# Source code for evennia.utils.ansi

    """
    ANSI - Gives colour to text.

    Use the codes defined in the *ANSIParser* class to apply colour to text. The
    `parse_ansi` function in this module parses text for markup and `strip_ansi`
    removes it.

    You should usually not need to call `parse_ansi` explicitly; it is run by
    Evennia just before returning data to/from the user. Alternative markup is
    possible by overriding the parser class (see also contrib/ for deprecated
    markup schemes).

    Supported standards:

    - ANSI 8 bright and 8 dark fg (foreground) colors
    - ANSI 8 dark bg (background) colors
    - 'ANSI' 8 bright bg colors 'faked' with xterm256 (bright bg not included in ANSI standard)
    - Xterm256 - 255 fg/bg colors + 26 greyscale fg/bg colors

    ## Markup

    ANSI colors: `r` ed, `g` reen, `y` ellow, `b` lue, `m` agenta, `c` yan, `n` ormal (no color).
    Capital letters indicate the 'dark' variant.

    - `|r` fg bright red
    - `|R` fg dark red
    - `|[r` bg bright red
    - `|[R` bg dark red
    - `|[R|g` bg dark red, fg bright green

    ```python
    "This is |rRed text|n and this is normal again."

    ```

    Xterm256 colors are given as RGB (Red-Green-Blue), with values 0-5:

    - `|500` fg bright red
    - `|050` fg bright green
    - `|005` fg bright blue
    - `|110` fg dark brown
    - `|425` fg pink
    - `|[431` bg orange

    Xterm256 greyscale:

    - `|=a` fg black
    - `|=g` fg dark grey
    - `|=o` fg middle grey
    - `|=v` fg bright grey
    - `|=z` fg white
    - `|[=r` bg middle grey

    ```python
    "This is |500Red text|n and this is normal again."
    "This is |[=jText on dark grey background"

    ```

    ----

    """
    import functools
    import re
    from collections import OrderedDict

    from django.conf import settings
    from evennia.utils import logger, utils
    from evennia.utils.utils import to_str

    MXP_ENABLED = settings.MXP_ENABLED

    # ANSI definitions

    ANSI_BEEP = "\07"
    ANSI_ESCAPE = "\033"
    ANSI_NORMAL = "\033[0m"

    ANSI_UNDERLINE = "\033[4m"
    ANSI_HILITE = "\033[1m"
    ANSI_UNHILITE = "\033[22m"
    ANSI_BLINK = "\033[5m"
    ANSI_INVERSE = "\033[7m"
    ANSI_INV_HILITE = "\033[1;7m"
    ANSI_INV_BLINK = "\033[7;5m"
    ANSI_BLINK_HILITE = "\033[1;5m"
    ANSI_INV_BLINK_HILITE = "\033[1;5;7m"

    # Foreground colors
    ANSI_BLACK = "\033[30m"
    ANSI_RED = "\033[31m"
    ANSI_GREEN = "\033[32m"
    ANSI_YELLOW = "\033[33m"
    ANSI_BLUE = "\033[34m"
    ANSI_MAGENTA = "\033[35m"
    ANSI_CYAN = "\033[36m"
    ANSI_WHITE = "\033[37m"

    # Background colors
    ANSI_BACK_BLACK = "\033[40m"
    ANSI_BACK_RED = "\033[41m"
    ANSI_BACK_GREEN = "\033[42m"
    ANSI_BACK_YELLOW = "\033[43m"
    ANSI_BACK_BLUE = "\033[44m"
    ANSI_BACK_MAGENTA = "\033[45m"
    ANSI_BACK_CYAN = "\033[46m"
    ANSI_BACK_WHITE = "\033[47m"

    # Formatting Characters
    ANSI_RETURN = "\r\n"
    ANSI_TAB = "\t"
    ANSI_SPACE = " "

    # Escapes
    ANSI_ESCAPES = ("{{", "\\\\", "\|\|")

    _PARSE_CACHE = OrderedDict()
    _PARSE_CACHE_SIZE = 10000

    _COLOR_NO_DEFAULT = settings.COLOR_NO_DEFAULT

    class ANSIParser(object):
        """
        A class that parses ANSI markup
        to ANSI command sequences

        We also allow to escape colour codes
        by prepending with an extra `|`.

        """

        # Mapping using {r {n etc

        ansi_map = [
            # alternative |-format
            (r"|n", ANSI_NORMAL),  # reset
            (r"|/", ANSI_RETURN),  # line break
            (r"|-", ANSI_TAB),  # tab
            (r"|>", ANSI_SPACE * 4),  # indent (4 spaces)
            (r"|_", ANSI_SPACE),  # space
            (r"|*", ANSI_INVERSE),  # invert
            (r"|^", ANSI_BLINK),  # blinking text (very annoying and not supported by all clients)
            (r"|u", ANSI_UNDERLINE),  # underline
            (r"|r", ANSI_HILITE + ANSI_RED),
            (r"|g", ANSI_HILITE + ANSI_GREEN),
            (r"|y", ANSI_HILITE + ANSI_YELLOW),
            (r"|b", ANSI_HILITE + ANSI_BLUE),
            (r"|m", ANSI_HILITE + ANSI_MAGENTA),
            (r"|c", ANSI_HILITE + ANSI_CYAN),
            (r"|w", ANSI_HILITE + ANSI_WHITE),  # pure white
            (r"|x", ANSI_HILITE + ANSI_BLACK),  # dark grey
            (r"|R", ANSI_UNHILITE + ANSI_RED),
            (r"|G", ANSI_UNHILITE + ANSI_GREEN),
            (r"|Y", ANSI_UNHILITE + ANSI_YELLOW),
            (r"|B", ANSI_UNHILITE + ANSI_BLUE),
            (r"|M", ANSI_UNHILITE + ANSI_MAGENTA),
            (r"|C", ANSI_UNHILITE + ANSI_CYAN),
            (r"|W", ANSI_UNHILITE + ANSI_WHITE),  # light grey
            (r"|X", ANSI_UNHILITE + ANSI_BLACK),  # pure black
            # hilight-able colors
            (r"|h", ANSI_HILITE),
            (r"|H", ANSI_UNHILITE),
            (r"|!R", ANSI_RED),
            (r"|!G", ANSI_GREEN),
            (r"|!Y", ANSI_YELLOW),
            (r"|!B", ANSI_BLUE),
            (r"|!M", ANSI_MAGENTA),
            (r"|!C", ANSI_CYAN),
            (r"|!W", ANSI_WHITE),  # light grey
            (r"|!X", ANSI_BLACK),  # pure black
            # normal ANSI backgrounds
            (r"|[R", ANSI_BACK_RED),
            (r"|[G", ANSI_BACK_GREEN),
            (r"|[Y", ANSI_BACK_YELLOW),
            (r"|[B", ANSI_BACK_BLUE),
            (r"|[M", ANSI_BACK_MAGENTA),
            (r"|[C", ANSI_BACK_CYAN),
            (r"|[W", ANSI_BACK_WHITE),  # light grey background
            (r"|[X", ANSI_BACK_BLACK),  # pure black background
        ]

