/*
 * 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.runtime.rest.handler.taskmanager;

import org.apache.flink.runtime.resourcemanager.ResourceManagerGateway;
import org.apache.flink.runtime.rest.handler.HandlerRequest;
import org.apache.flink.runtime.rest.handler.RestHandlerException;
import org.apache.flink.runtime.rest.handler.resourcemanager.AbstractResourceManagerHandler;
import org.apache.flink.runtime.rest.messages.EmptyMessageParameters;
import org.apache.flink.runtime.rest.messages.EmptyRequestBody;
import org.apache.flink.runtime.rest.messages.MessageHeaders;
import org.apache.flink.runtime.rest.messages.taskmanager.TaskManagersInfo;
import org.apache.flink.runtime.webmonitor.RestfulGateway;
import org.apache.flink.runtime.webmonitor.retriever.GatewayRetriever;

import javax.annotation.Nonnull;

import java.time.Duration;
import java.util.Map;
import java.util.concurrent.CompletableFuture;

/** Returns an overview over all registered TaskManagers of the cluster. */
public class TaskManagersHandler
        extends AbstractResourceManagerHandler<
                RestfulGateway, EmptyRequestBody, TaskManagersInfo, EmptyMessageParameters> {

    public TaskManagersHandler(
            GatewayRetriever<? extends RestfulGateway> leaderRetriever,
            Duration timeout,
            Map<String, String> responseHeaders,
            MessageHeaders<EmptyRequestBody, TaskManagersInfo, EmptyMessageParameters>
                    messageHeaders,
            GatewayRetriever<ResourceManagerGateway> resourceManagerGatewayRetriever) {
        super(
                leaderRetriever,
                timeout,
                responseHeaders,
                messageHeaders,
                resourceManagerGatewayRetriever);
    }

    @Override
    protected CompletableFuture<TaskManagersInfo> handleRequest(
            @Nonnull HandlerRequest<EmptyRequestBody> request,
            @Nonnull ResourceManagerGateway gateway)
            throws RestHandlerException {
        return gateway.requestTaskManagerInfo(timeout).thenApply(TaskManagersInfo::new);
    }
}
