"""Certbot display.

This module (`certbot.display.util`) or its companion `certbot.display.ops`
should be used whenever:

- Displaying status information to the user on the terminal
- Collecting information from the user via prompts

Other messages can use the `logging` module. See `log.py`.

"""
import logging
import sys
import textwrap

import zope.interface
import zope.component

from acme.magic_typing import List
from certbot import errors
from certbot import interfaces
from certbot._internal import constants
from certbot._internal.display import completer
from certbot.compat import misc
from certbot.compat import os

logger = logging.getLogger(__name__)

WIDTH = 72

# Display exit codes
OK = "ok"
"""Display exit code indicating user acceptance."""

CANCEL = "cancel"
"""Display exit code for a user canceling the display."""

HELP = "help"
"""Display exit code when for when the user requests more help. (UNUSED)"""

ESC = "esc"
"""Display exit code when the user hits Escape (UNUSED)"""

# Display constants
SIDE_FRAME = ("- " * 39) + "-"
"""Display boundary (alternates spaces, so when copy-pasted, markdown doesn't interpret
it as a heading)"""

def _wrap_lines(msg):
    """Format lines nicely to 80 chars.

    :param str msg: Original message

    :returns: Formatted message respecting newlines in message
    :rtype: str

    """
    lines = msg.splitlines()
    fixed_l = []

    for line in lines:
        fixed_l.append(textwrap.fill(
            line,
            80,
            break_long_words=False,
            break_on_hyphens=False))

    return '\n'.join(fixed_l)


def input_with_timeout(prompt=None, timeout=36000.0):
    """Get user input with a timeout.

    Behaves the same as six.moves.input, however, an error is raised if
    a user doesn't answer after timeout seconds. The default timeout
    value was chosen to place it just under 12 hours for users following
    our advice and running Certbot twice a day.

    :param str prompt: prompt to provide for input
    :param float timeout: maximum number of seconds to wait for input

    :returns: user response
    :rtype: str

    :raises errors.Error if no answer is given before the timeout

    """
    # use of sys.stdin and sys.stdout to mimic six.moves.input based on
    # https://github.com/python/cpython/blob/baf7bb30a02aabde260143136bdf5b3738a1d409/Lib/getpass.py#L129
    if prompt:
        sys.stdout.write(prompt)
        sys.stdout.flush()

    line = misc.readline_with_timeout(timeout, prompt)

    if not line:
        raise EOFError
    return line.rstrip('\n')


def notify(msg):
    # type: (str) -> None
    """Display a basic status message.

    :param str msg: message to display

    """
    zope.component.getUtility(interfaces.IDisplay).notification(
        msg, pause=False, decorate=False, wrap=False
    )


@zope.interface.implementer(interfaces.IDisplay)
class FileDisplay(object):
    """File-based display."""
    # see https://github.com/certbot/certbot/issues/3915

    def __init__(self, outfile, force_interactive):
        super(FileDisplay, self).__init__()
        self.outfile = outfile
        self.force_interactive = force_interactive
        self.skipped_interaction = False

    def notification(self, message, pause=True,
                     wrap=True, force_interactive=False,
                     decorate=True):
        """Displays a notification and waits for user acceptance.

        :param str message: Message to display
        :param bool pause: Whether or not the program should pause for the
            user's confirmation
        :param bool wrap: Whether or not the application should wrap text
        :param bool force_interactive: True if it's safe to prompt the user
            because it won't cause any workflow regressions
        :param bool decorate: Whether to surround the message with a
            decorated frame

        """
        if wrap:
            message = _wrap_lines(message)

        logger.debug("Notifying user: %s", message)

        self.outfile.write(
            (("{line}{frame}{line}" if decorate else "") +
             "{msg}{line}" +
             ("{frame}{line}" if decorate else ""))
            .format(line=os.linesep, frame=SIDE_FRAME, msg=message)
        )
        self.outfile.flush()

        if pause:
            if self._can_interact(force_interactive):
                input_with_timeout("Press Enter to Continue")
            else:
                logger.debug("Not pausing for user confirmation")

    def menu(self, message, choices, ok_label=None, cancel_label=None,  # pylint: disable=unused-argument
             help_label=None, default=None,  # pylint: disable=unused-argument
             cli_flag=None, force_interactive=False, **unused_kwargs):
        """Display a menu.

