"""
A module for finding, managing, and using fonts across platforms.

This module provides a single `FontManager` instance, ``fontManager``, that can
be shared across backends and platforms.  The `findfont`
function returns the best TrueType (TTF) font file in the local or
system font path that matches the specified `FontProperties`
instance.  The `FontManager` also handles Adobe Font Metrics
(AFM) font files for use by the PostScript backend.
The `FontManager.addfont` function adds a custom font from a file without
installing it into your operating system.

The design is based on the `W3C Cascading Style Sheet, Level 1 (CSS1)
font specification <http://www.w3.org/TR/1998/REC-CSS2-19980512/>`_.
Future versions may implement the Level 2 or 2.1 specifications.
"""

# KNOWN ISSUES
#
#   - documentation
#   - font variant is untested
#   - font stretch is incomplete
#   - font size is incomplete
#   - default font algorithm needs improvement and testing
#   - setWeights function needs improvement
#   - 'light' is an invalid weight value, remove it.

from __future__ import annotations

from base64 import b64encode
from collections import namedtuple
import copy
import dataclasses
from functools import lru_cache
from io import BytesIO
import json
import logging
from numbers import Number
import os
from pathlib import Path
import plistlib
import re
import subprocess
import sys
import threading

import matplotlib as mpl
from matplotlib import _api, _afm, cbook, ft2font
from matplotlib._fontconfig_pattern import (
    parse_fontconfig_pattern, generate_fontconfig_pattern)
from matplotlib.rcsetup import _validators

_log = logging.getLogger(__name__)

font_scalings = {
    'xx-small': 0.579,
    'x-small':  0.694,
    'small':    0.833,
    'medium':   1.0,
    'large':    1.200,
    'x-large':  1.440,
    'xx-large': 1.728,
    'larger':   1.2,
    'smaller':  0.833,
    None:       1.0,
}
stretch_dict = {
    'ultra-condensed': 100,
    'extra-condensed': 200,
    'condensed':       300,
    'semi-condensed':  400,
    'normal':          500,
    'semi-expanded':   600,
    'semi-extended':   600,
    'expanded':        700,
    'extended':        700,
    'extra-expanded':  800,
    'extra-extended':  800,
    'ultra-expanded':  900,
    'ultra-extended':  900,
}
weight_dict = {
    'ultralight': 100,
    'light':      200,
    'normal':     400,
    'regular':    400,
    'book':       400,
    'medium':     500,
    'roman':      500,
    'semibold':   600,
    'demibold':   600,
    'demi':       600,
    'bold':       700,
    'heavy':      800,
    'extra bold': 800,
    'black':      900,
}
_weight_regexes = [
    # From fontconfig's FcFreeTypeQueryFaceInternal; not the same as
    # weight_dict!
    ("thin", 100),
    ("extralight", 200),
    ("ultralight", 200),
    ("demilight", 350),
    ("semilight", 350),
    ("light", 300),  # Needs to come *after* demi/semilight!
    ("book", 380),
    ("regular", 400),
    ("normal", 400),
    ("medium", 500),
    ("demibold", 600),
    ("demi", 600),
    ("semibold", 600),
    ("extrabold", 800),
    ("superbold", 800),
    ("ultrabold", 800),
    ("bold", 700),  # Needs to come *after* extra/super/ultrabold!
    ("ultrablack", 1000),
    ("superblack", 1000),
    ("extrablack", 1000),
    (r"\bultra", 1000),
    ("black", 900),  # Needs to come *after* ultra/super/extrablack!
    ("heavy", 900),
]
font_family_aliases = {
    'serif',
    'sans-serif',
    'sans serif',
    'cursive',
    'fantasy',
    'monospace',
    'sans',
}

_ExceptionProxy = namedtuple('_ExceptionProxy', ['klass', 'message'])

# OS Font paths
try:
    _HOME = Path.home()
except Exception:  # Exceptions thrown by home() are not specified...
    _HOME = Path(os.devnull)  # Just an arbitrary path with no children.
MSFolders = \
    r'Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders'
MSFontDirectories = [
    r'SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts',
    r'SOFTWARE\Microsoft\Windows\CurrentVersion\Fonts']
MSUserFontDirectories = [
    str(_HOME / 'AppData/Local/Microsoft/Windows/Fonts'),
    str(_HOME / 'AppData/Roaming/Microsoft/Windows/Fonts'),
]
X11FontDirectories = [
    # an old standard installation point
    "/usr/X11R6/lib/X11/fonts/TTF/",
    "/usr/X11/lib/X11/fonts",
    # here is the new standard location for fonts
    "/usr/share/fonts/",
    # documented as a good place to install new fonts
    "/usr/local/share/fonts/",
    # common application, not really useful
    "/usr/lib/openoffice/share/fonts/truetype/",
    # user fonts
    str((Path(os.environ.get('XDG_DATA_HOME') or _HOME / ".local/share"))
        / "fonts"),
    str(_HOME / ".fonts"),
]
OSXFontDirectories = [
    "/Library/Fonts/",
    "/Network/Library/Fonts/",
    "/System/Library/Fonts/",
    # fonts installed via MacPorts
    "/opt/local/share/fonts",
    # user fonts
    str(_HOME / "Library/Fonts"),
]


def get_fontext_synonyms(fontext):
    """
    Return a list of file extensions that are synonyms for
    the given file extension *fileext*.
    """
    return {
        'afm': ['afm'],
        'otf': ['otf', 'ttc', 'ttf'],
        'ttc': ['otf', 'ttc', 'ttf'],
        'ttf': ['otf', 'ttc', 'ttf'],
    }[fontext]


def list_fonts(directory, extensions):
    """
    Return a list of all fonts matching any of the extensions, found
    recursively under the directory.
    """
    extensions = ["." + ext for ext in extensions]
    return [os.path.join(dirpath, filename)
            # os.walk ignores access errors, unlike Path.glob.
            for dirpath, _, filenames in os.walk(directory)
            for filename in filenames
            if Path(filename).suffix.lower() in extensions]


def win32FontDirectory():
    r"""
    Return the user-specified font directory for Win32.  This is
    looked up from the registry key ::

