gistfile1.scala

package org.mojito.core

import collection.mutable

/**
 * @author Blackrush
 * @todo implement Iterable[(Seq[K], V)]
 */
class NavigableTree[K, V](val key: K, val value: Option[V] = None, val parent: Option[NavigableTree[K, V]] = None) {
  type This = NavigableTree[K, V]

  private val children = new mutable.HashMap[K, This]

  def hasChildren = !children.isEmpty

  def root: This = if (parent.isEmpty) this else parent.get.root

  def path: Seq[K] = parent match {
    case None => Seq.empty
    case Some(p) => p.path :+ key
  }

  def get(key: K): Option[V] = children.get(key) match {
    case Some(v) => v.value
    case None => None
  }

  def put(key: K, value: Option[V]): This = {
    val child = new This(key, value, Some(this))
    children(key) = child
    child
  }

  private def recGet(it: Iterator[K]): Option[V] =
    if (!it.hasNext) value
    else children.get(it.next()) match {
      case Some(child) => child.recGet(it)
      case None => value
    }

  private def recPut(it: Iterator[K], value: Option[V]): This = {
    val key = it.next()
    if (!it.hasNext) put(key, value)
    else children.get(key).getOrElse(put(key, None)).recPut(it, value)
  }

  def get(keys: Seq[K]): Option[V] = recGet(keys.iterator)

  def put(keys: Seq[K], value: Option[V]): This = {
    val it = keys.iterator
    if (it.hasNext) recPut(it, value)
    else throw new UnsupportedOperationException
  }

  def apply(key: K): Option[V] = get(key)
  def apply(keys: Seq[K]): Option[V] = get(keys)

  def put(key: K, value: V): This = put(key, Option(value))
  def put(keys: Seq[K], value: V): This = put(keys, Option(value))

  def update(key: K, value: Option[V]) = put(key, value)
  def update(key: K, value: V) = put(key, value)
  def update(keys: Seq[K], value: Option[V]) = put(keys, value)
  def update(keys: Seq[K], value: V) = put(keys, value)
}