#!/usr/bin/env python


__license__   = 'GPL v3'
__copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
__docformat__ = 'restructuredtext en'

import array
from struct import calcsize, pack, unpack_from

from calibre.utils.fonts.sfnt import DateTimeProperty, FixedProperty, UnknownTable
from calibre.utils.fonts.sfnt.errors import UnsupportedFont
from calibre.utils.fonts.sfnt.loca import read_array


class HeadTable(UnknownTable):

    created = DateTimeProperty('_created')
    modified = DateTimeProperty('_modified')
    version_number = FixedProperty('_version_number')
    font_revision = FixedProperty('_font_revision')

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        field_types = (
                '_version_number' , 'l',
                '_font_revision'  , 'l',
                'checksum_adjustment' , 'L',
                'magic_number' , 'L',
                'flags' , 'H',
                'units_per_em' , 'H',
                '_created' , 'q',
                '_modified' , 'q',
                'x_min' , 'h',
                'y_min' , 'h',
                'x_max' , 'h',
                'y_max' , 'h',
                'mac_style' , 'H',
                'lowest_rec_ppem' , 'H',
                'font_direction_hint' , 'h',
                'index_to_loc_format' , 'h',
                'glyph_data_format'   , 'h'
        )

        self._fmt = ('>%s'%(''.join(field_types[1::2]))).encode('ascii')
        self._fields = field_types[0::2]

        for f, val in zip(self._fields, unpack_from(self._fmt, self.raw)):
            setattr(self, f, val)

    def update(self):
        vals = [getattr(self, f) for f in self._fields]
        self.raw = pack(self._fmt, *vals)


def read_metrics(raw, num_of_metrics, num_of_glyphs, table_name):
    rawsz = 4 * num_of_metrics
    if len(raw) < rawsz:
        raise UnsupportedFont(f'The {table_name} table has insufficient data')
    long_hor_metric = raw[:rawsz]
    a = read_array(long_hor_metric)
    advances = a[0::2]
    a = read_array(long_hor_metric, 'h')
    bearings = a[1::2]
    if num_of_glyphs > num_of_metrics:
        extra = num_of_glyphs - num_of_metrics
        raw = raw[rawsz:]
        rawsz = 2 * extra
        if len(raw) < rawsz:
            raise UnsupportedFont(f'The {table_name} table has insufficient data for trailing bearings')
        bearings += read_array(raw, 'h')
    return advances, bearings


def update_metrics_table(metrics_map, mtx_table):
    recs, aw, b = [], array.array('H'), array.array('h')
    for glyph_id in sorted(metrics_map):
        adv, bearing = metrics_map[glyph_id]
        aw.append(adv)
        b.append(bearing)
        recs.append(pack('>Hh', adv, bearing))
    mtx_table.raw = b''.join(recs)
    return aw, b


class HorizontalHeader(UnknownTable):

    version_number = FixedProperty('_version_number')
    field_types = (
        '_version_number' , 'l',
        'ascender', 'h',
        'descender', 'h',
        'line_gap', 'h',
        'advance_width_max', 'H',
        'min_left_side_bearing', 'h',
        'min_right_side_bearing', 'h',
        'x_max_extent', 'h',
        'caret_slope_rise', 'h',
        'caret_slop_run', 'h',
        'caret_offset', 'h',
        'r1', 'h',
        'r2', 'h',
        'r3', 'h',
        'r4', 'h',
        'metric_data_format', 'h',
        'number_of_h_metrics', 'H',
    )

    def read_data(self, hmtx, num_glyphs):
        self._fmt = ('>%s'%(''.join(self.field_types[1::2]))).encode('ascii')
        self._fields = self.field_types[0::2]

        for f, val in zip(self._fields, unpack_from(self._fmt, self.raw)):
            setattr(self, f, val)

        self.advance_widths, self.left_side_bearings = read_metrics(hmtx.raw, self.number_of_h_metrics, num_glyphs, 'hmtx')

    def metrics_for(self, glyph_id):
        lsb = self.left_side_bearings[glyph_id]
        if glyph_id >= len(self.advance_widths):
            glyph_id = -1
        return self.advance_widths[glyph_id], lsb

