import sys as _sys
from .console import Fore as fg

DISABLE_PROMPT = None
"""Whenever a prompt occurs and this value is not ``None`` it can be ``exit``
to call sys.exit (see EXIT_STATUS) or ``raise`` to throw a RuntimeError,
which can be caught if desired."""

EXIT_STATUS = 2

BOOL_TRUE_RESPONSES = ("yes", "y", "true")


class PromptExit(RuntimeError):
    """Raised when ``DISABLE_PROMPT`` is 'raise' and ``prompt`` is called."""
    pass


def parseIntList(resp):
    ints = set()
    resp = resp.replace(',', ' ')
    for c in resp.split():
        i = int(c)
        ints.add(i)
    return list(ints)


def prompt(msg, default=None, required=True, type_=str,
           validate=None, choices=None):
    """Prompt user for input, the prequest is in ``msg``. If ``default`` is
    not ``None`` it will be displayed as the default and returned if not
    input is entered. The value ``None`` is only returned if ``required`` is
    ``False``. The response is passed to ``type_`` for conversion (default
    is unicode) before being returned. An optional list of valid responses can
    be provided in ``choices``."""
    yes_no_prompt = default is True or default is False

    if yes_no_prompt:
        default_str = "Yn" if default is True else "yN"
    else:
        default_str = str(default) if default else None

    if default is not None:
        msg = "%s [%s]" % (msg, default_str)
    msg += ": " if not yes_no_prompt else "? "

    if DISABLE_PROMPT:
        if DISABLE_PROMPT == "exit":
            print(msg + "\nPrompting is disabled, exiting.")
            _sys.exit(EXIT_STATUS)
        else:
            raise PromptExit(msg)

    resp = None
    while resp is None:

        try:
            resp = input(msg)
        except EOFError:
            # Converting this allows main functions to catch without
            # catching other eofs
            raise PromptExit()

        if not resp and default not in (None, ""):
            resp = str(default)

        if resp:
            if yes_no_prompt:
                resp = True if resp.lower() in BOOL_TRUE_RESPONSES else False
            else:
                resp = resp.strip()
                try:
                    resp = type_(resp)
                except Exception as ex:
                    print(fg.red(str(ex)))
                    resp = None
        elif not required:
            return None
        else:
            resp = None

        if ((choices and resp not in choices) or
                (validate and not validate(resp))):
            if choices:
                print(fg.red("Invalid response, choose from: ") + str(choices))
            else:
                print(fg.red("Invalid response"))
            resp = None

    return resp