      \\HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders\Fonts

    If the key is not found, ``%WINDIR%\Fonts`` will be returned.
    """  # noqa: E501
    import winreg
    try:
        with winreg.OpenKey(winreg.HKEY_CURRENT_USER, MSFolders) as user:
            return winreg.QueryValueEx(user, 'Fonts')[0]
    except OSError:
        return os.path.join(os.environ['WINDIR'], 'Fonts')


def _get_win32_installed_fonts():
    """List the font paths known to the Windows registry."""
    import winreg
    items = set()
    # Search and resolve fonts listed in the registry.
    for domain, base_dirs in [
            (winreg.HKEY_LOCAL_MACHINE, [win32FontDirectory()]),  # System.
            (winreg.HKEY_CURRENT_USER, MSUserFontDirectories),  # User.
    ]:
        for base_dir in base_dirs:
            for reg_path in MSFontDirectories:
                try:
                    with winreg.OpenKey(domain, reg_path) as local:
                        for j in range(winreg.QueryInfoKey(local)[1]):
                            # value may contain the filename of the font or its
                            # absolute path.
                            key, value, tp = winreg.EnumValue(local, j)
                            if not isinstance(value, str):
                                continue
                            try:
                                # If value contains already an absolute path,
                                # then it is not changed further.
                                path = Path(base_dir, value).resolve()
                            except RuntimeError:
                                # Don't fail with invalid entries.
                                continue
                            items.add(path)
                except (OSError, MemoryError):
                    continue
    return items


@lru_cache
def _get_fontconfig_fonts():
    """Cache and list the font paths known to ``fc-list``."""
    try:
        if b'--format' not in subprocess.check_output(['fc-list', '--help']):
            _log.warning(  # fontconfig 2.7 implemented --format.
                'Matplotlib needs fontconfig>=2.7 to query system fonts.')
            return []
        out = subprocess.check_output(['fc-list', '--format=%{file}\\n'])
    except (OSError, subprocess.CalledProcessError):
        return []
    return [Path(os.fsdecode(fname)) for fname in out.split(b'\n')]


@lru_cache
def _get_macos_fonts():
    """Cache and list the font paths known to ``system_profiler SPFontsDataType``."""
    try:
        d, = plistlib.loads(
            subprocess.check_output(["system_profiler", "-xml", "SPFontsDataType"]))
    except (OSError, subprocess.CalledProcessError, plistlib.InvalidFileException):
        return []
    return [Path(entry["path"]) for entry in d["_items"]]


def findSystemFonts(fontpaths=None, fontext='ttf'):
    """
    Search for fonts in the specified font paths.  If no paths are
    given, will use a standard set of system paths, as well as the
    list of fonts tracked by fontconfig if fontconfig is installed and
    available.  A list of TrueType fonts are returned by default with
    AFM fonts as an option.
    """
    fontfiles = set()
    fontexts = get_fontext_synonyms(fontext)

    if fontpaths is None:
        if sys.platform == 'win32':
            installed_fonts = _get_win32_installed_fonts()
            fontpaths = []
        else:
            installed_fonts = _get_fontconfig_fonts()
            if sys.platform == 'darwin':
                installed_fonts += _get_macos_fonts()
                fontpaths = [*X11FontDirectories, *OSXFontDirectories]
            else:
                fontpaths = X11FontDirectories
        fontfiles.update(str(path) for path in installed_fonts
                         if path.suffix.lower()[1:] in fontexts)

    elif isinstance(fontpaths, str):
        fontpaths = [fontpaths]

    for path in fontpaths:
        fontfiles.update(map(os.path.abspath, list_fonts(path, fontexts)))

    return [fname for fname in fontfiles if os.path.exists(fname)]


@dataclasses.dataclass(frozen=True)
class FontEntry:
    """
    A class for storing Font properties.

    It is used when populating the font lookup dictionary.
    """

    fname: str = ''
    name: str = ''
    style: str = 'normal'
    variant: str = 'normal'
    weight: str | int = 'normal'
    stretch: str = 'normal'
    size: str = 'medium'

    def _repr_html_(self) -> str:
        png_stream = self._repr_png_()
        png_b64 = b64encode(png_stream).decode()
        return f"<img src=\"data:image/png;base64, {png_b64}\" />"

    def _repr_png_(self) -> bytes:
        from matplotlib.figure import Figure  # Circular import.
        fig = Figure()
        font_path = Path(self.fname) if self.fname != '' else None
        fig.text(0, 0, self.name, font=font_path)
        with BytesIO() as buf:
            fig.savefig(buf, bbox_inches='tight', transparent=True)
            return buf.getvalue()


def ttfFontProperty(font):
    """
    Extract information from a TrueType font file.

    Parameters
    ----------
    font : `.FT2Font`
        The TrueType font file from which information will be extracted.

    Returns
    -------
    `FontEntry`
        The extracted font properties.

    """
    name = font.family_name

    #  Styles are: italic, oblique, and normal (default)

    sfnt = font.get_sfnt()
    mac_key = (1,  # platform: macintosh
               0,  # id: roman
               0)  # langid: english
    ms_key = (3,  # platform: microsoft
              1,  # id: unicode_cs
              0x0409)  # langid: english_united_states

    # These tables are actually mac_roman-encoded, but mac_roman support may be
    # missing in some alternative Python implementations and we are only going
    # to look for ASCII substrings, where any ASCII-compatible encoding works
    # - or big-endian UTF-16, since important Microsoft fonts use that.
    sfnt2 = (sfnt.get((*mac_key, 2), b'').decode('latin-1').lower() or
             sfnt.get((*ms_key, 2), b'').decode('utf_16_be').lower())
    sfnt4 = (sfnt.get((*mac_key, 4), b'').decode('latin-1').lower() or
             sfnt.get((*ms_key, 4), b'').decode('utf_16_be').lower())

    if sfnt4.find('oblique') >= 0:
        style = 'oblique'
    elif sfnt4.find('italic') >= 0:
        style = 'italic'
    elif sfnt2.find('regular') >= 0:
        style = 'normal'
    elif font.style_flags & ft2font.ITALIC:
        style = 'italic'
    else:
        style = 'normal'

    #  Variants are: small-caps and normal (default)

    #  !!!!  Untested
    if name.lower() in ['capitals', 'small-caps']:
        variant = 'small-caps'
    else:
        variant = 'normal'

