#!/bin/sh
# arch_post_update_update_boot.sh
#
# In your /etc/profile, export the following variables
# LVM_VG_BOOT=vg0
# LVM_LG_BOOT_NAME=boot
# BOOT_DIR_SUFFIX=/archlinux
#
# Optional variables:
# PACMAN_BIN=/usr/bin/pacman # Alternative pacman binary (eg: aura)
# BOOT_SYMLINK=current (in good boot dir)

set -e

source /etc/profile

ask_overwrite() {
  echo "Existing destination folder ($ARCH_BOOT_DST_CURRENT_VERSION), do you want to overwrite? (y/n)";
  read OVERWRITE;
  return `test "$OVERWRITE" = "y"`
}

do_upgrade() {
    PKG_NAME=$1
    ARCH_INITRAMFS=$2
    ARCH_INITRAMFS_FALLBACK=$3
    ARCH_VMLINUZ=$4

    PACMAN_BIN=${PACMAN_BIN:-/usr/bin/pacman}
    BOOT_SYMLINK=${BOOT_SYMLINK:-$PKG_NAME}

    BOOT_ORIG=/boot

    ARCH_BOOT_DST=$TMP_BOOT_DST/$BOOT_DIR_SUFFIX


    CURRENT_VERSION=`${PACMAN_BIN} -Qi $PKG_NAME \
      | sed -n '/^Version *:/p' \
      | grep -o '[^ ]*$'`

    ARCH_BOOT_DST_CURRENT_VERSION=$ARCH_BOOT_DST/$CURRENT_VERSION 

    test -d $ARCH_BOOT_DST_CURRENT_VERSION \
      && test `realpath $ARCH_BOOT_DST/$BOOT_SYMLINK` = $ARCH_BOOT_DST_CURRENT_VERSION \
      && echo "$PKG_NAME version already up to date ($CURRENT_VERSION)" && return 1;

    mkdir $ARCH_BOOT_DST_CURRENT_VERSION || ask_overwrite || return 1;

    (
        cd $BOOT_ORIG;
        # Copy the new kernel files to the real destination in boot fs
        cp -t $ARCH_BOOT_DST_CURRENT_VERSION $ARCH_INITRAMFS $ARCH_INITRAMFS_FALLBACK $ARCH_VMLINUZ;
    )

    (
        cd $ARCH_BOOT_DST;
        # Re-link the good version
        test -h $BOOT_SYMLINK && rm $BOOT_SYMLINK;
        ln -s $CURRENT_VERSION $PKG_NAME;
    )

    echo "$PKG_NAME version updated to $CURRENT_VERSION"
}

TMP_BOOT_DST=`mktemp -d`
BOOT_BLK=/dev/$LVM_VG_BOOT/$LVM_LG_BOOT_NAME
mount $BOOT_BLK $TMP_BOOT_DST;

do_upgrade linux initramfs-linux.img initramfs-linux-fallback.img vmlinuz-linux \
    || echo "Skipped linux upgrade"

do_upgrade linux-lts initramfs-linux-lts.img initramfs-linux-lts-fallback.img vmlinuz-linux-lts \
    || echo "Skipped linux-lts upgrade"

umount $TMP_BOOT_DST;
rmdir $TMP_BOOT_DST;
exit 0;