#!/usr/bin/env python
#
# aof2obj - convert Artlantis Object Format files to Wavefront OBJ
#
# Copyright (C) 2012  Antonio Ospite <ospite@studenti.unina.it>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import os
import sys
from lxml import etree
import binascii


def usage(name):
    sys.stdout.write("usage: %s <aof file>\n" % name)


def aof2obj(aof_filename, obj_filename, basename):

    f = open(aof_filename, "r")

    # Use recover mode, because the xml format is ill-specified:
    # there is at least one element with the name starting with a number
    # <3D.Paths>, in violation to the XML spec.
    # And there is some elements with the UUID attribute specified multiple
    # times...
    parser = etree.XMLParser(recover=True)
    tree = etree.parse(f, parser)

    # The preview image could be some bitmap format, don't know yet
    preview = tree.find("Preview.Image")
    if preview is not None:
        heximage = preview.text.rstrip("\t\n")

        preview_file = open(basename + ".prw", "w")
        preview_file.write(binascii.unhexlify(heximage))
        preview_file.close()

    obj_file = open(obj_filename, "w")

    obj_file.write("# obj file created with aof2obj\n")
    obj_file.write("# by Antonio Ospite\n\n")

    # Vertices
    points = tree.find('Points')
    points_data = points.text.strip("\t\n").split("\n")

    for p in points_data[1:]:
        obj_file.write("v %s\n" % p.rstrip(' '))

    obj_file.write("# %d vertices\n\n" % int(points_data[0]))

    # Faces
    polygons = tree.find('Polygons')
    polygons_data = polygons.text.strip("\t\n").split("\n")

    current_object = -1

    for p in polygons_data[1:]:
        ptype, pdata = p.split("\t")
        if ptype != 'o' and ptype != 'p':
            sys.stderr.write("Unsupported polygon type")
            sys.exit(1)

        # If there is a M in pdata discard the line
        # don't know how to handle that
        if 'M' in pdata:
            sys.stdout.write("Warning, ignored M element\n")
            continue

        # Don't know what the 'I' stands for yet, for now just ignore it
        pdata = pdata.replace(' I ', ' ').strip(' ')

        pdata_list = pdata.split(' ')

        obj_number = int(pdata_list[0])
        num_verts = int(pdata_list[1])

        # Vert indices start from 1 in .obj files
        verts_data = " ".join([str(int(i) + 1) for i in pdata_list[2:]])

        if obj_number != current_object:
            obj_file.write("\n# defining Object_%d\n" % obj_number)
            obj_file.write("g Object_%d\n" % obj_number)
            current_object = obj_number

        obj_file.write("f %s\n" % verts_data)

    obj_file.write("# %d faces\n\n" % int(polygons_data[0]))

    obj_file.close()


if __name__ == "__main__":

    if len(sys.argv) < 2:
        usage(sys.argv[0])
        sys.exit(1)

    aof_filename = sys.argv[1]
    basename_no_ext = os.path.splitext(aof_filename)[0]
    obj_filename = basename_no_ext + ".obj"

    aof2obj(aof_filename, obj_filename, basename_no_ext)

    sys.exit(0)