# Source code for evennia.utils.utils

    # -*- encoding: utf-8 -*-
    """
    General helper functions that don't fit neatly under any given category.

    They provide some useful string and conversion methods that might
    be of use when designing your own game.

    """
    import gc
    import importlib
    import importlib.machinery
    import importlib.util
    import inspect
    import math
    import os
    import random
    import re
    import sys
    import textwrap
    import threading
    import traceback
    import types
    from ast import literal_eval
    from collections import OrderedDict, defaultdict
    from inspect import getmembers, getmodule, getmro, ismodule, trace
    from os.path import join as osjoin
    from unicodedata import east_asian_width

    from django.apps import apps
    from django.conf import settings
    from django.core.exceptions import ValidationError as DjangoValidationError
    from django.core.validators import validate_email as django_validate_email
    from django.utils import timezone
    from django.utils.html import strip_tags
    from django.utils.translation import gettext as _
    from evennia.utils import logger
    from simpleeval import simple_eval
    from twisted.internet import reactor, threads
    from twisted.internet.defer import returnValue  # noqa - used as import target
    from twisted.internet.task import deferLater

    _MULTIMATCH_TEMPLATE = settings.SEARCH_MULTIMATCH_TEMPLATE
    _EVENNIA_DIR = settings.EVENNIA_DIR
    _GAME_DIR = settings.GAME_DIR
    _IS_MAIN_THREAD = threading.current_thread().name == "MainThread"

    ENCODINGS = settings.ENCODINGS

    _TASK_HANDLER = None
    _TICKER_HANDLER = None
    _STRIP_UNSAFE_TOKENS = None

    _GA = object.__getattribute__
    _SA = object.__setattr__
    _DA = object.__delattr__

    def is_iter(obj):
        """
        Checks if an object behaves iterably.

        Args:
            obj (any): Entity to check for iterability.

        Returns:
            is_iterable (bool): If `obj` is iterable or not.

        Notes:
            Strings are *not* accepted as iterable (although they are
            actually iterable), since string iterations are usually not
            what we want to do with a string.

        """
        if isinstance(obj, (str, bytes)):
            return False

        try:
            return iter(obj) and True
        except TypeError:
            return False

    def make_iter(obj):
        """
        Makes sure that the object is always iterable.

        Args:
            obj (any): Object to make iterable.

        Returns:
            iterable (list or iterable): The same object
                passed-through or made iterable.

        """
        return not is_iter(obj) and [obj] or obj

    def wrap(text, width=None, indent=0):
        """
        Safely wrap text to a certain number of characters.

        Args:
            text (str): The text to wrap.
            width (int, optional): The number of characters to wrap to.
            indent (int): How much to indent each line (with whitespace).

        Returns:
            text (str): Properly wrapped text.

        """
        width = width if width else settings.CLIENT_DEFAULT_WIDTH
        if not text:
            return ""
        indent = " " * indent
        return to_str(textwrap.fill(text, width, initial_indent=indent, subsequent_indent=indent))

    # alias - fill
    fill = wrap

    def pad(text, width=None, align="c", fillchar=" "):
        """
        Pads to a given width.

        Args:
            text (str): Text to pad.
            width (int, optional): The width to pad to, in characters.
            align (str, optional): This is one of 'c', 'l' or 'r' (center,
                left or right).
            fillchar (str, optional): The character to fill with.

        Returns:
            text (str): The padded text.

        """
        width = width if width else settings.CLIENT_DEFAULT_WIDTH
        align = align if align in ("c", "l", "r") else "c"
        fillchar = fillchar[0] if fillchar else " "
        if align == "l":
            return text.ljust(width, fillchar)
        elif align == "r":
            return text.rjust(width, fillchar)
        else:
            return text.center(width, fillchar)

    def crop(text, width=None, suffix="[...]"):
        """
        Crop text to a certain width, throwing away text from too-long
        lines.

        Args:
            text (str): Text to crop.
            width (int, optional): Width of line to crop, in characters.
            suffix (str, optional): This is appended to the end of cropped
                lines to show that the line actually continues. Cropping
                will be done so that the suffix will also fit within the
                given width. If width is too small to fit both crop and
                suffix, the suffix will be dropped.

        Returns:
            text (str): The cropped text.

        """
        width = width if width else settings.CLIENT_DEFAULT_WIDTH
        ltext = len(text)
        if ltext <= width:
            return text
        else:
            lsuffix = len(suffix)
            text = text[:width] if lsuffix >= width else "%s%s" % (text[: width - lsuffix], suffix)
            return to_str(text)

    def dedent(text, baseline_index=None, indent=None):
        """
        Safely clean all whitespace at the left of a paragraph.

        Args:
            text (str): The text to dedent.
            baseline_index (int, optional): Which row to use as a 'base'
                for the indentation. Lines will be dedented to this level but
                no further. If None, indent so as to completely deindent the
                least indented text.
            indent (int, optional): If given, force all lines to this indent.
                This bypasses `baseline_index`.

        Returns:
            text (str): Dedented string.

        Notes:
            This is useful for preserving triple-quoted string indentation
            while still shifting it all to be next to the left edge of the
            display.

        """
        if not text:
            return ""
        if indent is not None:
            lines = text.split("\n")
            ind = " " * indent
            indline = "\n" + ind
            return ind + indline.join(line.strip() for line in lines)
        elif baseline_index is None:
            return textwrap.dedent(text)
        else:
            lines = text.split("\n")
            baseline = lines[baseline_index]
            spaceremove = len(baseline) - len(baseline.lstrip(" "))
            return "\n".join(
                line[min(spaceremove, len(line) - len(line.lstrip(" "))) :] for line in lines
            )

    def justify(text, width=None, align="f", indent=0):
        """
        Fully justify a text so that it fits inside `width`. When using
        full justification (default) this will be done by padding between
        words with extra whitespace where necessary. Paragraphs will
        be retained.

        Args:
            text (str): Text to justify.
            width (int, optional): The length of each line, in characters.
            align (str, optional): The alignment, 'l', 'c', 'r' or 'f'
                for left, center, right or full justification respectively.
            indent (int, optional): Number of characters indentation of
                entire justified text block.

        Returns:
            justified (str): The justified and indented block of text.

        """
        width = width if width else settings.CLIENT_DEFAULT_WIDTH

        def _process_line(line):
            """
            helper function that distributes extra spaces between words. The number
            of gaps is nwords - 1 but must be at least 1 for single-word lines. We
            distribute odd spaces randomly to one of the gaps.
            """
            line_rest = width - (wlen + ngaps)
            gap = " "  # minimum gap between words
            if line_rest > 0:
                if align == "l":
                    if line[-1] == "\n\n":
                        line[-1] = " " * (line_rest - 1) + "\n" + " " * width + "\n" + " " * width
                    else:
                        line[-1] += " " * line_rest
                elif align == "r":
                    line[0] = " " * line_rest + line[0]
                elif align == "c":
                    pad = " " * (line_rest // 2)
                    line[0] = pad + line[0]
                    if line[-1] == "\n\n":
                        line[-1] += (
                            pad + " " * (line_rest % 2 - 1) + "\n" + " " * width + "\n" + " " * width
                        )
                    else:
                        line[-1] = line[-1] + pad + " " * (line_rest % 2)
                else:  # align 'f'
                    gap += " " * (line_rest // max(1, ngaps))
                    rest_gap = line_rest % max(1, ngaps)
                    for i in range(rest_gap):
                        line[i] += " "
            elif not any(line):
                return [" " * width]
            return gap.join(line)

        # split into paragraphs and words
        paragraphs = re.split("\n\s*?\n", text, re.MULTILINE)
        words = []
        for ip, paragraph in enumerate(paragraphs):
            if ip > 0:
                words.append(("\n", 0))
            words.extend((word, len(word)) for word in paragraph.split())
        ngaps, wlen, line = 0, 0, []

        lines = []
        while words:
            if not line:
                # start a new line
                word = words.pop(0)
                wlen = word[1]
                line.append(word[0])
            elif (words[0][1] + wlen + ngaps) >= width:
                # next word would exceed word length of line + smallest gaps
                lines.append(_process_line(line))
                ngaps, wlen, line = 0, 0, []
            else:
                # put a new word on the line
                word = words.pop(0)
                line.append(word[0])
                if word[1] == 0:
                    # a new paragraph, process immediately
                    lines.append(_process_line(line))
                    ngaps, wlen, line = 0, 0, []
                else:
                    wlen += word[1]
                    ngaps += 1

        if line:  # catch any line left behind
            lines.append(_process_line(line))
        indentstring = " " * indent
        return "\n".join([indentstring + line for line in lines])

    def columnize(string, columns=2, spacing=4, align="l", width=None):
        """
        Break a string into a number of columns, using as little
        vertical space as possible.

        Args:
            string (str): The string to columnize.
            columns (int, optional): The number of columns to use.
            spacing (int, optional): How much space to have between columns.
            width (int, optional): The max width of the columns.
                Defaults to client's default width.

        Returns:
            columns (str): Text divided into columns.

        Raises:
            RuntimeError: If given invalid values.

        """
        columns = max(1, columns)
        spacing = max(1, spacing)
        width = width if width else settings.CLIENT_DEFAULT_WIDTH

        w_spaces = (columns - 1) * spacing
        w_txt = max(1, width - w_spaces)

        if w_spaces + columns > width:  # require at least 1 char per column
            raise RuntimeError("Width too small to fit columns")

        colwidth = int(w_txt / (1.0 * columns))

        # first make a single column which we then split
        onecol = justify(string, width=colwidth, align=align)
        onecol = onecol.split("\n")

        nrows, dangling = divmod(len(onecol), columns)
        nrows = [nrows + 1 if i < dangling else nrows for i in range(columns)]

        height = max(nrows)
        cols = []
        istart = 0
        for irows in nrows:
            cols.append(onecol[istart : istart + irows])
            istart = istart + irows
        for col in cols:
            if len(col) < height:
                col.append(" " * colwidth)

        sep = " " * spacing
        rows = []
        for irow in range(height):
            rows.append(sep.join(col[irow] for col in cols))

        return "\n".join(rows)

    def iter_to_str(iterable, sep=",", endsep=", and", addquote=False):
        """
        This pretty-formats an iterable list as string output, adding an optional
        alternative separator to the second to last entry.  If `addquote`
        is `True`, the outgoing strings will be surrounded by quotes.

