"""Fonts integration in PDF."""

import io
import re
from hashlib import md5
from math import ceil

import pydyf
from fontTools import subset
from fontTools.ttLib import TTFont, TTLibError, ttFont
from fontTools.varLib.instancer import instantiateVariableFont

from ..logger import LOGGER
from ..text.constants import PANGO_STRETCH_PERCENT
from ..text.ffi import FROM_UNITS, ffi, harfbuzz, harfbuzz_subset, pango
from ..text.fonts import get_hb_object_data, get_pango_font_hb_face


class Font:
    def __init__(self, pango_font, description, font_size):
        self.hb_font = pango.pango_font_get_hb_font(pango_font)
        self.hb_face = get_pango_font_hb_face(pango_font)
        self.file_content = get_hb_object_data(self.hb_face)
        self.index = harfbuzz.hb_face_get_index(self.hb_face)

        self.font_size = font_size
        self.style = pango.pango_font_description_get_style(description)
        self.family = ffi.string(
            pango.pango_font_description_get_family(description)).decode()

        self.variations = {}
        variations = pango.pango_font_description_get_variations(description)
        if variations != ffi.NULL:
            self.variations = {
                part.split('=')[0]: float(part.split('=')[1])
                for part in ffi.string(variations).decode().split(',')}
        if weight := self.variations.get('weight'):
            self.weight = round(weight)
            pango.pango_font_description_set_weight(description, weight)
        else:
            self.weight = pango.pango_font_description_get_weight(description)
        if self.variations.get('ital'):
            pango.pango_font_description_set_style(
                description, pango.PANGO_STYLE_ITALIC)
        elif self.variations.get('slnt'):
            pango.pango_font_description_set_style(
                description, pango.PANGO_STYLE_OBLIQUE)
        if (width := self.variations.get('wdth')) is not None:
            stretch = min(
                PANGO_STRETCH_PERCENT.items(),
                key=lambda item: abs(item[0] - width))[1]
            pango.pango_font_description_set_stretch(description, stretch)
        description_string = ffi.string(
            pango.pango_font_description_to_string(description))

        # Never use the built-in hash function here: it’s not stable.
        self.hash = ''.join(
            chr(65 + letter % 26) for letter
            in md5(description_string, usedforsecurity=False).digest()[:6])

        # Set font name.
        name = re.split(b' [#@]', description_string)[0]
        self.name = b'/' + self.hash.encode() + b'+' + name.replace(b' ', b'-')

        # Set ascent and descent.
        if self.font_size:
            pango_metrics = pango.pango_font_get_metrics(pango_font, ffi.NULL)
            self.ascent = round(
                pango.pango_font_metrics_get_ascent(pango_metrics) * FROM_UNITS /
                self.font_size * 1000)
            self.descent = -round(
                pango.pango_font_metrics_get_descent(pango_metrics) * FROM_UNITS /
                self.font_size * 1000)
        else:
            self.ascent = self.descent = 0

        # Get font tables and set metadata.
        table_count = ffi.new('unsigned int *', 100)
        table_tags = ffi.new('hb_tag_t[100]')
        table_name = ffi.new('char[4]')
        harfbuzz.hb_face_get_table_tags(self.hb_face, 0, table_count, table_tags)
        self.tables = []
        for i in range(table_count[0]):
            harfbuzz.hb_tag_to_string(table_tags[i], table_name)
            self.tables.append(ffi.string(table_name).decode())
        self.bitmap = False
        if 'EBDT' in self.tables and 'EBLC' in self.tables:
            if 'glyf' in self.tables:
                tag = harfbuzz.hb_tag_from_string(b'glyf', -1)
                blob = harfbuzz.hb_face_reference_table(self.hb_face, tag)
                if harfbuzz.hb_blob_get_length(blob) == 0:
                    self.bitmap = True
                harfbuzz.hb_blob_destroy(blob)
            else:
                self.bitmap = True
        self.italic_angle = 0  # TODO: this should be different
        self.upem = harfbuzz.hb_face_get_upem(self.hb_face)
        self.png = harfbuzz.hb_ot_color_has_png(self.hb_face)
        self.svg = harfbuzz.hb_ot_color_has_svg(self.hb_face)
        self.glyph_count = harfbuzz.hb_face_get_glyph_count(self.hb_face)
        self.stemv = 80
        self.stemh = 80
        self.widths = {}
        self.to_unicode = {}
        self.missing = {}
        self.used_in_forms = False

