#!/bin/sh

# Uncomment below to see more logs
# set -x

MISC_DEV=$(realpath /dev/block/by-name/misc 2>/dev/null)

BUSYBOX_MOUNT_OPTS="loop (a|)sync (no|)atime (no|)diratime (no|)relatime (no|)dev (no|)exec (no|)suid (r|)shared (r|)slave (r|)private (un|)bindable (r|)bind move remount ro"
NTFS_3G_MOUNT_OPTS="ro uid=[0-9]* gid=[0-9]* umask=[0-9]* fmask=[0-9]* dmask=[0-9]*"

check_tool()
{
	TOOL=$(echo $1 | grep -o "^[^ ]*")
	BR2_CONFIG=$2

	type $TOOL >/dev/null && return 0

	if grep -wq "ID=buildroot" /etc/os-release 2>/dev/null; then
		[ -n "$BR2_CONFIG" ] && \
			echo "You may need to enable $BR2_CONFIG"
	else
		echo "Missing tool: $TOOL"
	fi
	return 1
}

prepare_ubi()
{
	# Only support ubi for mtd device
	if echo $DEV | grep -vq /dev/mtd; then
		echo "$DEV is not a mtd device!"
		return 1
	fi

	[ "$PART_NO" ] || { echo "No valid part number!" && return 1; }

	if [ "$FSGROUP" = ubifs ]; then
		DEV=/dev/ubi${PART_NO}_0
	else
		DEV=/dev/ubiblock${PART_NO}_0
	fi

	MTDDEV=/dev/mtd${PART_NO}

	echo "Preparing $DEV from $MTDDEV"

	echo "Remove ubi block device"
	if echo $DEV | grep -q ubiblock; then
		check_tool ubiblock BR2_PACKAGE_MTD_UBIBLOCK || return 1
		ubiblock -r /dev/ubi${PART_NO}_0 &>/dev/null
	fi

	echo "Detach ubi device"
	check_tool ubidetach BR2_PACKAGE_MTD_UBIDETACH || return 1
	ubidetach -p $MTDDEV &>/dev/null

	echo "Attach ubi device"
	check_tool ubiattach BR2_PACKAGE_MTD_UBIATTACH || return 1
	ubiattach /dev/ubi_ctrl -m $PART_NO -d $PART_NO || return 1

	echo "Check for valid volume"
	if [ ! -e /dev/ubi${PART_NO}_0 ]; then
		echo "No valid ubi volume"
		return 1
	fi

	echo "Create ubi block device"
	if echo $DEV | grep -q ubiblock; then
		check_tool ubiblock BR2_PACKAGE_MTD_UBIBLOCK || return 1
		ubiblock -c /dev/ubi${PART_NO}_0 || return 1
	fi

	return 0
}

format_ubifs()
{
	echo "Formatting $MTDDEV for $DEV"

	echo "Remove ubi block device"
	if echo $DEV | grep -q ubiblock; then
		check_tool ubiblock BR2_PACKAGE_MTD_UBIBLOCK || return 1
		ubiblock -r /dev/ubi${PART_NO}_0 &>/dev/null
	fi

	echo "Detach ubi device"
	check_tool ubidetach BR2_PACKAGE_MTD_UBIDETACH || return 1
	ubidetach -p $MTDDEV &>/dev/null

	echo "Format device"
	check_tool ubiformat BR2_PACKAGE_MTD_UBIFORMAT || return 1
	ubiformat -yq $MTDDEV || return 1

	echo "Attach ubi device"
	ubiattach /dev/ubi_ctrl -m $PART_NO -d $PART_NO || return 1

	echo "Create ubi volume"
	check_tool ubimkvol BR2_PACKAGE_MTD_UBIMKVOL || return 1
	ubimkvol /dev/ubi$PART_NO -N $PART_NAME -m || return 1

	echo "Create ubi block device"
	if echo $DEV | grep -q ubiblock; then
		check_tool ubiblock BR2_PACKAGE_MTD_UBIBLOCK || return 1
		ubiblock -c /dev/ubi${PART_NO}_0 || return 1
	fi
}

is_rootfs()
{
	[ $MOUNT_POINT = "/" ]
}

remount_part()
{
	mountpoint -q $MOUNT_POINT || return

	if touch $MOUNT_POINT &>/dev/null; then
		[ "$1" = ro ] && mount -o remount,ro $MOUNT_POINT
	else
		[ "$1" = rw ] && mount -o remount,rw $MOUNT_POINT
	fi
}

format_part()
{
	echo "Formatting $DEV($FSTYPE)"