        Args:
            iterable (any): Usually an iterable to print. Each element must be possible to
                present with a string. Note that if this is a generator, it will be
                consumed by this operation.
            sep (str, optional): The string to use as a separator for each item in the iterable.
            endsep (str, optional): The last item separator will be replaced with this value.
            addquote (bool, optional): This will surround all outgoing
                values with double quotes.

        Returns:
            str: The list represented as a string.

        Notes:
            Default is to use 'Oxford comma', like 1, 2, 3, and 4.

        Examples:

            ```python
            >>> iter_to_string([1,2,3], endsep=',')
            '1, 2, 3'
            >>> iter_to_string([1,2,3], endsep='')
            '1, 2 3'
            >>> iter_to_string([1,2,3], ensdep='and')
            '1, 2 and 3'
            >>> iter_to_string([1,2,3], sep=';', endsep=';')
            '1; 2; 3'
            >>> iter_to_string([1,2,3], addquote=True)
            '"1", "2", and "3"'
            ```

        """
        iterable = list(make_iter(iterable))
        if not iterable:
            return ""
        len_iter = len(iterable)

        if addquote:
            iterable = tuple(f'"{val}"' for val in iterable)
        else:
            iterable = tuple(str(val) for val in iterable)

        if endsep.startswith(sep):
            # oxford comma alternative
            endsep = endsep[1:] if len_iter < 3 else endsep
        elif endsep:
            # normal space-separated end separator
            endsep = " " + str(endsep).strip()

        if len_iter == 1:
            return str(iterable[0])
        elif len_iter == 2:
            return f"{endsep} ".join(str(v) for v in iterable)
        else:
            return f"{sep} ".join(str(v) for v in iterable[:-1]) + f"{endsep} {iterable[-1]}"

    # legacy aliases
    list_to_string = iter_to_str
    iter_to_string = iter_to_str

    def wildcard_to_regexp(instring):
        """
        Converts a player-supplied string that may have wildcards in it to
        regular expressions. This is useful for name matching.

        Args:
            instring (string): A string that may potentially contain
                wildcards (`*` or `?`).

        Returns:
            regex (str): A string where wildcards were replaced with
                regular expressions.

        """
        regexp_string = ""

        # If the string starts with an asterisk, we can't impose the beginning of
        # string (^) limiter.
        if instring[0] != "*":
            regexp_string += "^"

        # Replace any occurances of * or ? with the appropriate groups.
        regexp_string += instring.replace("*", "(.*)").replace("?", "(.{1})")

        # If there's an asterisk at the end of the string, we can't impose the
        # end of string ($) limiter.
        if instring[-1] != "*":
            regexp_string += "$"

        return regexp_string

    def time_format(seconds, style=0):
        """
        Function to return a 'prettified' version of a value in seconds.

        Args:
            seconds (int): Number if seconds to format.
            style (int): One of the following styles:
                0. "1d 08:30"
                1. "1d"
                2. "1 day, 8 hours, 30 minutes"
                3. "1 day, 8 hours, 30 minutes, 10 seconds"
                4. highest unit (like "3 years" or "8 months" or "1 second")
        Returns:
            timeformatted (str): A pretty time string.
        """
        if seconds < 0:
            seconds = 0
        else:
            # We'll just use integer math, no need for decimal precision.
            seconds = int(seconds)

        days = seconds // 86400
        seconds -= days * 86400
        hours = seconds // 3600
        seconds -= hours * 3600
        minutes = seconds // 60
        seconds -= minutes * 60

        retval = ""
        if style == 0:
            """
            Standard colon-style output.
            """
            if days > 0:
                retval = "%id %02i:%02i" % (days, hours, minutes)
            else:
                retval = "%02i:%02i" % (hours, minutes)
            return retval

        elif style == 1:
            """
            Simple, abbreviated form that only shows the highest time amount.
            """
            if days > 0:
                return "%id" % (days,)
            elif hours > 0:
                return "%ih" % (hours,)
            elif minutes > 0:
                return "%im" % (minutes,)
            else:
                return "%is" % (seconds,)
        elif style == 2:
            """
            Full-detailed, long-winded format. We ignore seconds.
            """
            days_str = hours_str = ""
            minutes_str = "0 minutes"

            if days > 0:
                if days == 1:
                    days_str = "%i day, " % days
                else:
                    days_str = "%i days, " % days
            if days or hours > 0:
                if hours == 1:
                    hours_str = "%i hour, " % hours
                else:
                    hours_str = "%i hours, " % hours
            if hours or minutes > 0:
                if minutes == 1:
                    minutes_str = "%i minute " % minutes
                else:
                    minutes_str = "%i minutes " % minutes
            retval = "%s%s%s" % (days_str, hours_str, minutes_str)
        elif style == 3:
            """
            Full-detailed, long-winded format. Includes seconds.
            """
            days_str = hours_str = minutes_str = seconds_str = ""
            if days > 0:
                if days == 1:
                    days_str = "%i day, " % days
                else:
                    days_str = "%i days, " % days
            if days or hours > 0:
                if hours == 1:
                    hours_str = "%i hour, " % hours
                else:
                    hours_str = "%i hours, " % hours
            if hours or minutes > 0:
                if minutes == 1:
                    minutes_str = "%i minute " % minutes
                else:
                    minutes_str = "%i minutes " % minutes
            if minutes or seconds > 0:
                if seconds == 1:
                    seconds_str = "%i second " % seconds
                else:
                    seconds_str = "%i seconds " % seconds
            retval = "%s%s%s%s" % (days_str, hours_str, minutes_str, seconds_str)
        elif style == 4:
            """
            Only return the highest unit.
            """
            if days >= 730:  # Several years
                return "{} years".format(days // 365)
            elif days >= 365:  # One year
                return "a year"
            elif days >= 62:  # Several months
                return "{} months".format(days // 31)
            elif days >= 31:  # One month
                return "a month"
            elif days >= 2:  # Several days
                return "{} days".format(days)
            elif days > 0:
                return "a day"
            elif hours >= 2:  # Several hours
                return "{} hours".format(hours)
            elif hours > 0:  # One hour
                return "an hour"
            elif minutes >= 2:  # Several minutes
                return "{} minutes".format(minutes)
            elif minutes > 0:  # One minute
                return "a minute"
            elif seconds >= 2:  # Several seconds
                return "{} seconds".format(seconds)
            elif seconds == 1:
                return "a second"
            else:
                return "0 seconds"
        else:
            raise ValueError("Unknown style for time format: %s" % style)

        return retval.strip()

    def datetime_format(dtobj):
        """
        Pretty-prints the time since a given time.

        Args:
            dtobj (datetime): An datetime object, e.g. from Django's
                `DateTimeField`.

        Returns:
            deltatime (str): A string describing how long ago `dtobj`
                took place.

        """

        now = timezone.now()

        if dtobj.year < now.year:
            # another year (Apr 5, 2019)
            timestring = dtobj.strftime(f"%b {dtobj.day}, %Y")
        elif dtobj.date() < now.date():
            # another date, same year  (Apr 5)
            timestring = dtobj.strftime(f"%b {dtobj.day}")
        elif dtobj.hour < now.hour - 1:
            # same day, more than 1 hour ago (10:45)
            timestring = dtobj.strftime("%H:%M")
        else:
            # same day, less than 1 hour ago (10:45:33)
            timestring = dtobj.strftime("%H:%M:%S")
        return timestring

    def host_os_is(osname):
        """
        Check to see if the host OS matches the query.

        Args:
            osname (str): Common names are "posix" (linux/unix/mac) and
                "nt" (windows).

        Args:
            is_os (bool): If the os matches or not.

        """
        return os.name == osname

    def get_evennia_version(mode="long"):
        """
        Helper method for getting the current evennia version.

        Args:
            mode (str, optional): One of:
                - long: 0.9.0 rev342453534
                - short: 0.9.0
                - pretty: Evennia 0.9.0

        Returns:
            version (str): The version string.

        """
        import evennia

        vers = evennia.__version__
        if mode == "short":
            return vers.split()[0].strip()
        elif mode == "pretty":
            vers = vers.split()[0].strip()
            return f"Evennia {vers}"
        else:  # mode "long":
            return vers

    def pypath_to_realpath(python_path, file_ending=".py", pypath_prefixes=None):
        """
        Converts a dotted Python path to an absolute path under the
        Evennia library directory or under the current game directory.

        Args:
            python_path (str): A dot-python path
            file_ending (str): A file ending, including the period.
            pypath_prefixes (list): A list of paths to test for existence. These
                should be on python.path form. EVENNIA_DIR and GAME_DIR are automatically
                checked, they need not be added to this list.

        Returns:
            abspaths (list): All existing, absolute paths created by
                converting `python_path` to an absolute paths and/or
                prepending `python_path` by `settings.EVENNIA_DIR`,
                `settings.GAME_DIR` and by`pypath_prefixes` respectively.

        Notes:
            This will also try a few combinations of paths to allow cases
            where pypath is given including the "evennia." or "mygame."
            prefixes.

