# -*- coding: UTF-8 -*-
# Copyright (c) 2010, Pascal Volk
# See COPYING for distribution information.

"""
    VirtualMailManager.cli
    ~~~~~~~~~~~~~~~~~~~~~~

    VirtualMailManager's command line interface.
"""

import os
from array import array
from cStringIO import StringIO
from fcntl import ioctl
from getpass import getpass
from termios import TIOCGWINSZ

from VirtualMailManager import ENCODING
from VirtualMailManager.constants.ERROR import VMM_TOO_MANY_FAILURES
from VirtualMailManager.errors import VMMError


__all__ = ('get_winsize', 'read_pass', 'string_io', 'w_err', 'w_std')

_ = lambda msg: msg
_std_write = os.sys.stdout.write
_err_write = os.sys.stderr.write


def w_std(*args):
    """Writes a line for each arg of *args*, encoded in the current
    ENCODING, to stdout.
    """
    _std_write('\n'.join(a.encode(ENCODING, 'replace') for a in args) + '\n')


def w_err(code, *args):
    """Writes a line for each arg of *args*, encoded in the current
    ENCODING, to stderr.
    This function optionally interrupts the program execution if *code*
    does not equal to 0. *code* will be used as the system exit status.
    """
    _err_write('\n'.join(a.encode(ENCODING, 'replace') for a in args) + '\n')
    if code:
        os.sys.exit(code)


def get_winsize():
    """Returns a tuple of integers ``(ws_row, ws_col)`` with the height and
    width of the terminal."""
    fd = None
    for dev in (os.sys.stdout, os.sys.stderr, os.sys.stdin):
        if hasattr(dev, 'fileno') and os.isatty(dev.fileno()):
            fd = dev.fileno()
            break
    if fd is None:  # everything seems to be redirected
        # fall back to environment or assume some common defaults
        ws_row, ws_col = 24, 80
        try:
            ws_col = int(os.environ.get('COLUMNS', 80))
            ws_row = int(os.environ.get('LINES', 24))
        except ValueError:
            pass
        return ws_row, ws_col
    #"struct winsize" with the ``unsigned short int``s ws_{row,col,{x,y}pixel}
    ws = array('H', (0, 0, 0, 0))
    ioctl(fd, TIOCGWINSZ, ws, True)
    ws_row, ws_col = ws[:2]
    return ws_row, ws_col


def read_pass():
    """Interactive 'password chat', returns the password in plain format.

    Throws a VMMError after the third failure.
    """
    # TP: Please preserve the trailing space.
    readp_msg0 = _(u'Enter new password: ').encode(ENCODING, 'replace')
    # TP: Please preserve the trailing space.
    readp_msg1 = _(u'Retype new password: ').encode(ENCODING, 'replace')
    mismatched = True
    failures = 0
    while mismatched:
        if failures > 2:
            raise VMMError(_(u'Too many failures - try again later.'),
                           VMM_TOO_MANY_FAILURES)
        clear0 = getpass(prompt=readp_msg0)
        clear1 = getpass(prompt=readp_msg1)
        if clear0 != clear1:
            failures += 1
            w_err(0, _(u'Sorry, passwords do not match'))
            continue
        if not clear0:
            failures += 1
            w_err(0, _(u'Sorry, empty passwords are not permitted'))
            continue
        mismatched = False
    return clear0


def string_io():
    """Returns a new `cStringIO.StringIO` instance."""
    return StringIO()

del _