        ansi_xterm256_bright_bg_map = [
            # "bright" ANSI backgrounds using xterm256 since ANSI
            # standard does not support it (will
            # fallback to dark ANSI background colors if xterm256
            # is not supported by client)
            # |-style variations
            (r"|[r", r"|[500"),
            (r"|[g", r"|[050"),
            (r"|[y", r"|[550"),
            (r"|[b", r"|[005"),
            (r"|[m", r"|[505"),
            (r"|[c", r"|[055"),
            (r"|[w", r"|[555"),  # white background
            (r"|[x", r"|[222"),
        ]  # dark grey background

        # xterm256. These are replaced directly by
        # the sub_xterm256 method

        if settings.COLOR_NO_DEFAULT:
            ansi_map = settings.COLOR_ANSI_EXTRA_MAP
            xterm256_fg = settings.COLOR_XTERM256_EXTRA_FG
            xterm256_bg = settings.COLOR_XTERM256_EXTRA_BG
            xterm256_gfg = settings.COLOR_XTERM256_EXTRA_GFG
            xterm256_gbg = settings.COLOR_XTERM256_EXTRA_GBG
            ansi_xterm256_bright_bg_map = settings.COLOR_ANSI_XTERM256_BRIGHT_BG_EXTRA_MAP
        else:
            xterm256_fg = [r"\|([0-5])([0-5])([0-5])"]  # |123 - foreground colour
            xterm256_bg = [r"\|\[([0-5])([0-5])([0-5])"]  # |[123 - background colour
            xterm256_gfg = [r"\|=([a-z])"]  # |=a - greyscale foreground
            xterm256_gbg = [r"\|\[=([a-z])"]  # |[=a - greyscale background
            ansi_map += settings.COLOR_ANSI_EXTRA_MAP
            xterm256_fg += settings.COLOR_XTERM256_EXTRA_FG
            xterm256_bg += settings.COLOR_XTERM256_EXTRA_BG
            xterm256_gfg += settings.COLOR_XTERM256_EXTRA_GFG
            xterm256_gbg += settings.COLOR_XTERM256_EXTRA_GBG
            ansi_xterm256_bright_bg_map += settings.COLOR_ANSI_XTERM256_BRIGHT_BG_EXTRA_MAP

        mxp_re = r"\|lc(.*?)\|lt(.*?)\|le"
        mxp_url_re = r"\|lu(.*?)\|lt(.*?)\|le"

        # prepare regex matching
        brightbg_sub = re.compile(
            r"|".join([r"(?<!\|)%s" % re.escape(tup[0]) for tup in ansi_xterm256_bright_bg_map]),
            re.DOTALL,
        )
        xterm256_fg_sub = re.compile(r"|".join(xterm256_fg), re.DOTALL)
        xterm256_bg_sub = re.compile(r"|".join(xterm256_bg), re.DOTALL)
        xterm256_gfg_sub = re.compile(r"|".join(xterm256_gfg), re.DOTALL)
        xterm256_gbg_sub = re.compile(r"|".join(xterm256_gbg), re.DOTALL)

        # xterm256_sub = re.compile(r"|".join([tup[0] for tup in xterm256_map]), re.DOTALL)
        ansi_sub = re.compile(r"|".join([re.escape(tup[0]) for tup in ansi_map]), re.DOTALL)
        mxp_sub = re.compile(mxp_re, re.DOTALL)
        mxp_url_sub = re.compile(mxp_url_re, re.DOTALL)

        # used by regex replacer to correctly map ansi sequences
        ansi_map_dict = dict(ansi_map)
        ansi_xterm256_bright_bg_map_dict = dict(ansi_xterm256_bright_bg_map)

        # prepare matching ansi codes overall
        ansi_re = r"\033\[[0-9;]+m"
        ansi_regex = re.compile(ansi_re)

        # escapes - these double-chars will be replaced with a single
        # instance of each
        ansi_escapes = re.compile(r"(%s)" % "|".join(ANSI_ESCAPES), re.DOTALL)

        # tabs/linebreaks |/ and |- should be able to be cleaned
        unsafe_tokens = re.compile(r"\|\/|\|-", re.DOTALL)

        def sub_ansi(self, ansimatch):
            """
            Replacer used by `re.sub` to replace ANSI
            markers with correct ANSI sequences

            Args:
                ansimatch (re.matchobject): The match.

            Returns:
                processed (str): The processed match string.

            """
            return self.ansi_map_dict.get(ansimatch.group(), "")

        def sub_brightbg(self, ansimatch):
            """
            Replacer used by `re.sub` to replace ANSI
            bright background markers with Xterm256 replacement

            Args:
                ansimatch (re.matchobject): The match.

            Returns:
                processed (str): The processed match string.

