Source code for tea.console.utils

__author__ = 'Viktor Kerkez <alefnula@gmail.com>'
__date__ = '20 October 2010'
__copyright__ = 'Copyright (c) 2010 Viktor Kerkez'

import os
from tea.system import platform

if platform.is_a(platform.WINDOWS | platform.DOTNET):
    import msvcrt

    def _clear_screen(numlines):
        os.system('cls')

    _getch = msvcrt.getch

elif platform.is_a(platform.POSIX):
    import sys

    def _clear_screen(numlines):
        os.system('clear')

    def _getch():
        import tty
        import 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
else:
    raise platform.not_supported('tea.console.utils')


def clear_screen(numlines=100):
    """Clear the console.

    :param int numlines: This is an optional argument used only as a fall-back
        if the operating system console doesn't have clear screen function.
    :rtype: None
    """
    _clear_screen(numlines)


def getch():
    """Cross-platform getch() function.

    Same as the getch function from msvcrt library, but works on all platforms.
    :rtype:  str
    :return: One character got from standard input.
    """
    return _getch()