/* -----------------------------------------------------------------------------
Copyright 2019-2021,2023 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 SortedMap {
  @value AutoBinaryTree<SortedMapNode<#k, #v>, #k, #v, BinaryTreeNode<#k, #v>> map

  default () {
    return new()
  }

  new () {
    return #self{ AutoBinaryTree<SortedMapNode<#k, #v>, #k, #v, BinaryTreeNode<#k, #v>>.new() }
  }

  size () {
    return map.size()
  }

  member (k) {
    return `present` delegate -> `get`
  }

  duplicate () {
    return #self{ map.duplicate() }
  }

  get (k) {
    return map.get(k)
  }

  set (k, v) {
    \ swap(k, v)
    return self
  }

  remove (k) {
    \ swap(k, empty)
    return self
  }

  weakSet (k, v) {
    return map.weakSet(k, v)
  }

  swap (k, v) {
    return map.swap(k, v)
  }

  defaultOrder () {
    return ForwardTreeOrder:create(map.getRoot())
  }

  reverseOrder () {
    return ReverseTreeOrder:create(map.getRoot())
  }

  getForward (k) {
    return ForwardTreeOrder:seek(k, map.getRoot())
  }

  getReverse (k) {
    return ReverseTreeOrder:seek(k, map.getRoot())
  }

  keyOrder () {
    return MapKeyOrder:new(defaultOrder())
  }

  valueOrder () {
    return MapValueOrder:new(defaultOrder())
  }
}

define ValidatedTree {
  @value AutoBinaryTree<SortedMapNode<#k, #v>, #k, #v, BinaryTreeNode<#k, #v>> map

  new () { $NoTrace$
    return #self{ AutoBinaryTree<SortedMapNode<#k, #v>, #k, #v, BinaryTreeNode<#k, #v>>.new() }
  }

  size () { $NoTrace$
    return map.size()
  }

  set (k, v) { $NoTrace$
    \ map.swap(k, v)
    \ validate(map.getRoot())
    return self
  }

  remove (k) { $NoTrace$
    \ map.swap(k, empty)
    \ validate(map.getRoot())
    return self
  }

  get (k) { $NoTrace$
    return map.get(k)
  }

  @type validate (optional BinaryTreeNode<#k, #v>) -> ()
  validate (node) { $NoTrace$
    if (present(node)) {
      \ validateOrder(require(node))
      \ validateBalance(require(node))
    }
  }

  @type validateOrder (BinaryTreeNode<#k, #v>) -> ()
  validateOrder (node) { $NoTrace$
    if (present(node.getLower())) {
      if (!(require(node.getLower()).getKey() `#k.lessThan` node.getKey())) {
        fail("bad lower order")
      }
      \ validateOrder(require(node.getLower()))
    }
    if (present(node.getHigher())) {
      if (!(node.getKey() `#k.lessThan` require(node.getHigher()).getKey())) {
        fail("bad higher order")
      }
      \ validateOrder(require(node.getHigher()))
    }
  }

  @type validateBalance (BinaryTreeNode<#k, #v>) -> ()
  validateBalance (node) { $NoTrace$
    scoped {
      Int balance <- 0
      if (present(node.getLower())) {
        balance <- balance-require(node.getLower()).getHeight()
      }
      if (present(node.getHigher())) {
        balance <- balance+require(node.getHigher()).getHeight()
      }
      $ReadOnly[balance]$
    } in if (balance > 1 || balance < -1) {
      fail("out of balance: " + balance.formatted())
    }
    if (present(node.getLower())) {
      \ validateBalance(require(node.getLower()))
    }
    if (present(node.getHigher())) {
      \ validateBalance(require(node.getHigher()))
    }
  }
}

concrete SortedMapNode<#k, #v> {
  defines KVFactory<#k, #v>
  refines BalancedTreeNode<SortedMapNode<#k, #v>, #k, #v>
  refines Duplicate
}

define SortedMapNode {
  $ReadOnly[key]$

  @value Int height
  @value #k key
  @value #v value
  @value optional #self lower
  @value optional #self higher

  newNode (k, v) {
    return #self{ 1, k, v, empty, empty }
  }

  duplicate () {
    optional #self lower2 <- empty
    if (present(lower)) {
      lower2 <- require(lower).duplicate()
    }
    optional #self higher2 <- empty
    if (present(higher)) {
      higher2 <- require(higher).duplicate()
    }
    return #self{ height, key, value, lower2, higher2 }
  }

  getLower ()   { return lower }
  setLower (l)  { lower <- l }
  getHigher ()  { return higher }
  setHigher (h) { higher <- h }
  getKey ()     { return key }
  getValue ()   { return value }
  setValue (v)  { value <- v }
  getHeight ()  { return height }

  updateNode () {
    scoped {
      Int l <- 0
      Int h <- 0
      if (present(lower)) {
        l <- require(lower).getHeight()
      }
      if (present(higher)) {
        h <- require(higher).getHeight()
      }
    } in if (l > h) {
      height <- l + 1
    } else {
      height <- h + 1
    }
  }
}