#!/bin/sh

. samizdat-paths.sh

if [ -d "$1" ]
then
        samizdat_linux_dir=$1
fi

initrd=${samizdat_linux_dir}/initrd.img
vmlinuz=${samizdat_linux_dir}/vmlinuz

conf_dir=$samizdat_initramfs_conf_dir
apt_dependencies=$samizdat_initrd_files_dir/initrd-dependencies.txt

get_kernel_version()
{
    local pkgs_file="$1"
    egrep '^ii  linux-image-(amd64|686)' "$pkgs_file" |
        (read _ pkg ver _; apt-cache show "$pkg=$ver") |
        grep Depends |
        (read _ a; echo ${a#linux-image-})
}

pkgs_file=rootfs/_build/${rootfs:-samizdat}.pkgs.txt

[ -f "$pkgs_file" ] || exit

kernel_version=$(get_kernel_version rootfs/_build/${rootfs:-samizdat}.pkgs.txt)

[ "$kernel_version" ] || exit

debian_initrd=/boot/initrd.img-${kernel_version}

find_deps() {
    find "$conf_dir" "$samizdat_initrd_files_dir" "$debian_initrd" "$@"
}

force_rebuild()
{
    touch "$conf_dir"
    return 1
}

rebuild()
{
    [ ! -f "$apt_dependencies" ] ||
        sudo apt-get install -q=10 --no-upgrade -y $(cat "$apt_dependencies")

    set -ex
    cp -f /boot/vmlinuz-"${kernel_version}" "$vmlinuz"
    /usr/sbin/mkinitramfs -d "$conf_dir" -o "$initrd" "${kernel_version}" || force_rebuild
}

if [ ! -e "$initrd" -o ! -e "$vmlinuz" ]; then
    rebuild
else
    found=$(find_deps -newer "$initrd" -print -quit)
    if [ "$found" ]; then
        echo "initrd.sh: rebuild forced: found modified source: $found" >&2
        rebuild
    fi
fi