        # Set font flags.
        self.flags = 2 ** (3 - 1)  # Symbolic, custom character set
        if self.style:
            self.flags += 2 ** (7 - 1)  # Italic
        if b'Serif' in name.split(b' '):
            self.flags += 2 ** (2 - 1)  # Serif

    def get_unused_glyph_id(self, codepoint):
        """Get a glyph id that’s not used in the font, for given Unicode codepoint."""
        if codepoint not in self.missing:
            next_unused_glyph_id = self.glyph_count + len(self.missing)
            if next_unused_glyph_id > 2 ** 16 - 1:
                LOGGER.warning(
                    f'Too many glyphs missing from "{self.family}", '
                    'expect text selection problems')
                next_unused_glyph_id = 2 ** 16 - 1
            self.missing[codepoint] = next_unused_glyph_id
        return self.missing[codepoint]

    def clean(self, to_unicode, hinting):
        """Remove useless data from font."""

        # Subset font.
        self.subset(to_unicode, hinting)

        # Transform variable into static font.
        if 'fvar' in self.tables:
            full_font = io.BytesIO(self.file_content)
            ttfont = TTFont(full_font, fontNumber=self.index)
            axes = {axis.axisTag: axis for axis in ttfont['fvar'].axes}
            if 'wght' in axes and 'wght' not in self.variations:
                self.variations['wght'] = self.weight
            if 'opsz' in axes and 'opsz' not in self.variations:
                self.variations['opsz'] = self.font_size
            if 'slnt' in axes and 'slnt' not in self.variations:
                slnt = 0
                if self.style == 1:
                    if axes['slnt'].maxValue == 0:
                        slnt = axes['slnt'].minValue
                    else:
                        slnt = axes['slnt'].maxValue
                self.variations['slnt'] = slnt
            if 'ital' in axes and 'ital' not in self.variations:
                self.variations['ital'] = int(self.style == 2)
            partial_font = io.BytesIO()
            try:
                ttfont = instantiateVariableFont(ttfont, self.variations, static=True)
                ttfont.save(partial_font)
            except Exception as exception:
                LOGGER.warning(f'Unable to instantiate "{self.family}" variable font')
                LOGGER.debug('Original exception:', exc_info=exception)
            else:
                self.file_content = partial_font.getvalue()

        # Remove images.
        if self.png or self.svg:
            full_font = io.BytesIO(self.file_content)
            ttfont = TTFont(full_font, fontNumber=self.index)
            try:
                # Add empty glyphs instead of PNG or SVG emojis.
                if 'loca' not in self.tables or 'glyf' not in self.tables:
                    ttfont['loca'] = ttFont.getTableClass('loca')()
                    ttfont['glyf'] = ttFont.getTableClass('glyf')()
                    ttfont['glyf'].glyphOrder = ttfont.getGlyphOrder()
                    ttfont['glyf'].glyphs = {
                        name: ttFont.getTableModule('glyf').Glyph()
                        for name in ttfont['glyf'].glyphOrder}
                else:
                    for glyph in ttfont['glyf'].glyphs:
                        ttfont['glyf'][glyph] = ttFont.getTableModule('glyf').Glyph()
                for table_name in ('CBDT', 'CBLC', 'SVG '):
                    if table_name in ttfont:
                        del ttfont[table_name]
                output_font = io.BytesIO()
                ttfont.save(output_font)
                self.file_content = output_font.getvalue()
            except TTLibError as exception:
                LOGGER.warning(f'Unable to save emoji font "{self.family}"')
                LOGGER.debug('Original exception:', exc_info=exception)

