/*
 * 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.job;

import org.apache.flink.api.common.time.Time;
import org.apache.flink.runtime.accumulators.StringifiedAccumulatorResult;
import org.apache.flink.runtime.executiongraph.AccessExecution;
import org.apache.flink.runtime.executiongraph.AccessExecutionJobVertex;
import org.apache.flink.runtime.executiongraph.AccessExecutionVertex;
import org.apache.flink.runtime.jobgraph.JobVertexID;
import org.apache.flink.runtime.rest.handler.HandlerRequest;
import org.apache.flink.runtime.rest.handler.RestHandlerException;
import org.apache.flink.runtime.rest.handler.legacy.ExecutionGraphCache;
import org.apache.flink.runtime.rest.messages.EmptyRequestBody;
import org.apache.flink.runtime.rest.messages.JobVertexMessageParameters;
import org.apache.flink.runtime.rest.messages.MessageHeaders;
import org.apache.flink.runtime.rest.messages.job.SubtasksAllAccumulatorsInfo;
import org.apache.flink.runtime.rest.messages.job.UserAccumulator;
import org.apache.flink.runtime.taskmanager.TaskManagerLocation;
import org.apache.flink.runtime.webmonitor.RestfulGateway;
import org.apache.flink.runtime.webmonitor.retriever.GatewayRetriever;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Executor;

/** Request handler for the subtasks all accumulators. */
public class SubtasksAllAccumulatorsHandler
        extends AbstractJobVertexHandler<SubtasksAllAccumulatorsInfo, JobVertexMessageParameters> {

    public SubtasksAllAccumulatorsHandler(
            GatewayRetriever<? extends RestfulGateway> leaderRetriever,
            Time timeout,
            Map<String, String> responseHeaders,
            MessageHeaders<
                            EmptyRequestBody,
                            SubtasksAllAccumulatorsInfo,
                            JobVertexMessageParameters>
                    messageHeaders,
            ExecutionGraphCache executionGraphCache,
            Executor executor) {
        super(
                leaderRetriever,
                timeout,
                responseHeaders,
                messageHeaders,
                executionGraphCache,
                executor);
    }

    @Override
    protected SubtasksAllAccumulatorsInfo handleRequest(
            HandlerRequest<EmptyRequestBody> request, AccessExecutionJobVertex jobVertex)
            throws RestHandlerException {
        JobVertexID jobVertexId = jobVertex.getJobVertexId();
        int parallelism = jobVertex.getParallelism();

        final List<SubtasksAllAccumulatorsInfo.SubtaskAccumulatorsInfo> subtaskAccumulatorsInfos =
                new ArrayList<>();

        for (AccessExecutionVertex vertex : jobVertex.getTaskVertices()) {
            for (AccessExecution execution : vertex.getCurrentExecutions()) {
                TaskManagerLocation location = execution.getAssignedResourceLocation();
                String locationString = location == null ? "(unassigned)" : location.getHostname();

                StringifiedAccumulatorResult[] accs = execution.getUserAccumulatorsStringified();
                List<UserAccumulator> userAccumulators = new ArrayList<>(accs.length);
                for (StringifiedAccumulatorResult acc : accs) {
                    userAccumulators.add(
                            new UserAccumulator(acc.getName(), acc.getType(), acc.getValue()));
                }

                subtaskAccumulatorsInfos.add(
                        new SubtasksAllAccumulatorsInfo.SubtaskAccumulatorsInfo(
                                execution.getParallelSubtaskIndex(),
                                execution.getAttemptNumber(),
                                locationString,
                                userAccumulators));
            }
        }

        return new SubtasksAllAccumulatorsInfo(jobVertexId, parallelism, subtaskAccumulatorsInfos);
    }
}