        """
        path = python_path.strip().split(".")
        plong = osjoin(*path) + file_ending
        pshort = (
            osjoin(*path[1:]) + file_ending if len(path) > 1 else plong
        )  # in case we had evennia. or mygame.
        prefixlong = (
            [osjoin(*ppath.strip().split(".")) for ppath in make_iter(pypath_prefixes)]
            if pypath_prefixes
            else []
        )
        prefixshort = (
            [
                osjoin(*ppath.strip().split(".")[1:])
                for ppath in make_iter(pypath_prefixes)
                if len(ppath.strip().split(".")) > 1
            ]
            if pypath_prefixes
            else []
        )
        paths = (
            [plong]
            + [osjoin(_EVENNIA_DIR, prefix, plong) for prefix in prefixlong]
            + [osjoin(_GAME_DIR, prefix, plong) for prefix in prefixlong]
            + [osjoin(_EVENNIA_DIR, prefix, plong) for prefix in prefixshort]
            + [osjoin(_GAME_DIR, prefix, plong) for prefix in prefixshort]
            + [osjoin(_EVENNIA_DIR, plong), osjoin(_GAME_DIR, plong)]
            + [osjoin(_EVENNIA_DIR, prefix, pshort) for prefix in prefixshort]
            + [osjoin(_GAME_DIR, prefix, pshort) for prefix in prefixshort]
            + [osjoin(_EVENNIA_DIR, prefix, pshort) for prefix in prefixlong]
            + [osjoin(_GAME_DIR, prefix, pshort) for prefix in prefixlong]
            + [osjoin(_EVENNIA_DIR, pshort), osjoin(_GAME_DIR, pshort)]
        )
        # filter out non-existing paths
        return list(set(p for p in paths if os.path.isfile(p)))

    def dbref(inp, reqhash=True):
        """
        Converts/checks if input is a valid dbref.

        Args:
            inp (int, str): A database ref on the form N or #N.
            reqhash (bool, optional): Require the #N form to accept
                input as a valid dbref.

        Returns:
            dbref (int or None): The integer part of the dbref or `None`
                if input was not a valid dbref.

        """
        if reqhash:
            num = (
                int(inp.lstrip("#"))
                if (isinstance(inp, str) and inp.startswith("#") and inp.lstrip("#").isdigit())
                else None
            )
            return num if isinstance(num, int) and num > 0 else None
        elif isinstance(inp, str):
            inp = inp.lstrip("#")
            return int(inp) if inp.isdigit() and int(inp) > 0 else None
        else:
            return inp if isinstance(inp, int) else None

    def dbref_to_obj(inp, objclass, raise_errors=True):
        """
        Convert a #dbref to a valid object.

        Args:
            inp (str or int): A valid #dbref.
            objclass (class): A valid django model to filter against.
            raise_errors (bool, optional): Whether to raise errors
                or return `None` on errors.

        Returns:
            obj (Object or None): An entity loaded from the dbref.

        Raises:
            Exception: If `raise_errors` is `True` and
                `objclass.objects.get(id=dbref)` did not return a valid
                object.

        """
        dbid = dbref(inp)
        if not dbid:
            # we only convert #dbrefs
            return inp
        try:
            if dbid < 0:
                return None
        except ValueError:
            return None

        # if we get to this point, inp is an integer dbref; get the matching object
        try:
            return objclass.objects.get(id=dbid)
        except Exception:
            if raise_errors:
                raise
            return inp

    # legacy alias
    dbid_to_obj = dbref_to_obj

    # some direct translations for the latinify
    _UNICODE_MAP = {
        "EM DASH": "-",
        "FIGURE DASH": "-",
        "EN DASH": "-",
        "HORIZONTAL BAR": "-",
        "HORIZONTAL ELLIPSIS": "...",
        "LEFT SINGLE QUOTATION MARK": "'",
        "RIGHT SINGLE QUOTATION MARK": "'",
        "LEFT DOUBLE QUOTATION MARK": '"',
        "RIGHT DOUBLE QUOTATION MARK": '"',
    }

    def latinify(string, default="?", pure_ascii=False):
        """
        Convert a unicode string to "safe" ascii/latin-1 characters.
        This is used as a last resort when normal encoding does not work.

        Arguments:
            string (str): A string to convert to 'safe characters' convertible
                to an latin-1 bytestring later.
            default (str, optional): Characters resisting mapping will be replaced
                with this character or string. The intent is to apply an encode operation
                on the string soon after.

        Returns:
            string (str): A 'latinified' string where each unicode character has been
                replaced with a 'safe' equivalent available in the ascii/latin-1 charset.
        Notes:
            This is inspired by the gist by Ricardo Murri:
                https://gist.github.com/riccardomurri/3c3ccec30f037be174d3

        """

        from unicodedata import name

        if isinstance(string, bytes):
            string = string.decode("utf8")

        converted = []
        for unich in iter(string):
            try:
                ch = unich.encode("utf8").decode("ascii")
            except UnicodeDecodeError:
                # deduce a latin letter equivalent from the Unicode data
                # point name; e.g., since `name(u'á') == 'LATIN SMALL
                # LETTER A WITH ACUTE'` translate `á` to `a`.  However, in
                # some cases the unicode name is still "LATIN LETTER"
                # although no direct equivalent in the Latin alphabet
                # exists (e.g., Þ, "LATIN CAPITAL LETTER THORN") -- we can
                # avoid these cases by checking that the letter name is
                # composed of one letter only.
                # We also supply some direct-translations for some particular
                # common cases.
                what = name(unich)
                if what in _UNICODE_MAP:
                    ch = _UNICODE_MAP[what]
                else:
                    what = what.split()
                    if what[0] == "LATIN" and what[2] == "LETTER" and len(what[3]) == 1:
                        ch = what[3].lower() if what[1] == "SMALL" else what[3].upper()
                    else:
                        ch = default
            converted.append(chr(ord(ch)))
        return "".join(converted)

    def to_bytes(text, session=None):
        """
        Try to encode the given text to bytes, using encodings from settings or from Session. Will
        always return a bytes, even if given something that is not str or bytes.

        Args:
            text (any): The text to encode to bytes. If bytes, return unchanged. If not a str, convert
                to str before converting.
            session (Session, optional): A Session to get encoding info from. Will try this before
                falling back to settings.ENCODINGS.

        Returns:
            encoded_text (bytes): the encoded text following the session's protocol flag followed by the
                encodings specified in settings.ENCODINGS.  If all attempt fail, log the error and send
                the text with "?" in place of problematic characters.  If the specified encoding cannot
                be found, the protocol flag is reset to utf-8.  In any case, returns bytes.

        Notes:
            If `text` is already bytes, return it as is.

        """
        if isinstance(text, bytes):
            return text
        if not isinstance(text, str):
            # convert to a str representation before encoding
            try:
                text = str(text)
            except Exception:
                text = repr(text)

        default_encoding = session.protocol_flags.get("ENCODING", "utf-8") if session else "utf-8"
        try:
            return text.encode(default_encoding)
        except (LookupError, UnicodeEncodeError):
            for encoding in settings.ENCODINGS:
                try:
                    return text.encode(encoding)
                except (LookupError, UnicodeEncodeError):
                    pass
            # no valid encoding found. Replace unconvertable parts with ?
            return text.encode(default_encoding, errors="replace")

    def to_str(text, session=None):
        """
        Try to decode a bytestream to a python str, using encoding schemas from settings
        or from Session. Will always return a str(), also if not given a str/bytes.

        Args:
            text (any): The text to encode to bytes. If a str, return it. If also not bytes, convert
                to str using str() or repr() as a fallback.
            session (Session, optional): A Session to get encoding info from. Will try this before
                falling back to settings.ENCODINGS.

        Returns:
            decoded_text (str): The decoded text.

        Notes:
            If `text` is already str, return it as is.
        """
        if isinstance(text, str):
            return text
        if not isinstance(text, bytes):
            # not a byte, convert directly to str
            try:
                return str(text)
            except Exception:
                return repr(text)

        default_encoding = session.protocol_flags.get("ENCODING", "utf-8") if session else "utf-8"
        try:
            return text.decode(default_encoding)
        except (LookupError, UnicodeDecodeError):
            for encoding in settings.ENCODINGS:
                try:
                    return text.decode(encoding)
                except (LookupError, UnicodeDecodeError):
                    pass
            # no valid encoding found. Replace unconvertable parts with ?
            return text.decode(default_encoding, errors="replace")

    def validate_email_address(emailaddress):
        """
        Checks if an email address is syntactically correct. Makes use
        of the django email-validator for consistency.

        Args:
            emailaddress (str): Email address to validate.

        Returns:
            bool: If this is a valid email or not.

        """
        try:
            django_validate_email(str(emailaddress))
        except DjangoValidationError:
            return False
        except Exception:
            logger.log_trace()
            return False
        else:
            return True

    def inherits_from(obj, parent):
        """
        Takes an object and tries to determine if it inherits at *any*
        distance from parent.

        Args:
            obj (any): Object to analyze. This may be either an instance or
                a class.
            parent (any): Can be either an instance, a class or the python
                path to the class.

        Returns:
            inherits_from (bool): If `parent` is a parent to `obj` or not.

        Notes:
            What differentiates this function from Python's `isinstance()` is the
            flexibility in the types allowed for the object and parent being compared.

        """

        if callable(obj):
            # this is a class
            obj_paths = ["%s.%s" % (mod.__module__, mod.__name__) for mod in obj.mro()]
        else:
            obj_paths = ["%s.%s" % (mod.__module__, mod.__name__) for mod in obj.__class__.mro()]

        if isinstance(parent, str):
            # a given string path, for direct matching
            parent_path = parent
        elif callable(parent):
            # this is a class
            parent_path = "%s.%s" % (parent.__module__, parent.__name__)
        else:
            parent_path = "%s.%s" % (parent.__class__.__module__, parent.__class__.__name__)
        return any(1 for obj_path in obj_paths if obj_path == parent_path)

    def server_services():
        """
        Lists all services active on the Server. Observe that since
        services are launched in memory, this function will only return
        any results if called from inside the game.

        Returns:
            services (dict): A dict of available services.

        """
        from evennia.server.sessionhandler import SESSIONS

        if hasattr(SESSIONS, "server") and hasattr(SESSIONS.server, "services"):
            server = SESSIONS.server.services.namedServices
        else:
            # This function must be called from inside the evennia process.
            server = {}
        del SESSIONS
        return server

    def uses_database(name="sqlite3"):
        """
        Checks if the game is currently using a given database. This is a
        shortcut to having to use the full backend name.