    # The weight-guessing algorithm is directly translated from fontconfig
    # 2.13.1's FcFreeTypeQueryFaceInternal (fcfreetype.c).
    wws_subfamily = 22
    typographic_subfamily = 16
    font_subfamily = 2
    styles = [
        sfnt.get((*mac_key, wws_subfamily), b'').decode('latin-1'),
        sfnt.get((*mac_key, typographic_subfamily), b'').decode('latin-1'),
        sfnt.get((*mac_key, font_subfamily), b'').decode('latin-1'),
        sfnt.get((*ms_key, wws_subfamily), b'').decode('utf-16-be'),
        sfnt.get((*ms_key, typographic_subfamily), b'').decode('utf-16-be'),
        sfnt.get((*ms_key, font_subfamily), b'').decode('utf-16-be'),
    ]
    styles = [*filter(None, styles)] or [font.style_name]

    def get_weight():  # From fontconfig's FcFreeTypeQueryFaceInternal.
        # OS/2 table weight.
        os2 = font.get_sfnt_table("OS/2")
        if os2 and os2["version"] != 0xffff:
            return os2["usWeightClass"]
        # PostScript font info weight.
        try:
            ps_font_info_weight = (
                font.get_ps_font_info()["weight"].replace(" ", "") or "")
        except ValueError:
            pass
        else:
            for regex, weight in _weight_regexes:
                if re.fullmatch(regex, ps_font_info_weight, re.I):
                    return weight
        # Style name weight.
        for style in styles:
            style = style.replace(" ", "")
            for regex, weight in _weight_regexes:
                if re.search(regex, style, re.I):
                    return weight
        if font.style_flags & ft2font.BOLD:
            return 700  # "bold"
        return 500  # "medium", not "regular"!

    weight = int(get_weight())

    #  Stretch can be absolute and relative
    #  Absolute stretches are: ultra-condensed, extra-condensed, condensed,
    #    semi-condensed, normal, semi-expanded, expanded, extra-expanded,
    #    and ultra-expanded.
    #  Relative stretches are: wider, narrower
    #  Child value is: inherit

    if any(word in sfnt4 for word in ['narrow', 'condensed', 'cond']):
        stretch = 'condensed'
    elif 'demi cond' in sfnt4:
        stretch = 'semi-condensed'
    elif any(word in sfnt4 for word in ['wide', 'expanded', 'extended']):
        stretch = 'expanded'
    else:
        stretch = 'normal'

    #  Sizes can be absolute and relative.
    #  Absolute sizes are: xx-small, x-small, small, medium, large, x-large,
    #    and xx-large.
    #  Relative sizes are: larger, smaller
    #  Length value is an absolute font size, e.g., 12pt
    #  Percentage values are in 'em's.  Most robust specification.

    if not font.scalable:
        raise NotImplementedError("Non-scalable fonts are not supported")
    size = 'scalable'

    return FontEntry(font.fname, name, style, variant, weight, stretch, size)


def afmFontProperty(fontpath, font):
    """
    Extract information from an AFM font file.

    Parameters
    ----------
    fontpath : str
        The filename corresponding to *font*.
    font : AFM
        The AFM font file from which information will be extracted.

    Returns
    -------
    `FontEntry`
        The extracted font properties.
    """

    name = font.get_familyname()
    fontname = font.get_fontname().lower()

    #  Styles are: italic, oblique, and normal (default)

    if font.get_angle() != 0 or 'italic' in name.lower():
        style = 'italic'
    elif 'oblique' in name.lower():
        style = 'oblique'
    else:
        style = 'normal'

    #  Variants are: small-caps and normal (default)

    # !!!!  Untested
    if name.lower() in ['capitals', 'small-caps']:
        variant = 'small-caps'
    else:
        variant = 'normal'

    weight = font.get_weight().lower()
    if weight not in weight_dict:
        weight = 'normal'

    #  Stretch can be absolute and relative
    #  Absolute stretches are: ultra-condensed, extra-condensed, condensed,
    #    semi-condensed, normal, semi-expanded, expanded, extra-expanded,
    #    and ultra-expanded.
    #  Relative stretches are: wider, narrower
    #  Child value is: inherit
    if 'demi cond' in fontname:
        stretch = 'semi-condensed'
    elif any(word in fontname for word in ['narrow', 'cond']):
        stretch = 'condensed'
    elif any(word in fontname for word in ['wide', 'expanded', 'extended']):
        stretch = 'expanded'
    else:
        stretch = 'normal'

    #  Sizes can be absolute and relative.
    #  Absolute sizes are: xx-small, x-small, small, medium, large, x-large,
    #    and xx-large.
    #  Relative sizes are: larger, smaller
    #  Length value is an absolute font size, e.g., 12pt
    #  Percentage values are in 'em's.  Most robust specification.

    #  All AFM fonts are apparently scalable.

    size = 'scalable'

    return FontEntry(fontpath, name, style, variant, weight, stretch, size)


class FontProperties:
    """
    A class for storing and manipulating font properties.

    The font properties are the six properties described in the
    `W3C Cascading Style Sheet, Level 1
    <http://www.w3.org/TR/1998/REC-CSS2-19980512/>`_ font
    specification and *math_fontfamily* for math fonts:

    - family: A list of font names in decreasing order of priority.
      The items may include a generic font family name, either 'sans-serif',
      'serif', 'cursive', 'fantasy', or 'monospace'.  In that case, the actual
      font to be used will be looked up from the associated rcParam during the
      search process in `.findfont`. Default: :rc:`font.family`

    - style: Either 'normal', 'italic' or 'oblique'.
      Default: :rc:`font.style`

    - variant: Either 'normal' or 'small-caps'.
      Default: :rc:`font.variant`

    - stretch: A numeric value in the range 0-1000 or one of
      'ultra-condensed', 'extra-condensed', 'condensed',
      'semi-condensed', 'normal', 'semi-expanded', 'expanded',
      'extra-expanded' or 'ultra-expanded'. Default: :rc:`font.stretch`

    - weight: A numeric value in the range 0-1000 or one of
      'ultralight', 'light', 'normal', 'regular', 'book', 'medium',
      'roman', 'semibold', 'demibold', 'demi', 'bold', 'heavy',
      'extra bold', 'black'. Default: :rc:`font.weight`

    - size: Either a relative value of 'xx-small', 'x-small',
      'small', 'medium', 'large', 'x-large', 'xx-large' or an
      absolute font size, e.g., 10. Default: :rc:`font.size`

    - math_fontfamily: The family of fonts used to render math text.
      Supported values are: 'dejavusans', 'dejavuserif', 'cm',
      'stix', 'stixsans' and 'custom'. Default: :rc:`mathtext.fontset`

    Alternatively, a font may be specified using the absolute path to a font
    file, by using the *fname* kwarg.  However, in this case, it is typically
    simpler to just pass the path (as a `pathlib.Path`, not a `str`) to the
    *font* kwarg of the `.Text` object.

