/* -----------------------------------------------------------------------------
Copyright 2021 Kevin P. Barry

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.
----------------------------------------------------------------------------- */

// Author: Kevin P. Barry [ta0kira@gmail.com]

define TreeSet {
  @value SearchTree<#k,any> tree

  new () {
    return #self{ SearchTree<#k,any>.new() }
  }

  size () {
    return tree.size()
  }

  add (k) {
    \ tree.set(k,Void.void())
    return self
  }

  remove (k) {
    \ tree.remove(k)
    return self
  }

  member (k) {
    return present(tree.get(k))
  }

  defaultOrder () {
    return TreeSetOrder<#k>.wrap(tree.defaultOrder())
  }

  reverseOrder () {
    return TreeSetOrder<#k>.wrap(tree.reverseOrder())
  }

  getForward (k) {
    return TreeSetOrder<#k>.wrap(tree.getForward(k))
  }

  getReverse (k) {
    return TreeSetOrder<#k>.wrap(tree.getReverse(k))
  }
}

concrete TreeSetOrder<#k> {
  refines Order<#k>

  @type wrap (optional Order<KeyValue<#k,any>>) -> (optional TreeSetOrder<#k>)
}

define TreeSetOrder {
  @value Order<KeyValue<#k,any>> order

  wrap (order) {
    if (!present(order)) {
      return empty
    } else {
      return #self{ require(order) }
    }
  }

  next () {
    scoped {
      optional Order<KeyValue<#k,any>> order2 <- order.next()
    } in if (present(order2)) {
      order <- require(order2)
      return self
    } else {
      return empty
    }
  }

  get () {
    return order.get().getKey()
  }
}