        Args:
            name (str): One of 'sqlite3', 'mysql', 'postgresql' or 'oracle'.

        Returns:
            uses (bool): If the given database is used or not.

        """
        try:
            engine = settings.DATABASES["default"]["ENGINE"]
        except KeyError:
            engine = settings.DATABASE_ENGINE
        return engine == "django.db.backends.%s" % name

    def delay(timedelay, callback, *args, **kwargs):
        """
        Delay the calling of a callback (function).

        Args:
            timedelay (int or float): The delay in seconds.
            callback (callable): Will be called as `callback(*args, **kwargs)`
                after `timedelay` seconds.
            *args: Will be used as arguments to callback
        Keyword Args:
            persistent (bool, optional): If True the delay remains after a server restart.
                persistent is False by default.
            any (any): Will be used as keyword arguments to callback.

        Returns:
            task (TaskHandlerTask): An instance of a task.
                Refer to, evennia.scripts.taskhandler.TaskHandlerTask

        Notes:
            The task handler (`evennia.scripts.taskhandler.TASK_HANDLER`) will
            be called for persistent or non-persistent tasks.
            If persistent is set to True, the callback, its arguments
            and other keyword arguments will be saved (serialized) in the database,
            assuming they can be.  The callback will be executed even after
            a server restart/reload, taking into account the specified delay
            (and server down time).
            Keep in mind that persistent tasks arguments and callback should not
            use memory references.
            If persistent is set to True the delay function will return an int
            which is the task's id intended for use with TASK_HANDLER's do_task
            and remove methods.
            All persistent tasks whose time delays have passed will be called on server startup.

        """
        global _TASK_HANDLER
        if _TASK_HANDLER is None:
            from evennia.scripts.taskhandler import TASK_HANDLER as _TASK_HANDLER

        return _TASK_HANDLER.add(timedelay, callback, *args, **kwargs)

    def repeat(
        interval, callback, persistent=True, idstring="", stop=False, store_key=None, *args, **kwargs
    ):
        """
        Start a repeating task using the TickerHandler.

        Args:
            interval (int): How often to call callback.
            callback (callable): This will be called with `*args, **kwargs` every
                `interval` seconds. This must be possible to pickle regardless
                of if `persistent` is set or not!
            persistent (bool, optional): If ticker survives a server reload.
            idstring (str, optional): Separates multiple tickers. This is useful
                mainly if wanting to set up multiple repeats for the same
                interval/callback but with different args/kwargs.
            stop (bool, optional): If set, use the given parameters to _stop_ a running
                ticker instead of creating a new one.
            store_key (tuple, optional): This is only used in combination with `stop` and
                should be the return given from the original `repeat` call. If this
                is given, all other args except `stop` are ignored.
            *args: Used as arguments to `callback`.
            **kwargs: Keyword-arguments to pass to `callback`.

        Returns:
            tuple or None: The tuple is the `store_key` - the identifier for the
            created ticker.  Store this and pass into unrepat() in order to to stop
            this ticker later. Returns `None` if `stop=True`.

        Raises:
            KeyError: If trying to stop a ticker that was not found.

        """
        global _TICKER_HANDLER
        if _TICKER_HANDLER is None:
            from evennia.scripts.tickerhandler import TICKER_HANDLER as _TICKER_HANDLER

        if stop:
            # we pass all args, but only store_key matters if given
            _TICKER_HANDLER.remove(
                interval=interval,
                callback=callback,
                idstring=idstring,
                persistent=persistent,
                store_key=store_key,
            )
        else:
            return _TICKER_HANDLER.add(
                interval=interval, callback=callback, idstring=idstring, persistent=persistent
            )

    def unrepeat(store_key):
        """
        This is used to stop a ticker previously started with `repeat`.

        Args:
            store_key (tuple): This is the return from `repeat`, used to uniquely
                identify the ticker to stop. Without the store_key, the ticker
                must be stopped by passing its parameters to `TICKER_HANDLER.remove`
                directly.

        Returns:
            bool: True if a ticker was stopped, False if not (for example because no
                matching ticker was found or it was already stopped).

        """
        try:
            repeat(None, None, stop=True, store_key=store_key)
            return True
        except KeyError:
            return False

    _PPOOL = None
    _PCMD = None
    _PROC_ERR = "A process has ended with a probable error condition: process ended by signal 9."

    def run_async(to_execute, *args, **kwargs):
        """
        Runs a function or executes a code snippet asynchronously.

        Args:
            to_execute (callable): If this is a callable, it will be
                executed with `*args` and non-reserved `**kwargs` as arguments.
                The callable will be executed using ProcPool, or in a thread
                if ProcPool is not available.
        Keyword Args:
            at_return (callable): Should point to a callable with one
              argument.  It will be called with the return value from
              to_execute.
            at_return_kwargs (dict): This dictionary will be used as
              keyword arguments to the at_return callback.
            at_err (callable): This will be called with a Failure instance
              if there is an error in to_execute.
            at_err_kwargs (dict): This dictionary will be used as keyword
              arguments to the at_err errback.

        Notes:
            All other `*args` and `**kwargs` will be passed on to
            `to_execute`. Run_async will relay executed code to a thread
            or procpool.

            Use this function with restrain and only for features/commands
            that you know has no influence on the cause-and-effect order of your
            game (commands given after the async function might be executed before
            it has finished). Accessing the same property from different threads
            can lead to unpredicted behaviour if you are not careful (this is called a
            "race condition").

            Also note that some databases, notably sqlite3, don't support access from
            multiple threads simultaneously, so if you do heavy database access from
            your `to_execute` under sqlite3 you will probably run very slow or even get
            tracebacks.

        """

        # handle special reserved input kwargs
        callback = kwargs.pop("at_return", None)
        errback = kwargs.pop("at_err", None)
        callback_kwargs = kwargs.pop("at_return_kwargs", {})
        errback_kwargs = kwargs.pop("at_err_kwargs", {})

        if callable(to_execute):
            # no process pool available, fall back to old deferToThread mechanism.
            deferred = threads.deferToThread(to_execute, *args, **kwargs)
        else:
            # no appropriate input for this server setup
            raise RuntimeError("'%s' could not be handled by run_async" % to_execute)

        # attach callbacks
        if callback:
            deferred.addCallback(callback, **callback_kwargs)
        deferred.addErrback(errback, **errback_kwargs)

    def check_evennia_dependencies():
        """
        Checks the versions of Evennia's dependencies including making
        some checks for runtime libraries.

        Returns:
            result (bool): `False` if a show-stopping version mismatch is
                found.

        """

        # check main dependencies
        from evennia.server.evennia_launcher import check_main_evennia_dependencies

        not_error = check_main_evennia_dependencies()

        errstring = ""
        # South is no longer used ...
        if "south" in settings.INSTALLED_APPS:
            errstring += (
                "\n ERROR: 'south' found in settings.INSTALLED_APPS. "
                "\n   South is no longer used. If this was added manually, remove it."
            )
            not_error = False
        # IRC support
        if settings.IRC_ENABLED:
            try:
                import twisted.words

                twisted.words  # set to avoid debug info about not-used import
            except ImportError:
                errstring += (
                    "\n ERROR: IRC is enabled, but twisted.words is not installed. Please install it."
                    "\n   Linux Debian/Ubuntu users should install package 'python-twisted-words', "
                    "\n others can get it from http://twistedmatrix.com/trac/wiki/TwistedWords."
                )
                not_error = False
        errstring = errstring.strip()
        if errstring:
            mlen = max(len(line) for line in errstring.split("\n"))
            logger.log_err("%s\n%s\n%s" % ("-" * mlen, errstring, "-" * mlen))
        return not_error

    def has_parent(basepath, obj):
        """
        Checks if `basepath` is somewhere in obj's parent tree.

        Args:
            basepath (str): Python dotpath to compare against obj path.
            obj (any): Object whose path is to be checked.

        Returns:
            has_parent (bool): If the check was successful or not.

        """
        try:
            return any(
                cls
                for cls in obj.__class__.mro()
                if basepath == "%s.%s" % (cls.__module__, cls.__name__)
            )
        except (TypeError, AttributeError):
            # this can occur if we tried to store a class object, not an
            # instance. Not sure if one should defend against this.
            return False

    def mod_import_from_path(path):
        """
        Load a Python module at the specified path.

        Args:
            path (str): An absolute path to a Python module to load.

        Returns:
            (module or None): An imported module if the path was a valid
            Python module. Returns `None` if the import failed.

        """
        if not os.path.isabs(path):
            path = os.path.abspath(path)
        dirpath, filename = path.rsplit(os.path.sep, 1)
        modname = filename.rstrip(".py")

        try:
            return importlib.machinery.SourceFileLoader(modname, path).load_module()
        except OSError:
            logger.log_trace(f"Could not find module '{modname}' ({modname}.py) at path '{dirpath}'")
            return None

    def mod_import(module):
        """
        A generic Python module loader.

        Args:
            module (str, module): This can be either a Python path
                (dot-notation like `evennia.objects.models`), an absolute path
                (e.g. `/home/eve/evennia/evennia/objects/models.py`) or an
                already imported module object (e.g. `models`)
        Returns:
            (module or None): An imported module. If the input argument was
            already a module, this is returned as-is, otherwise the path is
            parsed and imported. Returns `None` and logs error if import failed.

        """
        if not module:
            return None

        if isinstance(module, types.ModuleType):
            # if this is already a module, we are done
            return module

        if module.endswith(".py") and os.path.exists(module):
            return mod_import_from_path(module)

        try:
            return importlib.import_module(module)
        except ImportError:
            return None

    def all_from_module(module):
        """
        Return all global-level variables defined in a module.

        Args:
            module (str, module): This can be either a Python path
                (dot-notation like `evennia.objects.models`), an absolute path
                (e.g. `/home/eve/evennia/evennia/objects.models.py`) or an
                already imported module object (e.g. `models`)

        Returns:
            dict: A dict of {variablename: variable} for all
                variables in the given module.

