/**
 * Copyright (c) 2010 Yahoo! Inc. All rights reserved.
 * Licensed 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. See accompanying LICENSE file.
 */
package org.apache.oozie.action.hadoop;

import org.apache.hadoop.mapred.Counters;
import org.apache.oozie.DagELFunctions;
import org.apache.oozie.util.ELEvaluationException;
import org.apache.oozie.util.XLog;
import org.apache.oozie.workflow.WorkflowInstance;
import org.json.simple.JSONValue;

import java.util.HashMap;
import java.util.Map;

/**
 * Hadoop EL functions.
 */
public class HadoopELFunctions {

    private static final String HADOOP_COUNTERS = "oozie.el.action.hadoop.counters";

    public static final String RECORDS = "org.apache.hadoop.mapred.Task$Counter";
    public static final String MAP_IN = "MAP_INPUT_RECORDS";
    public static final String MAP_OUT = "MAP_OUTPUT_RECORDS";
    public static final String REDUCE_IN = "REDUCE_INPUT_RECORDS";
    public static final String REDUCE_OUT = "REDUCE_OUTPUT_RECORDS";
    public static final String GROUPS = "REDUCE_INPUT_GROUPS";

    @SuppressWarnings("unchecked")
    public static Map<String, Map<String, Long>> hadoop_counters(String nodeName) throws ELEvaluationException {
        WorkflowInstance instance = DagELFunctions.getWorkflow().getWorkflowInstance();
        Object obj = instance.getTransientVar(nodeName + WorkflowInstance.NODE_VAR_SEPARATOR + HADOOP_COUNTERS);
        Map<String, Map<String, Long>> counters = (Map<String, Map<String, Long>>) obj;
        if (counters == null) {
            counters = getCounters(nodeName);
            instance.setTransientVar(nodeName + WorkflowInstance.NODE_VAR_SEPARATOR + HADOOP_COUNTERS, counters);
        }
        return counters;
    }

    @SuppressWarnings("unchecked")
    private static Map<String, Map<String, Long>> getCounters(String nodeName) throws ELEvaluationException {
        String jsonCounters = DagELFunctions.getActionVar(nodeName, MapReduceActionExecutor.HADOOP_COUNTERS);
        if (jsonCounters == null) {
            throw new IllegalArgumentException(XLog.format("Hadoop counters not available for action [{0}]", nodeName));
        }
        return (Map) JSONValue.parse(jsonCounters);
    }

}