        .. todo:: This doesn't enable the help label/button (I wasn't sold on
           any interface I came up with for this). It would be a nice feature

        :param str message: title of menu
        :param choices: Menu lines, len must be > 0
        :type choices: list of tuples (tag, item) or
            list of descriptions (tags will be enumerated)
        :param default: default value to return (if one exists)
        :param str cli_flag: option used to set this value with the CLI
        :param bool force_interactive: True if it's safe to prompt the user
            because it won't cause any workflow regressions

        :returns: tuple of (`code`, `index`) where
            `code` - str display exit code
            `index` - int index of the user's selection

        :rtype: tuple

        """
        if self._return_default(message, default, cli_flag, force_interactive):
            return OK, default

        self._print_menu(message, choices)

        code, selection = self._get_valid_int_ans(len(choices))

        return code, selection - 1

    def input(self, message, default=None,
              cli_flag=None, force_interactive=False, **unused_kwargs):
        """Accept input from the user.

        :param str message: message to display to the user
        :param default: default value to return (if one exists)
        :param str cli_flag: option used to set this value with the CLI
        :param bool force_interactive: True if it's safe to prompt the user
            because it won't cause any workflow regressions

        :returns: tuple of (`code`, `input`) where
            `code` - str display exit code
            `input` - str of the user's input
        :rtype: tuple

        """
        if self._return_default(message, default, cli_flag, force_interactive):
            return OK, default

        # Trailing space must be added outside of _wrap_lines to be preserved
        message = _wrap_lines("%s (Enter 'c' to cancel):" % message) + " "
        ans = input_with_timeout(message)

        if ans in ("c", "C"):
            return CANCEL, "-1"
        return OK, ans

    def yesno(self, message, yes_label="Yes", no_label="No", default=None,
              cli_flag=None, force_interactive=False, **unused_kwargs):
        """Query the user with a yes/no question.

        Yes and No label must begin with different letters, and must contain at
        least one letter each.

        :param str message: question for the user
        :param str yes_label: Label of the "Yes" parameter
        :param str no_label: Label of the "No" parameter
        :param default: default value to return (if one exists)
        :param str cli_flag: option used to set this value with the CLI
        :param bool force_interactive: True if it's safe to prompt the user
            because it won't cause any workflow regressions

        :returns: True for "Yes", False for "No"
        :rtype: bool

        """
        if self._return_default(message, default, cli_flag, force_interactive):
            return default

        message = _wrap_lines(message)

        self.outfile.write("{0}{frame}{msg}{0}{frame}".format(
            os.linesep, frame=SIDE_FRAME + os.linesep, msg=message))
        self.outfile.flush()

        while True:
            ans = input_with_timeout("{yes}/{no}: ".format(
                yes=_parens_around_char(yes_label),
                no=_parens_around_char(no_label)))

            # Couldn't get pylint indentation right with elif
            # elif doesn't matter in this situation
            if (ans.startswith(yes_label[0].lower()) or
                    ans.startswith(yes_label[0].upper())):
                return True
            if (ans.startswith(no_label[0].lower()) or
                    ans.startswith(no_label[0].upper())):
                return False

    def checklist(self, message, tags, default=None,
                  cli_flag=None, force_interactive=False, **unused_kwargs):
        """Display a checklist.