            """
            return self.ansi_xterm256_bright_bg_map_dict.get(ansimatch.group(), "")

        def sub_xterm256(self, rgbmatch, use_xterm256=False, color_type="fg"):
            """
            This is a replacer method called by `re.sub` with the matched
            tag. It must return the correct ansi sequence.

            It checks `self.do_xterm256` to determine if conversion
            to standard ANSI should be done or not.

            Args:
                rgbmatch (re.matchobject): The match.
                use_xterm256 (bool, optional): Don't convert 256-colors to 16.
                color_type (str): One of 'fg', 'bg', 'gfg', 'gbg'.

            Returns:
                processed (str): The processed match string.

            """
            if not rgbmatch:
                return ""

            # get tag, stripping the initial marker
            # rgbtag = rgbmatch.group()[1:]

            background = color_type in ("bg", "gbg")
            grayscale = color_type in ("gfg", "gbg")

            if not grayscale:
                # 6x6x6 color-cube (xterm indexes 16-231)
                try:
                    red, green, blue = [int(val) for val in rgbmatch.groups() if val is not None]
                except (IndexError, ValueError):
                    logger.log_trace()
                    return rgbmatch.group(0)
            else:
                # grayscale values (xterm indexes 0, 232-255, 15) for full spectrum
                try:
                    letter = [val for val in rgbmatch.groups() if val is not None][0]
                except IndexError:
                    logger.log_trace()
                    return rgbmatch.group(0)

                if letter == "a":
                    colval = 16  # pure black @ index 16 (first color cube entry)
                elif letter == "z":
                    colval = 231  # pure white @ index 231 (last color cube entry)
                else:
                    # letter in range [b..y] (exactly 24 values!)
                    colval = 134 + ord(letter)

                # ansi fallback logic expects r,g,b values in [0..5] range
                gray = (ord(letter) - 97) / 5.0
                red, green, blue = gray, gray, gray

            if use_xterm256:

                if not grayscale:
                    colval = 16 + (red * 36) + (green * 6) + blue

                return "\033[%s8;5;%sm" % (3 + int(background), colval)
                # replaced since some clients (like Potato) does not accept codes with leading zeroes,
                # see issue #1024.
                # return "\033[%s8;5;%s%s%sm" % (3 + int(background), colval // 100, (colval % 100) // 10, colval%10)  # noqa

            else:
                # xterm256 not supported, convert the rgb value to ansi instead
                if red == green == blue and red < 3:
                    if background:
                        return ANSI_BACK_BLACK
                    elif red >= 1:
                        return ANSI_HILITE + ANSI_BLACK
                    else:
                        return ANSI_NORMAL + ANSI_BLACK
                elif red == green == blue:
                    if background:
                        return ANSI_BACK_WHITE
                    elif red >= 4:
                        return ANSI_HILITE + ANSI_WHITE
                    else:
                        return ANSI_NORMAL + ANSI_WHITE
                elif red > green and red > blue:
                    if background:
                        return ANSI_BACK_RED
                    elif red >= 3:
                        return ANSI_HILITE + ANSI_RED
                    else:
                        return ANSI_NORMAL + ANSI_RED
                elif red == green and red > blue:
                    if background:
                        return ANSI_BACK_YELLOW
                    elif red >= 3:
                        return ANSI_HILITE + ANSI_YELLOW
                    else:
                        return ANSI_NORMAL + ANSI_YELLOW
                elif red == blue and red > green:
                    if background:
                        return ANSI_BACK_MAGENTA
                    elif red >= 3:
                        return ANSI_HILITE + ANSI_MAGENTA
                    else:
                        return ANSI_NORMAL + ANSI_MAGENTA
                elif green > blue:
                    if background:
                        return ANSI_BACK_GREEN
                    elif green >= 3:
                        return ANSI_HILITE + ANSI_GREEN
                    else:
                        return ANSI_NORMAL + ANSI_GREEN
                elif green == blue:
                    if background:
                        return ANSI_BACK_CYAN
                    elif green >= 3:
                        return ANSI_HILITE + ANSI_CYAN
                    else:
                        return ANSI_NORMAL + ANSI_CYAN
                else:  # mostly blue
                    if background:
                        return ANSI_BACK_BLUE
                    elif blue >= 3:
                        return ANSI_HILITE + ANSI_BLUE
                    else:
                        return ANSI_NORMAL + ANSI_BLUE

        def strip_raw_codes(self, string):
            """
            Strips raw ANSI codes from a string.

            Args:
                string (str): The string to strip.

            Returns:
                string (str): The processed string.

            """
            return self.ansi_regex.sub("", string)

        def strip_mxp(self, string):
            """
            Strips all MXP codes from a string.

            Args:
                string (str): The string to strip.

            Returns:
                string (str): The processed string.

            """
            string = self.mxp_sub.sub(r"\2", string)
            string = self.mxp_url_sub.sub(r"\1", string)  # replace with url verbatim
            return string

        def strip_unsafe_tokens(self, string):
            """
            Strip explicitly ansi line breaks and tabs.

            """
            return self.unsafe_tokens.sub("", string)

        def parse_ansi(self, string, strip_ansi=False, xterm256=False, mxp=False):
            """
            Parses a string, subbing color codes according to the stored
            mapping.

            Args:
                string (str): The string to parse.
                strip_ansi (boolean, optional): Strip all found ansi markup.
                xterm256 (boolean, optional): If actually using xterm256 or if
                    these values should be converted to 16-color ANSI.
                mxp (boolean, optional): Parse MXP commands in string.

            Returns:
                string (str): The parsed string.