    def update(self, metrics_map, mtx_table):
        aw, b = update_metrics_table(metrics_map, mtx_table)
        self.advance_widths = aw
        self.left_side_bearings = b
        self.number_of_h_metrics = len(metrics_map)
        self.advance_width_max = max(aw or (0,))
        self.min_left_side_bearing = min(b or (0,))
        data = (getattr(self, x) for x in self._fields)
        self.raw = pack('>' + ''.join(self.field_types[1::2]), *data)


class VerticalHeader(UnknownTable):

    version_number = FixedProperty('_version_number')
    field_types = (
        '_version_number' , 'l',
        'ascender', 'h',
        'descender', 'h',
        'line_gap', 'h',
        'advance_height_max', 'H',
        'min_top_side_bearing', 'h',
        'min_bottom_side_bearing', 'h',
        'y_max_extent', 'h',
        'caret_slope_rise', 'h',
        'caret_slop_run', 'h',
        'caret_offset', 'h',
        'r1', 'h',
        'r2', 'h',
        'r3', 'h',
        'r4', 'h',
        'metric_data_format', 'h',
        'number_of_v_metrics', 'H',
    )

    def read_data(self, vmtx, num_glyphs):
        self._fmt = ('>%s'%(''.join(self.field_types[1::2]))).encode('ascii')
        self._fields = self.field_types[0::2]

        for f, val in zip(self._fields, unpack_from(self._fmt, self.raw)):
            setattr(self, f, val)

        self.advance_heights, self.top_side_bearings = read_metrics(vmtx.raw, self.number_of_v_metrics, num_glyphs, 'vmtx')

    def metrics_for(self, glyph_id):
        tsb = self.top_side_bearings[glyph_id]
        if glyph_id >= len(self.advance_heights):
            glyph_id = -1
        return self.advance_heights[glyph_id], tsb

    def update(self, metrics_map, mtx_table):
        aw, b = update_metrics_table(metrics_map, mtx_table)
        self.advance_heights = aw
        self.top_side_bearings = b
        self.number_of_v_metrics = len(metrics_map)
        self.advance_height_max = max(aw or (0,))
        self.min_top_side_bearing = min(b or (0,))
        data = (getattr(self, x) for x in self._fields)
        self.raw = pack('>' + ''.join(self.field_types[1::2]), *data)


class OS2Table(UnknownTable):

    def read_data(self):
        if hasattr(self, 'char_width'):
            return
        ver, = unpack_from(b'>H', self.raw)
        field_types = [
            'version' , 'H',
            'average_char_width', 'h',
            'weight_class', 'H',
            'width_class', 'H',
            'fs_type', 'H',
            'subscript_x_size', 'h',
            'subscript_y_size', 'h',
            'subscript_x_offset', 'h',
            'subscript_y_offset', 'h',
            'superscript_x_size', 'h',
            'superscript_y_size', 'h',
            'superscript_x_offset', 'h',
            'superscript_y_offset', 'h',
            'strikeout_size', 'h',
            'strikeout_position', 'h',
            'family_class', 'h',
            'panose', '10s',
            'ranges', '16s',
            'vendor_id', '4s',
            'selection', 'H',
            'first_char_index', 'H',
            'last_char_index', 'H',
            'typo_ascender', 'h',
            'typo_descender', 'h',
            'typo_line_gap', 'h',
            'win_ascent', 'H',
            'win_descent', 'H',
        ]
        if ver > 1:
            field_types += [
                'code_page_range', '8s',
                'x_height', 'h',
                'cap_height', 'h',
                'default_char', 'H',
                'break_char', 'H',
                'max_context', 'H',
            ]

        self._fmt = ('>%s'%(''.join(field_types[1::2]))).encode('ascii')
        self._fields = field_types[0::2]

        for f, val in zip(self._fields, unpack_from(self._fmt, self.raw)):
            setattr(self, f, val)

    def zero_fstype(self):
        prefix = calcsize(b'>HhHH')
        self.raw = self.raw[:prefix] + b'\0\0' + self.raw[prefix+2:]
        self.fs_type = 0


class PostTable(UnknownTable):

    version_number = FixedProperty('_version')
    italic_angle = FixedProperty('_italic_angle')

    def read_data(self):
        if hasattr(self, 'underline_position'):
            return
        (self._version, self._italic_angle, self.underline_position,
         self.underline_thickness) = unpack_from(b'>llhh', self.raw)
