#!/usr/bin/env python2
# vim:fileencoding=utf-8
from __future__ import (unicode_literals, division, absolute_import,
                        print_function)

__license__ = 'GPL v3'
__copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'

import os, re
from collections import namedtuple

from calibre.ebooks.docx.block_styles import binary_property, inherit
from calibre.utils.filenames import ascii_filename
from calibre.utils.fonts.scanner import font_scanner, NoFonts
from calibre.utils.fonts.utils import panose_to_css_generic_family, is_truetype_font

Embed = namedtuple('Embed', 'name key subsetted')


def has_system_fonts(name):
    try:
        return bool(font_scanner.fonts_for_family(name))
    except NoFonts:
        return False


def get_variant(bold=False, italic=False):
    return {(False, False):'Regular', (False, True):'Italic',
            (True, False):'Bold', (True, True):'BoldItalic'}[(bold, italic)]


def find_fonts_matching(fonts, style='normal', stretch='normal'):
    for font in fonts:
        if font['font-style'] == style and font['font-stretch'] == stretch:
            yield font


def weight_key(font):
    w = font['font-weight']
    try:
        return abs(int(w) - 400)
    except Exception:
        return abs({'normal': 400, 'bold': 700}.get(w, 1000000) - 400)


def get_best_font(fonts, style, stretch):
    try:
        return sorted(find_fonts_matching(fonts, style, stretch), key=weight_key)[0]
    except Exception:
        pass


class Family(object):

    def __init__(self, elem, embed_relationships, XPath, get):
        self.name = self.family_name = get(elem, 'w:name')
        self.alt_names = tuple(get(x, 'w:val') for x in XPath('./w:altName')(elem))
        if self.alt_names and not has_system_fonts(self.name):
            for x in self.alt_names:
                if has_system_fonts(x):
                    self.family_name = x
                    break

        self.embedded = {}
        for x in ('Regular', 'Bold', 'Italic', 'BoldItalic'):
            for y in XPath('./w:embed%s[@r:id]' % x)(elem):
                rid = get(y, 'r:id')
                key = get(y, 'w:fontKey')
                subsetted = get(y, 'w:subsetted') in {'1', 'true', 'on'}
                if rid in embed_relationships:
                    self.embedded[x] = Embed(embed_relationships[rid], key, subsetted)

        self.generic_family = 'auto'
        for x in XPath('./w:family[@w:val]')(elem):
            self.generic_family = get(x, 'w:val', 'auto')

        ntt = binary_property(elem, 'notTrueType', XPath, get)
        self.is_ttf = ntt is inherit or not ntt

        self.panose1 = None
        self.panose_name = None
        for x in XPath('./w:panose1[@w:val]')(elem):
            try:
                v = get(x, 'w:val')
                v = tuple(int(v[i:i+2], 16) for i in xrange(0, len(v), 2))
            except (TypeError, ValueError, IndexError):
                pass
            else:
                self.panose1 = v
                self.panose_name = panose_to_css_generic_family(v)

        self.css_generic_family = {'roman':'serif', 'swiss':'sans-serif', 'modern':'monospace',
                                   'decorative':'fantasy', 'script':'cursive'}.get(self.generic_family, None)
        self.css_generic_family = self.css_generic_family or self.panose_name or 'serif'


class Fonts(object):

    def __init__(self, namespace):
        self.namespace = namespace
        self.fonts = {}
        self.used = set()

    def __call__(self, root, embed_relationships, docx, dest_dir):
        for elem in self.namespace.XPath('//w:font[@w:name]')(root):
            self.fonts[self.namespace.get(elem, 'w:name')] = Family(elem, embed_relationships, self.namespace.XPath, self.namespace.get)

    def family_for(self, name, bold=False, italic=False):
        f = self.fonts.get(name, None)
        if f is None:
            return 'serif'
        variant = get_variant(bold, italic)
        self.used.add((name, variant))
        name = f.name if variant in f.embedded else f.family_name
        return '"%s", %s' % (name.replace('"', ''), f.css_generic_family)

    def embed_fonts(self, dest_dir, docx):
        defs = []
        dest_dir = os.path.join(dest_dir, 'fonts')
        for name, variant in self.used:
            f = self.fonts[name]
            if variant in f.embedded:
                if not os.path.exists(dest_dir):
                    os.mkdir(dest_dir)
                fname = self.write(name, dest_dir, docx, variant)
                if fname is not None:
                    d = {'font-family':'"%s"' % name.replace('"', ''), 'src': 'url("fonts/%s")' % fname}
                    if 'Bold' in variant:
                        d['font-weight'] = 'bold'
                    if 'Italic' in variant:
                        d['font-style'] = 'italic'
                    d = ['%s: %s' % (k, v) for k, v in d.iteritems()]
                    d = ';\n\t'.join(d)
                    defs.append('@font-face {\n\t%s\n}\n' % d)
        return '\n'.join(defs)

    def write(self, name, dest_dir, docx, variant):
        f = self.fonts[name]
        ef = f.embedded[variant]
        raw = docx.read(ef.name)
        prefix = raw[:32]
        if ef.key:
            key = re.sub(r'[^A-Fa-f0-9]', '', ef.key)
            key = bytearray(reversed(tuple(int(key[i:i+2], 16) for i in xrange(0, len(key), 2))))
            prefix = bytearray(prefix)
            prefix = bytes(bytearray(prefix[i]^key[i % len(key)] for i in xrange(len(prefix))))
        if not is_truetype_font(prefix):
            return None
        ext = 'otf' if prefix.startswith(b'OTTO') else 'ttf'
        fname = ascii_filename('%s - %s.%s' % (name, variant, ext))
        with open(os.path.join(dest_dir, fname), 'wb') as dest:
            dest.write(prefix)
            dest.write(raw[32:])

        return fname
