from .node import Node
from . import skipWhitespace, ParserError
from .gameRecord import GameRecord


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.parent = 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.parent = 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):
		if len(self.nodes) == 0:
			return None
		for node in self.nodes[0].listGINodes():
			yield GameRecord(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 moved from the seedNode.
	def _buildSubtree(self, seedNode):
		node = seedNode.copy()
		node.setChildren(seedNode.children)
		seedNode.children = []

		while node.parent:
			newNode = node.parent.copy()
			newNode.addChild(node)
			node = newNode

		return node