#!/bin/sh -e
# Copyright 2024 Oliver Smith
# SPDX-License-Identifier: GPL-3.0-or-later

if [ "$1" != "CALLED_FROM_PMB" ]; then
	echo "ERROR: this script is only meant to be called by pmbootstrap"
	exit 1
fi

CHROOT="$2"

test -n "$CHROOT"
test -f "$CHROOT"/in-pmbootstrap

if [ -L "$CHROOT"/bin ]; then
	echo "ERROR: chroot has merged usr already: $CHROOT"
	exit 1
fi

dir_is_empty() {
	local dir="$1"
	local i

	for i in "$dir"/*; do
		if [ "$i" = "$dir/*" ]; then
			return 0
		else
			return 1
		fi
	done
}

merge() {
	local src="$1"
	local dest="$2"
	local dir

	cd "$CHROOT/$src"

	for dir in $(find . -type d | sort -r); do
		mkdir -p "$CHROOT/$dest/$dir"

		if ! dir_is_empty "$dir"; then
			mv "$dir"/* "$CHROOT/$dest/$dir"
		fi

		if [ "$dir" != "." ]; then
			rmdir "$dir"
		fi
	done

	cd "$CHROOT"
	rmdir "$src"

	ln -s "$dest" "$CHROOT/$src"
}

merge bin usr/bin
merge sbin usr/bin
merge lib usr/lib
merge usr/sbin bin