetcd.ByteSequence;
import io.etcd.jetcd.Client;
import io.etcd.jetcd.Watch;
import io.etcd.jetcd.api.Event;
import io.etcd.jetcd.api.WatchCancelRequest;
import io.etcd.jetcd.api.WatchCreateRequest;
import io.etcd.jetcd.api.WatchGrpc;
import io.etcd.jetcd.api.WatchRequest;
import io.etcd.jetcd.api.WatchResponse;
import io.etcd.jetcd.common.exception.ClosedClientException;
import io.etcd.jetcd.watch.WatchEvent;
import io.grpc.ManagedChannel;
import io.grpc.Status;
import io.grpc.stub.StreamObserver;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Disabled;
import org.junit.jupiter.api.Test;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;

import static java.nio.charset.StandardCharsets.UTF_8;
import static org.apache.dubbo.remoting.etcd.Constants.SESSION_TIMEOUT_KEY;

@Disabled
public class JEtcdClientTest {

    JEtcdClient client;

    @Test
    public void test_watch_when_create_path() throws InterruptedException {

        String path = "/dubbo/com.alibaba.dubbo.demo.DemoService/providers";
        String child = "/dubbo/com.alibaba.dubbo.demo.DemoService/providers/demoService1";

        final CountDownLatch notNotified = new CountDownLatch(1);

        ChildListener childListener = (parent, children) -> {
            Assertions.assertEquals(1, children.size());
            Assertions.assertEquals(child.substring(child.lastIndexOf("/") + 1), children.get(0));
            notNotified.countDown();
        };

        client.addChildListener(path, childListener);

        client.createEphemeral(child);
        Assertions.assertTrue(notNotified.await(10, TimeUnit.SECONDS));

        client.removeChildListener(path, childListener);
        client.delete(child);
    }

    @Test
    public void test_watch_when_modify() {
        String path = "/dubbo/config/jetcd-client-unit-test/configurators";
        String endpoint = "http://127.0.0.1:2379";
        CountDownLatch latch = new CountDownLatch(1);
        ByteSequence key = ByteSequence.from(path, UTF_8);

        Watch.Listener listener = Watch.listener(response -> {
            for (WatchEvent event : response.getEvents()) {
                Assertions.assertEquals("PUT", event.getEventType().toString());
                Assertions.assertEquals(path, event.getKeyValue().getKey().toString(UTF_8));
                Assertions.assertEquals("Hello", event.getKeyValue().getValue().toString(UTF_8));
                latch.countDown();
            }

        });

        try (Client client = Client.builder().endpoints(endpoint).build();
             Watch watch = client.getWatchClient();
             Watch.Watcher watcher = watch.watch(key, listener)) {
            // try to modify the key
            client.getKVClient().put(ByteSequence.from(path, UTF_8), ByteSequence.from("Hello", UTF_8));
            latch.await();
        } catch (Exception e) {
            Assertions.fail(e.getMessage());
        }
    }

    @Test
    public void testWatchWithGrpc() {
        String path = "/dubbo/config/test_watch_with_grpc/configurators";
        String endpoint = "http://127.0.0.1:2379";
        CountDownLatch latch = new CountDownLatch(1);
        try (Client client = Client.builder().endpoints(endpoint).build()) {
            ManagedChannel channel = getChannel(client);
            StreamObserver<WatchRequest> observer = WatchGrpc.newStub(channel).watch(new StreamObserver<WatchResponse>() {
                @Override
                public void onNext(WatchResponse response) {
                    for (Event event : response.getEventsList()) {
                        Assertions.assertEquals("PUT", event.getType().toString());
                        Assertions.assertEquals(path, event.getKv().getKey().toString(UTF_8));
                        Assertions.assertEquals("Hello", event.getKv().getValue().toString(UTF_8));
                        latch.countDown();
                    }
                }

                @Override
                public void onError(Throwable throwable) {

                }

                @Override
                public void onCompleted() {

                }
            });
            WatchCreateRequest.Builder builder = WatchCreateRequest.newBuilder()
                    .setKey(ByteString.copyFrom(path, UTF_8));

            observer.onNext(WatchRequest.newBuilder().setCreateRequest(builder).build());

            // try to modify the key
            client.getKVClient().put(ByteSequence.from(path, UTF_8), ByteSequence.from("Hello", UTF_8));
            latch.await(5, TimeUnit.SECONDS);
        } catch (Exception e) {
            Assertions.fail(e.getMessage());
        }
    }