            """
            if hasattr(string, "_raw_string"):
                if strip_ansi:
                    return string.clean()
                else:
                    return string.raw()

            if not string:
                return ""

            # check cached parsings
            global _PARSE_CACHE
            cachekey = "%s-%s-%s-%s" % (string, strip_ansi, xterm256, mxp)
            if cachekey in _PARSE_CACHE:
                return _PARSE_CACHE[cachekey]

            # pre-convert bright colors to xterm256 color tags
            string = self.brightbg_sub.sub(self.sub_brightbg, string)

            def do_xterm256_fg(part):
                return self.sub_xterm256(part, xterm256, "fg")

            def do_xterm256_bg(part):
                return self.sub_xterm256(part, xterm256, "bg")

            def do_xterm256_gfg(part):
                return self.sub_xterm256(part, xterm256, "gfg")

            def do_xterm256_gbg(part):
                return self.sub_xterm256(part, xterm256, "gbg")

            in_string = utils.to_str(string)

            # do string replacement
            parsed_string = []
            parts = self.ansi_escapes.split(in_string) + [" "]
            for part, sep in zip(parts[::2], parts[1::2]):
                pstring = self.xterm256_fg_sub.sub(do_xterm256_fg, part)
                pstring = self.xterm256_bg_sub.sub(do_xterm256_bg, pstring)
                pstring = self.xterm256_gfg_sub.sub(do_xterm256_gfg, pstring)
                pstring = self.xterm256_gbg_sub.sub(do_xterm256_gbg, pstring)
                pstring = self.ansi_sub.sub(self.sub_ansi, pstring)
                parsed_string.append("%s%s" % (pstring, sep[0].strip()))
            parsed_string = "".join(parsed_string)

            if not mxp:
                parsed_string = self.strip_mxp(parsed_string)

            if strip_ansi:
                # remove all ansi codes (including those manually
                # inserted in string)
                return self.strip_raw_codes(parsed_string)

            # cache and crop old cache
            _PARSE_CACHE[cachekey] = parsed_string
            if len(_PARSE_CACHE) > _PARSE_CACHE_SIZE:
                _PARSE_CACHE.popitem(last=False)

            return parsed_string

    ANSI_PARSER = ANSIParser()

    #
    # Access function
    #

    def parse_ansi(string, strip_ansi=False, parser=ANSI_PARSER, xterm256=False, mxp=False):
        """
        Parses a string, subbing color codes as needed.

        Args:
            string (str): The string to parse.
            strip_ansi (bool, optional): Strip all ANSI sequences.
            parser (ansi.AnsiParser, optional): A parser instance to use.
            xterm256 (bool, optional): Support xterm256 or not.
            mxp (bool, optional): Support MXP markup or not.

        Returns:
            string (str): The parsed string.

        """
        string = string or ""
        return parser.parse_ansi(string, strip_ansi=strip_ansi, xterm256=xterm256, mxp=mxp)

    def strip_ansi(string, parser=ANSI_PARSER):
        """
        Strip all ansi from the string. This handles the Evennia-specific
        markup.

        Args:
            string (str): The string to strip.
            parser (ansi.AnsiParser, optional): The parser to use.

        Returns:
            string (str): The stripped string.

        """
        string = string or ""
        return parser.parse_ansi(string, strip_ansi=True)

    def strip_raw_ansi(string, parser=ANSI_PARSER):
        """
        Remove raw ansi codes from string. This assumes pure
        ANSI-bytecodes in the string.

        Args:
            string (str): The string to parse.
            parser (bool, optional): The parser to use.

        Returns:
            string (str): the stripped string.

        """
        string = string or ""
        return parser.strip_raw_codes(string)

    def strip_unsafe_tokens(string, parser=ANSI_PARSER):
        """
        Strip markup that can be used to create visual exploits
        (notably linebreaks and tags)

        """
        return parser.strip_unsafe_tokens(string)

    def strip_mxp(string, parser=ANSI_PARSER):
        """
        Strip MXP markup.

        """
        string = string or ""
        return parser.strip_mxp(string)

    def raw(string):
        """
        Escapes a string into a form which won't be colorized by the ansi
        parser.

        Returns:
            string (str): The raw, escaped string.

        """
        string = string or ""
        return string.replace("{", "{{").replace("|", "||")

    # ------------------------------------------------------------
    #
    # ANSIString - ANSI-aware string class
    #
    # ------------------------------------------------------------

    def _spacing_preflight(func):
        """
        This wrapper function is used to do some preflight checks on
        functions used for padding ANSIStrings.

        """

        @functools.wraps(func)
        def wrapped(self, width=78, fillchar=None):
            if fillchar is None:
                fillchar = " "
            if (len(fillchar) != 1) or (not isinstance(fillchar, str)):
                raise TypeError("must be char, not %s" % type(fillchar))
            if not isinstance(width, int):
                raise TypeError("integer argument expected, got %s" % type(width))
            _difference = width - len(self)
            if _difference <= 0:
                return self
            return func(self, width, fillchar, _difference)

        return wrapped

    def _query_super(func_name):
        """
        Have the string class handle this with the cleaned string instead
        of ANSIString.

        """

        def wrapped(self, *args, **kwargs):
            return getattr(self.clean(), func_name)(*args, **kwargs)

        return wrapped

    def _on_raw(func_name):
        """
        Like query_super, but makes the operation run on the raw string.

        """

        def wrapped(self, *args, **kwargs):
            args = list(args)
            try:
                string = args.pop(0)
                if hasattr(string, "_raw_string"):
                    args.insert(0, string.raw())
                else:
                    args.insert(0, string)
            except IndexError:
                # just skip out if there are no more strings
                pass
            result = getattr(self._raw_string, func_name)(*args, **kwargs)
            if isinstance(result, str):
                return ANSIString(result, decoded=True)
            return result

        return wrapped

    def _transform(func_name):
        """
        Some string functions, like those manipulating capital letters,
        return a string the same length as the original. This function
        allows us to do the same, replacing all the non-coded characters
        with the resulting string.

        """

        def wrapped(self, *args, **kwargs):
            replacement_string = _query_super(func_name)(self, *args, **kwargs)
            to_string = []
            char_counter = 0
            for index in range(0, len(self._raw_string)):
                if index in self._code_indexes:
                    to_string.append(self._raw_string[index])
                elif index in self._char_indexes:
                    to_string.append(replacement_string[char_counter])
                    char_counter += 1
            return ANSIString(
                "".join(to_string),
                decoded=True,
                code_indexes=self._code_indexes,
                char_indexes=self._char_indexes,
                clean_string=replacement_string,
            )

        return wrapped

    class ANSIMeta(type):
        """
        Many functions on ANSIString are just light wrappers around the string
        base class. We apply them here, as part of the classes construction.

