# Duane's Dungeon - a rogue-like game
# Copyright (C) 2023 Duane Robertson

# btree.gd - simple b-tree

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program 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 General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.


extends RefCounted
class_name BTree


var leaf
var lchild
var rchild


func _init(in_leaf):
	leaf = in_leaf


func add(in_arr:Array):
	if len(in_arr) != 2:
		G.error('BTree.add requires an array of two elements')
		return

	lchild = BTree.new(in_arr[0])
	rchild = BTree.new(in_arr[1])


func get_leaves():
	var lexists:bool = (lchild != null)
	var rexists:bool = (rchild != null)

	if lexists and rexists:
		return lchild.get_leaves() + rchild.get_leaves()
	elif lexists or rexists:
		G.error('unbalanced BTree')
		return
	else:
		return [leaf]