#!/usr/bin/env python3

import sys
import array
from gi.repository import HarfBuzz as hb
from gi.repository import GLib

fontdata = open(sys.argv[1], 'rb').read()
text = sys.argv[2]
# Need to create GLib.Bytes explicitly until this bug is fixed:
# https://bugzilla.gnome.org/show_bug.cgi?id=729541
blob = hb.glib_blob_create(GLib.Bytes.new(fontdata))
face = hb.face_create(blob, 0)
del blob
font = hb.font_create(face)
upem = hb.face_get_upem(face)
del face
hb.font_set_scale(font, upem, upem)
# hb.ft_font_set_funcs (font)
hb.ot_font_set_funcs(font)

buf = hb.buffer_create()


class Debugger(object):
    def message(self, buf, font, msg, data, _x_what_is_this):
        print(msg)
        return True


debugger = Debugger()
hb.buffer_set_message_func(buf, debugger.message, 1, 0)

##
## Add text to buffer
##
#
# See https://github.com/harfbuzz/harfbuzz/pull/271
#
# If you do not care about cluster values reflecting Python
# string indices, then this is quickest way to add text to
# buffer:
# hb.buffer_add_utf8 (buf, text.encode('utf-8'), 0, -1)
# Otherwise, then following handles both narrow and wide
# Python builds (the first item in the array is BOM, so we skip it):
if sys.maxunicode == 0x10FFFF:
    hb.buffer_add_utf32(buf, array.array('I', text.encode('utf-32'))[1:], 0, -1)
else:
    hb.buffer_add_utf16(buf, array.array('H', text.encode('utf-16'))[1:], 0, -1)

hb.buffer_guess_segment_properties(buf)

hb.shape(font, buf, [])
del font

infos = hb.buffer_get_glyph_infos(buf)
positions = hb.buffer_get_glyph_positions(buf)

for info, pos in zip(infos, positions):
    gid = info.codepoint
    cluster = info.cluster
    x_advance = pos.x_advance
    x_offset = pos.x_offset
    y_offset = pos.y_offset

    print("gid%d=%d@%d,%d+%d" % (gid, cluster, x_advance, x_offset, y_offset))
