//::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
/** @author  Kevin Warrick, John Miller, Susan George
 *  @version 1.5
 *  @date    Tue Oct 16 17:03:00 EDT 2018
 *  @see     LICENSE (MIT style license file).
 */

package scalation.analytics.classifier

import scala.collection.mutable.HashMap

import scalation.linalgebra.VectoI

//::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
/** The `Node` class is used to hold inormation about a node in the decision tree.
 *  @param nu  the frequency count
 */
abstract class Node (nu: VectoI)
         extends Cloneable
{
    /** The sum of frequency counts
     */
    val nu_sum = nu.sum

    //::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
    /** Copy a node and all of its child nodes.
     *  @param vc  the value count
     */
    def copy (vc: Array [Int]): Node =
    {
        this match {
        case FeatureNode (f, branches, path, nu) => 
            deepCopy (FeatureNode (f, branches.clone (), path, nu), vc)
        case LeafNode (y, nu) =>
            LeafNode (y, nu)
        } // match
    } // copy

    //::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
    /** This method deep copies a node all the way down by creating new instances of feature node.
     *  This is required while pruning.
     *  @param curNode  the current node
     *  @param vc       the value count
     */
    def deepCopy (curNode: Node, vc: Array [Int]): Node =
    {
        val fn = curNode.asInstanceOf [FeatureNode]
        for (i <- 0 until vc(fn.f)) {
            if (fn.branches.get(i) != None) {
                val node = fn.branches(i)
                if (node.isInstanceOf [FeatureNode]) {
                    val tempFn    = node.asInstanceOf [FeatureNode]
                    val tempNewFn = new FeatureNode (tempFn.f, tempFn.branches.clone(), tempFn.path, tempFn.nu)
                    fn.branches  += i -> tempNewFn
                } // if
            } // if
        } // for
        fn
    } // deepCopy

} // Node class


//::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
/** The `FeatureNode` class is for internal nodes.
 *  @param f         the feature/variable number used for splitting
 *  @param branches  maps the branch value, e.g., f2 has values 0, 1, 3, for a node 
 *  @param path      the path from the current node to the root {(parent node feature, branch)}
 *  @param nu        the frequency count
 */
case class FeatureNode (f: Int, branches: HashMap [Int, Node], path: List [(Int, Int)], nu: VectoI)
     extends Node (nu) with Cloneable


//::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
/** The `LeafNode` class is for leaf nodes.
 *  @param y       the respone/decision value
 *  @param nu      the frequency count (count for each possible decision value for y)
 */
case class LeafNode (y: Int, nu: VectoI)
     extends Node (nu) with Cloneable
{
    var parent: FeatureNode = null

} // LeafNode class