	case $FSGROUP in
		ext2)
			# Set max-mount-counts to 0, and disable the time-dependent checking.
			check_tool mke2fs BR2_PACKAGE_E2FSPROGS && \
			mke2fs -F -L $PART_NAME $DEV && \
			tune2fs -c 0 -i 0 $DEV
			;;
		vfat)
			# Use fat32 by default
			check_tool mkfs.vfat BR2_PACKAGE_DOSFSTOOLS_MKFS_FAT && \
			mkfs.vfat -I -F 32 -n $PART_NAME $DEV
			;;
		ntfs)
			# Enable compression
			check_tool mkntfs BR2_PACKAGE_NTFS_3G_NTFSPROGS && \
			mkntfs -FCQ -L $PART_NAME $DEV
			;;
		ubifs)
			format_ubifs
			;;
		squashfs)
			# check_tool mksquashfs BR2_PACKAGE_SQUASHFS && \
			# mksquashfs $DEV
			echo "It's pointness to format a squashfs partition..."
			;;
		jffs2)
			echo "It's pointness to format a jffs2 partition..."
			;;
		auto)
			echo "Unable to format a auto partition..."
			;;
		*)
			echo Unsupported file system $FSTYPE for $DEV
			false
			;;
	esac
}

format_resize()
{
	BACKUP=$1
	SRC=$(realpath $MOUNT_POINT)

	echo "Format-resizing $DEV($FSTYPE)"

	echo "Backup original data"
	cp -a "$SRC" "$BACKUP/" || return 1
	umount "$SRC" || return 1

	echo "Format and mount rw"
	format_part || return 1
	mount_part || return 1
	remount_part rw

	echo "Restore backup data"
	cp -a "$BACKUP/$SRC" $(dirname "$SRC") || return 1
}

resize_ext2()
{
	check_tool resize2fs BR2_PACKAGE_E2FSPROGS_RESIZE2FS || return 1

	resize2fs $DEV
}

resize_vfat()
{
	check_tool fatresize BR2_PACKAGE_FATRESIZE || return 1

	SIZE=$(fatresize -i $DEV | grep "Size:" | grep -o "[0-9]*$")

	# Somehow fatresize only works for 256M+ fat
	[ "$SIZE" -gt $((256 * 1024 * 1024)) ] && return 1

	MAX_SIZE=$(( $(cat $SYS_PATH/size) * 512))
	MIN_SIZE=$(($MAX_SIZE - 16 * 1024 * 1024))
	[ $MIN_SIZE -lt $SIZE ] && return 0 # Large enough!
	while [ $MAX_SIZE -gt $MIN_SIZE ];do
		# Somehow fatresize cannot resize to max size
		MAX_SIZE=$(($MAX_SIZE - 512 * 1024))

		# Try to resize with fatresize, not always work
		fatresize -s $MAX_SIZE $DEV && return
	done
	return 1
}

resize_ntfs()
{
	check_tool ntfsresize BR2_PACKAGE_NTFS_3G_NTFSPROGS || return 1

	echo y | ntfsresize -f $DEV
}

resize_part()
{
	# Fixed size or already resized
	[ -f $MOUNT_POINT/.fixed -o -f $MOUNT_POINT/.resized ] && return

	if [ -z "$FSRESIZE" ]; then
		echo "No resize for $FSTYPE"
		return
	fi

	echo "Resizing $DEV($FSTYPE)"

	# Online resize needs read-write
	remount_part rw
	if eval $FSRESIZE; then
		touch $MOUNT_POINT/.resized
		return
	fi

	echo "Done with rootfs"
	is_rootfs && return

	echo "Fallback to format resize"
	TEMP_BACKUP=$(mktemp -d)
	format_resize $TEMP_BACKUP && touch $MOUNT_POINT/.resized
	rm -rf $TEMP_BACKUP
}

erase_oem_command()
{
	CMD=$1
	FILE=$2

	echo "OEM: Erasing $CMD in $FILE"

	COUNT=$(echo $CMD | wc -c)
	OFFSETS=$(strings -t d $FILE | grep -w "$CMD" | awk '{ print $1 }')

	for offset in $OFFSETS; do
		dd if=/dev/zero of=$FILE bs=1 count=$COUNT seek=$offset conv=notrunc 2>/dev/null
	done
}

done_oem_command()
{
	CMD=$1

	echo "OEM: Done with $CMD"

	if [ -b "$MISC_DEV" ]; then
		erase_oem_command $CMD $MISC_DEV
	else
		echo "OEM: Erase $CMD from mtd device"

		check_tool nanddump BR2_PACKAGE_MTD_NANDDUMP || return
		check_tool nandwrite BR2_PACKAGE_MTD_NANDWRITE || return
		check_tool flash_erase BR2_PACKAGE_MTD_FLASH_ERASE || return

