#!/bin/bash

linkname=/usr/syno/etc/preference  # path to symbolic link that points to preference folder
synoinfo=/etc/synoinfo.conf  # path to synoinfo.conf file

movepreferencetovolumeFn()  # main function to move preference folder to a different volume
{
	echo "pid: $$, movepreferencetovolumeFn"
	##############
	## Precheck ##
	##############

	# Early exit if migration is running or volume service is not ready
	if [[ $(/usr/syno/bin/synosystemctl get-active-status syno-volume.service) != "active" || -f /tmp/synomigrationassistant_vspace_stacking ]]
	then
		exit 0
	fi

	# Get the real preference folder path saved in synoinfo.conf, e.g., folderpath = /volume1/@userpreference
	folderpath=$(/bin/gawk 'match($0, /userpreference_realpath="(.*)"/, ary) { print ary[1] }' "$synoinfo")
	# If symbolic link doesn't exist and preference folder exists on volume, create symbolic link
	if [[ ! -e $linkname && -d $folderpath && $linkname != "$folderpath" ]]
	then
		/bin/ln -s "$folderpath" $linkname
	fi
	# If /usr/syno/etc/preference is still not exist or not a folder, create a new preference folder on md0
	# Represents that the realpath saved in synoinfo is lost or uninitialized
	if [[ ! -d $linkname ]]
	then
		/bin/rm $linkname >/dev/null 2>&1
		/bin/mkdir $linkname
	fi

	# Current preference storage path
	realpath="$(/bin/readlink -f $linkname)"

	# Handle restoration when encrypted volume mounted back with user preference configured
	encryptedvolumepath=$(/bin/gawk 'match($0, /userpreference_encryptedvolume="(.*)"/, ary) { print ary[1] }' "$synoinfo")
	if [[ -n "$encryptedvolumepath" ]]; then
		# Set the variable restorePath to the path of the folder containing the restored user preference data on the encrypted volume
		restorePath="$encryptedvolumepath"/@userpreference
		# If restorePath is a directory and realpath is not the same as restorePath
		if [[ -d "$restorePath" && "$realpath" != "$restorePath" ]]; then
			# Remove the existing symlink at realpath
			rm -rf "$realpath"
			# Create a symlink at linkname pointing to restorePath
			/bin/ln -s "$restorePath" "$linkname"
			synosetkeyvalue /etc/synoinfo.conf "userpreference_realpath" "$restorePath"
			echo "pid: $$, restore preference from encrypted volume $encryptedvolumepath"
			exit 0
		fi
	fi

	# Early exit if the preference is already on volume and not in skipped volume path
	if [[ -L $linkname &&  -d $realpath && $realpath =~ /volume[1-9][0-9]*/@userpreference && $realpath != $1/@userpreference ]]
	then
		# If the realpath has updated, save realpath into synoinfo
		if [[ "$realpath" != "$folderpath" ]]
		then
			synosetkeyvalue /etc/synoinfo.conf "userpreference_realpath" "$realpath"
		fi
		exit 0
	fi

	######################################
	## Find and move to new target path ##
	######################################

	preferencesize=$(/bin/du -sm $linkname/ | /bin/awk '{printf $1}')  # size of preference folder in MB
	# Get the target volume path to move preference folder to, e.g., /volume1, and skip any specified paths
	volumepath=$(/usr/syno/bin/servicetool --get-available-volume --space-requirement "$preferencesize" --skip-volume-path "$1")

	ret=$?
	if [[ $ret -eq 1 ]]; then
		# Move to volume
		target=$volumepath/@userpreference
		tmp=$volumepath/@userpreference.tmp
	else
		# Move to /usr/syno/etc/preference
		# preserve 100 MB in case of moving to md0
		md0availablesize=$(/bin/df /dev/md0 | /bin/tail -1 |  /bin/awk '{print $4}')
		if [[ "$((preferencesize + 100*1024))" -gt "$md0availablesize" ]]; then
			cp -ar $realpath $realpath.bak >/dev/null 2>&1
			exit 0
		fi
		target=$linkname
		tmp=${linkname}.tmp
	fi

	# Early exit if target == current path
	if [[ "$target" = "$realpath" ]]
	then
		if [[ "$realpath" != "$folderpath" ]]
		then
			synosetkeyvalue /etc/synoinfo.conf "userpreference_realpath" "$realpath"
		fi
		exit 0
	fi

	# Handle volume encryption
	# Check if the target volume is encrypted
	isTargetEncryptVolume=$(/usr/syno/sbin/synostgvolume --is-encrypted-volume "$volumepath"; echo $?)
	# If the target volume is encrypted, write the volume path to userpreference_encryptedvolume in synoinfo
	if [[ "$isTargetEncryptVolume" -eq 1 ]]; then
		synosetkeyvalue /etc/synoinfo.conf "userpreference_encryptedvolume" "$volumepath"
	else
		 # If the target volume is not encrypted, get the current volume path and check if it is encrypted
		currentVolume=$(echo "$realpath" | awk -F'/' '{print "/"$2}')
		isCurrentVolumeEncrypted=$(/usr/syno/sbin/synostgvolume --is-encrypted-volume "$currentVolume"; echo $?)
		# If moving user preferences out of encrypted volume to normal volume, reset userpreference_encryptedvolume in synoinfo
		if [[ "$isCurrentVolumeEncrypted" -eq 1 ]]; then
			synosetkeyvalue /etc/synoinfo.conf "userpreference_encryptedvolume" ""
		fi
	fi

	############################
	## Move Preference Folder ##
	############################

	# Copy preference to tmp folder
	/bin/mkdir -p $tmp
	/bin/cp -au "$realpath"/* $tmp/
	retVal=$?
	# Early exit if copying files fails, possibly because the disk is full
	if [[ $retVal -ne 0 ]]; then
		/bin/rm -rf $tmp
		exit 0
	fi

	# Remove original preference folder
	if [[ -L "$realpath" && -d "$realpath" ]]
	then
		/bin/rm -rf "$realpath" >/dev/null 2>&1
	else
		/bin/rm -rf "$realpath".old >/dev/null 2>&1
		/bin/mv -f "$realpath" "$realpath".old
	fi

	# Move tmp path to target path
	/bin/rm -rf $target >/dev/null 2>&1
	/bin/mv -f $tmp $target
	# Re-link to correct target path
	if [[ "$linkname" != "$target" ]]
	then
		/bin/rm -rf $linkname >/dev/null 2>&1
		/bin/ln -s $target $linkname
	fi

	synosetkeyvalue /etc/synoinfo.conf "userpreference_realpath" "$target"

	/bin/rm -rf "$realpath".old >/dev/null 2>&1
	echo "pid: $$, preference moved from $realpath to $target"
}

# due to DSM 7.0 has modified ssh shell umask to 0077, 0022 is needed to run this script
umask 0022 && movepreferencetovolumeFn "$1"