#!/usr/bin/python2
#
# -*- coding: utf-8 -*-
# ******************************************************************************
#  $Id: wcs_virtds_params.py e61505e755326f028d730384dcbd273681c97942 2018-04-19 08:23:03 +1000 Ben Elliston $
#
#  Name:     wcs_virtds_params.py
#  Project:  GDAL Python Interface
#  Purpose:  Generates MapServer WCS layer definition from a tileindex with mixed SRS
#  Author:   Even Rouault, <even dot rouault at mines-paris dot org>
#
# ******************************************************************************
#  Copyright (c) 2013, Even Rouault <even dot rouault at mines-paris dot org>
#
#  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.
# ******************************************************************************

import os
import sys

from osgeo import gdal
from osgeo import ogr
from osgeo import osr


def Usage():
    print('Usage: wcs_virtds_params.py [-lyr_name name] [-tileindex field_name] [-t_srs srsdef] -src_srs_name field_name ogr_ds_tileindex')
    sys.exit(1)


argv = sys.argv
argv = ogr.GeneralCmdLineProcessor(argv)

ogr_ds_name = None
lyr_name = None

tileitem = 'location'
tilesrs = None
srsname = None

nArgc = len(argv)
iArg = 1
while iArg < nArgc:

    if argv[iArg] == "-lyr_name" and iArg < nArgc - 1:
        iArg = iArg + 1
        lyr_name = argv[iArg]

    elif argv[iArg] == "-tileindex" and iArg < nArgc - 1:
        iArg = iArg + 1
        tileitem = argv[iArg]

    elif argv[iArg] == "-src_srs_name" and iArg < nArgc - 1:
        iArg = iArg + 1
        tilesrs = argv[iArg]

    elif argv[iArg] == "-t_srs" and iArg < nArgc - 1:
        iArg = iArg + 1
        srsname = argv[iArg]

    elif argv[iArg][0] == '-':
        Usage()

    elif ogr_ds_name is None:
        ogr_ds_name = argv[iArg]

    iArg = iArg + 1

if ogr_ds_name is None or tilesrs is None:
    Usage()

ogr_ds = ogr.Open(ogr_ds_name)
if ogr_ds is None:
    raise Exception('cannot open %s' % ogr_ds_name)
if ogr_ds.GetLayerCount() == 1:
    lyr = ogr_ds.GetLayer(0)
elif lyr_name is None:
    raise Exception('-lyr_name should be specified')
else:
    lyr = ogr_ds.GetLayerByName(lyr_name)

if lyr.GetLayerDefn().GetFieldIndex(tileitem) < 0:
    raise Exception('%s field cannot be found in layer definition' % tileitem)

if lyr.GetLayerDefn().GetFieldIndex(tilesrs) < 0:
    raise Exception('%s field cannot be found in layer definition' % tilesrs)

lyr_srs = lyr.GetSpatialRef()
if srsname is not None:
    srs = osr.SpatialReference()
    if srs.SetFromUserInput(srsname) != 0:
        raise Exception('invalid value for -t_srs : %s' % srsname)

    # Sanity check
    if lyr_srs is not None:
        lyr_srs_proj4 = lyr_srs.ExportToProj4()
        lyr_srs = osr.SpatialReference()
        lyr_srs.SetFromUserInput(lyr_srs_proj4)
        lyr_srs_proj4 = lyr_srs.ExportToProj4()

        srs_proj4 = srs.ExportToProj4()
        if lyr_srs_proj4 != srs_proj4:
            raise Exception('-t_srs overrides the layer SRS in an incompatible way : (%s, %s)' % (srs_proj4, lyr_srs_proj4))
else:
    srs = lyr_srs

if srs is None:
    raise Exception('cannot fetch source SRS')

srs.AutoIdentifyEPSG()
authority_name = srs.GetAuthorityName(None)
authority_code = srs.GetAuthorityCode(None)
dst_wkt = srs.ExportToWkt()
if authority_name != 'EPSG' or authority_code is None:
    raise Exception('cannot fetch source SRS as EPSG:XXXX code : %s' % dst_wkt)

counter = 0
xres = 0
yres = 0

while True:
    feat = lyr.GetNextFeature()
    if feat is None:
        break
    # feat.DumpReadable()

    gdal_ds_name = feat.GetField(tileitem)
    if not os.path.isabs(gdal_ds_name):
        gdal_ds_name = os.path.join(os.path.dirname(ogr_ds_name), gdal_ds_name)
    gdal_ds = gdal.Open(gdal_ds_name)
    if gdal_ds is None:
        raise Exception('cannot open %s' % gdal_ds_name)
    warped_vrt_ds = gdal.AutoCreateWarpedVRT(gdal_ds, None, dst_wkt)
    if warped_vrt_ds is None:
        raise Exception('cannot warp %s to %s' % (gdal_ds_name, dst_wkt))
    gt = warped_vrt_ds.GetGeoTransform()
    xres += gt[1]
    yres += gt[5]
    warped_vrt_ds = None

    counter = counter + 1

if counter == 0:
    raise Exception('tileindex is empty')

xres /= counter
yres /= counter
(xmin, xmax, ymin, ymax) = lyr.GetExtent()
xsize = (int)((xmax - xmin) / xres + 0.5)
ysize = (int)((ymax - ymin) / abs(yres) + 0.5)

layername = lyr.GetName()

if ogr_ds.GetDriver().GetName() != 'ESRI Shapefile':
    print("""LAYER
  NAME "%s_tileindex"
  TYPE POLYGON
  STATUS OFF
  CONNECTIONTYPE OGR
  CONNECTION "%s,%s"
  PROJECTION
    "+init=epsg:%s"
  END
END""" % (layername, ogr_ds_name, lyr.GetName(), authority_code))
    print("")

    tileindex = "%s_tileindex" % layername
else:
    tileindex = ogr_ds_name

print("""LAYER
  NAME "%s"
  TYPE RASTER
  STATUS ON
  TILEINDEX "%s"
  TILEITEM "%s"
  TILESRS "%s"
  PROJECTION
    "+init=epsg:%s"
  END
  METADATA
   "wcs_label"       "%s"
   "wcs_rangeset_name"   "Range 1"  ### required to support DescribeCoverage request
   "wcs_rangeset_label"  "My Label" ### required to support DescribeCoverage request
   "wcs_extent"      "%f %f %f %f"
   "wcs_size"        "%d %d"
   "wcs_resolution"  "%f %f"
  END
END""" % (layername, tileindex, tileitem, tilesrs, authority_code, layername, xmin, ymin, xmax, ymax, xsize, ysize, xres, abs(yres)))