'''
This is the visualization backend for bare_sim module
'''
try:
	import visual as vs
	from visual import vector as vv
except ImportError:
	from vector import Vector as vv
# 	from vector import Vector as vector
	pass
from vector import Vector as v

from geom import Camera

from util import drawAxes
# converts a vector object into a visual vector object
v_to_vv = lambda vec: vv(vec.x, vec.y, vec.z)

def drawCameraFrame(cam):  # create frame and draw its contents
	c = v(cam.t)
	cam.center = vs.sphere(pos=v_to_vv(c),
	                        radius=Camera.default_radius,
	                        color=vs.color.green)
	cam.dir = vs.arrow(pos=v_to_vv(c),
	                    axis=v_to_vv(v(cam.direction)) * cam.f,
	                    shaftwidth=1.0)
	# TODO: check for orientation of the camera, rotate plane accordingly
	cam.img_plane = vs.box(pos=v_to_vv(c) + v_to_vv(cam.dir.axis),
	                        length=cam.image_width, 
	                        width=0.5,
	                        height=cam.image_width,
	                        color=vs.color.white,
	                        opacity=0.5)

def castRays(cam, pts, frame = None):
	'''
	Cast rays from camera center towards pts
	'''
	for point in pts:
		pos = v(cam.t)
		diff = v(point) - pos
		drawLine(frame, pos, diff.mag, diff.norm())

class Ray:
	def __init__(self, position, length, direction, color = vs.color.white):
		self.position = position
		self.length = length
		self.direction = direction
		self.color = color



# a Simulation object which extends this class can be visualizable
class Visualizable:
	display_width = 800
	display_height = 600

	# no code interaction is possible if this is true
	# press esc to cancel visualization, change model parameters, then visualize again
	visualizing = False

	def visualize(self):
		self.visualizing = True
		# self.win = vs.window(width=self.display_width, height=self.display_height, title='')
		# self.scene = vs.display(window=self.win, width=self.display_width, height=self.display_height)
		# self.scene.bind('keydown', self.__keyInput__)
		vs.scene.bind('keydown', self.__keyInput__)

		print 'Visualizing model...'
		print '(Modifications are not allowed)'
		print 'Press Esc to stop visualization...'
		while self.visualizing:
			vs.rate(1)
			self.draw()

	def __keyInput__(self, evt):
		s = evt.key
		if s == 'esc':
			print 'You can modify model parameters now...'
			self.visualizing = False;
			# vs.exit()

	def draw(self):
		'''
		This method actually does some drawing in the scene
		'''
		# vs.sphere(pos = (0, 0, 0), radius = self.r, color=self.clr)
		pass