# node of the tree
class TreeNode:
	def __init__(self):
		self.item = None # Can be anything (a string currently)
		# Only one parent can exist
		self.parent = None
		self.is_sample = False
		self.children = []

	# creates a child node
	def create_leaf(self):
		node = TreeNode()
		node.parent = self
		self.children.append(node)
		return node
	
	# returns true if this node is an "leaf" node, i.e:
	# it has no children to continue with
	def is_leaf(self):
		if len(self.children) == 0:
			return True
		return False

	def create_child_leaf(self, item):
		node = self.create_leaf()
		node.item = item
		return node

	def walk_children(self, fn):
		fn(self)
		# walk children nodes if this node isn't an leaf node
		if not self.is_leaf():
			for node in self.children:
				node.walk_children(fn)

	# find a single child. Returns None if no child with name ecists
	def find_child(self, name):
		if self.item == name:
			return self
		for node in self.children:
			if node.item == name:
				return node
		return None

	def get_parent_count(self):
		# Walk the parents to figure out current tree depth
		# and how many
		parent = self.parent
		parent_count = 0
		while parent is not None:
			parent_count += 1
			parent = parent.parent
		return parent_count

		

#	def walk_children(self, fn):
#		fn(self)
#		for node in self.children:
#			fn(node)
#			for other_node in node.children:
#				fn(other_node)

class Tree:
	def __init__(self):
		# create a root node
		self.root = TreeNode()
		#self.root.item = '(root)'
	
	def walk(self, fn):
		self.root.walk_children(fn)
		#for node in self.root.children:
		#	node.walk_children(fn)
			#fn(node)
			#for other_node in node.children:
			#	fn(other_node)

	# creates a leaf in the root node and populates it
	def create_leaf(self, item):
		leaf_node = self.root.create_child()
		leaf_node.item = item
		return leaf_node