    @Test
    public void testCancelWatchWithGrpc() {
        String path = "/dubbo/config/testCancelWatchWithGrpc/configurators";
        String endpoint = "http://127.0.0.1:2379";
        CountDownLatch updateLatch = new CountDownLatch(1);
        CountDownLatch cancelLatch = new CountDownLatch(1);
        final AtomicLong watchID = new AtomicLong(-1L);
        try (Client client = Client.builder().endpoints(endpoint).build()) {
            ManagedChannel channel = getChannel(client);
            StreamObserver<WatchRequest> observer = WatchGrpc.newStub(channel).watch(new StreamObserver<WatchResponse>() {
                @Override
                public void onNext(WatchResponse response) {
                    watchID.set(response.getWatchId());
                    for (Event event : response.getEventsList()) {
                        Assertions.assertEquals("PUT", event.getType().toString());
                        Assertions.assertEquals(path, event.getKv().getKey().toString(UTF_8));
                        Assertions.assertEquals("Hello", event.getKv().getValue().toString(UTF_8));
                        updateLatch.countDown();
                    }
                    if (response.getCanceled()) {
                        // received the cancel response
                        cancelLatch.countDown();
                    }
                }

                @Override
                public void onError(Throwable throwable) {

                }

                @Override
                public void onCompleted() {

                }
            });
            // create
            WatchCreateRequest.Builder builder = WatchCreateRequest.newBuilder()
                    .setKey(ByteString.copyFrom(path, UTF_8));

            // make the grpc call to watch the key
            observer.onNext(WatchRequest.newBuilder().setCreateRequest(builder).build());

            // try to put the value
            client.getKVClient().put(ByteSequence.from(path, UTF_8), ByteSequence.from("Hello", UTF_8));

            // response received, latch counts down to zero
            updateLatch.await();

            WatchCancelRequest watchCancelRequest =
                    WatchCancelRequest.newBuilder().setWatchId(watchID.get()).build();
            WatchRequest cancelRequest = WatchRequest.newBuilder()
                    .setCancelRequest(watchCancelRequest).build();
            observer.onNext(cancelRequest);

            // try to put the value
            client.getKVClient().put(ByteSequence.from(path, UTF_8), ByteSequence.from("Hello world", UTF_8));

            cancelLatch.await();
        } catch (Exception e) {
            Assertions.fail(e.getMessage());
        }

    }

    @Test
    public void test_watch_when_create_wrong_path() throws InterruptedException {

        String path = "/dubbo/com.alibaba.dubbo.demo.DemoService/providers";
        String child = "/dubbo/com.alibaba.dubbo.demo.DemoService/routers/demoService1";

        final CountDownLatch notNotified = new CountDownLatch(1);

        ChildListener childListener = (parent, children) -> {
            Assertions.assertEquals(1, children.size());
            Assertions.assertEquals(child, children.get(0));
            notNotified.countDown();
        };

        client.addChildListener(path, childListener);

        client.createEphemeral(child);
        Assertions.assertFalse(notNotified.await(1, TimeUnit.SECONDS));

        client.removeChildListener(path, childListener);
        client.delete(child);
    }

    @Test
    public void test_watch_when_delete_path() throws InterruptedException {

        String path = "/dubbo/com.alibaba.dubbo.demo.DemoService/providers";
        String child = "/dubbo/com.alibaba.dubbo.demo.DemoService/providers/demoService1";

        final CountDownLatch notNotified = new CountDownLatch(1);

        ChildListener childListener = (parent, children) -> {
            Assertions.assertEquals(0, children.size());
            notNotified.countDown();
        };

        client.createEphemeral(child);

        client.addChildListener(path, childListener);
        client.delete(child);

        Assertions.assertTrue(notNotified.await(10, TimeUnit.SECONDS));
        client.removeChildListener(path, childListener);
    }

    @Test
    public void test_watch_then_unwatch() throws InterruptedException {

        String path = "/dubbo/com.alibaba.dubbo.demo.DemoService/providers";
        String child = "/dubbo/com.alibaba.dubbo.demo.DemoService/providers/demoService2";

        final CountDownLatch notNotified = new CountDownLatch(1);
        final CountDownLatch notTwiceNotified = new CountDownLatch(2);

        final Holder notified = new Holder();

