#!/bin/sh

PREFIX=@PREFIX@
: ${LIBDIR=$PREFIX/lib}
. "$LIBDIR/libalpine.sh"

usage() {
	cat <<-__EOF__
		usage: setup-apkcache [-h] [DIR]

		Setup apk caching.

		If DIR is not specified user will be asked for location.

		options:
		 -h  Show this help
	__EOF__
	exit $1
}

is_mounted() {
	awk '{print $2}' /proc/mounts | grep -q "^$1$"
}

find_fstab_mount_point() {
	local dir="$1"
	local res=
	if ! [ -r "${ROOT}"etc/fstab ]; then
		return
	fi
	while [ -n "$dir" ]; do
		res=$(awk "\$2 == \"$dir\" {print \$2}" "${ROOT}"etc/fstab)
		if [ -n "$res" ]; then
			echo $res
			return
		fi
		dir=${dir%/*}
	done
}

# figure out mount point
find_mount_point() {
	local dir="$(find_fstab_mount_point "$1")"
	if [ -d "$dir" ] && [ "$dir" != "/" ]; then
		echo $dir
		return
	fi

	local dir="$1"
	while [ -n "$dir" ] && ! [ -d "$dir" ]; do
		dir=${dir%/*}
	done

	local fs_id="$(stat -f -c %i "${dir:-/}")"
	local parent="${dir%/*}"
	while [ -n "$dir" ] && [ "$(stat -f -c %i "$parent/")" = "$fs_id" ]; do
		dir=$parent
		parent=${parent%/*}
	done
	[ -z "$dir" ] && dir=/
	echo $dir
}

# get device for a given mount point
get_dev_from_mountpoint() {
	local mnt="$1"
	local fstab="$2"
	awk "\$2 == \"$mnt\" {print \$1}" "$fstab"
}

get_mount_opts_from_mountpoint() {
	local mnt="$1"
	local fstab="$2"
	awk "\$2 == \"$mnt\" {gsub(/,/, \" \", \$4); print \$4}" "$fstab"
}

has_mount_opt() {
	local searchfor="$1"
	local mnt="$2"
	local fstab="$3"
	local opts="$(get_mount_opts_from_mountpoint "$mnt" "$fstab")"
	local opt=
	for opt in $opts; do
		if [ "$opt" = "$searchfor" ]; then
			return 0
		fi
	done
	return 1
}

is_mounted_ro() {
	has_mount_opt ro "$1" /proc/mounts
}

# get the fstype of the given mount point
mount_fstype() {
	# we only want the last mount in case there are several
	awk -v mnt="$1" '$2 == "/" {fstype = mnt} END {print fstype}' \
		/proc/mounts
}

apk_cache_help() {
	cat <<-__EOF__

		Packages installed from network can be cached locally to be available during
		boot, before the network is started. Specifying a directory here will make apk
		cache the packages locally in this directory.

		Enter 'none' if you do not want to cache packages from network.

	__EOF__
}

while getopts "h" opt; do
	case $opt in
		h) usage 0;;
		'?') usage "1" >&2;;
	esac
done
shift $(( OPTIND - 1 ))

# try auto detetect what we suggest
suggestion=
if [ -L "${ROOT}"etc/apk/cache ]; then
	suggestion=$(readlink "${ROOT}"etc/apk/cache)
fi

if [ -z "$suggestion" ] && [ -f "$ROOT"etc/lbu/lbu.conf ]; then
	. "$ROOT"etc/lbu/lbu.conf
	if [ -n "$LBU_MEDIA" ]; then
		suggestion=/media/$LBU_MEDIA/cache
	fi
fi

if [ -z "$suggestion" ] && [ -L /dev/usbdisk ]; then
	suggestion=/media/usb/cache
fi

if [ -z "$suggestion" ] && [ "$(mount_fstype /)" != "tmpfs" ]; then
	suggestion=/var/cache/apk
fi

if [ -z "$suggestion" ]; then
	suggestion=none
fi
cachedir="$1"

resp=
while [ $# -eq 0 ] && [ -z "$cachedir" ]; do
	ask "Enter apk cache directory (or '?' or 'none')" "$suggestion"
	cachedir="$resp"
	if [ "$cachedir" = "?" ]; then
		apk_cache_help
		cachedir=
	fi
done

if [ "$cachedir" = "none" ]; then
	exit 0
fi

case "$cachedir" in
	/*) ;;
	*) cachedir="${PWD#${ROOT%/}}/$cachedir";;
esac
mount=$(find_mount_point "$cachedir")

cleanup=

if ! is_mounted "$mount"; then
	# remove noauto that setup-lbu might have added
	if has_mount_opt noauto "$mount" /etc/fstab; then
		fstabtmp=$(mktemp)
		awk -v mnt="$mount" \
			'$2 != mnt {print $0}
			 $2 == mnt {
			 	sub(/noauto,|,noauto/, "", $4);
				sub(/^noauto$/, "defaults", $4);
				print $0
			}' /etc/fstab > "$fstabtmp"
		mv "$fstabtmp" /etc/fstab
	fi
	mount "$mount" || exit 1
elif is_mounted_ro "$mount"; then
	mount -o remount,rw "$mount" || exit 1
	cleanup="remount"
fi

mkdir -p "$ROOT$cachedir"
if [ -L "$ROOT"etc/apk/cache ]; then
	rm -f "$ROOT"etc/apk/cache
fi
mkdir -p "$ROOT"etc/apk
ln -s "$cachedir" "$ROOT"etc/apk/cache

case "$cleanup" in
	umount) umount "$mount";;
	remount) mount -o remount,ro "$mount";;
esac