#!/bin/bash
if [ ! -z "${2}" ]; then
	echo "Expected only one argument"
	exit 1
elif [ -z "${1}" ]; then
	echo "No file path provided"
	exit 1
fi

set -euo pipefail

destfile_pfx="$(cat /dev/urandom | tr -cd 'a-f0-9' | head -c 32)" || true

while [ -d "/tmp/doasedit/$destfile_pfx" ]; do
	destfile_pfx="$(cat /dev/urandom | tr -cd 'a-f0-9' | head -c 32)"
done

mkdir -p /tmp/doasedit/$destfile_pfx
srcfile="$(doas realpath $1)"

if doas [ -f "$srcfile" ]; then
	doas cp $srcfile /tmp/doasedit/$destfile_pfx/edit
	doas chown -R $USER:$USER /tmp/doasedit/$destfile_pfx/edit
	doas cp $srcfile /tmp/doasedit/$destfile_pfx/file
else
	# create file with "regular" system permissions (root:root 644)
	touch /tmp/doasedit/$destfile_pfx/file
	doas chown root:root /tmp/doasedit/$destfile_pfx/file
fi

$EDITOR /tmp/doasedit/$destfile_pfx/edit

cat /tmp/doasedit/$destfile_pfx/edit | doas tee /tmp/doasedit/$destfile_pfx/file 1>/dev/null

if cmp -s "/tmp/doasedit/$destfile_pfx/file" "$srcfile"; then
	echo "Skipping write; no changes."
else
	doas mv -f /tmp/doasedit/$destfile_pfx/file $srcfile
fi

rm -rf /tmp/doasedit/$destfile_pfx