    The preferred usage of font sizes is to use the relative values,
    e.g.,  'large', instead of absolute font sizes, e.g., 12.  This
    approach allows all text sizes to be made larger or smaller based
    on the font manager's default font size.

    This class will also accept a fontconfig_ pattern_, if it is the only
    argument provided.  This support does not depend on fontconfig; we are
    merely borrowing its pattern syntax for use here.

    .. _fontconfig: https://www.freedesktop.org/wiki/Software/fontconfig/
    .. _pattern:
       https://www.freedesktop.org/software/fontconfig/fontconfig-user.html

    Note that Matplotlib's internal font manager and fontconfig use a
    different algorithm to lookup fonts, so the results of the same pattern
    may be different in Matplotlib than in other applications that use
    fontconfig.
    """

    def __init__(self, family=None, style=None, variant=None, weight=None,
                 stretch=None, size=None,
                 fname=None,  # if set, it's a hardcoded filename to use
                 math_fontfamily=None):
        self.set_family(family)
        self.set_style(style)
        self.set_variant(variant)
        self.set_weight(weight)
        self.set_stretch(stretch)
        self.set_file(fname)
        self.set_size(size)
        self.set_math_fontfamily(math_fontfamily)
        # Treat family as a fontconfig pattern if it is the only parameter
        # provided.  Even in that case, call the other setters first to set
        # attributes not specified by the pattern to the rcParams defaults.
        if (isinstance(family, str)
                and style is None and variant is None and weight is None
                and stretch is None and size is None and fname is None):
            self.set_fontconfig_pattern(family)

    @classmethod
    def _from_any(cls, arg):
        """
        Generic constructor which can build a `.FontProperties` from any of the
        following:

        - a `.FontProperties`: it is passed through as is;
        - `None`: a `.FontProperties` using rc values is used;
        - an `os.PathLike`: it is used as path to the font file;
        - a `str`: it is parsed as a fontconfig pattern;
        - a `dict`: it is passed as ``**kwargs`` to `.FontProperties`.
        """
        if arg is None:
            return cls()
        elif isinstance(arg, cls):
            return arg
        elif isinstance(arg, os.PathLike):
            return cls(fname=arg)
        elif isinstance(arg, str):
            return cls(arg)
        else:
            return cls(**arg)

    def __hash__(self):
        l = (tuple(self.get_family()),
             self.get_slant(),
             self.get_variant(),
             self.get_weight(),
             self.get_stretch(),
             self.get_size(),
             self.get_file(),
             self.get_math_fontfamily())
        return hash(l)

    def __eq__(self, other):
        return hash(self) == hash(other)

    def __str__(self):
        return self.get_fontconfig_pattern()

    def get_family(self):
        """
        Return a list of individual font family names or generic family names.

        The font families or generic font families (which will be resolved
        from their respective rcParams when searching for a matching font) in
        the order of preference.
        """
        return self._family

    def get_name(self):
        """
        Return the name of the font that best matches the font properties.
        """
        return get_font(findfont(self)).family_name

    def get_style(self):
        """
        Return the font style.  Values are: 'normal', 'italic' or 'oblique'.
        """
        return self._slant

    def get_variant(self):
        """
        Return the font variant.  Values are: 'normal' or 'small-caps'.
        """
        return self._variant

    def get_weight(self):
        """
        Set the font weight.  Options are: A numeric value in the
        range 0-1000 or one of 'light', 'normal', 'regular', 'book',
        'medium', 'roman', 'semibold', 'demibold', 'demi', 'bold',
        'heavy', 'extra bold', 'black'
        """
        return self._weight

    def get_stretch(self):
        """
        Return the font stretch or width.  Options are: 'ultra-condensed',
        'extra-condensed', 'condensed', 'semi-condensed', 'normal',
        'semi-expanded', 'expanded', 'extra-expanded', 'ultra-expanded'.
        """
        return self._stretch

    def get_size(self):
        """
        Return the font size.
        """
        return self._size

    def get_file(self):
        """
        Return the filename of the associated font.
        """
        return self._file

    def get_fontconfig_pattern(self):
        """
        Get a fontconfig_ pattern_ suitable for looking up the font as
        specified with fontconfig's ``fc-match`` utility.

        This support does not depend on fontconfig; we are merely borrowing its
        pattern syntax for use here.
        """
        return generate_fontconfig_pattern(self)

    def set_family(self, family):
        """
        Change the font family.  Can be either an alias (generic name
        is CSS parlance), such as: 'serif', 'sans-serif', 'cursive',
        'fantasy', or 'monospace', a real font name or a list of real
        font names.  Real font names are not supported when
        :rc:`text.usetex` is `True`. Default: :rc:`font.family`
        """
        if family is None:
            family = mpl.rcParams['font.family']
        if isinstance(family, str):
            family = [family]
        self._family = family

    def set_style(self, style):
        """
        Set the font style.

        Parameters
        ----------
        style : {'normal', 'italic', 'oblique'}, default: :rc:`font.style`
        """
        if style is None:
            style = mpl.rcParams['font.style']
        _api.check_in_list(['normal', 'italic', 'oblique'], style=style)
        self._slant = style

    def set_variant(self, variant):
        """
        Set the font variant.

        Parameters
        ----------
        variant : {'normal', 'small-caps'}, default: :rc:`font.variant`
        """
        if variant is None:
            variant = mpl.rcParams['font.variant']
        _api.check_in_list(['normal', 'small-caps'], variant=variant)
        self._variant = variant

    def set_weight(self, weight):
        """
        Set the font weight.

