#!/bin/bash

MAPDIR=$1
SPAWNPOS=$2
DIMENSIONS=$3

if [ -z $MAPPERDIR ]; then
	MAPPERDIR=.
fi

mapperpath=$MAPPERDIR/minetestmapper

if [ ! -f $mapperpath ]; then
	echo "Error, "$mapperpath" doesn't exist."
	echo "Please specify the path to the minetestmapper executable via the MAPPERDIR variable"
	exit 1
fi

if [ -z "$JOBNUM" ]; then
	JOBNUM=1
fi

case "$JOBNUM" in
	''|*[!0-9]*) echo "Bad number of jobs '$JOBNUM'. Please specify a positive integer." ; exit 1 ;;
	*) ;;
esac

# echo "Number of jobs: $JOBNUM"

scriptdir=`readlink -f $0`
scriptdir=`dirname $scriptdir`

tiledir=$scriptdir/www/tiles

spawnx=${SPAWNPOS%%,*}
spawny=${SPAWNPOS##*,}
#echo "spawn position: $spawnx $spawny"
tilesize=256
zoomlevelnum=3

tilenum=$(($DIMENSIONS/$tilesize))

mkdir -p ${tiledir}/20
rm -f ${tiledir}/20/*

jobparam="-P$JOBNUM"

#create tile images
for x in $(seq 0 $tilenum)
do
	for y in $(seq 0 $tilenum)
	do
		posx=$(($spawnx+$tilesize*($x-$tilenum/2)))
		posy=$(($spawny+$tilesize*($tilenum/2-$y)))
		# Execute sh -c "something"
		echo "-c"
		echo "$mapperpath ${MAPPERPARAMS} -i ${MAPDIR} --geometry ${posx},${posy}+${tilesize}+${tilesize} -o ${tiledir}/20/map_${x}_${y}.png \
		|| (>&2 echo 'minetesmapper ended with non zero exit code'; exit 255)"
	done
done | xargs -n2 $jobparam -d '\n' sh

xargs_exit=$?
if [ $xargs_exit -ne 0 ]; then
	# xargs unfortunately exits immediately, without even waiting for sub-processes
	sleep 1
	>&2 echo "Error: xargs ended with non-zero exit code $xargs_exit."
	exit 1
fi

#join the images and make them smaller
mult=1
for s in $(seq 1 $zoomlevelnum)
do
	mult=$(($mult*2))
	tnum=$(($tilenum/$mult-1))
	zoomlevel=$((20-$s))
	zoomlevelbefore=$((20-$s+1))
	dir=$tiledir/$zoomlevel
	dirb=$tiledir/$zoomlevelbefore
	mkdir -p $dir
	rm -f ${dir}/20/*
	for x in $(seq 0 $tnum)
	do
		for y in $(seq 0 $tnum)
		do
			montage $dirb/map_$(($x*2))_$((y*2)).png $dirb/map_$(($x*2+1))_$((y*2)).png $dirb/map_$(($x*2))_$((y*2+1)).png $dirb/map_$(($x*2+1))_$((y*2+1)).png -geometry +0+0 $dir/map_${x}_${y}.png
			if [ $? -ne 0 ]; then
				echo "montage exited with non zero exit code, aborting."
				exit 1
			fi
			convert $dir/map_${x}_${y}.png -resize 50% $dir/map_${x}_${y}.png
			if [ $? -ne 0 ]; then
				echo "convert exited with non zero exit code, aborting."
				exit 1
			fi
		done
	done
done

zoommin=$((20-$zoomlevelnum))
#write the resulting config into a json file
echo "{\"mapsize\":$DIMENSIONS, \"spawn\":{\"x\":$spawnx,\"y\":$spawny}, \"zoommin\":$zoommin}" > $scriptdir/www/conf.json