#!/bin/bash -e

if [ -z "$IMG_DIR" ] || [ -z "$BOARD" ]; then
    echo "this script must be invoked from board specific mkimage.sh"
    exit 1
fi

test "root" != "$USER" && exec sudo -E $0 "$@"

function msg() {
    echo ":: $1"
}

function cleanup {
    set +e

    # unmount loop mounts
    mount | grep /dev/loop | cut -d ' ' -f 3 | xargs -r umount

    # remove loop devices
    losetup -a | cut -d ':' -f 1 | xargs -r losetup -d
}

trap cleanup EXIT

BOOT_SRC=$IMG_DIR/boot
BOOT=$IMG_DIR/.boot
BOOT_IMG=$IMG_DIR/boot.img
BOOT_SIZE="16" # MB

ROOT_SRC=$IMG_DIR/rootfs.tar
ROOT=$IMG_DIR/.root
ROOT_IMG=$IMG_DIR/root.img
ROOT_SIZE="120" # MB

DISK_SIZE="140" # MB

# boot filesystem
msg "creating boot loop device"
dd if=/dev/zero of=$BOOT_IMG bs=1M count=$BOOT_SIZE
loop_dev=$(losetup -f)
losetup -f $BOOT_IMG

msg "creating boot filesystem"
mkfs.vfat -F16 $loop_dev

msg "mounting boot loop device"
mkdir -p $BOOT
mount -o loop $loop_dev $BOOT

msg "copying boot filesystem contents"
cp $BOOT_SRC/* $BOOT
sync

msg "unmounting boot filesystem"
umount $BOOT

msg "destroying boot loop device"
losetup -d $loop_dev
sync

# root filesystem
msg "creating root loop device"
dd if=/dev/zero of=$ROOT_IMG bs=1M count=$ROOT_SIZE
loop_dev=$(losetup -f)
losetup -f $ROOT_IMG

msg "creating root filesystem"
mkfs.ext4 $loop_dev
tune2fs -O^has_journal $loop_dev

msg "mounting root loop device"
mkdir -p $ROOT
mount -o loop $loop_dev $ROOT

msg "copying root filesystem contents"
tar -xpsf $ROOT_SRC -C $ROOT

msg "unmounting root filesystem"
umount $ROOT

msg "destroying root loop device"
losetup -d $loop_dev
sync

DISK_IMG=$IMG_DIR/disk.img
BOOT_IMG=$IMG_DIR/boot.img
ROOT_IMG=$IMG_DIR/root.img

if ! [ -r $BOOT_IMG ]; then
    echo "boot image missing"
    exit -1
fi

if ! [ -r $ROOT_IMG ]; then
    echo "root image missing"
    exit -1
fi

# disk image
msg "creating disk loop device"
dd if=/dev/zero of=$DISK_IMG bs=1M count=$DISK_SIZE
if [ -n "$UBOOT_BIN" ] && [ -n "$UBOOT_SEEK" ]; then
    msg "copying u-boot image"
    dd conv=notrunc if=$UBOOT_BIN of=$DISK_IMG bs=512 seek=$UBOOT_SEEK
fi
loop_dev=$(losetup -f)
losetup -f $DISK_IMG

msg "partitioning disk"
set +e
fdisk -u=sectors $loop_dev <<END
o
n
p
1

+${BOOT_SIZE}M
n
p
2

+${ROOT_SIZE}M

t
1
e
a
1
w
END
set -e
sync

msg "reading partition offsets"
boot_offs=$(fdisk -u=sectors -l $loop_dev | grep -E 'loop[[:digit:]]p1' | tr -d '*' | tr -s ' ' | cut -d ' ' -f 2)
root_offs=$(fdisk -u=sectors -l $loop_dev | grep -E 'loop[[:digit:]]p2' | tr -d '*' | tr -s ' ' | cut -d ' ' -f 2)

msg "destroying disk loop device"
losetup -d $loop_dev

msg "creating boot loop device"
loop_dev=$(losetup -f)
losetup -f -o $(($boot_offs * 512)) $DISK_IMG

msg "copying boot image"
dd if=$BOOT_IMG of=$loop_dev
sync

msg "destroying boot loop device"
losetup -d $loop_dev

msg "creating root loop device"
loop_dev=$(losetup -f)
losetup -f -o $(($root_offs * 512)) $DISK_IMG
sync

msg "copying root image"
dd if=$ROOT_IMG of=$loop_dev
sync

msg "destroying root loop device"
losetup -d $loop_dev
sync

mv $DISK_IMG $(dirname $DISK_IMG)/motionpie-$BOARD.img
DISK_IMG=$(dirname $DISK_IMG)/motionpie-$BOARD.img

msg "$(realpath "$DISK_IMG") is ready"