        """

        def __init__(cls, *args, **kwargs):
            for func_name in [
                "count",
                "startswith",
                "endswith",
                "find",
                "index",
                "isalnum",
                "isalpha",
                "isdigit",
                "islower",
                "isspace",
                "istitle",
                "isupper",
                "rfind",
                "rindex",
                "__len__",
            ]:
                setattr(cls, func_name, _query_super(func_name))
            for func_name in ["__mod__", "expandtabs", "decode", "replace", "format", "encode"]:
                setattr(cls, func_name, _on_raw(func_name))
            for func_name in ["capitalize", "translate", "lower", "upper", "swapcase"]:
                setattr(cls, func_name, _transform(func_name))
            super().__init__(*args, **kwargs)

    class ANSIString(str, metaclass=ANSIMeta):
        """
        Unicode-like object that is aware of ANSI codes.

        This class can be used nearly identically to strings, in that it will
        report string length, handle slices, etc, much like a string object
        would. The methods should be used identically as string methods are.

        There is at least one exception to this (and there may be more, though
        they have not come up yet). When using ''.join() or u''.join() on an
        ANSIString, color information will get lost. You must use
        ANSIString('').join() to preserve color information.

        This implementation isn't perfectly clean, as it doesn't really have an
        understanding of what the codes mean in order to eliminate
        redundant characters-- though cleaning up the strings might end up being
        inefficient and slow without some C code when dealing with larger values.
        Such enhancements could be made as an enhancement to ANSI_PARSER
        if needed, however.

        If one is going to use ANSIString, one should generally avoid converting
        away from it until one is about to send information on the wire. This is
        because escape sequences in the string may otherwise already be decoded,
        and taken literally the second time around.

        """

        # A compiled Regex for the format mini-language:
        # https://docs.python.org/3/library/string.html#formatspec
        re_format = re.compile(
            r"(?i)(?P<just>(?P<fill>.)?(?P<align>\<|\>|\=|\^))?(?P<sign>\+|\-| )?(?P<alt>\#)?"
            r"(?P<zero>0)?(?P<width>\d+)?(?P<grouping>\_|\,)?(?:\.(?P<precision>\d+))?"
            r"(?P<type>b|c|d|e|E|f|F|g|G|n|o|s|x|X|%)?"
        )

        def __new__(cls, *args, **kwargs):
            """
            When creating a new ANSIString, you may use a custom parser that has
            the same attributes as the standard one, and you may declare the
            string to be handled as already decoded. It is important not to double
            decode strings, as escapes can only be respected once.

            Internally, ANSIString can also passes itself precached code/character
            indexes and clean strings to avoid doing extra work when combining
            ANSIStrings.

            """
            string = args[0]
            if not isinstance(string, str):
                string = to_str(string)
            parser = kwargs.get("parser", ANSI_PARSER)
            decoded = kwargs.get("decoded", False) or hasattr(string, "_raw_string")
            code_indexes = kwargs.pop("code_indexes", None)
            char_indexes = kwargs.pop("char_indexes", None)
            clean_string = kwargs.pop("clean_string", None)
            # All True, or All False, not just one.
            checks = [x is None for x in [code_indexes, char_indexes, clean_string]]
            if not len(set(checks)) == 1:
                raise ValueError(
                    "You must specify code_indexes, char_indexes, "
                    "and clean_string together, or not at all."
                )
            if not all(checks):
                decoded = True
            if not decoded:
                # Completely new ANSI String
                clean_string = parser.parse_ansi(string, strip_ansi=True, mxp=MXP_ENABLED)
                string = parser.parse_ansi(string, xterm256=True, mxp=MXP_ENABLED)
            elif clean_string is not None:
                # We have an explicit clean string.
                pass
            elif hasattr(string, "_clean_string"):
                # It's already an ANSIString
                clean_string = string._clean_string
                code_indexes = string._code_indexes
                char_indexes = string._char_indexes
                string = string._raw_string
            else:
                # It's a string that has been pre-ansi decoded.
                clean_string = parser.strip_raw_codes(string)

            if not isinstance(string, str):
                string = string.decode("utf-8")

            ansi_string = super().__new__(ANSIString, to_str(clean_string))
            ansi_string._raw_string = string
            ansi_string._clean_string = clean_string
            ansi_string._code_indexes = code_indexes
            ansi_string._char_indexes = char_indexes
            return ansi_string

        def __str__(self):
            return self._raw_string

        def __format__(self, format_spec):
            """
            This magic method covers ANSIString's behavior within a str.format() or f-string.

            Current features supported: fill, align, width.

            Args:
                format_spec (str): The format specification passed by f-string or str.format(). This is
                a string such as "0<30" which would mean "left justify to 30, filling with zeros".
                The full specification can be found at
                https://docs.python.org/3/library/string.html#formatspec

            Returns:
                ansi_str (str): The formatted ANSIString's .raw() form, for display.

            """
            # This calls the compiled regex stored on ANSIString's class to analyze the format spec.
            # It returns a dictionary.
            format_data = self.re_format.match(format_spec).groupdict()
            clean = self.clean()
            base_output = ANSIString(self.raw())
            align = format_data.get("align", "<")
            fill = format_data.get("fill", " ")

            # Need to coerce width into an integer. We can be certain that it's numeric thanks to regex.
            width = format_data.get("width", None)
            if width is None:
                width = len(clean)
            else:
                width = int(width)

            if align == "<":
                base_output = self.ljust(width, fill)
            elif align == ">":
                base_output = self.rjust(width, fill)
            elif align == "^":
                base_output = self.center(width, fill)
            elif align == "=":
                pass

            # Return the raw string with ANSI markup, ready to be displayed.
            return base_output.raw()

        def __repr__(self):
            """
            Let's make the repr the command that would actually be used to
            construct this object, for convenience and reference.

