#!/bin/sh
set -e

export LC_ALL=C

usage() {
  echo "Usage: $0 input.img(.xz|.gz|) output.img recipes/recipe.sh"
}

# Usage check:
in="$1"
out="$2"
recipe="$3"
if [ -z "$in" ] || [ -z "$out" ] || [ -z "$recipe" ]; then
  echo "E: missing parameters"
  usage
  exit 1
fi

if [ ! -f "$in" ]; then
  echo "E: specified input file cannot be found"
  usage
  exit 1
fi

if [ ! -f "$recipe" ]; then
  echo "E: specified recipe file cannot be found"
  usage
  exit 1
fi

# Environment check:
if [ "$(id -u)" != 0 ]; then
  echo "E: must run as root"
  exit 1
fi

# Duplicate input into output:
echo "🍞 Duplicating"
case "$in" in
  *.img)    cp "$in" "$out";;
  *.img.gz) zcat "$in" > "$out";;
  *.img.xz) xzcat "$in" > "$out";;
  *)        echo "E: unsupported extension for specified input file"; usage; exit 1;;
esac

# Load recipe, then use functions:
. "$recipe"

# Possible resizing (image and partition table first, filesystem later):
resize=$(resize_me 2>/dev/null || echo 0)
if [ "$resize" != 0 ]; then
  echo "🍞 Resizing"
  size=$(stat -c %s "$out")
  fallocate -l $((size + resize)) "$out"

  kpartx -asv "$out"
  loop=$(losetup -j "$out" | sed 's,:.*$,,;s,^/dev/,,')
  echo ', +' | sfdisk --force -N 2 "/dev/$loop"
  kpartx -dsv "$out"
fi

# Map:
kpartx -asv "$out"
loop=$(losetup -j "$out" | sed 's,:.*$,,;s,^/dev/,,')

# Resize root filesystem:
if [ "$resize" != 0 ]; then
  resize2fs "/dev/mapper/${loop}p2"
fi

# Mount filesystems:
echo "🍞 Mounting"
MNT=$(mktemp -d -t toaster.XXXX)
mount "/dev/mapper/${loop}p2" "$MNT"/
for mountpoint in /boot/firmware /boot/efi; do
  if [ -e "$MNT/$mountpoint" ]; then
    mount "/dev/mapper/${loop}p1" "$MNT/$mountpoint"
  fi
done

# Toast!
echo "🍞 Modifying"
export MNT
toast_me

# Free all resources:
echo "🍞 Cleaning up"
umount -R "$MNT"
zerofree "/dev/mapper/${loop}p2"
kpartx -dsv "$out"
rmdir "$MNT"

echo "🍞 Toasted!"
echo " → $out"