    @property
    def type(self):
        return 'otf' if self.file_content[:4] == b'OTTO' else 'ttf'

    def subset(self, to_unicode, hinting):
        """Remove unused glyphs and tables from font."""
        if not to_unicode:
            return

        if harfbuzz_subset and harfbuzz.hb_version_atleast(4, 1, 0):
            # 4.1.0 is required for hb_set_add_sorted_array.
            self._harfbuzz_subset(to_unicode, hinting)
        else:
            self._fonttools_subset(to_unicode, hinting)

    def _harfbuzz_subset(self, to_unicode, hinting):
        """Subset font using Harfbuzz."""
        hb_subset = ffi.gc(
            harfbuzz_subset.hb_subset_input_create_or_fail(),
            harfbuzz_subset.hb_subset_input_destroy)

        # Only keep used glyphs.
        gid_set = harfbuzz_subset.hb_subset_input_glyph_set(hb_subset)
        gid_array = ffi.new(f'hb_codepoint_t[{len(to_unicode)}]', sorted(to_unicode))
        harfbuzz.hb_set_add_sorted_array(gid_set, gid_array, len(to_unicode))

        # Set flags.
        flags = (
            harfbuzz_subset.HB_SUBSET_FLAGS_RETAIN_GIDS |
            harfbuzz_subset.HB_SUBSET_FLAGS_PASSTHROUGH_UNRECOGNIZED |
            harfbuzz_subset.HB_SUBSET_FLAGS_DESUBROUTINIZE)
        if self.missing:
            flags |= harfbuzz_subset.HB_SUBSET_FLAGS_NOTDEF_OUTLINE
        harfbuzz_subset.hb_subset_input_set_flags(hb_subset, flags)

        # Drop useless tables.
        drop_set = harfbuzz_subset.hb_subset_input_set(
            hb_subset, harfbuzz_subset.HB_SUBSET_SETS_DROP_TABLE_TAG)
        drop_tables = tuple(harfbuzz.hb_tag_from_string(name, -1) for name in (
            b'BASE', b'DSIG', b'EBDT', b'EBLC', b'EBSC', b'GPOS', b'GSUB', b'JSTF',
            b'LTSH', b'PCLT', b'SVG '))
        drop_tables_array = ffi.new(f'hb_codepoint_t[{len(drop_tables)}]', drop_tables)
        harfbuzz.hb_set_add_sorted_array(drop_set, drop_tables_array, len(drop_tables))

        # Subset font.
        hb_face = ffi.gc(
            harfbuzz_subset.hb_subset_or_fail(self.hb_face, hb_subset),
            harfbuzz.hb_face_destroy)

        # Drop empty glyphs after last one used.
        gid_set = harfbuzz_subset.hb_subset_input_glyph_set(hb_subset)
        keep = tuple(range(max(to_unicode) + 1))
        gid_array = ffi.new(f'hb_codepoint_t[{len(keep)}]', keep)
        harfbuzz.hb_set_add_sorted_array(gid_set, gid_array, len(keep))

        # Set flags.
        flags = (
            harfbuzz_subset.HB_SUBSET_FLAGS_PASSTHROUGH_UNRECOGNIZED |
            harfbuzz_subset.HB_SUBSET_FLAGS_DESUBROUTINIZE)
        if not hinting:
            flags |= harfbuzz_subset.HB_SUBSET_FLAGS_NO_HINTING
        if self.missing:
            flags |= harfbuzz_subset.HB_SUBSET_FLAGS_NOTDEF_OUTLINE
        harfbuzz_subset.hb_subset_input_set_flags(hb_subset, flags)

        # Subset font.
        hb_face = ffi.gc(
            harfbuzz_subset.hb_subset_or_fail(hb_face, hb_subset),
            harfbuzz.hb_face_destroy)

        # Store new font.
        if hb_face:
            file_content = get_hb_object_data(hb_face)
            if file_content:
                self.file_content = file_content
                return

        LOGGER.warning(f'Unable to subset "{self.family}" with HarfBuzz')

    def _fonttools_subset(self, to_unicode, hinting):
        """Subset font using Fonttools."""
        full_font = io.BytesIO(self.file_content)

