#!/bin/bash

# this script can be used to generate merged screenshots from the output of Henpemaz' MapExporter

coproc json {
	# unbuffered output
	# cat is to preserve python's stdin
	python3 -u <(cat <<- __EOF__
		import sys, json
		for file in sys.stdin:
		    if(file.rstrip() == "---"):
		        break
		    with open(file.rstrip(), "r") as metadata:
		        metadata = json.load(metadata)
		        if not "rooms" in metadata:
		            print("---")
		            continue
		        for room in metadata["rooms"].values():
		            if room["cameras"] is None:
		                continue
		            print(room["roomName"])
		            minx = round( min(room["cameras"], key=lambda c:  c[0])[0])
		            miny = round(-min(room["cameras"], key=lambda c: -c[1])[1])
		            for camera in room["cameras"]:
		                print("{},{}".format(round(camera[0])-minx, round(-camera[1])-miny))
		            print("---")
		        print("---")
		__EOF__
	)
}
mkdir -p out
command -v python3 &>/dev/null && command -v magick &>/dev/null || {
	printf "This requires python3 and magick!\n" >&2
	exit 1
}
[ "${PWD##*/}" = "export" ] || {
	printf "This must be run in the MapExporter export directory!\n" >&2
	exit 1
}
p=""
while IFS= read -r slugcat; do
	while IFS= read -r region; do
		printf "$region/metadata.json\n" >&"${json[1]}"
		out_region="${region##*/}"
		out_region="out/${region%/*}/${out_region^^}"
		mkdir -p "$out_region"
		while IFS= read -r room; do
			[ "$room" != "---" ] || break
			screens="-background transparent"
			i=0
			while IFS= read -r screen; do
				[ "$screen" != "---" ] || break
				x="${screen%,*}"; y="${screen#*,}"
				[ "${x::1}" = "-" ] || x="+$x"
				[ "${y::1}" = "-" ] || y="+$y"
				screens="$screens -page $x$y $region/${room,,}_$i.png"
				i=$(($i+1))
			done
			magick convert $screens -reverse -layers merge +repage "$out_region/$room.png" &
			p="$p$!"$'\n'
			if [ $(wc -l <<< "${p%?}") -ge 20 ]; then
				while IFS= read -r pid; do
					wait "$pid"
				done <<< "${p%?}"
				p=""
			fi
		done <&"${json[0]}"
# subshells can't access coprocess FDs so can't pipe to the loops
	done < <(find "$slugcat" -mindepth 1 -maxdepth 1 -type d)
done < <(find . -mindepth 1 -maxdepth 1 -type d -not -name "out")
while IFS= read -r pid; do
	wait "$pid"
done <<< "${p%?}"
printf -- "---\n" >&"${json[1]}"
[ -n "$json_PID" ] && wait "$json_PID" || true
find out -name "GATE_*" | while IFS= read -r gate; do
	region="${gate#*_}"
	region="${region%_*}"
	old="${gate%/*}"
	old="${old##*/}"
	mkdir -p "${gate%/*/*}/$region"
	[ "$old" != "$region" ] && mv "$gate" "${gate%/*/*}/$region/${gate##*/}"
done
find out -type d -empty -delete
if command -v oxipng &>/dev/null; then
	find out -mindepth 2 -maxdepth 2 -type d -exec oxipng -o max -s -r {} \;
else
	printf "oxipng not found, not compressing\n" >&2
fi