        Parameters
        ----------
        weight : int or {'ultralight', 'light', 'normal', 'regular', 'book', \
'medium', 'roman', 'semibold', 'demibold', 'demi', 'bold', 'heavy', \
'extra bold', 'black'}, default: :rc:`font.weight`
            If int, must be in the range  0-1000.
        """
        if weight is None:
            weight = mpl.rcParams['font.weight']
        if weight in weight_dict:
            self._weight = weight
            return
        try:
            weight = int(weight)
        except ValueError:
            pass
        else:
            if 0 <= weight <= 1000:
                self._weight = weight
                return
        raise ValueError(f"{weight=} is invalid")

    def set_stretch(self, stretch):
        """
        Set the font stretch or width.

        Parameters
        ----------
        stretch : int or {'ultra-condensed', 'extra-condensed', 'condensed', \
'semi-condensed', 'normal', 'semi-expanded', 'expanded', 'extra-expanded', \
'ultra-expanded'}, default: :rc:`font.stretch`
            If int, must be in the range  0-1000.
        """
        if stretch is None:
            stretch = mpl.rcParams['font.stretch']
        if stretch in stretch_dict:
            self._stretch = stretch
            return
        try:
            stretch = int(stretch)
        except ValueError:
            pass
        else:
            if 0 <= stretch <= 1000:
                self._stretch = stretch
                return
        raise ValueError(f"{stretch=} is invalid")

    def set_size(self, size):
        """
        Set the font size.

        Parameters
        ----------
        size : float or {'xx-small', 'x-small', 'small', 'medium', \
'large', 'x-large', 'xx-large'}, default: :rc:`font.size`
            If a float, the font size in points. The string values denote
            sizes relative to the default font size.
        """
        if size is None:
            size = mpl.rcParams['font.size']
        try:
            size = float(size)
        except ValueError:
            try:
                scale = font_scalings[size]
            except KeyError as err:
                raise ValueError(
                    "Size is invalid. Valid font size are "
                    + ", ".join(map(str, font_scalings))) from err
            else:
                size = scale * FontManager.get_default_size()
        if size < 1.0:
            _log.info('Fontsize %1.2f < 1.0 pt not allowed by FreeType. '
                      'Setting fontsize = 1 pt', size)
            size = 1.0
        self._size = size

    def set_file(self, file):
        """
        Set the filename of the fontfile to use.  In this case, all
        other properties will be ignored.
        """
        self._file = os.fspath(file) if file is not None else None

    def set_fontconfig_pattern(self, pattern):
        """
        Set the properties by parsing a fontconfig_ *pattern*.

        This support does not depend on fontconfig; we are merely borrowing its
        pattern syntax for use here.
        """
        for key, val in parse_fontconfig_pattern(pattern).items():
            if type(val) is list:
                getattr(self, "set_" + key)(val[0])
            else:
                getattr(self, "set_" + key)(val)

    def get_math_fontfamily(self):
        """
        Return the name of the font family used for math text.

        The default font is :rc:`mathtext.fontset`.
        """
        return self._math_fontfamily

    def set_math_fontfamily(self, fontfamily):
        """
        Set the font family for text in math mode.

        If not set explicitly, :rc:`mathtext.fontset` will be used.

        Parameters
        ----------
        fontfamily : str
            The name of the font family.

            Available font families are defined in the
            :ref:`default matplotlibrc file <customizing-with-matplotlibrc-files>`.

        See Also
        --------
        .text.Text.get_math_fontfamily
        """
        if fontfamily is None:
            fontfamily = mpl.rcParams['mathtext.fontset']
        else:
            valid_fonts = _validators['mathtext.fontset'].valid.values()
            # _check_in_list() Validates the parameter math_fontfamily as
            # if it were passed to rcParams['mathtext.fontset']
            _api.check_in_list(valid_fonts, math_fontfamily=fontfamily)
        self._math_fontfamily = fontfamily

    def copy(self):
        """Return a copy of self."""
        return copy.copy(self)

    # Aliases
    set_name = set_family
    get_slant = get_style
    set_slant = set_style
    get_size_in_points = get_size


class _JSONEncoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, FontManager):
            return dict(o.__dict__, __class__='FontManager')
        elif isinstance(o, FontEntry):
            d = dict(o.__dict__, __class__='FontEntry')
            try:
                # Cache paths of fonts shipped with Matplotlib relative to the
                # Matplotlib data path, which helps in the presence of venvs.
                d["fname"] = str(Path(d["fname"]).relative_to(mpl.get_data_path()))
            except ValueError:
                pass
            return d
        else:
            return super().default(o)


def _json_decode(o):
    cls = o.pop('__class__', None)
    if cls is None:
        return o
    elif cls == 'FontManager':
        r = FontManager.__new__(FontManager)
        r.__dict__.update(o)
        return r
    elif cls == 'FontEntry':
        if not os.path.isabs(o['fname']):
            o['fname'] = os.path.join(mpl.get_data_path(), o['fname'])
        r = FontEntry(**o)
        return r
    else:
        raise ValueError("Don't know how to deserialize __class__=%s" % cls)


def json_dump(data, filename):
    """
    Dump `FontManager` *data* as JSON to the file named *filename*.

    See Also
    --------
    json_load

    Notes
    -----
    File paths that are children of the Matplotlib data path (typically, fonts
    shipped with Matplotlib) are stored relative to that data path (to remain
    valid across virtualenvs).

    This function temporarily locks the output file to prevent multiple
    processes from overwriting one another's output.
    """
    with cbook._lock_path(filename), open(filename, 'w') as fh:
        try:
            json.dump(data, fh, cls=_JSONEncoder, indent=2)
        except OSError as e:
            _log.warning('Could not save font_manager cache %s', e)


def json_load(filename):
    """
    Load a `FontManager` from the JSON file named *filename*.

    See Also
    --------
    json_dump
    """
    with open(filename) as fh:
        return json.load(fh, object_hook=_json_decode)


class FontManager:
    """
    On import, the `FontManager` singleton instance creates a list of ttf and
    afm fonts and caches their `FontProperties`.  The `FontManager.findfont`
    method does a nearest neighbor search to find the font that most closely
    matches the specification.  If no good enough match is found, the default
    font is returned.

