#!/usr/bin/python
#
# Copyright 2015 Google Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Post-build changes for Roboto for Android."""

import os
from os import path
import sys

from fontTools import ttLib
from nototools import font_data


def apply_temporary_fixes(font):
    """Apply some temporary fixes.
    """
    # Fix version number from buildnumber.txt
    from datetime import date

    build_number_txt = path.join(
        path.dirname(__file__), os.pardir, 'res', 'buildnumber.txt')
    build_number = open(build_number_txt).read().strip()

    version_record = 'Version 2.%s; %d' % (build_number, date.today().year)

    for record in font['name'].names:
        if record.nameID == 5:
            if record.platformID == 1 and record.platEncID == 0:  # MacRoman
                record.string = version_record
            elif record.platformID == 3 and record.platEncID == 1:
                # Windows UCS-2
                record.string = version_record.encode('UTF-16BE')
            else:
                assert False


def apply_android_specific_fixes(font):
    """Apply fixes needed for Android."""
    # Set ascent, descent, and lineGap values to Android K values
    hhea = font['hhea']
    hhea.ascent = 1900
    hhea.descent = -500
    hhea.lineGap = 0

    # Remove combining keycap and the arrows from the cmap table:
    # https://code.google.com/a/google.com/p/roboto/issues/detail?id=52
    font_data.delete_from_cmap(font, [
        0x20E3, # COMBINING ENCLOSING KEYCAP
        0x2191, # UPWARDS ARROW
        0x2193, # DOWNWARDS ARROW
        ])

    # Drop tables not useful on Android
    for table in ['LTSH', 'hdmx', 'VDMX', 'gasp']:
        if table in font:
            del font[table]


def correct_font(source_font_name, target_font_name):
    """Corrects metrics and other meta information."""
    font = ttLib.TTFont(source_font_name)
    apply_temporary_fixes(font)
    apply_android_specific_fixes(font)
    font.save(target_font_name)


def main(argv):
    """Correct the font specified in the command line."""
    correct_font(argv[1], argv[2])


if __name__ == "__main__":
    main(sys.argv)