import math

def normalize(n):
	d = n[0]*n[0] + n[1]*n[1] + n[2]*n[2]
	d = math.sqrt(d)

	if d == 0:
		return [0.0, 0.0, 0.0]
	
	n[0] /= d
	n[1] /= d
	n[2] /= d

	return n

def normal3((v1, v2, v3)):
	n = [0.0, 0.0, 0.0]
	n1 = [0.0, 0.0, 0.0]
	n2 = [0.0, 0.0, 0.0]

	n1[0] = v1[0] - v2[0]
	n2[0] = v2[0] - v3[0]
	n1[1] = v1[1] - v2[1]
	n2[1] = v2[1] - v3[1]
	n1[2] = v1[2] - v2[2]
	n2[2] = v2[2] - v3[2]

	n[0] = n1[1]*n2[2] - n1[2]*n2[1]
	n[1] = n1[2]*n2[0] - n1[0]*n2[2]
	n[2] = n1[0]*n2[1] - n1[1]*n2[0]

	return normalize(n)

def normal4((v1, v2, v3, v4)):
	n = [0.0, 0.0, 0.0]
	n1 = [0.0, 0.0, 0.0]
	n2 = [0.0, 0.0, 0.0]

	n1[0] = v1[0] - v3[0]
	n1[1] = v1[1] - v3[1]
	n1[2] = v1[2] - v3[2]

	n2[0] = v2[0] - v4[0]
	n2[1] = v2[1] - v4[1]
	n2[2] = v2[2] - v4[2]

	n[0] = n1[1]*n2[2] - n1[2]*n2[1]
	n[1] = n1[2]*n2[0] - n1[0]*n2[2]
	n[2] = n1[0]*n2[1] - n1[1]*n2[0]

	return normalize(n)


class vGeometry:
	def __init__(self):
		self.v = {}
		self.f = {}
		self.bbox = [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]]

	def setVertex(self, id, xyz=(0.0, 0.0, 0.0)):

		# find an empty spot
		if id == -1:
			m = 0
			for v in self.v:
				m = max(v, m)
			id = m + 1

		self.v[id] = Vertex(xyz)

		self.bbox[0][0] = min(self.bbox[0][0], xyz[0])
		self.bbox[0][1] = min(self.bbox[0][1], xyz[1])
		self.bbox[0][2] = min(self.bbox[0][2], xyz[2])

		self.bbox[1][0] = max(self.bbox[1][0], xyz[0])
		self.bbox[1][1] = max(self.bbox[1][1], xyz[1])
		self.bbox[1][2] = max(self.bbox[1][2], xyz[2])

		return id
	
	def delVertex(self, id):
		if id in self.v:
			del self.v[id]

	def setTriangle(self, id, verts=(None, None, None)):
		pid = self._setFace(id, verts, 3)
		return pid

	def setQuad(self, id, verts=(None, None, None, None)):
		pid = self._setFace(id, verts, 4)
		return pid

	def delFace(self, id):
		if id in self.f:
			del self.f[id]

	def _setFace(self, id, verts, corners):

		face = None

		if id in self.f:
			face = self.f[id]
			face.setCorners(corners)
		else:
			face = Face(self, corners)

		for i in range(0, corners):
			if verts[i] == None:
				face.v[i] = self.setVertex(-1)
			else:
				face.v[i] = verts[i]

		self.f[id] = face
		return id

class Vertex:
	def __init__(self, xyz=(0.0, 0.0, 0.0)):
		self.co = list(xyz);

class Face:
	def __init__(self, parent, corners=3):
		self.parent = parent
		self.corners = corners
		self.n = [0.0, 0.0, 0.0]

		if corners == 3:
			self.v = [None, None, None]
			self.uv = [[0.0, 0.0], [0.0, 0.0], [0.0, 0.0]]
		elif corners == 4:
			self.v = [None, None, None, None]
			self.uv = [[0.0, 0.0], [0.0, 0.0], [0.0, 0.0], [0.0, 0.0]]
	
	def setCorners(self, corners=3):
		if self.corners != corners:
			if (self.corners == 4) and (corners == 3):
				del self.v[3]
				del self.uv[3]
			else:
				self.v.append(None)
				self.uv.append([0.0, 0.0])
			self.corners = corners

	def getCoords(self):
		verts = self.parent.v

		if None in self.v:
			return None, None

		for v in self.v:
			if not (v in verts):	
				return None, None

		co = []
		for v in self.v:
			co.append(verts[v].co)

		return co, self.uv
	
	def calcNorm(self):
		verts = self.parent.v

		if None in self.v:
			return

		for v in self.v:
			if not (v in verts):	
				return

		if self.corners == 3:
			co = [None, None, None]
			for i in range(0, 3):
				co[i] = verts[self.v[i]].co
			self.n = normal3(co)

		elif self.corners == 4:
			co = [None, None, None, None]
			for i in range(0, 4):
				co[i] = verts[self.v[i]].co
			self.n = normal4(co)

	def getNorm(self):
		return self.n