        Notes:
            Ignores modules and variable names starting with an underscore, as well
            as variables imported into the module from other modules.

        """
        mod = mod_import(module)
        if not mod:
            return {}
        # make sure to only return variables actually defined in this
        # module if available (try to avoid imports)
        members = getmembers(mod, predicate=lambda obj: getmodule(obj) in (mod, None))
        return dict((key, val) for key, val in members if not key.startswith("_"))

    def callables_from_module(module):
        """
        Return all global-level callables defined in a module.

        Args:
            module (str, module): A python-path to a module or an actual
                module object.

        Returns:
            callables (dict): A dict of {name: callable, ...} from the module.

        Notes:
            Will ignore callables whose names start with underscore "_".

        """
        mod = mod_import(module)
        if not mod:
            return {}
        # make sure to only return callables actually defined in this module (not imports)
        members = getmembers(mod, predicate=lambda obj: callable(obj) and getmodule(obj) == mod)
        return dict((key, val) for key, val in members if not key.startswith("_"))

    def variable_from_module(module, variable=None, default=None):
        """
        Retrieve a variable or list of variables from a module. The
        variable(s) must be defined globally in the module. If no variable
        is given (or a list entry is `None`), all global variables are
        extracted from the module.

        Args:
          module (string or module): Python path, absolute path or a module.
          variable (string or iterable, optional): Single variable name or iterable
              of variable names to extract. If not given, all variables in
              the module will be returned.
          default (string, optional): Default value to use if a variable fails to
              be extracted. Ignored if `variable` is not given.

        Returns:
            variables (value or list): A single value or a list of values
            depending on if `variable` is given or not. Errors in lists
            are replaced by the `default` argument.

        """

        if not module:
            return default

        mod = mod_import(module)

        if not mod:
            return default

        if variable:
            result = []
            for var in make_iter(variable):
                if var:
                    # try to pick a named variable
                    result.append(mod.__dict__.get(var, default))
        else:
            # get all
            result = [
                val for key, val in mod.__dict__.items() if not (key.startswith("_") or ismodule(val))
            ]

        if len(result) == 1:
            return result[0]
        return result

    def string_from_module(module, variable=None, default=None):
        """
        This is a wrapper for `variable_from_module` that requires return
        value to be a string to pass. It's primarily used by login screen.

        Args:
          module (string or module): Python path, absolute path or a module.
          variable (string or iterable, optional): Single variable name or iterable
              of variable names to extract. If not given, all variables in
              the module will be returned.
          default (string, optional): Default value to use if a variable fails to
              be extracted. Ignored if `variable` is not given.

        Returns:
            variables (value or list): A single (string) value or a list of values
            depending on if `variable` is given or not. Errors in lists (such
            as the value not being a string) are replaced by the `default` argument.

        """
        val = variable_from_module(module, variable=variable, default=default)
        if val:
            if variable:
                return val
            else:
                result = [v for v in make_iter(val) if isinstance(v, str)]
                return result if result else default
        return default

    def random_string_from_module(module):
        """
        Returns a random global string from a module.

        Args:
            module (string or module): Python path, absolute path or a module.

        Returns:
            random (string): A random stribg variable from `module`.
        """
        return random.choice(string_from_module(module))

    def fuzzy_import_from_module(path, variable, default=None, defaultpaths=None):
        """
        Import a variable based on a fuzzy path. First the literal
        `path` will be tried, then all given `defaultpaths` will be
        prepended to see a match is found.

        Args:
            path (str): Full or partial python path.
            variable (str): Name of variable to import from module.
            default (string, optional): Default value to use if a variable fails to
              be extracted. Ignored if `variable` is not given.
            defaultpaths (iterable, options): Python paths to attempt in order if
                importing directly from `path` doesn't work.

        Returns:
            value (any): The variable imported from the module, or `default`, if
                not found.

        """
        paths = [path] + make_iter(defaultpaths)
        for modpath in paths:
            try:
                mod = importlib.import_module(modpath)
            except ImportError as ex:
                if not str(ex).startswith("No module named %s" % modpath):
                    # this means the module was found but it
                    # triggers an ImportError on import.
                    raise ex
                return getattr(mod, variable, default)
        return default

    def class_from_module(path, defaultpaths=None, fallback=None):
        """
        Return a class from a module, given the class' full python path. This is
        primarily used to convert db_typeclass_path:s to classes.

        Args:
            path (str): Full Python dot-path to module.
            defaultpaths (iterable, optional): If a direct import from `path` fails,
                try subsequent imports by prepending those paths to `path`.
            fallback (str): If all other attempts fail, use this path as a fallback.
                This is intended as a last-resort. In the example of Evennia
                loading, this would be a path to a default parent class in the
                evennia repo itself.

        Returns:
            class (Class): An uninstantiated class recovered from path.

        Raises:
            ImportError: If all loading failed.

        """
        cls = None
        err = ""
        if defaultpaths:
            paths = (
                [path] + ["%s.%s" % (dpath, path) for dpath in make_iter(defaultpaths)]
                if defaultpaths
                else []
            )
        else:
            paths = [path]

        for testpath in paths:
            if "." in path:
                testpath, clsname = testpath.rsplit(".", 1)
            else:
                raise ImportError("the path '%s' is not on the form modulepath.Classname." % path)

            try:
                if not importlib.util.find_spec(testpath, package="evennia"):
                    continue
            except ModuleNotFoundError:
                continue

            try:
                mod = importlib.import_module(testpath, package="evennia")
            except ModuleNotFoundError:
                err = traceback.format_exc(30)
                break

            try:
                cls = getattr(mod, clsname)
                break
            except AttributeError:
                if len(trace()) > 2:
                    # AttributeError within the module, don't hide it
                    err = traceback.format_exc(30)
                    break
        if not cls:
            err = "\nCould not load typeclass '{}'{}".format(
                path, " with the following traceback:\n" + err if err else ""
            )
            if defaultpaths:
                err += "\nPaths searched:\n    %s" % "\n    ".join(paths)
            else:
                err += "."
            logger.log_err(err)
            if fallback:
                logger.log_warn(f"Falling back to {fallback}.")
                return class_from_module(fallback)
            else:
                # even fallback fails
                raise ImportError(err)
        return cls

    # alias
    object_from_module = class_from_module

    def init_new_account(account):
        """
        Deprecated.
        """
        from evennia.utils import logger

        logger.log_dep("evennia.utils.utils.init_new_account is DEPRECATED and should not be used.")

    def string_similarity(string1, string2):
        """
        This implements a "cosine-similarity" algorithm as described for example in
        *Proceedings of the 22nd International Conference on Computation
        Linguistics* (Coling 2008), pages 593-600, Manchester, August 2008.
        The measure-vectors used is simply a "bag of words" type histogram
        (but for letters).

        Args:
            string1 (str): String to compare (may contain any number of words).
            string2 (str): Second string to compare (any number of words).

        Returns:
            similarity (float): A value 0...1 rating how similar the two
                strings are.

        """
        vocabulary = set(list(string1 + string2))
        vec1 = [string1.count(v) for v in vocabulary]
        vec2 = [string2.count(v) for v in vocabulary]
        try:
            return float(sum(vec1[i] * vec2[i] for i in range(len(vocabulary)))) / (
                math.sqrt(sum(v1**2 for v1 in vec1)) * math.sqrt(sum(v2**2 for v2 in vec2))
            )
        except ZeroDivisionError:
            # can happen if empty-string cmdnames appear for some reason.
            # This is a no-match.
            return 0

    def string_suggestions(string, vocabulary, cutoff=0.6, maxnum=3):
        """
        Given a `string` and a `vocabulary`, return a match or a list of
        suggestions based on string similarity.

        Args:
            string (str): A string to search for.
            vocabulary (iterable): A list of available strings.
            cutoff (int, 0-1): Limit the similarity matches (the higher
                the value, the more exact a match is required).
            maxnum (int): Maximum number of suggestions to return.

        Returns:
            suggestions (list): Suggestions from `vocabulary` with a
            similarity-rating that higher than or equal to `cutoff`.
            Could be empty if there are no matches.

        """
        return [
            tup[1]
            for tup in sorted(
                [(string_similarity(string, sugg), sugg) for sugg in vocabulary],
                key=lambda tup: tup[0],
                reverse=True,
            )
            if tup[0] >= cutoff
        ][:maxnum]

    def string_partial_matching(alternatives, inp, ret_index=True):
        """
        Partially matches a string based on a list of `alternatives`.
        Matching is made from the start of each subword in each
        alternative. Case is not important. So e.g. "bi sh sw" or just
        "big" or "shiny" or "sw" will match "Big shiny sword". Scoring is
        done to allow to separate by most common denominator. You will get
        multiple matches returned if appropriate.

        Args:
            alternatives (list of str): A list of possible strings to
                match.
            inp (str): Search criterion.
            ret_index (bool, optional): Return list of indices (from alternatives
                array) instead of strings.
        Returns:
            matches (list): String-matches or indices if `ret_index` is `True`.

        """
        if not alternatives or not inp:
            return []

        matches = defaultdict(list)
        inp_words = inp.lower().split()
        for altindex, alt in enumerate(alternatives):
            alt_words = alt.lower().split()
            last_index = 0
            score = 0
            for inp_word in inp_words:
                # loop over parts, making sure only to visit each part once
                # (this will invalidate input in the wrong word order)
                submatch = [
                    last_index + alt_num
                    for alt_num, alt_word in enumerate(alt_words[last_index:])
                    if alt_word.startswith(inp_word)
                ]
                if submatch:
                    last_index = min(submatch) + 1
                    score += 1
                else:
                    score = 0
                    break
            if score:
                if ret_index:
                    matches[score].append(altindex)
                else:
                    matches[score].append(alt)
        if matches:
            return matches[max(matches)]
        return []

    def format_table(table, extra_space=1):
        """
        Format a 2D array of strings into a multi-column table.

