/*
 * 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.webmonitor.handlers;

import com.fasterxml.jackson.core.JsonGenerator;
import org.apache.flink.runtime.accumulators.StringifiedAccumulatorResult;
import org.apache.flink.runtime.executiongraph.AccessExecution;
import org.apache.flink.runtime.executiongraph.AccessExecutionGraph;
import org.apache.flink.runtime.executiongraph.AccessExecutionJobVertex;
import org.apache.flink.runtime.executiongraph.AccessExecutionVertex;
import org.apache.flink.runtime.webmonitor.ExecutionGraphHolder;
import org.apache.flink.runtime.webmonitor.history.ArchivedJson;
import org.apache.flink.runtime.webmonitor.history.JsonArchivist;

import java.io.IOException;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;

/**
 * Base class for request handlers whose response depends on a specific job vertex (defined
 * via the "vertexid" parameter) in a specific job, defined via (defined voa the "jobid" parameter).  
 */
public class SubtaskExecutionAttemptAccumulatorsHandler extends AbstractSubtaskAttemptRequestHandler {

	private static final String SUBTASK_ATTEMPT_ACCUMULATORS_REST_PATH = "/jobs/:jobid/vertices/:vertexid/subtasks/:subtasknum/attempts/:attempt/accumulators";
	
	public SubtaskExecutionAttemptAccumulatorsHandler(ExecutionGraphHolder executionGraphHolder) {
		super(executionGraphHolder);
	}

	@Override
	public String[] getPaths() {
		return new String[]{SUBTASK_ATTEMPT_ACCUMULATORS_REST_PATH};
	}

	@Override
	public String handleRequest(AccessExecution execAttempt, Map<String, String> params) throws Exception {
		return createAttemptAccumulatorsJson(execAttempt);
	}
		
	public static class SubtaskExecutionAttemptAccumulatorsJsonArchivist implements JsonArchivist {

		@Override
		public Collection<ArchivedJson> archiveJsonWithPath(AccessExecutionGraph graph) throws IOException {
			List<ArchivedJson> archive = new ArrayList<>();
			for (AccessExecutionJobVertex task : graph.getAllVertices().values()) {
				for (AccessExecutionVertex subtask : task.getTaskVertices()) {
					String curAttemptJson = createAttemptAccumulatorsJson(subtask.getCurrentExecutionAttempt());
					String curAttemptPath = SUBTASK_ATTEMPT_ACCUMULATORS_REST_PATH
						.replace(":jobid", graph.getJobID().toString())
						.replace(":vertexid", task.getJobVertexId().toString())
						.replace(":subtasknum", String.valueOf(subtask.getParallelSubtaskIndex()))
						.replace(":attempt", String.valueOf(subtask.getCurrentExecutionAttempt().getAttemptNumber()));

					archive.add(new ArchivedJson(curAttemptPath, curAttemptJson));

					for (int x = 0; x < subtask.getCurrentExecutionAttempt().getAttemptNumber(); x++) {
						AccessExecution attempt = subtask.getPriorExecutionAttempt(x);
						String json = createAttemptAccumulatorsJson(attempt);
						String path = SUBTASK_ATTEMPT_ACCUMULATORS_REST_PATH
							.replace(":jobid", graph.getJobID().toString())
							.replace(":vertexid", task.getJobVertexId().toString())
							.replace(":subtasknum", String.valueOf(subtask.getParallelSubtaskIndex()))
							.replace(":attempt", String.valueOf(attempt.getAttemptNumber()));
						archive.add(new ArchivedJson(path, json));
					}
				}
			}
			return archive;
		}
	}

	public static String createAttemptAccumulatorsJson(AccessExecution execAttempt) throws IOException {
		StringWriter writer = new StringWriter();
		JsonGenerator gen = JsonFactory.jacksonFactory.createGenerator(writer);
		
		final StringifiedAccumulatorResult[] accs = execAttempt.getUserAccumulatorsStringified();

		gen.writeStartObject();

		gen.writeNumberField("subtask", execAttempt.getParallelSubtaskIndex());
		gen.writeNumberField("attempt", execAttempt.getAttemptNumber());
		gen.writeStringField("id", execAttempt.getAttemptId().toString());
		
		gen.writeArrayFieldStart("user-accumulators");
		for (StringifiedAccumulatorResult acc : accs) {
			gen.writeStartObject();
			gen.writeStringField("name", acc.getName());
			gen.writeStringField("type", acc.getType());
			gen.writeStringField("value", acc.getValue());
			gen.writeEndObject();
		}
		gen.writeEndArray();
		
		gen.writeEndObject();
		
		gen.close();
		return writer.toString();
	}
}