GLIDER = [[False, False, False, False, False, False, False, False],
          [False, False, False, False, True, False, False, False],
          [False, False, True, False, True, False, False, False],
          [False, False, False, True, True, False, False, False],
          [False, False, False, False, False, False, False, False],
          [False, False, False, False, False, False, False, False],
          [False, False, False, False, False, False, False, False],
          [False, False, False, False, False, False, False, False]]

OFF = (0, 0, 0)
ON = (100, 100, 80)

def draw_universe(trellis, universe):
    for x in range(8):
        for y in range(8):
            #activate rising edge events on all keys
            if universe[x][y]:
                trellis.color(x, y, ON)
            else:
                trellis.color(x, y, OFF)


def extend_universe(universe):
    """Extend an 8x8 universe to 10x10 with first and last columns and rows as in an donut-shaped universe"""
    ext_universe = [[False for x_ext in range(10)] for y_ext in range(10)]

    # Copy universe in an extended donut-shaped universe
    for x_ext in range(10):
        for y_ext in range(10):
            if x_ext == 0:
                loc_x = 7
            elif x_ext == 9:
                loc_x = 0
            else:
                loc_x = x_ext-1
            if y_ext == 0:
                loc_y = 7
            elif y_ext == 9:
                loc_y = 0
            else:
                loc_y = y_ext-1

            ext_universe[x_ext][y_ext] = universe[loc_x][loc_y]
    return ext_universe


def living_neighbour_count(xcoord, ycoord, ext_universe):
    """Count living cells around xcoord, ycoord"""

    living_neighbours = []
    living_neighbours.append(ext_universe[xcoord][ycoord])
    living_neighbours.append(ext_universe[xcoord][ycoord+1])
    living_neighbours.append(ext_universe[xcoord][ycoord+2])
    living_neighbours.append(ext_universe[xcoord+1][ycoord])
    living_neighbours.append(ext_universe[xcoord+1][ycoord+2])
    living_neighbours.append(ext_universe[xcoord+2][ycoord])
    living_neighbours.append(ext_universe[xcoord+2][ycoord+1])
    living_neighbours.append(ext_universe[xcoord+2][ycoord+2])
    # print(living_neighbours.count(True), living_neighbours)
    return living_neighbours.count(True)