/*
 * INESC-ID, Instituto de Engenharia de Sistemas e Computadores Investigação e Desevolvimento em Lisboa
 * Copyright 2013 INESC-ID and/or its affiliates and other
 * contributors as indicated by the @author tags. All rights reserved.
 * See the copyright.txt in the distribution for a full listing of
 * individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 3.0 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.infinispan.dataplacement.c50.tree;

import org.infinispan.dataplacement.c50.keyfeature.Feature;
import org.infinispan.dataplacement.c50.keyfeature.FeatureValue;
import org.infinispan.dataplacement.c50.tree.node.DecisionTreeNode;
import org.infinispan.dataplacement.c50.tree.node.Type0Node;
import org.infinispan.dataplacement.c50.tree.node.Type1Node;
import org.infinispan.dataplacement.c50.tree.node.Type2Node;
import org.infinispan.dataplacement.c50.tree.node.Type3Node;

import java.util.Map;

/**
 * Builds a queryable decision tree based on the parsed tree
 *
 * @author Pedro Ruivo
 * @since 5.2
 */
public class DecisionTreeBuilder {
   /**
    * returns a queryable decision tree that represents the parsed tree
    *
    * @param root       the root node
    * @param featureMap the feature map to translate the attributes names in Feature instances
    * @return           the queryable decision tree
    */
   public static  DecisionTree build(ParseTreeNode root, Map<String, Feature> featureMap) {
      DecisionTreeNode node = parseNode(root, featureMap);
      return new DecisionTree(node);
   }

   private static DecisionTreeNode parseNode(ParseTreeNode node, Map<String, Feature> featureMap) {
      switch (node.getType()) {
         case 0:
            return parseType0Node(node);
         case 1:
            return parseType1Node(node, featureMap);
         case 2:
            return parseType2Node(node, featureMap);
         case 3:
            return parseType3Node(node, featureMap);
         default:
            throw new IllegalArgumentException("Unkown parsed node type");
      }
   }

   private static DecisionTreeNode parseType0Node(ParseTreeNode node) {
      return new Type0Node(getValue(node));
   }

   private static DecisionTreeNode parseType1Node(ParseTreeNode node, Map<String, Feature> featureMap) {
      return new Type1Node(getValue(node), getFeature(node, featureMap), getForks(node, featureMap));
   }

   private static DecisionTreeNode parseType2Node(ParseTreeNode node, Map<String, Feature> featureMap) {
      Feature feature = getFeature(node, featureMap);
      return new Type2Node(getValue(node), feature, getForks(node, featureMap), getCut(node, feature));
   }

   private static DecisionTreeNode parseType3Node(ParseTreeNode node, Map<String, Feature> featureMap) {
      return new Type3Node(getValue(node), getFeature(node, featureMap), getForks(node, featureMap), node.getElts());
   }

   private static int getValue(ParseTreeNode node) {
      return Integer.parseInt(node.getClazz());
   }

   private static Feature getFeature(ParseTreeNode node, Map<String, Feature> featureMap) {
      Feature feature = featureMap.get(node.getAttribute());

      if (feature == null) {
         throw new IllegalStateException("Unknown attribute " + node.getAttribute());
      }
      return feature;
   }

   /*
   Decision tree nodes. Each type node has it own find rules and each node has it own attribute (except the leaf node)
    */

   private static DecisionTreeNode[] getForks(ParseTreeNode node, Map<String, Feature> featureMap) {
      DecisionTreeNode[] forks = new DecisionTreeNode[node.getNumberOfForks()];
      ParseTreeNode[] parseForks = node.getForks();

      for (int i = 0; i < forks.length; ++i) {
         forks[i] = parseNode(parseForks[i], featureMap);
      }

      return forks;
   }

   private static FeatureValue getCut(ParseTreeNode node, Feature feature) {
      String cut = node.getCut();
      return feature.featureValueFromParser(cut);
   }
}