#!/bin/sh
set -euf

###### USAGE #####
#run in new directory(will be polluted with images
#just run ./make-realwallpaper

curl -sSz Nightmap_bare.jpg http://awka.sourceforge.net/Night_le_huge.jpg -o Nightmap_bare.jpg &
curl -sSz Daymap_bare.png http://www.nnvl.noaa.gov/images/globaldata/SnowIceCover_Daily.png -o Daymap_bare.png &
curl -sSz Clouds.jpg http://user.chol.com/~winxplanet/cloud_data/clouds_2048.jpg -o Clouds.jpg &
wait

if ! file -ib Nightmap_bare.jpg|grep -q ^image/; then
    rm Nightmap_bare.jpg
    exit 1
fi
if ! file -ib Daymap_bare.png|grep -q ^image/; then
    rm Daymap_bare.png
    exit 1
fi
if ! file -ib Clouds.jpg|grep -q ^image/; then
    rm Clouds.jpg
    exit 1
fi

#resize the Daymap
convert Daymap_bare.png -scale 4000x2000 Daymap.png
#convert Daymap to a snow only alphamap
convert Daymap.png  -threshold '95%' Daymap_snowmask.png

#create a full snowmap in the nightcolor
convert Daymap.png -fill '#0a3b5c' -colorize '100%' Nightmap_fullsnow.png
#get nightlights out of Nightmap_bare
convert Nightmap_bare.jpg -threshold '25%' -transparent '#000000' Nightmap_lightmask.png
#composite Snowmask and Fullsnow to Nightmap_snowlayer
convert Nightmap_fullsnow.png Daymap_snowmask.png -alpha off -compose copy_opacity -composite Nightmap_snowlayer.png
#cut out the lights in Nightmap_lightmask and put them in Nightmap_lightlayer
convert Nightmap_bare.jpg Nightmap_lightmask.png -alpha off -compose copy_opacity -composite Nightmap_lightlayer.png

#Composite the Nightmap_snowlayer and the Nightmap_lightlayer with the Nightmap
composite Nightmap_lightlayer.png Nightmap_snowlayer.png Nightmap_lightsnowlayer.png
composite Nightmap_lightsnowlayer.png Nightmap_bare.jpg Nightmap.png

#write the xplanet-configfile
cat > xplanet-config << EOF
[earth]
"Earth"
map=Daymap.png
night_map=Nightmap.png
cloud_map=Clouds.jpg
EOF

xplanet --num_times 1 --geometry 1466x1200 --output xplanet-output.jpg --projection merc -config xplanet-config
convert xplanet-output.jpg -crop 1366x768+100+160 realwallpaper.png