        # Set subset options.
        options = subset.Options(
            retain_gids=True, passthrough_tables=True, ignore_missing_glyphs=True,
            hinting=hinting, desubroutinize=True, notdef_outline=bool(self.missing))
        options.drop_tables += ['GSUB', 'GPOS', 'SVG']
        subsetter = subset.Subsetter(options)
        subsetter.populate(gids=to_unicode)

        # Subset font.
        try:
            ttfont = TTFont(full_font, fontNumber=self.index)
            subsetter.subset(ttfont)
        except TTLibError as exception:
            LOGGER.warning(f'Unable to subset "{self.family}" with fontTools')
            LOGGER.debug('Original exception:', exc_info=exception)
        else:
            optimized_font = io.BytesIO()
            ttfont.save(optimized_font)
            self.file_content = optimized_font.getvalue()


def build_fonts_dictionary(pdf, fonts, compress, subset, options):
    """Build PDF dictionary for fonts."""
    pdf_fonts = pydyf.Dictionary()
    fonts_by_file_hash = {}
    for font in fonts.values():
        fonts_by_file_hash.setdefault(font.hash, []).append(font)
    font_references_by_file_hash = {}
    for file_hash, file_fonts in fonts_by_file_hash.items():
        # TODO: Find why we can have multiple fonts for one font file.
        font = file_fonts[0]
        if font.bitmap:
            continue

        # Clean font, optimize and handle emojis.
        to_unicode = {}
        if subset and not font.used_in_forms:
            for file_font in file_fonts:
                to_unicode = {**to_unicode, **file_font.to_unicode}
        font.clean(to_unicode, options['hinting'])

        # Include font.
        if font.type == 'otf':
            font_extra = pydyf.Dictionary({'Subtype': '/OpenType'})
        else:
            font_extra = pydyf.Dictionary({'Length1': len(font.file_content)})
        font_stream = pydyf.Stream([font.file_content], font_extra, compress=compress)
        pdf.add_object(font_stream)
        font_references_by_file_hash[file_hash] = font_stream.reference

    for font in fonts.values():
        if subset and not font.used_in_forms:
            # Only store widths and map for used glyphs
            font_widths = font.widths
            to_unicode = font.to_unicode
        else:
            # Store width and Unicode map for all glyphs
            full_font = io.BytesIO(font.file_content)
            ttfont = TTFont(full_font, fontNumber=font.index)
            font_widths, to_unicode = {}, {}
            for i, glyph in enumerate(ttfont.getGlyphSet().values()):
                font_widths[i] = glyph.width * 1000 / font.upem
            for letter, key in ttfont.getBestCmap().items():
                glyph_id = ttfont.getGlyphID(key)
                if glyph_id not in to_unicode:
                    to_unicode[glyph_id] = chr(letter)

        to_unicode_object = pydyf.Stream([
            b'/CIDInit /ProcSet findresource begin',
            b'12 dict begin',
            b'begincmap',
            b'/CIDSystemInfo',
            b'<< /Registry (Adobe)',
            b'/Ordering (UCS)',
            b'/Supplement 0',
            b'>> def',
            b'/CMapName /Adobe-Identity-UCS def',
            b'/CMapType 2 def',
            b'1 begincodespacerange',
            b'<0000> <ffff>',
            b'endcodespacerange'], compress=compress)
        to_unicode_stream = to_unicode_object.stream
        to_unicode_length = len(to_unicode)
        to_unicode_items = tuple(to_unicode.items())
        for i in range(ceil(to_unicode_length / 100)):
            batch_length = min(100, to_unicode_length - i * 100)
            to_unicode_stream.append(f'{batch_length} beginbfchar'.encode())
            for glyph, text in to_unicode_items[i*100:(i+1)*100]:
                unicode_codepoints = ''.join(
                    f'{letter.encode("utf-16-be").hex()}' for letter in text)
                to_unicode_stream.append(
                    f'<{glyph:04x}> <{unicode_codepoints}>'.encode())
            to_unicode_stream.append(b'endbfchar')
        to_unicode_stream.extend([
            b'endcmap',
            b'CMapName currentdict /CMap defineresource pop',
            b'end',
            b'end'])
        pdf.add_object(to_unicode_object)
        font_dictionary = pydyf.Dictionary({
            'Type': '/Font',
            'Subtype': f'/Type{3 if font.bitmap else 0}',
            'BaseFont': font.name,
            'ToUnicode': to_unicode_object.reference,
        })