        :param str message: Message to display to user
        :param list tags: `str` tags to select, len(tags) > 0
        :param default: default value to return (if one exists)
        :param str cli_flag: option used to set this value with the CLI
        :param bool force_interactive: True if it's safe to prompt the user
            because it won't cause any workflow regressions

        :returns: tuple of (`code`, `tags`) where
            `code` - str display exit code
            `tags` - list of selected tags
        :rtype: tuple

        """
        if self._return_default(message, default, cli_flag, force_interactive):
            return OK, default

        while True:
            self._print_menu(message, tags)

            code, ans = self.input("Select the appropriate numbers separated "
                                   "by commas and/or spaces, or leave input "
                                   "blank to select all options shown",
                                   force_interactive=True)

            if code == OK:
                if not ans.strip():
                    ans = " ".join(str(x) for x in range(1, len(tags)+1))
                indices = separate_list_input(ans)
                selected_tags = self._scrub_checklist_input(indices, tags)
                if selected_tags:
                    return code, selected_tags
                self.outfile.write(
                    "** Error - Invalid selection **%s" % os.linesep)
                self.outfile.flush()
            else:
                return code, []

    def _return_default(self, prompt, default, cli_flag, force_interactive):
        """Should we return the default instead of prompting the user?

        :param str prompt: prompt for the user
        :param default: default answer to prompt
        :param str cli_flag: command line option for setting an answer
            to this question
        :param bool force_interactive: if interactivity is forced by the
            IDisplay call

        :returns: True if we should return the default without prompting
        :rtype: bool

        """
        # assert_valid_call(prompt, default, cli_flag, force_interactive)
        if self._can_interact(force_interactive):
            return False
        if default is None:
            msg = "Unable to get an answer for the question:\n{0}".format(prompt)
            if cli_flag:
                msg += (
                    "\nYou can provide an answer on the "
                    "command line with the {0} flag.".format(cli_flag))
            raise errors.Error(msg)
        logger.debug(
            "Falling back to default %s for the prompt:\n%s",
            default, prompt)
        return True

    def _can_interact(self, force_interactive):
        """Can we safely interact with the user?

        :param bool force_interactive: if interactivity is forced by the
            IDisplay call

        :returns: True if the display can interact with the user
        :rtype: bool

        """
        if (self.force_interactive or force_interactive or
                sys.stdin.isatty() and self.outfile.isatty()):
            return True
        if not self.skipped_interaction:
            logger.warning(
                "Skipped user interaction because Certbot doesn't appear to "
                "be running in a terminal. You should probably include "
                "--non-interactive or %s on the command line.",
                constants.FORCE_INTERACTIVE_FLAG)
            self.skipped_interaction = True
        return False

    def directory_select(self, message, default=None, cli_flag=None,
                         force_interactive=False, **unused_kwargs):
        """Display a directory selection screen.

        :param str message: prompt to give the user
        :param default: default value to return (if one exists)
        :param str cli_flag: option used to set this value with the CLI
        :param bool force_interactive: True if it's safe to prompt the user
            because it won't cause any workflow regressions

        :returns: tuple of the form (`code`, `string`) where
            `code` - display exit code
            `string` - input entered by the user

        """
        with completer.Completer():
            return self.input(message, default, cli_flag, force_interactive)

    def _scrub_checklist_input(self, indices, tags):
        """Validate input and transform indices to appropriate tags.

        :param list indices: input
        :param list tags: Original tags of the checklist

        :returns: valid tags the user selected
        :rtype: :class:`list` of :class:`str`

        """
        # They should all be of type int
        try:
            indices = [int(index) for index in indices]
        except ValueError:
            return []

        # Remove duplicates
        indices = list(set(indices))

        # Check all input is within range
        for index in indices:
            if index < 1 or index > len(tags):
                return []
        # Transform indices to appropriate tags
        return [tags[index - 1] for index in indices]

    def _print_menu(self, message, choices):
        """Print a menu on the screen.