    Fonts added with the `FontManager.addfont` method will not persist in the
    cache; therefore, `addfont` will need to be called every time Matplotlib is
    imported. This method should only be used if and when a font cannot be
    installed on your operating system by other means.

    Notes
    -----
    The `FontManager.addfont` method must be called on the global `FontManager`
    instance.

    Example usage::

        import matplotlib.pyplot as plt
        from matplotlib import font_manager

        font_dirs = ["/resources/fonts"]  # The path to the custom font file.
        font_files = font_manager.findSystemFonts(fontpaths=font_dirs)

        for font_file in font_files:
            font_manager.fontManager.addfont(font_file)
    """
    # Increment this version number whenever the font cache data
    # format or behavior has changed and requires an existing font
    # cache files to be rebuilt.
    __version__ = 390

    def __init__(self, size=None, weight='normal'):
        self._version = self.__version__

        self.__default_weight = weight
        self.default_size = size

        # Create list of font paths.
        paths = [cbook._get_data_path('fonts', subdir)
                 for subdir in ['ttf', 'afm', 'pdfcorefonts']]
        _log.debug('font search path %s', paths)

        self.defaultFamily = {
            'ttf': 'DejaVu Sans',
            'afm': 'Helvetica'}

        self.afmlist = []
        self.ttflist = []

        # Delay the warning by 5s.
        timer = threading.Timer(5, lambda: _log.warning(
            'Matplotlib is building the font cache; this may take a moment.'))
        timer.start()
        try:
            for fontext in ["afm", "ttf"]:
                for path in [*findSystemFonts(paths, fontext=fontext),
                             *findSystemFonts(fontext=fontext)]:
                    try:
                        self.addfont(path)
                    except OSError as exc:
                        _log.info("Failed to open font file %s: %s", path, exc)
                    except Exception as exc:
                        _log.info("Failed to extract font properties from %s: "
                                  "%s", path, exc)
        finally:
            timer.cancel()

    def addfont(self, path):
        """
        Cache the properties of the font at *path* to make it available to the
        `FontManager`.  The type of font is inferred from the path suffix.

        Parameters
        ----------
        path : str or path-like

        Notes
        -----
        This method is useful for adding a custom font without installing it in
        your operating system. See the `FontManager` singleton instance for
        usage and caveats about this function.
        """
        # Convert to string in case of a path as
        # afmFontProperty and FT2Font expect this
        path = os.fsdecode(path)
        if Path(path).suffix.lower() == ".afm":
            with open(path, "rb") as fh:
                font = _afm.AFM(fh)
            prop = afmFontProperty(path, font)
            self.afmlist.append(prop)
        else:
            font = ft2font.FT2Font(path)
            prop = ttfFontProperty(font)
            self.ttflist.append(prop)
        self._findfont_cached.cache_clear()

    @property
    def defaultFont(self):
        # Lazily evaluated (findfont then caches the result) to avoid including
        # the venv path in the json serialization.
        return {ext: self.findfont(family, fontext=ext)
                for ext, family in self.defaultFamily.items()}

    def get_default_weight(self):
        """
        Return the default font weight.
        """
        return self.__default_weight

    @staticmethod
    def get_default_size():
        """
        Return the default font size.
        """
        return mpl.rcParams['font.size']

    def set_default_weight(self, weight):
        """
        Set the default font weight.  The initial value is 'normal'.
        """
        self.__default_weight = weight

    @staticmethod
    def _expand_aliases(family):
        if family in ('sans', 'sans serif'):
            family = 'sans-serif'
        return mpl.rcParams['font.' + family]

    # Each of the scoring functions below should return a value between
    # 0.0 (perfect match) and 1.0 (terrible match)
    def score_family(self, families, family2):
        """
        Return a match score between the list of font families in
        *families* and the font family name *family2*.

        An exact match at the head of the list returns 0.0.

        A match further down the list will return between 0 and 1.

        No match will return 1.0.
        """
        if not isinstance(families, (list, tuple)):
            families = [families]
        elif len(families) == 0:
            return 1.0
        family2 = family2.lower()
        step = 1 / len(families)
        for i, family1 in enumerate(families):
            family1 = family1.lower()
            if family1 in font_family_aliases:
                options = [*map(str.lower, self._expand_aliases(family1))]
                if family2 in options:
                    idx = options.index(family2)
                    return (i + (idx / len(options))) * step
            elif family1 == family2:
                # The score should be weighted by where in the
                # list the font was found.
                return i * step
        return 1.0

    def score_style(self, style1, style2):
        """
        Return a match score between *style1* and *style2*.

        An exact match returns 0.0.

        A match between 'italic' and 'oblique' returns 0.1.

        No match returns 1.0.
        """
        if style1 == style2:
            return 0.0
        elif (style1 in ('italic', 'oblique')
              and style2 in ('italic', 'oblique')):
            return 0.1
        return 1.0

    def score_variant(self, variant1, variant2):
        """
        Return a match score between *variant1* and *variant2*.

        An exact match returns 0.0, otherwise 1.0.
        """
        if variant1 == variant2:
            return 0.0
        else:
            return 1.0

    def score_stretch(self, stretch1, stretch2):
        """
        Return a match score between *stretch1* and *stretch2*.

        The result is the absolute value of the difference between the
        CSS numeric values of *stretch1* and *stretch2*, normalized
        between 0.0 and 1.0.
        """
        try:
            stretchval1 = int(stretch1)
        except ValueError:
            stretchval1 = stretch_dict.get(stretch1, 500)
        try:
            stretchval2 = int(stretch2)
        except ValueError:
            stretchval2 = stretch_dict.get(stretch2, 500)
        return abs(stretchval1 - stretchval2) / 1000.0

    def score_weight(self, weight1, weight2):
        """
        Return a match score between *weight1* and *weight2*.

        The result is 0.0 if both weight1 and weight 2 are given as strings
        and have the same value.

