from . import skipWhitespace, ParserError

class Collection:

	def __init__(self,s):

		self.gameTrees=[]

		i=skipWhitespace(s,0)

		if i>=len(s): return

		elif not GameTree.fits(s,i):

			raise ParserError("expected a GameTree starting with '('",s,i)

		while GameTree.fits(s,i):

			i,x=GameTree.create(s,i)

			self.gameTrees.append(x)

		if i<len(s):

			raise ParserError("expected EOF",s,i)

	def listGames(self):

		for tree in self.gameTrees:

			for game in tree.listGames(): yield game

class GameTree:

	def __init__(self):

		self.nodes=[]

		self.branches=[]

	@staticmethod

	def fits(s,i):

		return i<len(s) and s[i]=="("

	@staticmethod

	def create(s,start):

		assert GameTree.fits(s,start)

		res=GameTree()

		i=skipWhitespace(s,start+1)

		if not Node.fits(s,i):

			raise ParserError("expected a Node starting with ';'",s,i)

		y=None

		while Node.fits(s,i):

			i,x=Node.create(s,i)

			res.nodes.append(x)

			if y: y.addChild(x)

			x.setParent(y)

			y=x

			i=skipWhitespace(s,i)

		while GameTree.fits(s,i):

			i,x=GameTree.create(s,i)

			res.branches.append(x)

			subroot=x.getNode(0)

			subroot.setParent(y)

			if y: y.addChild(subroot)

			i=skipWhitespace(s,i)

		if i>=len(s) or s[i]!=")":

			raise ParserError("expected end of a GameTree marked by ')'",s,i)

		i=skipWhitespace(s,i+1)

		return (i,res)

	## Expand multiple games into distinct GameTrees and yield each.

	def listGames(self):

		for node in self._listGINodes():

			yield self._buildSubtree(node)

	def getNode(self,i):

		if 0<=i<len(self.nodes):

			return self.nodes[i]

		return None

	## Create and return a new game tree containing the provided Node.

	#

	# Ancestor nodes are copied, descendants are shared.

	def _buildSubtree(self,seedNode):

		node=seedNode.copy()

		while node.parent:

			newNode=node.parent.copy()

			node.parent=newNode

			newNode.setChildren([node])

			node=newNode

		return node

	## Find and yield Game Info nodes.

	def _listGINodes(self):

		for node in self.nodes:

			if node.isGINode():

				yield node

		for tree in self.branches:

			for node in tree._listGINodes():

				yield node