        :param str message: title of menu
        :param choices: Menu lines
        :type choices: list of tuples (tag, item) or
            list of descriptions (tags will be enumerated)

        """
        # Can take either tuples or single items in choices list
        if choices and isinstance(choices[0], tuple):
            choices = ["%s - %s" % (c[0], c[1]) for c in choices]

        # Write out the message to the user
        self.outfile.write(
            "{new}{msg}{new}".format(new=os.linesep, msg=message))
        self.outfile.write(SIDE_FRAME + os.linesep)

        # Write out the menu choices
        for i, desc in enumerate(choices, 1):
            msg = "{num}: {desc}".format(num=i, desc=desc)
            self.outfile.write(_wrap_lines(msg))

            # Keep this outside of the textwrap
            self.outfile.write(os.linesep)

        self.outfile.write(SIDE_FRAME + os.linesep)
        self.outfile.flush()

    def _get_valid_int_ans(self, max_):
        """Get a numerical selection.

        :param int max: The maximum entry (len of choices), must be positive

        :returns: tuple of the form (`code`, `selection`) where
            `code` - str display exit code ('ok' or cancel')
            `selection` - int user's selection
        :rtype: tuple

        """
        selection = -1
        if max_ > 1:
            input_msg = ("Select the appropriate number "
                         "[1-{max_}] then [enter] (press 'c' to "
                         "cancel): ".format(max_=max_))
        else:
            input_msg = ("Press 1 [enter] to confirm the selection "
                         "(press 'c' to cancel): ")
        while selection < 1:
            ans = input_with_timeout(input_msg)
            if ans.startswith("c") or ans.startswith("C"):
                return CANCEL, -1
            try:
                selection = int(ans)
                if selection < 1 or selection > max_:
                    selection = -1
                    raise ValueError

            except ValueError:
                self.outfile.write(
                    "{0}** Invalid input **{0}".format(os.linesep))
                self.outfile.flush()

        return OK, selection


def assert_valid_call(prompt, default, cli_flag, force_interactive):
    """Verify that provided arguments is a valid IDisplay call.

    :param str prompt: prompt for the user
    :param default: default answer to prompt
    :param str cli_flag: command line option for setting an answer
        to this question
    :param bool force_interactive: if interactivity is forced by the
        IDisplay call

    """
    msg = "Invalid IDisplay call for this prompt:\n{0}".format(prompt)
    if cli_flag:
        msg += ("\nYou can set an answer to "
                "this prompt with the {0} flag".format(cli_flag))
    assert default is not None or force_interactive, msg


@zope.interface.implementer(interfaces.IDisplay)
class NoninteractiveDisplay(object):
    """An iDisplay implementation that never asks for interactive user input"""

    def __init__(self, outfile, *unused_args, **unused_kwargs):
        super(NoninteractiveDisplay, self).__init__()
        self.outfile = outfile

    def _interaction_fail(self, message, cli_flag, extra=""):
        "Error out in case of an attempt to interact in noninteractive mode"
        msg = "Missing command line flag or config entry for this setting:\n"
        msg += message
        if extra:
            msg += "\n" + extra
        if cli_flag:
            msg += "\n\n(You can set this with the {0} flag)".format(cli_flag)
        raise errors.MissingCommandlineFlag(msg)

    def notification(self, message, pause=False, wrap=True, decorate=True, **unused_kwargs):  # pylint: disable=unused-argument
        """Displays a notification without waiting for user acceptance.

        :param str message: Message to display to stdout
        :param bool pause: The NoninteractiveDisplay waits for no keyboard
        :param bool wrap: Whether or not the application should wrap text
        :param bool decorate: Whether to apply a decorated frame to the message

        """
        if wrap:
            message = _wrap_lines(message)

        logger.debug("Notifying user: %s", message)

        self.outfile.write(
            (("{line}{frame}{line}" if decorate else "") +
             "{msg}{line}" +
             ("{frame}{line}" if decorate else ""))
            .format(line=os.linesep, frame=SIDE_FRAME, msg=message)
        )
        self.outfile.flush()

    def menu(self, message, choices, ok_label=None, cancel_label=None,
             help_label=None, default=None, cli_flag=None, **unused_kwargs):
        # pylint: disable=unused-argument
        """Avoid displaying a menu.

