# Python 2.7.7 Code
# Jonathan Frech 7th of September, 2016
#         edited 8th of September, 2016
#         edited 9th of September, 2016

# import
import curses, random, time

# set the cursor's visibility (sometimes does not work on Mac OS)
def curs_set(bool):
	try:
		curses.curs_set(bool)
	except:
		pass

# add a string at (y, x) with color on scr without any errors
def addstr(scr, y, x, string, color = 0):
	my, mx = scr.getmaxyx()
	if y >= 0 and x >= 0 and y < my and x < mx and not (x == mx-1 and y == my-1):
		scr.addstr(y, x, string, color)

# init
def init():
	global scr, t, my, mx
	
	# screem
	scr = curses.initscr()
	scr.keypad(True)
	scr.nodelay(True)
	
	# curses
	curses.noecho()
	curses.cbreak()
	curs_set(False)
	curses.start_color()
	curses.use_default_colors()
	
	# color used
	#curses.init_pair(1, curses.COLOR_CYAN, curses.COLOR_BLACK)
	curses.init_pair(1, curses.COLOR_GREEN, curses.COLOR_BLACK)
	
	# screen size
	my, mx = scr.getmaxyx()
		
	# ticks
	t = 0

# run
def run():
	global scr, seed, t, my, mx
	
	# init
	init()
	
	# strips
	strips = [strip() for _ in range(0, 100)]
	
	# while loop
	while True:
		# render strips
		for s in strips:
			s.render()
			
			# new strip
			if s.out:
				strips.remove(s)
				strips.append(strip(top = True))
		
		# get char (nodelay mode!)
		c = scr.getch()
		
		# quit
		if c == curses.KEY_F12:
			break
		
		# sleep
		time.sleep(.1)
		
		# handle resizement
		if curses.is_term_resized(my, mx):
			# update screen size
			my, mx = scr.getmaxyx()
			
			# reset
			strips = [strip() for _ in range(0, 100)]
			
			# clear
			scr.clear()
				
		# one more tick
		t += 1
	
	# cleanup
	cleanup()

# cleanup
def cleanup():
	curses.echo()
	curses.nocbreak()
	curs_set(True)
	curses.endwin()

# get a random character (string with lengh one)
def char():
	#s = "+-*%/&"
	s = "01"
	return s[random.randint(0, len(s)-1)]

# strip class
class strip():
	# init
	def __init__(self, top = False):
		global scr
		
		# defin pos, length and speed
		my, mx = scr.getmaxyx()
		self.pos = [random.randint(0, my-2), random.randint(0, mx-1)]
		self.length = random.randint(3, 10)
		if top:
			self.pos[0] = -self.length
		self.speed = random.randint(1, 5)
		
		# outside screen?
		self.out = False
		
	# render
	def render(self):
		global scr
		
		# render individual chars
		for Y in range(-1, self.length):
			y, x = self.pos[0]+Y, self.pos[1]
			addstr(scr, y, x, [char(), " "][Y == -1], curses.color_pair(1))
		
		# screen size
		my, mx = scr.getmaxyx()
		
		# move down
		if t % self.speed == 0:
			self.pos[0] += 1
			if self.pos[0] > my or self.pos[1] > mx:
				self.out = True
		
		# move cursor
		scr.move(my-1, mx-1)

# run animation
run()