        Otherwise, the result is the absolute value of the difference between
        the CSS numeric values of *weight1* and *weight2*, normalized between
        0.05 and 1.0.
        """
        # exact match of the weight names, e.g. weight1 == weight2 == "regular"
        if cbook._str_equal(weight1, weight2):
            return 0.0
        w1 = weight1 if isinstance(weight1, Number) else weight_dict[weight1]
        w2 = weight2 if isinstance(weight2, Number) else weight_dict[weight2]
        return 0.95 * (abs(w1 - w2) / 1000) + 0.05

    def score_size(self, size1, size2):
        """
        Return a match score between *size1* and *size2*.

        If *size2* (the size specified in the font file) is 'scalable', this
        function always returns 0.0, since any font size can be generated.

        Otherwise, the result is the absolute distance between *size1* and
        *size2*, normalized so that the usual range of font sizes (6pt -
        72pt) will lie between 0.0 and 1.0.
        """
        if size2 == 'scalable':
            return 0.0
        # Size value should have already been
        try:
            sizeval1 = float(size1)
        except ValueError:
            sizeval1 = self.default_size * font_scalings[size1]
        try:
            sizeval2 = float(size2)
        except ValueError:
            return 1.0
        return abs(sizeval1 - sizeval2) / 72

    def findfont(self, prop, fontext='ttf', directory=None,
                 fallback_to_default=True, rebuild_if_missing=True):
        """
        Find the path to the font file most closely matching the given font properties.

        Parameters
        ----------
        prop : str or `~matplotlib.font_manager.FontProperties`
            The font properties to search for. This can be either a
            `.FontProperties` object or a string defining a
            `fontconfig patterns`_.

        fontext : {'ttf', 'afm'}, default: 'ttf'
            The extension of the font file:

            - 'ttf': TrueType and OpenType fonts (.ttf, .ttc, .otf)
            - 'afm': Adobe Font Metrics (.afm)

        directory : str, optional
            If given, only search this directory and its subdirectories.

        fallback_to_default : bool
            If True, will fall back to the default font family (usually
            "DejaVu Sans" or "Helvetica") if the first lookup hard-fails.

        rebuild_if_missing : bool
            Whether to rebuild the font cache and search again if the first
            match appears to point to a nonexisting font (i.e., the font cache
            contains outdated entries).

        Returns
        -------
        str
            The filename of the best matching font.

        Notes
        -----
        This performs a nearest neighbor search.  Each font is given a
        similarity score to the target font properties.  The first font with
        the highest score is returned.  If no matches below a certain
        threshold are found, the default font (usually DejaVu Sans) is
        returned.

        The result is cached, so subsequent lookups don't have to
        perform the O(n) nearest neighbor search.

        See the `W3C Cascading Style Sheet, Level 1
        <http://www.w3.org/TR/1998/REC-CSS2-19980512/>`_ documentation
        for a description of the font finding algorithm.

        .. _fontconfig patterns:
           https://www.freedesktop.org/software/fontconfig/fontconfig-user.html
        """
        # Pass the relevant rcParams (and the font manager, as `self`) to
        # _findfont_cached so to prevent using a stale cache entry after an
        # rcParam was changed.
        rc_params = tuple(tuple(mpl.rcParams[key]) for key in [
            "font.serif", "font.sans-serif", "font.cursive", "font.fantasy",
            "font.monospace"])
        ret = self._findfont_cached(
            prop, fontext, directory, fallback_to_default, rebuild_if_missing,
            rc_params)
        if isinstance(ret, _ExceptionProxy):
            raise ret.klass(ret.message)
        return ret

    def get_font_names(self):
        """Return the list of available fonts."""
        return list({font.name for font in self.ttflist})

    def _find_fonts_by_props(self, prop, fontext='ttf', directory=None,
                             fallback_to_default=True, rebuild_if_missing=True):
        """
        Find the paths to the font files most closely matching the given properties.

        Parameters
        ----------
        prop : str or `~matplotlib.font_manager.FontProperties`
            The font properties to search for. This can be either a
            `.FontProperties` object or a string defining a
            `fontconfig patterns`_.

        fontext : {'ttf', 'afm'}, default: 'ttf'
            The extension of the font file:

            - 'ttf': TrueType and OpenType fonts (.ttf, .ttc, .otf)
            - 'afm': Adobe Font Metrics (.afm)

        directory : str, optional
            If given, only search this directory and its subdirectories.

        fallback_to_default : bool
            If True, will fall back to the default font family (usually
            "DejaVu Sans" or "Helvetica") if none of the families were found.

        rebuild_if_missing : bool
            Whether to rebuild the font cache and search again if the first
            match appears to point to a nonexisting font (i.e., the font cache
            contains outdated entries).

        Returns
        -------
        list[str]
            The paths of the fonts found.

        Notes
        -----
        This is an extension/wrapper of the original findfont API, which only
        returns a single font for given font properties. Instead, this API
        returns a list of filepaths of multiple fonts which closely match the
        given font properties.  Since this internally uses the original API,
        there's no change to the logic of performing the nearest neighbor
        search.  See `findfont` for more details.
        """

        prop = FontProperties._from_any(prop)

        fpaths = []
        for family in prop.get_family():
            cprop = prop.copy()
            cprop.set_family(family)  # set current prop's family

            try:
                fpaths.append(
                    self.findfont(
                        cprop, fontext, directory,
                        fallback_to_default=False,  # don't fallback to default
                        rebuild_if_missing=rebuild_if_missing,
                    )
                )
            except ValueError:
                if family in font_family_aliases:
                    _log.warning(
                        "findfont: Generic family %r not found because "
                        "none of the following families were found: %s",
                        family, ", ".join(self._expand_aliases(family))
                    )
                else:
                    _log.warning("findfont: Font family %r not found.", family)