        :param str message: title of menu
        :param choices: Menu lines, len must be > 0
        :type choices: list of tuples (tag, item) or
            list of descriptions (tags will be enumerated)
        :param int default: the default choice
        :param dict kwargs: absorbs various irrelevant labelling arguments

        :returns: tuple of (`code`, `index`) where
            `code` - str display exit code
            `index` - int index of the user's selection
        :rtype: tuple
        :raises errors.MissingCommandlineFlag: if there was no default

        """
        if default is None:
            self._interaction_fail(message, cli_flag, "Choices: " + repr(choices))

        return OK, default

    def input(self, message, default=None, cli_flag=None, **unused_kwargs):
        """Accept input from the user.

        :param str message: message to display to the user

        :returns: tuple of (`code`, `input`) where
            `code` - str display exit code
            `input` - str of the user's input
        :rtype: tuple
        :raises errors.MissingCommandlineFlag: if there was no default

        """
        if default is None:
            self._interaction_fail(message, cli_flag)
        return OK, default

    def yesno(self, message, yes_label=None, no_label=None,  # pylint: disable=unused-argument
              default=None, cli_flag=None, **unused_kwargs):
        """Decide Yes or No, without asking anybody

        :param str message: question for the user
        :param dict kwargs: absorbs yes_label, no_label

        :raises errors.MissingCommandlineFlag: if there was no default
        :returns: True for "Yes", False for "No"
        :rtype: bool

        """
        if default is None:
            self._interaction_fail(message, cli_flag)
        return default

    def checklist(self, message, tags, default=None,
                  cli_flag=None, **unused_kwargs):
        """Display a checklist.

        :param str message: Message to display to user
        :param list tags: `str` tags to select, len(tags) > 0
        :param dict kwargs: absorbs default_status arg

        :returns: tuple of (`code`, `tags`) where
            `code` - str display exit code
            `tags` - list of selected tags
        :rtype: tuple

        """
        if default is None:
            self._interaction_fail(message, cli_flag, "? ".join(tags))
        return OK, default

    def directory_select(self, message, default=None,
                         cli_flag=None, **unused_kwargs):
        """Simulate prompting the user for a directory.

        This function returns default if it is not ``None``, otherwise,
        an exception is raised explaining the problem. If cli_flag is
        not ``None``, the error message will include the flag that can
        be used to set this value with the CLI.

        :param str message: prompt to give the user
        :param default: default value to return (if one exists)
        :param str cli_flag: option used to set this value with the CLI

        :returns: tuple of the form (`code`, `string`) where
            `code` - int display exit code
            `string` - input entered by the user

        """
        return self.input(message, default, cli_flag)


def separate_list_input(input_):
    """Separate a comma or space separated list.

    :param str input_: input from the user

    :returns: strings
    :rtype: list

    """
    no_commas = input_.replace(",", " ")
    # Each string is naturally unicode, this causes problems with M2Crypto SANs
    # TODO: check if above is still true when M2Crypto is gone ^
    return [str(string) for string in no_commas.split()]


def _parens_around_char(label):
    """Place parens around first character of label.

    :param str label: Must contain at least one character

    """
    return "({first}){rest}".format(first=label[0], rest=label[1:])


def summarize_domain_list(domains):
    # type: (List[str]) -> str
    """Summarizes a list of domains in the format of:
        example.com.com and N more domains
    or if there is are only two domains:
        example.com and www.example.com
    or if there is only one domain:
        example.com

    :param list domains: `str` list of domains
    :returns: the domain list summary
    :rtype: str
    """
    if not domains:
        return ""

    l = len(domains)
    if l == 1:
        return domains[0]
    elif l == 2:
        return " and ".join(domains)
    else:
        return "{0} and {1} more domains".format(domains[0], l-1)
