#!/sbin/sh

is_mounted() {
	if [ ! -z "$2" ]; then
		cat /proc/mounts | grep $1 | grep $2, >/dev/null
	else
		cat /proc/mounts | grep $1 >/dev/null
	fi
	return $?
}

request_size_check() {
	reqSizeM=`unzip -l "$1" 2>/dev/null | tail -n 1 | awk '{ print $1 }'`
	reqSizeM=$((reqSizeM / 1048576 + 1))
}

image_size_check() {
	e2fsck -yf $1
	curBlocks=`e2fsck -n $1 2>/dev/null | grep $1 | cut -d, -f3 | cut -d\  -f2`;
	curUsedM=`echo "$curBlocks" | cut -d/ -f1`
	curSizeM=`echo "$curBlocks" | cut -d/ -f1`
	curFreeM=$(((curSizeM - curUsedM) * 4 / 1024))
	curUsedM=$((curUsedM * 4 / 1024 + 1))
	curSizeM=$((curSizeM * 4 / 1024))
}

grow_magisk_img () {
	request_size_check /tmp/services.jar
	image_size_check /data/adb/magisk.img
	if [ "$reqSizeM" -gt "$curFreeM" ]; then
		SIZE=$(((reqSizeM + curUsedM) / 32 * 32 + 64))
		resize2fs /data/adb/magisk.img ${SIZE}M
	fi
}

shrink_magisk_img () {
	image_size_check /data/adb/magisk.img
	NEWDATASIZE=$((curUsedM / 32 * 32 + 32))
	if [ "$curSizeM" -gt "$NEWDATASIZE" ]; then
		resize2fs $IMG ${NEWDATASIZE}M
	fi
}

mount_image() {
	if [ ! -d "$2" ]; then
		mount -o rw,remount rootfs /
		mkdir -p "$2" 2>/dev/null
		[ ! -d "$2" ] && return 1
	fi

	if ! is_mounted "$2"; then
		LOOPDEVICE=
		for LOOP in 0 1 2 3 4 5 6 7; do
			if ! is_mounted "$2"; then
				LOOPDEVICE=/dev/block/loop$LOOP
				[ -e $LOOPDEVICE ] || mknod $LOOPDEVICE b 7 $LOOP 2>/dev/null
				losetup $LOOPDEVICE "$1" && mount -t ext4 -o loop $LOOPDEVICE "$2"
				if is_mounted "$2"; then
					echo "$LOOPDEVICE" > /tmp/loopdevice
					break;
				fi
			fi
		done
	fi
}

mount_magisk () {
	mount /data &>/dev/null
	mount_image /data/adb/magisk.img /magisk
}

umount_magisk () {
	umount /magisk
	losetup -d $(cat /tmp/loopdevice)
	rm /tmp/loopdevice
}

grep_cmdline() {
	local REGEX="s/^${1}=//p"
	sed -E 's/ +/\n/g' /proc/cmdline | \
		sed -n "${REGEX}" 2>/dev/null
}

# taken from Magisk, with minor modifications for NanoDroid
mount_partitions () {
	SLOT=$(grep_cmdline androidboot.slot_suffix)
	if [ -z ${SLOT} ]; then
		SLOT=_$(grep_cmdline androidboot.slot)
		[ "${SLOT}" = "_" ] && SLOT=
	fi

	is_mounted /data || mount /data

	! is_mounted /system && mount -o rw /system

	if [ ! -f /system/build.prop ]; then
		SYSTEMBLOCK=$(find /dev/block -iname system${SLOT} | head -n 1)
		mount -t ext4 -o rw ${SYSTEMBLOCK} /system
	fi

	[ -f /system/build.prop ] || is_mounted /system || exit 1

	if [ -f /system/init ]; then
		mkdir /system_root 2>/dev/null
		mount --move /system /system_root
		mount -o bind /system_root/system /system
	fi

	[ ! -f /system/build.prop ] && exit 1
}

patch_system () {
	if [[ -f /data/adb/magisk.img ]]; then
		grow_magisk_img
		echo "magisk found: mount to /magisk"
		mount_magisk
	fi

	if [[ -f /data/adb/.nanodroid-patcher ]]; then
		echo " ++ /data/adb/.nanodroid-patcher exists"
		echo " ++ assuming ROM is already patched"
		exit 0
	elif [[ -f /data/adb/NanoDroid_Patched ]]; then
		echo " ++ /data/adb/NanoDroid_Patched exists"
		echo " ++ assuming ROM is already patched"
		exit 0
	fi

	install_path=""

	if [[ -d /magisk/NanoDroid ]]; then
		echo "NanoDroid detected"
		install_path="/magisk/NanoDroid/system"
		mkdir -p "${install_path}"
	elif [[ -d /magisk/NanoDroid_microG ]]; then
		echo "NanoDroid microG detected"
		install_path="/magisk/NanoDroid_microG/system"
		mkdir -p "${install_path}"
	else
		echo "backing up services.jar to /sdcard/nanodroid_backups"
		mkdir -p /sdcard/nanodroid_backups
		cp /tmp/services.jar /sdcard/nanodroid_backups

		echo "using ROM as destination"
		install_path="/system"

		echo /system/framework/services.jar >> \
			/data/adb/NanoDroid_FileList
	fi

	echo "install to \"${install_path}\""
	cp /tmp/services.jar "${install_path}/framework" || exit 1

	touch /data/adb/NanoDroid_Patched

	if (is_mounted /magisk); then
		echo "unmount /magisk"
		umount_magisk
		shrink_magisk_img
	fi

	echo "unmount /system"
	umount /system
}

case ${1} in
	*mount )
		mount_partitions || exit 1
	;;

	*patch )
		patch_system || exit 1
	;;
esac