        # only add default family if no other font was found and
        # fallback_to_default is enabled
        if not fpaths:
            if fallback_to_default:
                dfamily = self.defaultFamily[fontext]
                cprop = prop.copy()
                cprop.set_family(dfamily)
                fpaths.append(
                    self.findfont(
                        cprop, fontext, directory,
                        fallback_to_default=True,
                        rebuild_if_missing=rebuild_if_missing,
                    )
                )
            else:
                raise ValueError("Failed to find any font, and fallback "
                                 "to the default font was disabled")

        return fpaths

    @lru_cache(1024)
    def _findfont_cached(self, prop, fontext, directory, fallback_to_default,
                         rebuild_if_missing, rc_params):

        prop = FontProperties._from_any(prop)

        fname = prop.get_file()
        if fname is not None:
            return fname

        if fontext == 'afm':
            fontlist = self.afmlist
        else:
            fontlist = self.ttflist

        best_score = 1e64
        best_font = None

        _log.debug('findfont: Matching %s.', prop)
        for font in fontlist:
            if (directory is not None and
                    Path(directory) not in Path(font.fname).parents):
                continue
            # Matching family should have top priority, so multiply it by 10.
            score = (self.score_family(prop.get_family(), font.name) * 10
                     + self.score_style(prop.get_style(), font.style)
                     + self.score_variant(prop.get_variant(), font.variant)
                     + self.score_weight(prop.get_weight(), font.weight)
                     + self.score_stretch(prop.get_stretch(), font.stretch)
                     + self.score_size(prop.get_size(), font.size))
            _log.debug('findfont: score(%s) = %s', font, score)
            if score < best_score:
                best_score = score
                best_font = font
            if score == 0:
                break

        if best_font is None or best_score >= 10.0:
            if fallback_to_default:
                _log.warning(
                    'findfont: Font family %s not found. Falling back to %s.',
                    prop.get_family(), self.defaultFamily[fontext])
                for family in map(str.lower, prop.get_family()):
                    if family in font_family_aliases:
                        _log.warning(
                            "findfont: Generic family %r not found because "
                            "none of the following families were found: %s",
                            family, ", ".join(self._expand_aliases(family)))
                default_prop = prop.copy()
                default_prop.set_family(self.defaultFamily[fontext])
                return self.findfont(default_prop, fontext, directory,
                                     fallback_to_default=False)
            else:
                # This return instead of raise is intentional, as we wish to
                # cache that it was not found, which will not occur if it was
                # actually raised.
                return _ExceptionProxy(
                    ValueError,
                    f"Failed to find font {prop}, and fallback to the default font was "
                    f"disabled"
                )
        else:
            _log.debug('findfont: Matching %s to %s (%r) with score of %f.',
                       prop, best_font.name, best_font.fname, best_score)
            result = best_font.fname

        if not os.path.isfile(result):
            if rebuild_if_missing:
                _log.info(
                    'findfont: Found a missing font file.  Rebuilding cache.')
                new_fm = _load_fontmanager(try_read_cache=False)
                # Replace self by the new fontmanager, because users may have
                # a reference to this specific instance.
                # TODO: _load_fontmanager should really be (used by) a method
                # modifying the instance in place.
                vars(self).update(vars(new_fm))
                return self.findfont(
                    prop, fontext, directory, rebuild_if_missing=False)
            else:
                # This return instead of raise is intentional, as we wish to
                # cache that it was not found, which will not occur if it was
                # actually raised.
                return _ExceptionProxy(ValueError, "No valid font could be found")

        return _cached_realpath(result)


@lru_cache
def is_opentype_cff_font(filename):
    """
    Return whether the given font is a Postscript Compact Font Format Font
    embedded in an OpenType wrapper.  Used by the PostScript and PDF backends
    that cannot subset these fonts.
    """
    if os.path.splitext(filename)[1].lower() == '.otf':
        with open(filename, 'rb') as fd:
            return fd.read(4) == b"OTTO"
    else:
        return False


@lru_cache(64)
def _get_font(font_filepaths, hinting_factor, *, _kerning_factor, thread_id):
    first_fontpath, *rest = font_filepaths
    return ft2font.FT2Font(
        first_fontpath, hinting_factor,
        _fallback_list=[
            ft2font.FT2Font(
                fpath, hinting_factor,
                _kerning_factor=_kerning_factor
            )
            for fpath in rest
        ],
        _kerning_factor=_kerning_factor
    )


# FT2Font objects cannot be used across fork()s because they reference the same
# FT_Library object.  While invalidating *all* existing FT2Fonts after a fork
# would be too complicated to be worth it, the main way FT2Fonts get reused is
# via the cache of _get_font, which we can empty upon forking (not on Windows,
# which has no fork() or register_at_fork()).
if hasattr(os, "register_at_fork"):
    os.register_at_fork(after_in_child=_get_font.cache_clear)


@lru_cache(64)
def _cached_realpath(path):
    # Resolving the path avoids embedding the font twice in pdf/ps output if a
    # single font is selected using two different relative paths.
    return os.path.realpath(path)


def get_font(font_filepaths, hinting_factor=None):
    """
    Get an `.ft2font.FT2Font` object given a list of file paths.

    Parameters
    ----------
    font_filepaths : Iterable[str, Path, bytes], str, Path, bytes
        Relative or absolute paths to the font files to be used.

        If a single string, bytes, or `pathlib.Path`, then it will be treated
        as a list with that entry only.

        If more than one filepath is passed, then the returned FT2Font object
        will fall back through the fonts, in the order given, to find a needed
        glyph.

    Returns
    -------
    `.ft2font.FT2Font`

    """
    if isinstance(font_filepaths, (str, Path, bytes)):
        paths = (_cached_realpath(font_filepaths),)
    else:
        paths = tuple(_cached_realpath(fname) for fname in font_filepaths)

    if hinting_factor is None:
        hinting_factor = mpl.rcParams['text.hinting_factor']

    return _get_font(
        # must be a tuple to be cached
        paths,
        hinting_factor,
        _kerning_factor=mpl.rcParams['text.kerning_factor'],
        # also key on the thread ID to prevent segfaults with multi-threading
        thread_id=threading.get_ident()
    )


def _load_fontmanager(*, try_read_cache=True):
    fm_path = Path(
        mpl.get_cachedir(), f"fontlist-v{FontManager.__version__}.json")
    if try_read_cache:
        try:
            fm = json_load(fm_path)
        except Exception:
            pass
        else:
            if getattr(fm, "_version", object()) == FontManager.__version__:
                _log.debug("Using fontManager instance from %s", fm_path)
                return fm
    fm = FontManager()
    json_dump(fm, fm_path)
    _log.info("generated new fontManager")
    return fm


fontManager = _load_fontmanager()
findfont = fontManager.findfont
get_font_names = fontManager.get_font_names
