/*
 * Copyright (c) 2013 DataTorrent, 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.
 */
package com.datatorrent.lib.math;

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

import org.apache.commons.lang.mutable.MutableDouble;

import com.datatorrent.lib.util.BaseNumberKeyValueOperator;
import com.datatorrent.lib.util.KeyValPair;

import com.datatorrent.api.DefaultInputPort;
import com.datatorrent.api.DefaultOutputPort;
import com.datatorrent.api.StreamCodec;

/**
 *
 * This operator adds all values for each key in "numerator" and "denominator", and emits the margin for each key at the end of window.
 * <p>
 * <br>
 * Margin Formula used by this operator: 1 - numerator/denominator.
 * The values are added for each key within the window and for each stream.<br>
 * <br>
 * <b>Ports</b>:<br>
 * <b>numerator</b>: expects KeyValPair&lt;K,V&gt;<br>
 * <b>denominator</b>: expects KeyValPair&lt;K,V&gt;<br>
 * <b>margin</b>: emits HashMap&lt;K,Double&gt;, one entry per key per window<br>
 * <br>
 * <b>Properties</b>:<br>
 * <b>inverse</b>: if set to true the key in the filter will block tuple<br>
 * <b>filterBy</b>: List of keys to filter on<br>
 * <br>
 * @displayName Margin Key Value
 * @category Math
 * @tags sum, division, numeric, key value
 * @since 0.3.3
 */
public class MarginKeyVal<K, V extends Number> extends
		BaseNumberKeyValueOperator<K, V>
{
        /**
	 * Numerator input port that takes a key value pair.
	 */
	public final transient DefaultInputPort<KeyValPair<K, V>> numerator = new DefaultInputPort<KeyValPair<K, V>>()
	{
		/**
		 * Adds tuple to the numerator hash.
		 */
		@Override
		public void process(KeyValPair<K, V> tuple)
		{
			addTuple(tuple, numerators);
		}

		/**
		 * Set StreamCodec used for partitioning.
		 */
		@Override
		public StreamCodec<KeyValPair<K, V>> getStreamCodec()
		{
			return getKeyValPairStreamCodec();
		}
	};

        /**
	 * Denominator input port that takes a key value pair.
	 */
	public final transient DefaultInputPort<KeyValPair<K, V>> denominator = new DefaultInputPort<KeyValPair<K, V>>()
	{
		/**
		 * Adds tuple to the denominator hash.
		 */
		@Override
		public void process(KeyValPair<K, V> tuple)
		{
			addTuple(tuple, denominators);
		}

		/**
		 * Set StreamCodec used for partitioning.
		 */
		@Override
		public StreamCodec<KeyValPair<K, V>> getStreamCodec()
		{
			return getKeyValPairStreamCodec();
		}
	};

	/**
	 * Adds the value for each key.
	 *
	 * @param tuple
	 * @param map
	 */
	public void addTuple(KeyValPair<K, V> tuple, Map<K, MutableDouble> map)
	{
		K key = tuple.getKey();
		if (!doprocessKey(key) || (tuple.getValue() == null)) {
			return;
		}
		MutableDouble val = map.get(key);
		if (val == null) {
			val = new MutableDouble(0.0);
			map.put(cloneKey(key), val);
		}
		val.add(tuple.getValue().doubleValue());
	}

        /**
	 * Output margin port that emits Key Value pairs.
	 */
	public final transient DefaultOutputPort<KeyValPair<K, V>> margin = new DefaultOutputPort<KeyValPair<K, V>>();

	protected HashMap<K, MutableDouble> numerators = new HashMap<K, MutableDouble>();
	protected HashMap<K, MutableDouble> denominators = new HashMap<K, MutableDouble>();
	protected boolean percent = false;

	/**
	 * getter function for percent
	 *
	 * @return percent
	 */
	public boolean getPercent()
	{
		return percent;
	}

	/**
	 * setter function for percent
	 *
	 * @param val
	 *          sets percent
	 */
	public void setPercent(boolean val)
	{
		percent = val;
	}

	/**
	 * Generates tuples for each key and emits them. Only keys that are in the
	 * denominator are iterated on If the key is only in the numerator, it gets
	 * ignored (cannot do divide by 0) Clears internal data
	 */
	@SuppressWarnings({ "rawtypes", "unchecked" })
	@Override
	public void endWindow()
	{
		Double val;
		for (Map.Entry<K, MutableDouble> e : denominators.entrySet()) {
			K key = e.getKey();
			MutableDouble nval = numerators.get(key);
			if (nval == null) {
				nval = new MutableDouble(0.0);
			} else {
				numerators.remove(key); // so that all left over keys can be reported
			}
			if (percent) {
				val = (1 - nval.doubleValue() / e.getValue().doubleValue()) * 100;
			} else {
				val = 1 - nval.doubleValue() / e.getValue().doubleValue();
			}

			margin.emit(new KeyValPair(key, getValue(val.doubleValue())));
		}

		numerators.clear();
		denominators.clear();
	}
}