        ChildListener childListener = (parent, children) -> {
            Assertions.assertEquals(1, children.size());
            Assertions.assertEquals(child.substring(child.lastIndexOf("/") + 1), children.get(0));
            notNotified.countDown();
            notTwiceNotified.countDown();
            notified.getAndIncrease();
        };

        client.addChildListener(path, childListener);

        client.createEphemeral(child);
        Assertions.assertTrue(notNotified.await(15, TimeUnit.SECONDS));

        client.removeChildListener(path, childListener);
        client.delete(child);

        Assertions.assertFalse(notTwiceNotified.await(5, TimeUnit.SECONDS));
        Assertions.assertEquals(1, notified.value);
        client.delete(child);
    }

    @Test
    public void test_watch_on_unrecoverable_connection() throws InterruptedException {

        String path = "/dubbo/com.alibaba.dubbo.demo.DemoService/providers";
        JEtcdClient.EtcdWatcher watcher = null;
        try {
            ChildListener childListener = (parent, children) -> {
                Assertions.assertEquals(path, parent);
            };
            client.addChildListener(path, childListener);
            watcher = client.getChildListener(path, childListener);
            watcher.watchRequest.onError(Status.ABORTED.withDescription("connection error").asRuntimeException());

            watcher.watchRequest.onNext(watcher.nextRequest());
        } catch (Exception e) {
            Assertions.assertTrue(e.getMessage().contains("call was cancelled"));
        }
    }

    @Test
    public void test_watch_on_recoverable_connection() throws InterruptedException {

        String path = "/dubbo/com.alibaba.dubbo.demo.DemoService/connection";
        String child = "/dubbo/com.alibaba.dubbo.demo.DemoService/connection/demoService1";

        final CountDownLatch notNotified = new CountDownLatch(1);
        final CountDownLatch notTwiceNotified = new CountDownLatch(2);
        final Holder notified = new Holder();
        ChildListener childListener = (parent, children) -> {
            notTwiceNotified.countDown();
            switch (notified.increaseAndGet()) {
                case 1: {
                    notNotified.countDown();
                    Assertions.assertEquals(1, children.size());
                    Assertions.assertEquals(child.substring(child.lastIndexOf("/") + 1), children.get(0));
                    break;
                }
                case 2: {
                    Assertions.assertEquals(0, children.size());
                    Assertions.assertEquals(path, parent);
                    break;
                }
                default:
                    Assertions.fail("two many callback invoked.");
            }
        };

        client.addChildListener(path, childListener);
        client.createEphemeral(child);

        // make sure first time callback successfully
        Assertions.assertTrue(notNotified.await(15, TimeUnit.SECONDS));

        // connection error causes client to release all resources including current watcher
        JEtcdClient.EtcdWatcher watcher = client.getChildListener(path, childListener);
        watcher.onError(Status.UNAVAILABLE.withDescription("temporary connection issue").asRuntimeException());

        // trigger delete after unavailable
        client.delete(child);
        Assertions.assertTrue(notTwiceNotified.await(15, TimeUnit.SECONDS));

        client.removeChildListener(path, childListener);
    }

    @Test
    public void test_watch_after_client_closed() throws InterruptedException {

        String path = "/dubbo/com.alibaba.dubbo.demo.DemoService/providers";
        client.close();

        try {
            client.addChildListener(path, (parent, children) -> {
                Assertions.assertEquals(path, parent);
            });
        } catch (ClosedClientException e) {
            Assertions.assertEquals("watch client has been closed, path '" + path + "'", e.getMessage());
        }
    }

    @BeforeEach
    public void setUp() {
        // timeout in 15 seconds.
        URL url = URL.valueOf("etcd3://127.0.0.1:2379/com.alibaba.dubbo.registry.RegistryService")
                .addParameter(SESSION_TIMEOUT_KEY, 15000);

        client = new JEtcdClient(url);
    }

    @AfterEach
    public void tearDown() {
        client.close();
    }

    static class Holder {

        volatile int value;

        synchronized int getAndIncrease() {
            return value++;
        }

        synchronized int increaseAndGet() {
            return ++value;
        }
    }

    private ManagedChannel getChannel(Client client) {
        try {
            // hack, use reflection to get the shared channel.
            Field connectionField = client.getClass().getDeclaredField("connectionManager");
            connectionField.setAccessible(true);
            Object connection = connectionField.get(client);
            Method channelMethod = connection.getClass().getDeclaredMethod("getChannel");
            ReflectUtils.makeAccessible(channelMethod);
            ManagedChannel channel = (ManagedChannel) channelMethod.invoke(connection);
            return channel;
        } catch (Exception e) {
            return null;
        }
    }
}
