#!/usr/bin/env python

############################################################################
#
# MODULE:       i.in.spot
#
# AUTHOR(S):    Markus Neteler
#               Converted to Python by Glynn Clements
#
# PURPOSE:      Import SPOT VEGETATION data into a GRASS raster map
#               SPOT Vegetation (1km, global) data:
#               http://free.vgt.vito.be/
#
# COPYRIGHT:    (c) 2004-2011 GRASS Development Team
#
#               This program is free software under the GNU General Public
#               License (>=v2). Read the file COPYING that comes with GRASS
#               for details.
#
#############################################################################
#
# REQUIREMENTS:
#      -  gdal: http://www.gdal.org
#
# Notes:
# * According to the faq (http://www.vgt.vito.be/faq/faq.html), SPOT vegetation 
#   coordinates refer to the center of a pixel.
# * GDAL coordinates refer to the corner of a pixel
#   -> correction of 0001/0001_LOG.TXT coordinates by 0.5 pixel
#############################################################################

#%module
#% description: Imports SPOT VGT NDVI data into a raster map.
#% keywords: imagery
#% keywords: import
#%end
#%flag
#% key: a
#% description: Also import quality map (SM status map layer) and filter NDVI map
#%end
#%option G_OPT_F_INPUT
#% description: Name of input SPOT VGT NDVI HDF file
#%end
#% option G_OPT_R_OUTPUT
#% required : no
#%end

import sys
import os
import atexit
import string
import grass.script as grass

vrt = """<VRTDataset rasterXSize="$XSIZE" rasterYSize="$YSIZE">
 <SRS>GEOGCS[&quot;wgs84&quot;,DATUM[&quot;WGS_1984&quot;,SPHEROID[&quot;wgs84&quot;,6378137,298.257223563],TOWGS84[0.000,0.000,0.000]],PRIMEM[&quot;Greenwich&quot;,0],UNIT[&quot;degree&quot;,0.0174532925199433]]</SRS>
   <GeoTransform>$WESTCORNER, $RESOLUTION, 0.0000000000000000e+00, $NORTHCORNER, 0.0000000000000e+00, -$RESOLUTION</GeoTransform>
   <VRTRasterBand dataType="Byte" band="1">
    <NoDataValue>0.00000000000000E+00</NoDataValue>
    <ColorInterp>Gray</ColorInterp>
    <SimpleSource>
     <SourceFilename>$FILENAME</SourceFilename>
      <SourceBand>1</SourceBand>
      <SrcRect xOff="0" yOff="0" xSize="$XSIZE" ySize="$YSIZE"/>
      <DstRect xOff="0" yOff="0" xSize="$XSIZE" ySize="$YSIZE"/>
    </SimpleSource>
 </VRTRasterBand>
</VRTDataset>"""

#### a function for writing VRT files
def create_VRT_file(projfile, vrtfile, infile):
    fh = file(projfile)
    kv = {}
    for l in fh:
	f = l.rstrip('\r\n').split()
	if f < 2:
	    continue
	kv[f[0]] = f[1]
    fh.close()

    north_center = kv['CARTO_UPPER_LEFT_Y']
    south_center = kv['CARTO_LOWER_LEFT_Y']
    east_center  = kv['CARTO_UPPER_RIGHT_X']
    west_center  = kv['CARTO_UPPER_LEFT_X']
    map_proj_res = kv['MAP_PROJ_RESOLUTION']
    xsize        = kv['IMAGE_UPPER_RIGHT_COL']
    ysize        = kv['IMAGE_LOWER_RIGHT_ROW']

    resolution   = float(map_proj_res)
    north_corner = float(north_center) + resolution / 2
    south_corner = float(south_center) - resolution / 2
    east_corner  = float(east_center ) + resolution / 2
    west_corner  = float(west_center ) - resolution / 2

    t = string.Template(vrt)
    s = t.substitute(NORTHCORNER = north_corner, WESTCORNER = west_corner,
		     XSIZE = xsize, YSIZE = ysize, RESOLUTION = map_proj_res,
		     FILENAME = infile)
    outf = file(vrtfile, 'w')
    outf.write(s)
    outf.close()

def cleanup():
   #### clean up the mess
   grass.try_remove(vrtfile)
   grass.try_remove(tmpfile)

def main():
    global vrtfile, tmpfile

    infile  = options['input']
    rast = options['output']
    also = flags['a']

    #### check for gdalinfo (just to check if installation is complete)
    if not grass.find_program('gdalinfo', '--help'):
	grass.fatal(_("'gdalinfo' not found, install GDAL tools first (http://www.gdal.org)"))

    pid = str(os.getpid())
    tmpfile = grass.tempfile()

    ################### let's go

    spotdir = os.path.dirname(infile)
    spotname = grass.basename(infile, 'hdf')

    if rast:
	name = rast
    else:
	name = spotname

    if not grass.overwrite() and grass.find_file(name)['file']:
	grass.fatal(_("<%s> already exists. Aborting.") % name)