        Args:
            table (list): A list of lists to represent columns in the
                table: `[[val,val,val,...], [val,val,val,...], ...]`, where
                each val will be placed on a separate row in the
                column. All columns must have the same number of rows (some
                positions may be empty though).
            extra_space (int, optional): Sets how much *minimum* extra
                padding (in characters) should  be left between columns.

        Returns:
            list: A list of lists representing the rows to print out one by one.

        Notes:
            The function formats the columns to be as wide as the widest member
            of each column.

            `evennia.utils.evtable` is more powerful than this, but this
            function can be useful when the number of columns and rows are
            unknown and must be calculated on the fly.

        Examples: ::

            ftable = format_table([[1,2,3], [4,5,6]])
            string = ""
            for ir, row in enumerate(ftable):
                if ir == 0:
                    # make first row white
                    string += "\\n|w" + "".join(row) + "|n"
                else:
                    string += "\\n" + "".join(row)
            print(string)

        """

        if not table:
            return [[]]

        max_widths = [max([len(str(val)) for val in col]) for col in table]
        ftable = []
        for irow in range(len(table[0])):
            ftable.append(
                [
                    str(col[irow]).ljust(max_widths[icol]) + " " * extra_space
                    for icol, col in enumerate(table)
                ]
            )
        return ftable

    def percent(value, minval, maxval, formatting="{:3.1f}%"):
        """
        Get a value in an interval as a percentage of its position
        in that interval. This also understands negative numbers.

        Args:
            value (number): This should be a value minval<=value<=maxval.
            minval (number or None): Smallest value in interval. This could be None
                for an open interval (then return will always be 100%)
            maxval (number or None): Biggest value in interval. This could be None
                for an open interval (then return will always be 100%)
            formatted (str, optional): This is a string that should
                accept one formatting tag. This will receive the
                current value as a percentage. If None, the
                raw float will be returned instead.
        Returns:
            str or float: The formatted value or the raw percentage as a float.
        Notes:
            We try to handle a weird interval gracefully.

            - If either maxval or minval is None (open interval), we (aribtrarily) assume 100%.
            - If minval > maxval, we return 0%.
            - If minval == maxval == value we are looking at a single value match and return 100%.
            - If minval == maxval != value we return 0%.
            - If value not in [minval..maxval], we set value to the  closest
              boundary, so the result will be 0% or 100%, respectively.

        """
        result = None
        if None in (minval, maxval):
            # we have no boundaries, percent calculation makes no sense,
            # we set this to 100% since it
            result = 100.0
        elif minval > maxval:
            # interval has no width so we cannot
            # occupy any position within it.
            result = 0.0
        elif minval == maxval == value:
            # this is a single value that we match
            result = 100.0
        elif minval == maxval != value:
            # interval has no width so we cannot be in it.
            result = 0.0

        if result is None:
            # constrain value to interval
            value = min(max(minval, value), maxval)

            # these should both be >0
            dpart = value - minval
            dfull = maxval - minval
            result = (dpart / dfull) * 100.0

        if isinstance(formatting, str):
            return formatting.format(result)
        return result

    import functools  # noqa

    def percentile(iterable, percent, key=lambda x: x):
        """
        Find the percentile of a list of values.

        Args:
            iterable (iterable): A list of values. Note N MUST BE already sorted.
            percent (float): A value from 0.0 to 1.0.
            key (callable, optional). Function to compute value from each element of N.

        Returns:
            float: The percentile of the values

        """
        if not iterable:
            return None
        k = (len(iterable) - 1) * percent
        f = math.floor(k)
        c = math.ceil(k)
        if f == c:
            return key(iterable[int(k)])
        d0 = key(iterable[int(f)]) * (c - k)
        d1 = key(iterable[int(c)]) * (k - f)
        return d0 + d1

    def format_grid(elements, width=78, sep="  ", verbatim_elements=None, line_prefix=""):
        """
        This helper function makes a 'grid' output, where it distributes the given
        string-elements as evenly as possible to fill out the given width.
        will not work well if the variation of length is very big!

        Args:
            elements (iterable): A 1D list of string elements to put in the grid.
            width (int, optional): The width of the grid area to fill.
            sep (str, optional): The extra separator to put between words. If
                set to the empty string, words may run into each other.
            verbatim_elements (list, optional): This is a list of indices pointing to
                specific items in the `elements` list. An element at this index will
                not be included in the calculation of the slot sizes. It will still
                be inserted into the grid at the correct position and may be surrounded
                by padding unless filling the entire line. This is useful for embedding
                decorations in the grid, such as horizontal bars.
            ignore_ansi (bool, optional): Ignore ansi markups when calculating white spacing.
            line_prefix (str, optional): A prefix to add at the beginning of each line.
                This can e.g. be used to preserve line color across line breaks.

        Returns:
            list: The grid as a list of ready-formatted rows. We return it
            like this to make it easier to insert decorations between rows, such
            as horizontal bars.
        """

        def _minimal_rows(elements):
            """
            Minimalistic distribution with minimal spacing, good for single-line
            grids but will look messy over many lines.
            """
            rows = [""]
            for element in elements:
                rowlen = display_len((rows[-1]))
                elen = display_len((element))
                if rowlen + elen <= width:
                    rows[-1] += element
                else:
                    rows.append(element)
            return rows

        def _weighted_rows(elements):
            """
            Dynamic-space, good for making even columns in a multi-line grid but
            will look strange for a single line.
            """
            wls = [display_len((elem)) for elem in elements]
            wls_percentile = [wl for iw, wl in enumerate(wls) if iw not in verbatim_elements]

            if wls_percentile:
                # get the nth percentile as a good representation of average width
                averlen = int(percentile(sorted(wls_percentile), 0.9)) + 2  # include extra space
                aver_per_row = width // averlen + 1
            else:
                # no adjustable rows, just keep all as-is
                aver_per_row = 1

            if aver_per_row == 1:
                # one line per row, output directly since this is trivial
                # we use rstrip here to remove extra spaces added by sep
                return [
                    crop(element.rstrip(), width)
                    + " " * max(0, width - display_len((element.rstrip())))
                    for iel, element in enumerate(elements)
                ]

            indices = [averlen * ind for ind in range(aver_per_row - 1)]

            rows = []
            ic = 0
            row = ""
            for ie, element in enumerate(elements):

                wl = wls[ie]
                lrow = display_len((row))
                # debug = row.replace(" ", ".")

                if lrow + wl > width:
                    # this slot extends outside grid, move to next line
                    row += " " * (width - lrow)
                    rows.append(row)
                    if wl >= width:
                        # remove sep if this fills the entire line
                        element = element.rstrip()
                    row = crop(element, width)
                    ic = 0
                elif ic >= aver_per_row - 1:
                    # no more slots available on this line
                    row += " " * max(0, (width - lrow))
                    rows.append(row)
                    row = crop(element, width)
                    ic = 0
                else:
                    try:
                        while lrow > max(0, indices[ic]):
                            # slot too wide, extend into adjacent slot
                            ic += 1
                        row += " " * max(0, indices[ic] - lrow)
                    except IndexError:
                        # we extended past edge of grid, crop or move to next line
                        if ic == 0:
                            row = crop(element, width)
                        else:
                            row += " " * max(0, width - lrow)
                        rows.append(row)
                        row = ""
                        ic = 0
                    else:
                        # add a new slot
                        row += element + " " * max(0, averlen - wl)
                        ic += 1

                if ie >= nelements - 1:
                    # last element, make sure to store
                    row += " " * max(0, width - display_len((row)))
                    rows.append(row)
            return rows

        if not elements:
            return []
        if not verbatim_elements:
            verbatim_elements = []

        nelements = len(elements)
        # add sep to all but the very last element
        elements = [elements[ie] + sep for ie in range(nelements - 1)] + [elements[-1]]

        if sum(display_len((element)) for element in elements) <= width:
            # grid fits in one line
            rows = _minimal_rows(elements)
        else:
            # full multi-line grid
            rows = _weighted_rows(elements)

        if line_prefix:
            return [line_prefix + row for row in rows]
        return rows

    def get_evennia_pids():
        """
        Get the currently valid PIDs (Process IDs) of the Portal and
        Server by trying to access a PID file.

        Returns:
            server, portal (tuple): The PIDs of the respective processes,
                or two `None` values if not found.

        Examples:
            This can be used to determine if we are in a subprocess by

            ```python
            self_pid = os.getpid()
            server_pid, portal_pid = get_evennia_pids()
            is_subprocess = self_pid not in (server_pid, portal_pid)
            ```

        """
        server_pidfile = os.path.join(settings.GAME_DIR, "server.pid")
        portal_pidfile = os.path.join(settings.GAME_DIR, "portal.pid")
        server_pid, portal_pid = None, None
        if os.path.exists(server_pidfile):
            with open(server_pidfile, "r") as f:
                server_pid = f.read()
        if os.path.exists(portal_pidfile):
            with open(portal_pidfile, "r") as f:
                portal_pid = f.read()
        if server_pid and portal_pid:
            return int(server_pid), int(portal_pid)
        return None, None

    def deepsize(obj, max_depth=4):
        """
        Get not only size of the given object, but also the size of
        objects referenced by the object, down to `max_depth` distance
        from the object.

        Args:
            obj (object): the object to be measured.
            max_depth (int, optional): maximum referential distance
                from `obj` that `deepsize()` should cover for
                measuring objects referenced by `obj`.

        Returns:
            size (int): deepsize of `obj` in Bytes.

        Notes:
            This measure is necessarily approximate since some
            memory is shared between objects. The `max_depth` of 4 is roughly
            tested to give reasonable size information about database models
            and their handlers.

