#!/bin/sh

PREFIX=

. "$PREFIX/lib/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="$1"
	local res=
	while [ -n "$dir" ]; do
		res=$(awk "\$2 == \"$dir\" {print \$2}" /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="$1"
	while ! [ -d "$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_mount_opts() {
	local mnt="$1"
	awk "\$2 == \"$mnt\" {gsub(/,/, \" \", \$4); print \$4}" /proc/mounts
}

is_mounted_ro() {
	local mnt="$1"
	local opts=$(get_mount_opts $mnt)
	local opt=
	for opt in $opts; do
		if [ "$opt" = "ro" ]; then
			return 0
		fi
	done
	return 1
}

# 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;;
        esac
done
shift $(( $OPTIND - 1 ))

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

if [ -z "$suggestion" ] && [ -f /etc/lbu/lbu.conf ]; then
	. /etc/lbu/lbu.conf
	if [ -n "$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

while [ -z "$cachedir" ]; do
	echo -n "Enter apk cache directory (or '?' or 'none') [$suggestion]: "
	default_read cachedir $suggestion
	if [ "$cachedir" = "?" ]; then
		apk_cache_help
		cachedir=
	fi
done

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

mount=$(find_mount_point $cachedir)

cleanup=

if ! is_mounted $mount; then
	mount $mount || exit 1
	cleanup="umount"
elif is_mounted_ro $mount; then
	mount -o remount,rw $mount || exit 1
	cleanup="remount"
fi

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

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