        if font.bitmap:
            _build_bitmap_font_dictionary(
                font_dictionary, pdf, font, font_widths, compress, subset)
        else:
            _build_vector_font_dictionary(
                font_dictionary, pdf, font, font_widths, compress,
                font_references_by_file_hash[font.hash], options['pdf_version'])
        pdf.add_object(font_dictionary)
        pdf_fonts[font.hash] = font_dictionary.reference

    return pdf_fonts


def _build_bitmap_font_dictionary(font_dictionary, pdf, font, widths, compress, subset):
    # https://docs.microsoft.com/typography/opentype/spec/ebdt
    font_dictionary['FontBBox'] = pydyf.Array([0, 0, 1, 1])
    font_dictionary['FontMatrix'] = pydyf.Array([1, 0, 0, 1, 0, 0])
    if subset:
        chars = tuple(sorted(font.to_unicode))
    else:
        chars = tuple(range(256))
    first, last = chars[0], chars[-1]
    differences = []
    for glyph in sorted(widths):
        if glyph - 1 not in widths:
            differences.append(glyph)
        differences.append(f'/{glyph}')
    font_dictionary['FirstChar'] = first
    font_dictionary['LastChar'] = last
    font_dictionary['Encoding'] = pydyf.Dictionary({
        'Type': '/Encoding',
        'Differences': pydyf.Array(differences),
    })
    char_procs = pydyf.Dictionary({})
    full_font = io.BytesIO(font.file_content)
    ttfont = TTFont(full_font, fontNumber=font.index)
    font_glyphs = ttfont['EBDT'].strikeData[0]
    widths = [0] * (last - first + 1)
    glyphs_info = {}
    for key, glyph in font_glyphs.items():
        glyph_format = glyph.getFormat()
        glyph_id = ttfont.getGlyphID(key)

        # Get and store glyph metrics.
        if glyph_format == 5:
            data = glyph.data
            subtables = ttfont['EBLC'].strikes[0].indexSubTables
            for subtable in subtables:
                first_index = subtable.firstGlyphIndex
                last_index = subtable.lastGlyphIndex
                if first_index <= glyph_id <= last_index:
                    height = subtable.metrics.height
                    advance = width = subtable.metrics.width
                    bearing_x = subtable.metrics.horiBearingX
                    bearing_y = subtable.metrics.horiBearingY
                    break
            else:
                LOGGER.warning(
                    f'Unknown bitmap metrics in "{font.family}" for glyph: {glyph_id}')
                continue
        else:
            data_start = 5 if glyph_format in (1, 2, 8) else 8
            data = glyph.data[data_start:]
            height, width = glyph.data[0:2]
            bearing_x = int.from_bytes(glyph.data[2:3], 'big', signed=True)
            bearing_y = int.from_bytes(glyph.data[3:4], 'big', signed=True)
            advance = glyph.data[4]
        position_y = bearing_y - height
        if glyph_id in chars:
            widths[glyph_id - first] = advance
        stride = ceil(width / 8)
        glyph_info = glyphs_info[glyph_id] = {
            'width': width,
            'height': height,
            'x': bearing_x,
            'y': position_y,
            'stride': stride,
            'bitmap': None,
            'subglyphs': None,
        }