    # still a ZIP file?  (is this portable?? see the r.in.srtm script for ideas)
    if infile.lower().endswith('.zip'):
	grass.fatal(_("Please extract %s before import.") % infile)

    try:
	p = grass.Popen(['file', '-ib', infile], stdout = grass.PIPE)
	s = p.communicate()[0]
	if s == "application/x-zip":
	    grass.fatal(_("Please extract %s before import.") % infile)
    except:
	pass

    ### create VRT header for NDVI

    projfile = os.path.join(spotdir, "0001_LOG.TXT")
    vrtfile = tmpfile + '.vrt'

    # first process the NDVI:
    grass.try_remove(vrtfile)
    create_VRT_file(projfile, vrtfile, infile)

    ## let's import the NDVI map...
    grass.message(_("Importing SPOT VGT NDVI map..."))
    if grass.run_command('r.in.gdal', input = vrtfile, output = name) != 0:
	grass.fatal(_("An error occurred. Stop."))

    grass.message(_("Imported SPOT VEGETATION NDVI map <%s>.") % name)

    #################
    ## http://www.vgt.vito.be/faq/FAQS/faq19.html
    # What is the relation between the digital number and the real NDVI ?
    # Real NDVI =coefficient a * Digital Number + coefficient b
    #           = a * DN +b
    #
    # Coefficient a = 0.004
    # Coefficient b = -0.1

    # clone current region
    # switch to a temporary region
    grass.use_temp_region()

    grass.run_command('g.region', rast = name, quiet = True)

    grass.message(_("Remapping digital numbers to NDVI..."))
    tmpname = "%s_%s" % (name, pid)
    grass.mapcalc("$tmpname = 0.004 * $name - 0.1", tmpname = tmpname, name = name)
    grass.run_command('g.remove', rast = name, quiet = True)
    grass.run_command('g.rename', rast = (tmpname, name), quiet = True)

    # write cmd history:
    grass.raster_history(name)

    #apply color table:
    grass.run_command('r.colors', map = name, color = 'ndvi', quiet = True)

    ##########################
    # second, optionally process the SM quality map:
    
    #SM Status Map
    # http://nieuw.vgt.vito.be/faq/FAQS/faq22.html
    #Data about
    # Bit NR 7: Radiometric quality for B0 coded as 0 if bad and 1 if good
    # Bit NR 6: Radiometric quality for B2 coded as 0 if bad and 1 if good
    # Bit NR 5: Radiometric quality for B3 coded as 0 if bad and 1 if good
    # Bit NR 4: Radiometric quality for MIR coded as 0 if bad and 1 if good
    # Bit NR 3: land code 1 or water code 0
    # Bit NR 2: ice/snow code 1 , code 0 if there is no ice/snow
    # Bit NR 1:	0	0	1		1
    # Bit NR 0:	0	1	0		1
    # 		clear	shadow	uncertain	cloud
    #
    #Note:
    # pos 7     6    5    4    3    2   1   0 (bit position)
    #   128    64   32   16    8    4   2   1 (values for 8 bit)
    #
    #
    # Bit 4-7 should be 1: their sum is 240
    # Bit 3   land code, should be 1, sum up to 248 along with higher bits
    # Bit 2   ice/snow code
    # Bit 0-1 should be 0
    #
    # A good map threshold: >= 248

    if also:
	grass.message(_("Importing SPOT VGT NDVI quality map..."))
	grass.try_remove(vrtfile)
	qname = spotname.replace('NDV','SM')
	qfile = os.path.join(spotdir, qname)
	create_VRT_file(projfile, vrtfile, qfile)

	## let's import the SM quality map...
	smfile = name + '.sm'
	if grass.run_command('r.in.gdal', input = vrtfile, output = smfile) != 0:
	    grass.fatal(_("An error occurred. Stop."))

	# some of the possible values:
	rules = [r + '\n' for r in [
	    '8 50 50 50',
	    '11 70 70 70',
	    '12 90 90 90',
	    '60 grey',
	    '155 blue',
	    '232 violet',
	    '235 red',
	    '236 brown',
	    '248 orange',
	    '251 yellow',
	    '252 green'
	    ]]
	grass.write_command('r.colors', map = smfile, rules = '-', stdin = rules)

	grass.message(_("Imported SPOT VEGETATION SM quality map <%s>.") % smfile)
	grass.message(_("Note: A snow map can be extracted by category 252 (d.rast %s cat=252)") % smfile)
	grass.message("")
	grass.message(_("Filtering NDVI map by Status Map quality layer..."))

	filtfile = "%s_filt" % name
	grass.mapcalc("$filtfile = if($smfile % 4 == 3 || ($smfile / 16) % 16 == 0, null(), $name)",
		      filtfile = filtfile, smfile = smfile, name = name)
	grass.run_command('r.colors', map = filtfile, color = 'ndvi', quiet = True)
	grass.message(_("Filtered SPOT VEGETATION NDVI map <%s>.") % filtfile)

	# write cmd history:
	grass.raster_history(smfile)
	grass.raster_history(filtfile)

    grass.message(_("Done."))

if __name__ == "__main__":
    options, flags = grass.parser()
    atexit.register(cleanup)
    main()