		TEMP=$(mktemp)
		nanddump $MISC_DEV -f $TEMP
		erase_oem_command $CMD $TEMP
		flash_erase $MISC_DEV 0 0
		nandwrite $MISC_DEV $TEMP
	fi
}

handle_oem_command()
{
	[ "$OEM_CMD" ] || return

	for cmd in $OEM_CMD; do
		case $cmd in
			cmd_wipe_$PART_NAME)
				is_rootfs && continue

				echo "OEM: $cmd - Wiping $DEV"
				format_part && done_oem_command $cmd
				;;
		esac
	done
}

convert_mount_opts()
{
	# Accept all opts by default for standard mount tool
	if [ -z "$@" ] && [ "$(readlink $(which mount))" != busybox ]; then
		echo $OPTS
		return
	fi

	# Filter out unsupported opts
	for opt in ${@:-$BUSYBOX_MOUNT_OPTS}; do
		echo ${OPTS//,/ } | xargs -n 1 | grep -oE "^$opt$"
	done | tr "\n" ","
}

prepare_part()
{
	# Ignore external storages
	echo $MOUNT_POINT | grep -q "^\/mnt\/" && return 1

	# Find real dev for root dev
	if is_rootfs; then
		DEV=$(findmnt -n -o source /)

		# Fallback to the by-name link
		[ "$DEV" ] || DEV=/dev/block/by-name/rootfs
	fi

	DEV=$(realpath $DEV 2>/dev/null)
	PART_NO=$(echo $DEV | grep -oE "[0-9]*$")

	# Unknown device
	[ -b "$DEV" -o -c "$DEV" ] || return 1

	SYS_PATH=$(echo /sys/class/*/${DEV##*/})
	if [ -f "$SYS_PATH/name" ]; then
		PART_NAME=$(cat $SYS_PATH/name)
	else
		PART_NAME=$(grep PARTNAME ${SYS_PATH}/uevent | cut -d '=' -f 2)
	fi
	PART_NAME=${PART_NAME:-${DEV##*/}}

	case $FSTYPE in
		ext[234])
			FSGROUP=ext2
			FSCK="fsck.$FSTYPE -y"
			FSCK_CONFIG=BR2_PACKAGE_E2FSPROGS_FSCK
			FSRESIZE=resize_ext2
			;;
		msdos|fat|vfat)
			FSGROUP=vfat
			FSCK="fsck.vfat -y"
			FSCK_CONFIG=BR2_PACKAGE_DOSFSTOOLS_FSCK_FAT
			FSRESIZE=resize_vfat
			;;
		ntfs)
			FSGROUP=ntfs
			FSCK=ntfsfix
			FSCK_CONFIG=BR2_PACKAGE_NTFS_3G_NTFSPROGS
			FSRESIZE=resize_ntfs
			;;
		ubi|ubifs)
			FSGROUP=ubifs
			unset FSCK
			unset FSRESIZE
			;;
		squashfs)
			FSGROUP=squashfs
			unset FSCK
			unset FSRESIZE
			;;
		jffs2)
			FSGROUP=jffs2
			unset FSCK
			unset FSRESIZE
			;;
		auto)
			FSGROUP=auto
			echo "Running fsck on a random fs is dangerous"
			unset FSCK
			unset FSRESIZE
			;;
		*)
			echo "Unsupported file system $FSTYPE for $DEV"
			return
	esac

	# Setup mount tool and opts
	case $FSGROUP in
		ntfs)
			MOUNT=ntfs-3g
			check_tool ntfs-3g BR2_PACKAGE_NTFS_3G || return 1
			OPTS=$(convert_mount_opts "$NTFS_3G_MOUNT_OPTS")
			;;
		ubifs)
			MOUNT="mount -t ubifs"
			OPTS=$(convert_mount_opts)
			;;
		*)
			MOUNT=mount
			OPTS=$(convert_mount_opts)
			;;
	esac
	MOUNT_OPTS=${OPTS:+" -o ${OPTS%,}"}

	# Prepare for ubi (consider /dev/mtdX as ubiblock)
	if [ "$FSGROUP" = ubifs ] || echo $DEV | grep -q "/dev/mtd[0-9]";then
		if ! prepare_ubi; then
			echo "Failed to prepare ubi for $DEV"
			[ "$AUTO_MKFS" ] || return

			echo "Auto formatting"
			format_ubifs || return
		fi
	fi
}

check_part()
{
	[ "$SKIP_FSCK" -o "$PASS" -eq 0 ] && return

	if [ -z "$FSCK" ]; then
		echo "No fsck for $FSTYPE"
		return
	fi

	echo "Checking $DEV($FSTYPE)"

	check_tool "$FSCK" $FSCK_CONFIG || return

	# Fsck needs read-only
	remount_part ro

	$FSCK $DEV
}

mount_part()
{
	echo "Mounting $DEV($FSTYPE) on $MOUNT_POINT ${MOUNT_OPTS:+with$MOUNT_OPTS}"
	$MOUNT $DEV $MOUNT_POINT $MOUNT_OPTS && return
	[ "$AUTO_MKFS" ] || return

	echo "Failed to mount $DEV, try to format it"
	format_part && \
		$MOUNT $DEV $MOUNT_POINT $MOUNT_OPTS
}