field = {}
field[(0, 0)] = 1

x = 0
y = 0

# Start in an upward facing position (index 0)
# Turning left will move the index left, turning right will move the index right (wrapping around in both cases)
dir_vectors = [(0, 1), (1, 0), (0, -1), (-1, 0)]
dir_idx = 0

class IntcodeComputerFieldInput:

    def read(self):
        color = field.get((x, y))
        if color is None:
            return 0
        else:
            return color


class IntcodeComputerFieldOutput:

    def __init__(self):
        # Store partial instruction
        self.color = None

    def write(self, output):
        if self.color is None:
            self.color = output
        else:
            global x, y, dir_idx

            # Paint the square
            field[(x, y)] = self.color

            # Turn and move
            # 0 is left, 1 is right
            if output == 0:
                dir_idx = (dir_idx - 1) % 4
            elif output == 1:
                dir_idx = (dir_idx + 1) % 4
            else:
                raise Exception("Unknown direction code: {}".format(output))

            x += dir_vectors[dir_idx][0]
            y += dir_vectors[dir_idx][1]

            # That finishes the two part instruction
            self.color = None