        """

        def _recurse(o, dct, depth):
            if 0 <= max_depth < depth:
                return
            for ref in gc.get_referents(o):
                idr = id(ref)
                if idr not in dct:
                    dct[idr] = (ref, sys.getsizeof(ref, default=0))
                    _recurse(ref, dct, depth + 1)

        sizedict = {}
        _recurse(obj, sizedict, 0)
        size = sys.getsizeof(obj) + sum([p[1] for p in sizedict.values()])
        return size

    # lazy load handler
    _missing = object()

    class lazy_property:
        """
        Delays loading of property until first access. Credit goes to the
        Implementation in the werkzeug suite:
        http://werkzeug.pocoo.org/docs/utils/#werkzeug.utils.cached_property

        This should be used as a decorator in a class and in Evennia is
        mainly used to lazy-load handlers:

            ```python
            @lazy_property
            def attributes(self):
                return AttributeHandler(self)
            ```

        Once initialized, the `AttributeHandler` will be available as a
        property "attributes" on the object. This is read-only since
        this functionality is pretty much exclusively used by handlers.

        """

        def __init__(self, func, name=None, doc=None):
            """Store all properties for now"""
            self.__name__ = name or func.__name__
            self.__module__ = func.__module__
            self.__doc__ = doc or func.__doc__
            self.func = func

        def __get__(self, obj, type=None):
            """Triggers initialization"""
            if obj is None:
                return self
            value = obj.__dict__.get(self.__name__, _missing)
            if value is _missing:
                value = self.func(obj)
            obj.__dict__[self.__name__] = value
            return value

        def __set__(self, obj, value):
            """Protect against setting"""
            handlername = self.__name__
            raise AttributeError(
                _(
                    "{obj}.{handlername} is a handler and can't be set directly. "
                    "To add values, use `{obj}.{handlername}.add()` instead."
                ).format(obj=obj, handlername=handlername)
            )

        def __delete__(self, obj):
            """Protect against deleting"""
            handlername = self.__name__
            raise AttributeError(
                _(
                    "{obj}.{handlername} is a handler and can't be deleted directly. "
                    "To remove values, use `{obj}.{handlername}.remove()` instead."
                ).format(obj=obj, handlername=handlername)
            )

    _STRIP_ANSI = None
    _RE_CONTROL_CHAR = re.compile(
        "[%s]" % re.escape("".join([chr(c) for c in range(0, 32)]))
    )  # + range(127,160)])))

    def strip_control_sequences(string):
        """
        Remove non-print text sequences.

        Args:
            string (str): Text to strip.

        Returns.
            text (str): Stripped text.

        """
        global _STRIP_ANSI
        if not _STRIP_ANSI:
            from evennia.utils.ansi import strip_raw_ansi as _STRIP_ANSI
        return _RE_CONTROL_CHAR.sub("", _STRIP_ANSI(string))

    def calledby(callerdepth=1):
        """
        Only to be used for debug purposes. Insert this debug function in
        another function; it will print which function called it.

        Args:
            callerdepth (int): Must be larger than 0. When > 1, it will
                print the caller of the caller etc.

        Returns:
            calledby (str): A debug string detailing which routine called
                us.

        """
        import inspect

        stack = inspect.stack()
        # we must step one extra level back in stack since we don't want
        # to include the call of this function itself.
        callerdepth = min(max(2, callerdepth + 1), len(stack) - 1)
        frame = inspect.stack()[callerdepth]
        path = os.path.sep.join(frame[1].rsplit(os.path.sep, 2)[-2:])
        return "[called by '%s': %s:%s %s]" % (frame[3], path, frame[2], frame[4])

    def m_len(target):
        """
        Provides length checking for strings with MXP patterns, and falls
        back to normal len for other objects.

        Args:
            target (str): A string with potential MXP components
                to search.

        Returns:
            length (int): The length of `target`, ignoring MXP components.

        """
        # Would create circular import if in module root.
        from evennia.utils.ansi import ANSI_PARSER

        if inherits_from(target, str) and "|lt" in target:
            return len(ANSI_PARSER.strip_mxp(target))
        return len(target)

    def display_len(target):
        """
        Calculate the 'visible width' of text. This is not necessarily the same as the
        number of characters in the case of certain asian characters. This will also
        strip MXP patterns.

        Args:
            target (any): Something to measure the length of. If a string, it will be
                measured keeping asian-character and MXP links in mind.

        Return:
            int: The visible width of the target.

        """
        # Would create circular import if in module root.
        from evennia.utils.ansi import ANSI_PARSER

        if inherits_from(target, str):
            # str or ANSIString
            target = ANSI_PARSER.strip_mxp(target)
            target = ANSI_PARSER.parse_ansi(target, strip_ansi=True)
            extra_wide = ("F", "W")
            return sum(2 if east_asian_width(char) in extra_wide else 1 for char in target)
        else:
            return len(target)

    # -------------------------------------------------------------------
    # Search handler function
    # -------------------------------------------------------------------
    #
    # Replace this hook function by changing settings.SEARCH_AT_RESULT.

    def at_search_result(matches, caller, query="", quiet=False, **kwargs):
        """
        This is a generic hook for handling all processing of a search
        result, including error reporting. This is also called by the cmdhandler
        to manage errors in command lookup.

        Args:
            matches (list): This is a list of 0, 1 or more typeclass
                instances or Command instances, the matched result of the
                search. If 0, a nomatch error should be echoed, and if >1,
                multimatch errors should be given. Only if a single match
                should the result pass through.
            caller (Object): The object performing the search and/or which should
            receive error messages.
            query (str, optional): The search query used to produce `matches`.
            quiet (bool, optional): If `True`, no messages will be echoed to caller
                on errors.
        Keyword Args:
            nofound_string (str): Replacement string to echo on a notfound error.
            multimatch_string (str): Replacement string to echo on a multimatch error.

        Returns:
            processed_result (Object or None): This is always a single result
            or `None`. If `None`, any error reporting/handling should
            already have happened. The returned object is of the type we are
            checking multimatches for (e.g. Objects or Commands)

        """

        error = ""
        if not matches:
            # no results.
            error = kwargs.get("nofound_string") or _("Could not find '{query}'.").format(query=query)
            matches = None
        elif len(matches) > 1:
            multimatch_string = kwargs.get("multimatch_string")
            if multimatch_string:
                error = "%s\n" % multimatch_string
            else:
                error = _("More than one match for '{query}' (please narrow target):\n").format(
                    query=query
                )

            for num, result in enumerate(matches):
                # we need to consider Commands, where .aliases is a list
                aliases = result.aliases.all() if hasattr(result.aliases, "all") else result.aliases
                # remove any pluralization aliases
                aliases = [
                    alias
                    for alias in aliases
                    if hasattr(alias, "category") and alias.category not in ("plural_key",)
                ]
                error += _MULTIMATCH_TEMPLATE.format(
                    number=num + 1,
                    name=result.get_display_name(caller)
                    if hasattr(result, "get_display_name")
                    else query,
                    aliases=" [{alias}]".format(alias=";".join(aliases) if aliases else ""),
                    info=result.get_extra_info(caller),
                )
            matches = None
        else:
            # exactly one match
            matches = matches[0]

        if error and not quiet:
            caller.msg(error.strip())
        return matches

    class LimitedSizeOrderedDict(OrderedDict):
        """
        This dictionary subclass is both ordered and limited to a maximum
        number of elements. Its main use is to hold a cache that can never
        grow out of bounds.

        """

        def __init__(self, *args, **kwargs):
            """
            Limited-size ordered dict.

            Keyword Args:
                size_limit (int): Use this to limit the number of elements
                  alloweds to be in this list. By default the overshooting elements
                  will be removed in FIFO order.
                fifo (bool, optional): Defaults to `True`. Remove overshooting elements
                  in FIFO order. If `False`, remove in FILO order.

            """
            super().__init__()
            self.size_limit = kwargs.get("size_limit", None)
            self.filo = not kwargs.get("fifo", True)  # FIFO inverse of FILO
            self._check_size()

        def __eq__(self, other):
            ret = super().__eq__(other)
            if ret:
                return (
                    ret
                    and hasattr(other, "size_limit")
                    and self.size_limit == other.size_limit
                    and hasattr(other, "fifo")
                    and self.fifo == other.fifo
                )
            return False

        def __ne__(self, other):
            return not self.__eq__(other)

        def _check_size(self):
            filo = self.filo
            if self.size_limit is not None:
                while self.size_limit < len(self):
                    self.popitem(last=filo)

        def __setitem__(self, key, value):
            super().__setitem__(key, value)
            self._check_size()

        def update(self, *args, **kwargs):
            super().update(*args, **kwargs)
            self._check_size()

    def get_game_dir_path():
        """
        This is called by settings_default in order to determine the path
        of the game directory.

        Returns:
            path (str): Full OS path to the game dir

        """
        # current working directory, assumed to be somewhere inside gamedir.
        for inum in range(10):
            gpath = os.getcwd()
            if "server" in os.listdir(gpath):
                if os.path.isfile(os.path.join("server", "conf", "settings.py")):
                    return gpath
            else:
                os.chdir(os.pardir)
        raise RuntimeError("server/conf/settings.py not found: Must start from inside game dir.")

    def get_all_typeclasses(parent=None):
        """
        List available typeclasses from all available modules.

        Args:
            parent (str, optional): If given, only return typeclasses inheriting
                (at any distance) from this parent.

        Returns:
            dict: On the form `{"typeclass.path": typeclass, ...}`

        Notes:
            This will dynamically retrieve all abstract django models inheriting at
            any distance from the TypedObject base (aka a Typeclass) so it will
            work fine with any custom classes being added.

        """
        from evennia.typeclasses.models import TypedObject

        typeclasses = {
            "{}.{}".format(model.__module__, model.__name__): model
            for model in apps.get_models()
            if TypedObject in getmro(model)
        }
        if parent:
            typeclasses = {
                name: typeclass
                for name, typeclass in typeclasses.items()
                if inherits_from(typeclass, parent)
            }
        return typeclasses

    def get_all_cmdsets(parent=None):
        """
        List available cmdsets from all available modules.

        Args:
            parent (str, optional): If given, only return cmdsets inheriting (at
                any distance) from this parent.

