#!/bin/bash
#input is path to one MODIS image of specific tile
input=$1
indir=$2
outdir=$3
py=$4

indirALL=$(dirname $indir | cut -d'/' -f1-5)
echo "$indirALL input data here"

doy=$(basename $input .tif | cut -d'.' -f2 | cut -c2-)
echo "processing date: $doy"
year=${doy:0:4}
echo "processing year: $year"

#copy all input files being MODIS tiles to working directory
cp ${indirALL}/h*/${year}/INT*.A${doy}*.tif .

#change data type to Byte for all files
for i in INT*.tif
do
	gdal_translate $i $(basename $i .tif)_byte.tif -ot Byte -co compress=deflate
done

rm *.BIN.tif

#check input files
ls $PWD

mkdir -p output/

#convert day of year string to julian date
ymd=$(python $py $doy)

if [ -z "$ymd" ]
then
      echo "\$ymd is empty"
      exit 1
fi

if [ ! -f ${outdir}/swat_${ymd}.tif ];
then	
	#mosaic all MODIS tiles
	gdalbuildvrt swat_${ymd}.vrt INT*.A${doy}*_byte.tif
	
	#change projection to WGS84
    gdalwarp -t_srs EPSG:4326 swat_${ymd}.vrt swat_${ymd}_1.tif -te -180 -70 180 70 -ts 172800 67200 -co compress=deflate -dstnodata 255 -r near
	
	#convert to tif
	gdal_translate swat_${ymd}_1.tif swat_${ymd}.tif -co compress=deflate -a_nodata 255 -mo TIFFTAG_DOCUMENTNAME=swat_${ymd}.vrt
	mv swat_${ymd}.tif output/swat_${ymd}.tif
else        
	echo "${outdir}/swat_${ymd}.tif already exists"
fi

exit 0