        # Decode bitmaps.
        if 0 in (width, height) or not data:
            glyph_info['bitmap'] = b''
        elif glyph_format in (1, 6):
            glyph_info['bitmap'] = data
        elif glyph_format in (2, 5, 7):
            padding = (8 - (width % 8)) % 8
            bits = bin(int(data.hex(), 16))[2:]
            bits = bits.zfill(8 * len(data))
            bitmap_bits = ''.join(
                bits[i * width:(i + 1) * width] + padding * '0'
                for i in range(height))
            glyph_info['bitmap'] = int(bitmap_bits, 2).to_bytes(height * stride, 'big')
        elif glyph_format in (8, 9):
            subglyphs = glyph_info['subglyphs'] = []
            i = 0 if glyph_format == 9 else 1
            number_of_components = int.from_bytes(data[i:i+2], 'big')
            for j in range(number_of_components):
                index = (i + 2) + (j * 4)
                subglyph_id = int.from_bytes(data[index:index+2], 'big')
                x = int.from_bytes(data[index+2:index+3], 'big', signed=True)
                y = int.from_bytes(data[index+3:index+4], 'big', signed=True)
                subglyphs.append({'id': subglyph_id, 'x': x, 'y': y})
        else:  # pragma: no cover
            LOGGER.warning(
                f'Unsupported bitmap glyph format in "{font.family}": {glyph_format}')
            glyph_info['bitmap'] = bytes(height * stride)

    for glyph_id, glyph_info in glyphs_info.items():
        # Don’t store glyph not in to_unicode.
        if glyph_id not in chars:
            continue

        # Draw glyph.
        stride = glyph_info['stride']
        width = glyph_info['width']
        height = glyph_info['height']
        x = glyph_info['x']
        y = glyph_info['y']
        if glyph_info['bitmap'] is None:
            length = height * stride
            bitmap_int = int.from_bytes(bytes(length), 'big')
            for subglyph in glyph_info['subglyphs']:
                sub_x = subglyph['x']
                sub_y = subglyph['y']
                sub_id = subglyph['id']
                if sub_id not in glyphs_info:
                    LOGGER.warning(f'Unknown subglyph in "{font.family}": {sub_id}')
                    continue
                subglyph = glyphs_info[sub_id]
                if subglyph['bitmap'] is None:
                    # TODO: Support subglyph in subglyph.
                    LOGGER.warning(
                        'Unsupported subglyph in subglyph in '
                        f'"{font.family}": {sub_id}')
                    continue
                for row_y in range(subglyph['height']):
                    row_slice = slice(
                        row_y * subglyph['stride'],
                        (row_y + 1) * subglyph['stride'])
                    row = subglyph['bitmap'][row_slice]
                    row_int = int.from_bytes(row, 'big')
                    shift = stride * 8 * (height - sub_y - row_y - 1)
                    stride_difference = stride - subglyph['stride']
                    if stride_difference > 0:
                        row_int <<= stride_difference * 8
                    elif stride_difference < 0:
                        row_int >>= -stride_difference * 8
                    if sub_x > 0:
                        row_int >>= sub_x
                    elif sub_x < 0:
                        row_int <<= -sub_x
                    row_int %= 1 << stride * 8
                    row_int <<= shift
                    bitmap_int |= row_int
            bitmap = bitmap_int.to_bytes(length, 'big')
        else:
            bitmap = glyph_info['bitmap']
        bitmap_stream = pydyf.Stream([
            b'0 0 d0',
            f'{width} 0 0 {height} {x} {y} cm'.encode(),
            b'BI',
            b'/IM true',
            b'/W', width,
            b'/H', height,
            b'/BPC 1',
            b'/D [1 0]',
            b'ID', bitmap, b'EI'
        ], compress=compress)
        pdf.add_object(bitmap_stream)
        char_procs[glyph_id] = bitmap_stream.reference

    pdf.add_object(char_procs)
    font_dictionary['Widths'] = pydyf.Array(widths)
    font_dictionary['CharProcs'] = char_procs.reference


