#!/usr/bin/env python3
# -*- coding: utf-8 -*-
###############################################################################
# $Id: gdal_remove_towgs84.py 9b2aff83ee7cfdeecb8770109ac4d5dd193c933d 2020-03-13 16:17:52 +0100 Even Rouault $
#
#  Project:  GDAL samples
#  Purpose:  Remove TOWGS84[] clause from dataset SRS definitions
#  Author:   Even Rouault <even dot rouault at spatialys.com>
#
###############################################################################
#  Copyright (c) 2020, Even Rouault <even dot rouault at spatialys.com>
#
#  Permission is hereby granted, free of charge, to any person obtaining a
#  copy of this software and associated documentation files (the "Software"),
#  to deal in the Software without restriction, including without limitation
#  the rights to use, copy, modify, merge, publish, distribute, sublicense,
#  and/or sell copies of the Software, and to permit persons to whom the
#  Software is furnished to do so, subject to the following conditions:
#
#  The above copyright notice and this permission notice shall be included
#  in all copies or substantial portions of the Software.
#
#  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
#  OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
#  THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
#  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
#  DEALINGS IN THE SOFTWARE.
###############################################################################

from osgeo import gdal, osr
import os
import subprocess
import sys

def Usage():
    print('Usage: gdal_remove_towgs84.py [-q] filename')
    print('')
    print('(Try to) remove TOWGS84 clause from the dataset SRS definition, ')
    print('when it contains a EPSG code.')
    return -1

quiet = False
filename = None
for arg in sys.argv[1:]:
    if arg == '-q':
        quiet = True
    elif arg[0] == '-':
        Usage()
    elif filename is None:
        filename = arg
    else:
        Usage()

if filename is None:
    print('Missing filename.')
    Usage()

ds = gdal.Open(filename, gdal.GA_Update)
if ds is None:
    sys.exit(1)

wkt = ds.GetProjectionRef()
towgs84_pos = wkt.find('TOWGS84[')
sr = osr.SpatialReference()
sr.ImportFromWkt(wkt)

version = gdal.VersionInfo('RELEASE_NAME')
version_major = int(version[0:version.find('.')])

if ds.GetDriver().ShortName == 'GTiff' and version_major < 3:
    output = None
    try:
        output = subprocess.check_output(['listgeo', filename]).decode('LATIN1')
    except:
        pass
    if output and output.find('GeogTOWGS84GeoKey') < 0:
        # Check if listgeo is recent enough
        tmp_filename = 'tmp_gdal_remove_towgs84.tif'
        tmp_ds = gdal.GetDriverByName('GTiff').Create(tmp_filename,1,1)
        tmp_ds.SetProjection("""GEOGCS["test",
        DATUM["test",
            SPHEROID["test",1,0],
            TOWGS84[1,2,3,4,5,6,7]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433]]""")
        tmp_ds = None
        output = subprocess.check_output(['listgeo', tmp_filename]).decode('LATIN1')
        os.remove(tmp_filename)
        if output.find('GeogTOWGS84GeoKey') > 0:
            # The TOWGS84[] has been added by GDAL 2 GTiff driver, but is not
            # in the file
            towgs84_pos = -1

if towgs84_pos > 0 and sr.GetAuthorityName(None) == 'EPSG':
    endpos = wkt.find('],', towgs84_pos)
    assert endpos > 0
    wkt = wkt[0:towgs84_pos] + wkt[endpos+2:]
    assert ds.SetProjection(wkt) == 0
    if not quiet:
        print('%s patched to remove TOWGS84[] clause' % filename)
        if ds.GetDriver().ShortName == 'GTiff' and version_major < 3:
            print('Note: Running gdalinfo on the patched file with GDAL < 3 will still show the TOWGS84[] clause, but it will not be seen by GDAL >= 3')
else:
    if not quiet:
        print('%s does not need patching' % filename)