        Returns:
            dict: On the form {"cmdset.path": cmdset, ...}

        Notes:
            This will dynamically retrieve all abstract django models inheriting at
            any distance from the CmdSet base so it will work fine with any custom
            classes being added.

        """
        from evennia.commands.cmdset import CmdSet

        base_cmdset = class_from_module(parent) if parent else CmdSet

        cmdsets = {
            "{}.{}".format(subclass.__module__, subclass.__name__): subclass
            for subclass in base_cmdset.__subclasses__()
        }
        return cmdsets

    def interactive(func):
        """
        Decorator to make a method pausable with `yield(seconds)`
        and able to ask for user-input with `response=yield(question)`.
        For the question-asking to work, one of the args or kwargs to the
        decorated function must be named 'caller'.

        Raises:
            ValueError: If asking an interactive question but the decorated
                function has no arg or kwarg named 'caller'.
            ValueError: If passing non int/float to yield using for pausing.

        Examples:

            ```python
            @interactive
            def myfunc(caller):
                caller.msg("This is a test")
                # wait five seconds
                yield(5)
                # ask user (caller) a question
                response = yield("Do you want to continue waiting?")
                if response == "yes":
                    yield(5)
                else:
                    # ...
            ```

        Notes:
           This turns the decorated function or method into a generator.

        """
        from evennia.utils.evmenu import get_input

        def _process_input(caller, prompt, result, generator):
            deferLater(reactor, 0, _iterate, generator, caller, response=result)
            return False

        def _iterate(generator, caller=None, response=None):
            try:
                if response is None:
                    value = next(generator)
                else:
                    value = generator.send(response)
            except StopIteration:
                pass
            else:
                if isinstance(value, (int, float)):
                    delay(value, _iterate, generator, caller=caller)
                elif isinstance(value, str):
                    if not caller:
                        raise ValueError(
                            "To retrieve input from a @pausable method, that method "
                            "must be called with a 'caller' argument)"
                        )
                    get_input(caller, value, _process_input, generator=generator)
                else:
                    raise ValueError("yield(val) in a @pausable method must have an int/float as arg.")

        def decorator(*args, **kwargs):
            argnames = inspect.getfullargspec(func).args
            caller = None
            if "caller" in argnames:
                # we assume this is an object
                caller = args[argnames.index("caller")]

            ret = func(*args, **kwargs)
            if isinstance(ret, types.GeneratorType):
                _iterate(ret, caller)
            else:
                return ret

        return decorator

    def safe_convert_to_types(converters, *args, raise_errors=True, **kwargs):
        """
        Helper function to safely convert inputs to expected data types.

        Args:
            converters (tuple): A tuple `((converter, converter,...), {kwarg: converter, ...})` to
                match a converter to each element in `*args` and `**kwargs`.
                Each converter will will be called with the arg/kwarg-value as the only argument.
                If there are too few converters given, the others will simply not be converter. If the
                converter is given as the string 'py', it attempts to run
                `safe_eval`/`literal_eval` on  the input arg or kwarg value. It's possible to
                skip the arg/kwarg part of the tuple, an empty tuple/dict will then be assumed.
            *args: The arguments to convert with `argtypes`.
            raise_errors (bool, optional): If set, raise any errors. This will
                abort the conversion at that arg/kwarg. Otherwise, just skip the
                conversion of the failing arg/kwarg. This will be set by the FuncParser if
                this is used as a part of a FuncParser callable.
            **kwargs: The kwargs to convert with `kwargtypes`

        Returns:
            tuple: `(args, kwargs)` in converted form.

        Raises:
            utils.funcparser.ParsingError: If parsing failed in the `'py'`
                converter. This also makes this compatible with the FuncParser
                interface.
            any: Any other exception raised from other converters, if raise_errors is True.

        Notes:
            This function is often used to validate/convert input from untrusted sources. For
            security, the "py"-converter is deliberately limited and uses `safe_eval`/`literal_eval`
            which  only supports simple expressions or simple containers with literals. NEVER
            use the python `eval` or `exec` methods as a converter for any untrusted input! Allowing
            untrusted sources to execute arbitrary python on your server is a severe security risk,

        Example:
        ::

            $funcname(1, 2, 3.0, c=[1,2,3])

            def _funcname(*args, **kwargs):
                args, kwargs = safe_convert_input(((int, int, float), {'c': 'py'}), *args, **kwargs)
                # ...

        """

        def _safe_eval(inp):
            if not inp:
                return ""
            if not isinstance(inp, str):
                # already converted
                return inp

            try:
                return literal_eval(inp)
            except Exception as err:
                literal_err = f"{err.__class__.__name__}: {err}"
                try:
                    return simple_eval(inp)
                except Exception as err:
                    simple_err = f"{str(err.__class__.__name__)}: {err}"
                    pass

            if raise_errors:
                from evennia.utils.funcparser import ParsingError

                err = (
                    f"Errors converting '{inp}' to python:\n"
                    f"literal_eval raised {literal_err}\n"
                    f"simple_eval raised {simple_err}"
                )
                raise ParsingError(err)

        # handle an incomplete/mixed set of input converters
        if not converters:
            return args, kwargs
        arg_converters, *kwarg_converters = converters
        arg_converters = make_iter(arg_converters)
        kwarg_converters = kwarg_converters[0] if kwarg_converters else {}

        # apply the converters
        if args and arg_converters:
            args = list(args)
            arg_converters = make_iter(arg_converters)
            for iarg, arg in enumerate(args[: len(arg_converters)]):
                converter = arg_converters[iarg]
                converter = _safe_eval if converter in ("py", "python") else converter
                try:
                    args[iarg] = converter(arg)
                except Exception:
                    if raise_errors:
                        raise
            args = tuple(args)
        if kwarg_converters and isinstance(kwarg_converters, dict):
            for key, converter in kwarg_converters.items():
                converter = _safe_eval if converter in ("py", "python") else converter
                if key in {**kwargs}:
                    try:
                        kwargs[key] = converter(kwargs[key])
                    except Exception:
                        if raise_errors:
                            raise
        return args, kwargs

    def strip_unsafe_input(txt, session=None, bypass_perms=None):
        """
        Remove 'unsafe' text codes from text; these are used to elimitate
        exploits in user-provided data, such as html-tags, line breaks etc.

        Args:
            txt (str): The text to clean.
            session (Session, optional): A Session in order to determine if
                the check should be bypassed by permission (will be checked
                with the 'perm' lock, taking permission hierarchies into account).
            bypass_perms (list, optional): Iterable of permission strings
                to check for bypassing the strip. If not given, use
                `settings.INPUT_CLEANUP_BYPASS_PERMISSIONS`.

        Returns:
            str: The cleaned string.

        Notes:
            The `INPUT_CLEANUP_BYPASS_PERMISSIONS` list defines what account
            permissions are required to bypass this strip.

        """
        global _STRIP_UNSAFE_TOKENS
        if not _STRIP_UNSAFE_TOKENS:
            from evennia.utils.ansi import strip_unsafe_tokens as _STRIP_UNSAFE_TOKENS

        if session:
            obj = session.puppet if session.puppet else session.account
            bypass_perms = bypass_perms or settings.INPUT_CLEANUP_BYPASS_PERMISSIONS
            if obj.permissions.check(*bypass_perms):
                return txt

        # remove html codes
        txt = strip_tags(txt)
        txt = _STRIP_UNSAFE_TOKENS(txt)
        return txt

    def copy_word_case(base_word, new_word):
        """
        Converts a word to use the same capitalization as a first word.

        Args:
            base_word (str): A word to get the capitalization from.
            new_word (str): A new word to capitalize in the same way as `base_word`.

        Returns:
            str: The `new_word` with capitalization matching the first word.

        Notes:
            This is meant for words. Longer sentences may get unexpected results.

            If the two words have a mix of capital/lower letters _and_ `new_word`
            is longer than `base_word`, the excess will retain its original case.

        """

        # Word
        if base_word.istitle():
            return new_word.title()
        # word
        elif base_word.islower():
            return new_word.lower()
        # WORD
        elif base_word.isupper():
            return new_word.upper()
        else:
            # WorD - a mix. Handle each character
            maxlen = len(base_word)
            shared, excess = new_word[:maxlen], new_word[maxlen - 1 :]
            return (
                "".join(
                    char.upper() if base_word[ic].isupper() else char.lower()
                    for ic, char in enumerate(new_word)
                )
                + excess
            )

    def run_in_main_thread(function_or_method, *args, **kwargs):
        """
        Force a callable to execute in the main Evennia thread. This is only relevant when
        calling code from e.g. web views, which run in a separate threadpool. Use this
        to avoid race conditions.

        Args:
            function_or_method (callable): A function or method to fire.
            *args: Will be passed into the callable.
            **kwargs: Will be passed into the callable.

        """
        if _IS_MAIN_THREAD:
            return function_or_method(*args, **kwargs)
        else:
            return threads.blockingCallFromThread(reactor, function_or_method, *args, **kwargs)

    _INT2STR_MAP_NOUN = {
        0: "no",
        1: "one",
        2: "two",
        3: "three",
        4: "four",
        5: "five",
        6: "six",
        7: "seven",
        8: "eight",
        9: "nine",
        10: "ten",
        11: "eleven",
        12: "twelve",
    }
    _INT2STR_MAP_ADJ = {1: "1st", 2: "2nd", 3: "3rd"}  # rest is Xth.

    def int2str(number, adjective=False):
        """
        Convert a number to an English string for better display; so 1 -> one, 2 -> two etc
        up until 12, after which it will be '13', '14' etc.

        Args:
            number (int): The number to convert. Floats will be converted to ints.
            adjective (int): If set, map 1->1st, 2->2nd etc. If unset, map 1->one, 2->two etc.
                up to twelve.
        Return:
            str: The number expressed as a string.

        """
        number = int(number)
        if adjective:
            return _INT2STR_MAP_ADJ.get(number, f"{number}th")
        return _INT2STR_MAP_NOUN.get(number, str(number))