#!/bin/sh
set -e

rel () {
	to="$1"
	from="$2"
	while test $(printf '%s\n' "$to" "$from" | grep / | wc -l) = 2; do
		todir="$(printf '%s\n' "$to" | cut -d / -f 1)"
		fromdir="$(printf '%s\n' "$from" | cut -d / -f 1)"
		if test ! "$todir" = "$fromdir"; then
			break
		fi
		to="$(printf '%s\n' "$to" | cut -d / -f 2-)"
		from="$(printf '%s\n' "$frm" | cut -d / -f 2-)"
	done
	while test -n "$(printf '%s\n' "$from" | grep /)"; do
		from="$(printf '%s\n' "$from" | cut -d / -f 2-)"
		to="../$to"
	done
	printf '%s\n' "$to"
}

lines=$(sed 's/\\$//' < icons.mk | sed '/^\s*\(#.*\|\)$/d' | sed 1d | wc -l)
test ! $lines = 0

test $(sed 's/\\$//' < icons.mk | sed '/^\s*\(#.*\|\)$/d' | sed 1d | sed 's/\t/ /g' | grep '^ ' | wc -l) = $lines

test $(sed 's/\\$//' < icons.mk | sed '/^\s*\(#.*\|\)$/d' | sed '1s/^.*$//' | grep -n ' ' | wc -l) = 0

stack=""
i=0
sed 's/\\$//' < icons.mk | sed '/^\s*\(#.*\|\)$/d' | sed 1d | sed 's/^\t/x/' | while read L; do
	i=$(( i + 1 ))
	printf 'Checking %i of %i\n\033[A' $i $lines >&2
	tabs=0
	while test ! $(printf '%s\n' "$L" | sed -n '/^x\t/p' | wc -l) = 0; do
		L="$(printf '%s\n' "$L" | sed 's/^x\t/x/')"
		tabs=$(( tabs + 1 ))
	done
	L="$(printf '%s\n' "$L" | sed 's/^x//')"
	f="scalable/$L.svg"
	if test ! $(printf '%s\n' $f | wc -l) = 1; then
		printf '\033[K%s contains whitespace\n' "$L" >&2
		exit 1
	fi
	tabsplus1=$(( tabs + 1 ))
	if test -z "$(printf '%s\n' $stack x | sed -n ${tabsplus1}p)"; then
		printf '\033[K%s is overtabulated\n' "$L" >&2
		exit 1
	else
		stack="$(printf '%s\n' $stack | head -n $tabs; printf '%s\n' "$L")"
	fi
	if test ! -e "$f"; then
		if test -L "$f"; then
			printf '\033[K%s is a dangling symlink\n' "$L" >&2
		else
			printf '\033[K%s is listed but does not exist\n' "$L" >&2
		fi
		exit 1
	fi
	if test $tabs = 0; then
		if test -L "$f"; then
			printf '\033[K%s is a symlink but not indented\n' "$L" >&2
			exit 1
		fi
	else
		goal_="$(printf '%s\n' $stack | sed -n "${tabs}p")"
		if test ! -L "$f"; then
			printf '\033[K%s is not a symlink but listed as linking to %s\n' "$L" "$goal" >&2
			exit 1
		fi
		target="$(realpath -- "$f")"
		goal="$(realpath -- "scalable/${goal_}.svg")"
		if test "$target" = "$goal"; then
			diff="same real file"
		else
			diff="different real file"
		fi
		target="$(readlink -- "$f")"
		goal="$(rel "${goal_}.svg" "$L.svg")"
		if test "$target" = "./$goal"; then
			ln -sf -- "$target" "$f"
		elif test ! "$target" = "$goal"; then
			printf '\033[K%s links to %s but should link to %s (%s)\n' "$L" "$target" "$goal" "$diff" >&2
			exit 1
		fi
	fi
done
printf '\033[K' >&2