            """
            return "ANSIString(%s, decoded=True)" % repr(self._raw_string)

        def __init__(self, *_, **kwargs):
            """
            When the ANSIString is first initialized, a few internal variables
            have to be set.

            The first is the parser. It is possible to replace Evennia's standard
            ANSI parser with one of your own syntax if you wish, so long as it
            implements the same interface.

            The second is the _raw_string. This is the original "dumb" string
            with ansi escapes that ANSIString represents.

            The third thing to set is the _clean_string. This is a string that is
            devoid of all ANSI Escapes.

            Finally, _code_indexes and _char_indexes are defined. These are lookup
            tables for which characters in the raw string are related to ANSI
            escapes, and which are for the readable text.

            """
            self.parser = kwargs.pop("parser", ANSI_PARSER)
            super().__init__()
            if self._code_indexes is None:
                self._code_indexes, self._char_indexes = self._get_indexes()

        @staticmethod
        def _shifter(iterable, offset):
            """
            Takes a list of integers, and produces a new one incrementing all
            by a number.

            """
            if not offset:
                return iterable
            return [i + offset for i in iterable]

        @classmethod
        def _adder(cls, first, second):
            """
            Joins two ANSIStrings, preserving calculated info.

            """

            raw_string = first._raw_string + second._raw_string
            clean_string = first._clean_string + second._clean_string
            code_indexes = first._code_indexes[:]
            char_indexes = first._char_indexes[:]
            code_indexes.extend(cls._shifter(second._code_indexes, len(first._raw_string)))
            char_indexes.extend(cls._shifter(second._char_indexes, len(first._raw_string)))
            return ANSIString(
                raw_string,
                code_indexes=code_indexes,
                char_indexes=char_indexes,
                clean_string=clean_string,
            )

        def __add__(self, other):
            """
            We have to be careful when adding two strings not to reprocess things
            that don't need to be reprocessed, lest we end up with escapes being
            interpreted literally.

            """
            if not isinstance(other, str):
                return NotImplemented
            if not isinstance(other, ANSIString):
                other = ANSIString(other)
            return self._adder(self, other)

        def __radd__(self, other):
            """
            Likewise, if we're on the other end.

            """
            if not isinstance(other, str):
                return NotImplemented
            if not isinstance(other, ANSIString):
                other = ANSIString(other)
            return self._adder(other, self)

        def __getslice__(self, i, j):
            """
            This function is deprecated, so we just make it call the proper
            function.

            """
            return self.__getitem__(slice(i, j))

        def _slice(self, slc):
            """
            This function takes a slice() object.

            Slices have to be handled specially. Not only are they able to specify
            a start and end with [x:y], but many forget that they can also specify
            an interval with [x:y:z]. As a result, not only do we have to track
            the ANSI Escapes that have played before the start of the slice, we
            must also replay any in these intervals, should they exist.

            Thankfully, slicing the _char_indexes table gives us the actual
            indexes that need slicing in the raw string. We can check between
            those indexes to figure out what escape characters need to be
            replayed.

            """
            char_indexes = self._char_indexes
            slice_indexes = char_indexes[slc]
            # If it's the end of the string, we need to append final color codes.
            if not slice_indexes:
                # if we find no characters it may be because we are just outside
                # of the interval, using an open-ended slice. We must replay all
                # of the escape characters until/after this point.
                if char_indexes:
                    if slc.start is None and slc.stop is None:
                        # a [:] slice of only escape characters
                        return ANSIString(self._raw_string[slc])
                    if slc.start is None:
                        # this is a [:x] slice
                        return ANSIString(self._raw_string[: char_indexes[0]])
                    if slc.stop is None:
                        # a [x:] slice
                        return ANSIString(self._raw_string[char_indexes[-1] + 1 :])
                return ANSIString("")
            try:
                string = self[slc.start or 0]._raw_string
            except IndexError:
                return ANSIString("")
            last_mark = slice_indexes[0]
            # Check between the slice intervals for escape sequences.
            i = None
            for i in slice_indexes[1:]:
                for index in range(last_mark, i):
                    if index in self._code_indexes:
                        string += self._raw_string[index]
                last_mark = i
                try:
                    string += self._raw_string[i]
                except IndexError:
                    # raw_string not long enough
                    pass
            if i is not None:
                append_tail = self._get_interleving(char_indexes.index(i) + 1)
            else:
                append_tail = ""
            return ANSIString(string + append_tail, decoded=True)

        def __getitem__(self, item):
            """
            Gateway for slices and getting specific indexes in the ANSIString. If
            this is a regexable ANSIString, it will get the data from the raw
            string instead, bypassing ANSIString's intelligent escape skipping,
            for reasons explained in the __new__ method's docstring.

            """
            if isinstance(item, slice):
                # Slices must be handled specially.
                return self._slice(item)
            try:
                self._char_indexes[item]
            except IndexError:
                raise IndexError("ANSIString Index out of range")
            # Get character codes after the index as well.
            if self._char_indexes[-1] == self._char_indexes[item]:
                append_tail = self._get_interleving(item + 1)
            else:
                append_tail = ""
            item = self._char_indexes[item]

            clean = self._raw_string[item]
            result = ""
            # Get the character they're after, and replay all escape sequences
            # previous to it.
            for index in range(0, item + 1):
                if index in self._code_indexes:
                    result += self._raw_string[index]
            return ANSIString(result + clean + append_tail, decoded=True)

        def clean(self):
            """
            Return a string object *without* the ANSI escapes.

            Returns:
                clean_string (str): A unicode object with no ANSI escapes.

            """
            return self._clean_string

        def raw(self):
            """
            Return a string object with the ANSI escapes.

            Returns:
                raw (str): A unicode object *with* the raw ANSI escape sequences.

            """
            return self._raw_string

        def partition(self, sep, reverse=False):
            """
            Splits once into three sections (with the separator being the middle section)

            We use the same techniques we used in split() to make sure each are
            colored.

