/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch 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.elasticsearch.test.tasks;

import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.tasks.Task;
import org.elasticsearch.tasks.TaskManager;
import org.elasticsearch.transport.TransportRequest;

import java.util.Collection;
import java.util.concurrent.CopyOnWriteArrayList;

/**
 * A mock task manager that allows adding listeners for events
 */
public class MockTaskManager extends TaskManager {

    public static final String USE_MOCK_TASK_MANAGER = "tests.mock.taskmanager.enabled";

    private final Collection<MockTaskManagerListener> listeners = new CopyOnWriteArrayList<>();

    public MockTaskManager(Settings settings) {
        super(settings);
    }

    @Override
    public Task register(String type, String action, TransportRequest request) {
        Task task = super.register(type, action, request);
        if (task != null) {
            for (MockTaskManagerListener listener : listeners) {
                try {
                    listener.onTaskRegistered(task);
                } catch (Throwable t) {
                    logger.warn("failed to notify task manager listener about unregistering the task with id {}", t, task.getId());
                }
            }
        }
        return task;
    }

    @Override
    public Task unregister(Task task) {
        Task removedTask = super.unregister(task);
        if (removedTask != null) {
            for (MockTaskManagerListener listener : listeners) {
                try {
                    listener.onTaskUnregistered(task);
                } catch (Throwable t) {
                    logger.warn("failed to notify task manager listener about unregistering the task with id {}", t, task.getId());
                }
            }
        } else {
            logger.warn("trying to remove the same with id {} twice", task.getId());
        }
        return removedTask;
    }

    public void addListener(MockTaskManagerListener listener) {
        listeners.add(listener);
    }

    public void removeListener(MockTaskManagerListener listener) {
        listeners.remove(listener);
    }
}