import enum
import pyglet
import random
import rectangulararray

field_width = 60
field_height = 20
max_level = 2
field = rectangulararray.RectangularArray((field_width, field_height), default = int(max_level / 2))

do_update = True
run_simulation = True

def update(dt):
	if not do_update or not run_simulation:
		return

	deltas = rectangulararray.RectangularArray((field_width, field_height), default = 0)

	# Calculate deltas
	for y in range(field_height):
		for x in range(field_width):
			# First drop down
			if (y + 1) in range(field_height) and field[x, y + 1] < max_level:
				change = min(field[x, y] + deltas [x, y], max_level - field[x, y + 1] - deltas[x, y + 1])
				deltas[x, y] -= change
				deltas[x, y + 1] += change

			# Then see if any side-neighbour is lower than us
			left_lower = (x - 1) in range(field_width) and field[x - 1, y] < field[x, y]
			right_lower = (x + 1) in range(field_width) and field[x + 1, y] < field[x, y]

			# Move to lower side, or if both have same level, randomly
			move_left = False
			move_right = False
			if left_lower and not right_lower:
				move_left = True
			elif not left_lower and right_lower:
				move_right = True
			elif left_lower and right_lower:
				left_value = field[x - 1, y]
				right_value = field[x + 1, y]
				move_left = left_value < right_value
				move_right = left_value > right_value

				if not move_left and not move_right:
					move_left = random.randint(0, 1) == 0
					move_right = not move_left

			assert(not (move_left and move_right))

			if move_left:
				change = min(int((field[x, y] + deltas [x, y]) / 2), max_level - field[x - 1, y] - deltas[x - 1, y])
				deltas[x, y] -= change
				deltas[x - 1, y] += change
			elif move_right:
				change = min(int((field[x, y] + deltas [x, y]) / 2), max_level - field[x + 1, y] - deltas[x + 1, y])
				deltas[x, y] -= change
				deltas[x + 1, y] += change
	
	# Apply deltas
	for y in range(field_height):
		for x in range(field_width):
			field[x, y] += deltas[x, y]

window_width = field_width * (max_level * 7 + 1) + 1
window_height = field_height * (max_level * 7 + 1) + 1
window = pyglet.window.Window(window_width, window_height, resizable = True)

pyglet.clock.schedule_interval(update, 1/4)

def get_cell(x, y):
	y = window_height - y - 1
	cell_x = int((x - 1) * field_width / window_width)
	cell_y = int((y - 1) * field_height / window_height)
	return cell_x, cell_y

@window.event
def on_mouse_press(x, y, button, modifiers):
	global do_update

	assert(0 < x <= window_width)
	assert(0 < y <= window_height)

	if button == pyglet.window.mouse.LEFT:
		cell_x, cell_y = get_cell(x, y)
		field[cell_x, cell_y] = max_level
		do_update = False

	elif button == pyglet.window.mouse.RIGHT:
		cell_x, cell_y = get_cell(x, y)
		field[cell_x, cell_y] = 0
		do_update = False

@window.event
def on_key_press(symbol, modifiers):
	global run_simulation
	if symbol == pyglet.window.key.SPACE:
		run_simulation = not run_simulation

def scale_h(x):
	return int(x * (window_width - 1) / field_width)

def scale_v(y):
	return int(y * (window_height - 1) / field_height)

def draw_cell(coordinates):
	x1, y1, x2, y2 = coordinates
	color = (127, 127, 255)
	# Tranform coordinates from the internal top-left origin to OpenGL's bottom-left origin
	y1 = window_height - y1 - 1
	y2 = window_height - y2 - 1
	pyglet.graphics.draw(4, pyglet.gl.GL_QUADS, ('v2i', (x1, y1, x2, y1, x2, y2, x1, y2)), ('c3B', 4*color))

def get_coordinates(x, y, level):
	assert(0 <= x <= field_width)
	assert(0 <= y <= field_height)
	assert(0 <= level <= max_level)
	screen_x1 = scale_h(x) + 1
	screen_y1 = scale_v(y) + 1
	screen_y1 += int((max_level - level) / max_level * ((window_height - 1) / field_height - 1))
	screen_x2 = scale_h(x + 1)
	screen_y2 = scale_v(y + 1)
	return (screen_x1, screen_y1, screen_x2, screen_y2)

@window.event
def on_draw():
	global do_update
	window.clear()
	for y in range(field_height):
		for x in range(field_width):
			coordinates = get_coordinates(x, y, field[x, y])
			draw_cell(coordinates)

	do_update = True

@window.event
def on_resize(width, height):
	global window_width, window_height
	window_width, window_height =  width, height

pyglet.app.run()