import os

#
# getch in a platform-independent way
# Credit: http://code.activestate.com/recipes/134892/
#
class _Getch:
    """Gets a single character from standard input.  Does not echo to the
    screen."""
    def __init__(self):
        try:
            self.impl = _GetchWindows()
        except ImportError:
            try:
                self.impl = _GetchMacCarbon()
            except(AttributeError, ImportError):
                self.impl = _GetchUnix()

    def __call__(self): return self.impl()


class _GetchUnix:
    def __init__(self):
        import tty, sys

    def __call__(self):
        import sys, tty, termios
        fd = sys.stdin.fileno()
        old_settings = termios.tcgetattr(fd)
        try:
            tty.setraw(sys.stdin.fileno())
            ch = sys.stdin.read(1)
        finally:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
        return ch

class _GetchWindows:
    def __init__(self):
        import msvcrt
    def __call__(self):
        import msvcrt
        return msvcrt.getch()

class _GetchMacCarbon:
    def __init__(self):
        import Carbon

    def __call__(self):
        import Carbon
        if Carbon.Evt.EventAvail(0x0008)[0]==0: # 0x0008 is the keyDownMask
            return ''
        else:
            (what,msg,when,where,mod)=Carbon.Evt.GetNextEvent(0x0008)[1]
            return chr(msg & 0x000000FF)

getch = _Getch()

def cls():
    os.system(['clear','cls'][os.name == 'nt'])


interactive = True
def get_input():
    global interactive
    if not interactive:
        return True

    while True:
        key = ord(getch())
        if key == 32: # space bar
            return True
        elif key == 27: # ESC
            interactive = False
            return True