            Args:
                sep (str): The separator to split the string on.
                reverse (boolean): Whether to split the string on the last
                    occurrence of the separator rather than the first.

            Returns:
                ANSIString: The part of the string before the separator
                ANSIString: The separator itself
                ANSIString: The part of the string after the separator.

            """
            if hasattr(sep, "_clean_string"):
                sep = sep.clean()
            if reverse:
                parent_result = self._clean_string.rpartition(sep)
            else:
                parent_result = self._clean_string.partition(sep)
            current_index = 0
            result = tuple()
            for section in parent_result:
                result += (self[current_index : current_index + len(section)],)
                current_index += len(section)
            return result

        def _get_indexes(self):
            """
            Two tables need to be made, one which contains the indexes of all
            readable characters, and one which contains the indexes of all ANSI
            escapes. It's important to remember that ANSI escapes require more
            that one character at a time, though no readable character needs more
            than one character, since the string base class abstracts that away
            from us. However, several readable characters can be placed in a row.

            We must use regexes here to figure out where all the escape sequences
            are hiding in the string. Then we use the ranges of their starts and
            ends to create a final, comprehensive list of all indexes which are
            dedicated to code, and all dedicated to text.

            It's possible that only one of these tables is actually needed, the
            other assumed to be what isn't in the first.

            """

            code_indexes = []
            for match in self.parser.ansi_regex.finditer(self._raw_string):
                code_indexes.extend(list(range(match.start(), match.end())))
            if not code_indexes:
                # Plain string, no ANSI codes.
                return code_indexes, list(range(0, len(self._raw_string)))
            # all indexes not occupied by ansi codes are normal characters
            char_indexes = [i for i in range(len(self._raw_string)) if i not in code_indexes]
            return code_indexes, char_indexes

        def _get_interleving(self, index):
            """
            Get the code characters from the given slice end to the next
            character.

            """
            try:
                index = self._char_indexes[index - 1]
            except IndexError:
                return ""
            s = ""
            while True:
                index += 1
                if index in self._char_indexes:
                    break
                elif index in self._code_indexes:
                    s += self._raw_string[index]
                else:
                    break
            return s

        def __mul__(self, other):
            """
            Multiplication method. Implemented for performance reasons.

            """
            if not isinstance(other, int):
                return NotImplemented
            raw_string = self._raw_string * other
            clean_string = self._clean_string * other
            code_indexes = self._code_indexes[:]
            char_indexes = self._char_indexes[:]
            for i in range(other):
                code_indexes.extend(self._shifter(self._code_indexes, i * len(self._raw_string)))
                char_indexes.extend(self._shifter(self._char_indexes, i * len(self._raw_string)))
            return ANSIString(
                raw_string,
                code_indexes=code_indexes,
                char_indexes=char_indexes,
                clean_string=clean_string,
            )

        def __rmul__(self, other):
            return self.__mul__(other)

        def split(self, by=None, maxsplit=-1):
            """
            Splits a string based on a separator.

            Stolen from PyPy's pure Python string implementation, tweaked for
            ANSIString.

            PyPy is distributed under the MIT licence.
            http://opensource.org/licenses/MIT

            Args:
                by (str): A string to search for which will be used to split
                    the string. For instance, ',' for 'Hello,world' would
                    result in ['Hello', 'world']
                maxsplit (int): The maximum number of times to split the string.
                    For example, a maxsplit of 2 with a by of ',' on the string
                    'Hello,world,test,string' would result in
                    ['Hello', 'world', 'test,string']
            Returns:
                result (list of ANSIStrings): A list of ANSIStrings derived from
                    this string.

            """
            drop_spaces = by is None
            if drop_spaces:
                by = " "

            bylen = len(by)
            if bylen == 0:
                raise ValueError("empty separator")

            res = []
            start = 0
            while maxsplit != 0:
                next = self._clean_string.find(by, start)
                if next < 0:
                    break
                # Get character codes after the index as well.
                res.append(self[start:next])
                start = next + bylen
                maxsplit -= 1  # NB. if it's already < 0, it stays < 0

            res.append(self[start : len(self)])
            if drop_spaces:
                return [part for part in res if part != ""]
            return res

        def rsplit(self, by=None, maxsplit=-1):
            """
            Like split, but starts from the end of the string rather than the
            beginning.

            Stolen from PyPy's pure Python string implementation, tweaked for
            ANSIString.

            PyPy is distributed under the MIT licence.
            http://opensource.org/licenses/MIT

            Args:
                by (str): A string to search for which will be used to split
                    the string. For instance, ',' for 'Hello,world' would
                    result in ['Hello', 'world']
                maxsplit (int): The maximum number of times to split the string.
                    For example, a maxsplit of 2 with a by of ',' on the string
                    'Hello,world,test,string' would result in
                    ['Hello,world', 'test', 'string']
            Returns:
                result (list of ANSIStrings): A list of ANSIStrings derived from
                    this string.

            """
            res = []
            end = len(self)
            drop_spaces = by is None
            if drop_spaces:
                by = " "
            bylen = len(by)
            if bylen == 0:
                raise ValueError("empty separator")

            while maxsplit != 0:
                next = self._clean_string.rfind(by, 0, end)
                if next < 0:
                    break
                # Get character codes after the index as well.
                res.append(self[next + bylen : end])
                end = next
                maxsplit -= 1  # NB. if it's already < 0, it stays < 0

            res.append(self[:end])
            res.reverse()
            if drop_spaces:
                return [part for part in res if part != ""]
            return res

        def strip(self, chars=None):
            """
            Strip from both ends, taking ANSI markers into account.

            Args:
                chars (str, optional): A string containing individual characters
                    to strip off of both ends of the string. By default, any blank
                    spaces are trimmed.
            Returns:
                result (ANSIString): A new ANSIString with the ends trimmed of the
                    relevant characters.

