/*
 * 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.AccessExecutionGraph;
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.AccumulatorsIncludeSerializedValueQueryParameter;
import org.apache.flink.runtime.rest.messages.EmptyRequestBody;
import org.apache.flink.runtime.rest.messages.JobAccumulatorsInfo;
import org.apache.flink.runtime.rest.messages.JobAccumulatorsMessageParameters;
import org.apache.flink.runtime.rest.messages.JobIDPathParameter;
import org.apache.flink.runtime.rest.messages.MessageHeaders;
import org.apache.flink.runtime.rest.messages.ResponseBody;
import org.apache.flink.runtime.webmonitor.RestfulGateway;
import org.apache.flink.runtime.webmonitor.history.ArchivedJson;
import org.apache.flink.runtime.webmonitor.history.OnlyExecutionGraphJsonArchivist;
import org.apache.flink.runtime.webmonitor.retriever.GatewayRetriever;
import org.apache.flink.util.OptionalFailure;
import org.apache.flink.util.SerializedValue;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Executor;

/** Request handler that returns the aggregated accumulators of a job. */
public class JobAccumulatorsHandler
        extends AbstractAccessExecutionGraphHandler<
                JobAccumulatorsInfo, JobAccumulatorsMessageParameters>
        implements OnlyExecutionGraphJsonArchivist {

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

    @Override
    protected JobAccumulatorsInfo handleRequest(
            HandlerRequest<EmptyRequestBody> request, AccessExecutionGraph graph)
            throws RestHandlerException {
        List<Boolean> queryParams =
                request.getQueryParameter(AccumulatorsIncludeSerializedValueQueryParameter.class);

        final boolean includeSerializedValue;
        if (!queryParams.isEmpty()) {
            includeSerializedValue = queryParams.get(0);
        } else {
            includeSerializedValue = false;
        }

        return createJobAccumulatorsInfo(graph, includeSerializedValue);
    }

    @Override
    public Collection<ArchivedJson> archiveJsonWithPath(AccessExecutionGraph graph)
            throws IOException {
        ResponseBody json = createJobAccumulatorsInfo(graph, true);
        String path =
                getMessageHeaders()
                        .getTargetRestEndpointURL()
                        .replace(':' + JobIDPathParameter.KEY, graph.getJobID().toString());
        return Collections.singleton(new ArchivedJson(path, json));
    }

    private static JobAccumulatorsInfo createJobAccumulatorsInfo(
            AccessExecutionGraph graph, boolean includeSerializedValue) {
        StringifiedAccumulatorResult[] stringifiedAccs = graph.getAccumulatorResultsStringified();
        List<JobAccumulatorsInfo.UserTaskAccumulator> userTaskAccumulators =
                new ArrayList<>(stringifiedAccs.length);

        for (StringifiedAccumulatorResult acc : stringifiedAccs) {
            userTaskAccumulators.add(
                    new JobAccumulatorsInfo.UserTaskAccumulator(
                            acc.getName(), acc.getType(), acc.getValue()));
        }

        JobAccumulatorsInfo accumulatorsInfo;
        if (includeSerializedValue) {
            Map<String, SerializedValue<OptionalFailure<Object>>> serializedUserTaskAccumulators =
                    graph.getAccumulatorsSerialized();
            accumulatorsInfo =
                    new JobAccumulatorsInfo(
                            Collections.emptyList(),
                            userTaskAccumulators,
                            serializedUserTaskAccumulators);
        } else {
            accumulatorsInfo =
                    new JobAccumulatorsInfo(
                            Collections.emptyList(), userTaskAccumulators, Collections.emptyMap());
        }

        return accumulatorsInfo;
    }
}