def _build_vector_font_dictionary(font_dictionary, pdf, font, widths, compress,
                                  reference, pdf_version):
    font_file = f'FontFile{3 if font.type == "otf" else 2}'
    max_x = max(widths.values()) if widths else 0
    bbox = (0, font.descent, max_x, font.ascent)
    flags = font.flags
    if len(widths) > 1 and len(set(font.widths.values())) == 1:
        flags += 2 ** (1 - 1)  # FixedPitch
    font_descriptor = pydyf.Dictionary({
        'Type': '/FontDescriptor',
        'FontName': font.name,
        'FontFamily': pydyf.String(font.family),
        'Flags': flags,
        'FontBBox': pydyf.Array(bbox),
        'ItalicAngle': font.italic_angle,
        'Ascent': font.ascent,
        'Descent': font.descent,
        'CapHeight': bbox[3],
        'StemV': font.stemv,
        'StemH': font.stemh,
        font_file: reference,
    })
    if str(pdf_version) <= '1.4':  # Cast for bytes and None
        cids = sorted(font.widths)
        padded_width = ceil((cids[-1] + 1) / 8)
        bits = ['0'] * padded_width * 8
        for cid in cids:
            bits[cid] = '1'
        stream = pydyf.Stream(
            (int(''.join(bits), 2).to_bytes(padded_width, 'big'),),
            compress=compress)
        pdf.add_object(stream)
        font_descriptor['CIDSet'] = stream.reference
    pdf.add_object(font_descriptor)

    pdf_widths = pydyf.Array()
    for i in sorted(widths):
        if i - 1 not in widths:
            pdf_widths.append(i)
            current_widths = pydyf.Array()
            pdf_widths.append(current_widths)
        current_widths.append(widths[i])

    subfont_dictionary = pydyf.Dictionary({
        'Type': '/Font',
        'Subtype': f'/CIDFontType{0 if font.type == "otf" else 2}',
        'BaseFont': font.name,
        'CIDSystemInfo': pydyf.Dictionary({
            'Registry': pydyf.String('Adobe'),
            'Ordering': pydyf.String('Identity'),
            'Supplement': 0,
        }),
        'CIDToGIDMap': '/Identity',
        'W': pdf_widths,
        'FontDescriptor': font_descriptor.reference,
    })
    pdf.add_object(subfont_dictionary)
    if font.missing:
        # Add CMap that doesn’t include missing glyphs, so that they can be replaced by
        # .notdef.
        cmap_extra = pydyf.Dictionary({
            'Type': '/CMap',
            'CMapName': '/WP-Encod-0',
            'CIDSystemInfo': pydyf.Dictionary({
                'Registry': pydyf.String('Adobe'),
                'Ordering': pydyf.String('Identity'),
                'Supplement': 0,
            }),
        })
        encoding = pydyf.Stream([
            b'/CIDInit /ProcSet findresource begin',
            b'12 dict begin',
            b'begincmap',
            b'/CIDSystemInfo',
            b'3 dict dup begin',
            b'/Registry (Adobe) def',
            b'/Ordering (Identity) def',
            b'/Supplement 0 def',
            b'end def',
            b'/CMapName /WP-Encod-0 def',
            b'/CMapType 1 def',
            b'1 begincodespacerange',
            b'<0000> <ffff>',
            b'endcodespacerange',
        ], cmap_extra, compress=compress)
        available = tuple(font.to_unicode)
        available_length = len(available)
        for i in range(ceil(available_length / 100)):
            batch_length = min(100, available_length - i * 100)
            encoding.stream.append(f'{batch_length} begincidchar'.encode())
            for glyph_id in available[i*100:(i+1)*100]:
                font_glyph_id = 0 if glyph_id in font.missing.values() else glyph_id
                encoding.stream.append(f'<{glyph_id:04x}> {font_glyph_id}'.encode())
            encoding.stream.append(b'endcidchar')
        encoding.stream.extend([
            b'endcmap',
            b'CMapName currentdict /CMap defineresource pop',
            b'end',
            b'end'])
        pdf.add_object(encoding)
        font_dictionary['Encoding'] = encoding.reference
    else:
        # No missing glyph in this font, use the identity mapping to map all glyphs.
        font_dictionary['Encoding'] = '/Identity-H'
    font_dictionary['DescendantFonts'] = pydyf.Array([subfont_dictionary.reference])