            """
            clean = self._clean_string
            raw = self._raw_string

            # count continuous sequence of chars from left and right
            nlen = len(clean)
            nlstripped = nlen - len(clean.lstrip(chars))
            nrstripped = nlen - len(clean.rstrip(chars))

            # within the stripped regions, only retain parts of the raw
            # string *not* matching the clean string (these are ansi/mxp tags)
            lstripped = ""
            ic, ir1 = 0, 0
            while nlstripped:
                if ic >= nlstripped:
                    break
                elif raw[ir1] != clean[ic]:
                    lstripped += raw[ir1]
                else:
                    ic += 1
                ir1 += 1
            rstripped = ""
            ic, ir2 = nlen - 1, len(raw) - 1
            while nrstripped:
                if nlen - ic > nrstripped:
                    break
                elif raw[ir2] != clean[ic]:
                    rstripped += raw[ir2]
                else:
                    ic -= 1
                ir2 -= 1
            rstripped = rstripped[::-1]
            return ANSIString(lstripped + raw[ir1 : ir2 + 1] + rstripped)

        def lstrip(self, chars=None):
            """
            Strip from the left, taking ANSI markers into account.

            Args:
                chars (str, optional): A string containing individual characters
                    to strip off of the left end of the string. By default, any
                    blank spaces are trimmed.
            Returns:
                result (ANSIString): A new ANSIString with the left end trimmed of
                    the relevant characters.

            """
            clean = self._clean_string
            raw = self._raw_string

            # count continuous sequence of chars from left and right
            nlen = len(clean)
            nlstripped = nlen - len(clean.lstrip(chars))
            # within the stripped regions, only retain parts of the raw
            # string *not* matching the clean string (these are ansi/mxp tags)
            lstripped = ""
            ic, ir1 = 0, 0
            while nlstripped:
                if ic >= nlstripped:
                    break
                elif raw[ir1] != clean[ic]:
                    lstripped += raw[ir1]
                else:
                    ic += 1
                ir1 += 1
            return ANSIString(lstripped + raw[ir1:])

        def rstrip(self, chars=None):
            """
            Strip from the right, taking ANSI markers into account.

            Args:
                chars (str, optional): A string containing individual characters
                    to strip off of the right end of the string. By default, any
                    blank spaces are trimmed.
            Returns:
                result (ANSIString): A new ANSIString with the right end trimmed of
                    the relevant characters.

            """
            clean = self._clean_string
            raw = self._raw_string
            nlen = len(clean)
            nrstripped = nlen - len(clean.rstrip(chars))
            rstripped = ""
            ic, ir2 = nlen - 1, len(raw) - 1
            while nrstripped:
                if nlen - ic > nrstripped:
                    break
                elif raw[ir2] != clean[ic]:
                    rstripped += raw[ir2]
                else:
                    ic -= 1
                ir2 -= 1
            rstripped = rstripped[::-1]
            return ANSIString(raw[: ir2 + 1] + rstripped)

        def join(self, iterable):
            """
            Joins together strings in an iterable, using this string between each
            one.

            NOTE: This should always be used for joining strings when ANSIStrings
            are involved. Otherwise color information will be discarded by python,
            due to details in the C implementation of strings.

            Args:
                iterable (list of strings): A list of strings to join together

            Returns:
                ANSIString: A single string with all of the iterable's
                    contents concatenated, with this string between each.

            Examples:
                ::

                    >>> ANSIString(', ').join(['up', 'right', 'left', 'down'])
                    ANSIString('up, right, left, down')

            """
            result = ANSIString("")
            last_item = None
            for item in iterable:
                if last_item is not None:
                    result += self._raw_string
                if not isinstance(item, ANSIString):
                    item = ANSIString(item)
                result += item
                last_item = item
            return result

        def _filler(self, char, amount):
            """
            Generate a line of characters in a more efficient way than just adding
            ANSIStrings.

            """
            if not isinstance(char, ANSIString):
                line = char * amount
                return ANSIString(
                    char * amount,
                    code_indexes=[],
                    char_indexes=list(range(0, len(line))),
                    clean_string=char,
                )
            try:
                start = char._code_indexes[0]
            except IndexError:
                start = None
            end = char._char_indexes[0]
            prefix = char._raw_string[start:end]
            postfix = char._raw_string[end + 1 :]
            line = char._clean_string * amount
            code_indexes = [i for i in range(0, len(prefix))]
            length = len(prefix) + len(line)
            code_indexes.extend([i for i in range(length, length + len(postfix))])
            char_indexes = self._shifter(list(range(0, len(line))), len(prefix))
            raw_string = prefix + line + postfix
            return ANSIString(
                raw_string, clean_string=line, char_indexes=char_indexes, code_indexes=code_indexes
            )

        # The following methods should not be called with the '_difference' argument explicitly. This is
        # data provided by the wrapper _spacing_preflight.
        @_spacing_preflight
        def center(self, width, fillchar, _difference):
            """
            Center some text with some spaces padding both sides.

            Args:
                width (int): The target width of the output string.
                fillchar (str): A single character string to pad the output string
                    with.
            Returns:
                result (ANSIString): A string padded on both ends with fillchar.

            """
            remainder = _difference % 2
            _difference //= 2
            spacing = self._filler(fillchar, _difference)
            result = spacing + self + spacing + self._filler(fillchar, remainder)
            return result

        @_spacing_preflight
        def ljust(self, width, fillchar, _difference):
            """
            Left justify some text.

            Args:
                width (int): The target width of the output string.
                fillchar (str): A single character string to pad the output string
                    with.
            Returns:
                result (ANSIString): A string padded on the right with fillchar.

            """
            return self + self._filler(fillchar, _difference)

        @_spacing_preflight
        def rjust(self, width, fillchar, _difference):
            """
            Right justify some text.

            Args:
                width (int): The target width of the output string.
                fillchar (str): A single character string to pad the output string
                    with.
            Returns:
                result (ANSIString): A string padded on the left with fillchar.

            """
            return self._filler(fillchar, _difference) + self