#!/bin/bash

set -e
set -x

CWD=$(pwd)
THIS_HOST=${THIS_HOST:-$(hostname -s)}
PRGNAM=$(basename $CWD)-$THIS_HOST
BUILD=${BUILD:-1}
BRANCH=${BRANCH:-mainline}        # stable ; mainline
ARCH=$(uname -m)

TAG=gwh
TMP=/tmp/$TAG
PKG=$TMP/pkg-$PRGNAM
OUTPUT=/tmp

NUMJOBS=${NUMJOBS:-" -j$(nproc)"}

ANEW=${ANEW:-true}

rm -fr $PKG

VERSION=${VERSION:-$(curl https://www.kernel.org/feeds/kdist.xml | grep -o "[0-9.rc-]*: $BRANCH" | head -n1 | cut -d: -f1)}

mkdir -p $PKG/usr/src/
if [ -e /usr/src/linux-$VERSION ] && [[ "$ANEW" != "true" ]]; then
    cp -a /usr/src/linux-$VERSION $PKG/usr/src/
else
    if [ $BRANCH == "stable" ]; then
        SRC_URL="https://cdn.kernel.org/pub/linux/kernel/v$(echo $VERSION | cut -d. -f1).x"
    else
        SRC_URL="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/snapshot"
    fi

    [ ! -e $CWD/linux-$VERSION.tar.?z* ] && wget -c "$SRC_URL/linux-$VERSION.tar.gz" -O $CWD/linux-$VERSION.tar.gz
    tar xf $CWD/linux-$VERSION.tar.gz -C $PKG/usr/src/
fi

cd $PKG/usr/src/
ln -s linux-$VERSION linux
cd linux-$VERSION

if [ -e $CWD/config-$THIS_HOST-$VERSION ] ; then
    cp $CWD/config-$THIS_HOST-$VERSION .config
else
    if [ -e $CWD/config-$THIS_HOST ] ; then
        cp $CWD/config-$THIS_HOST .config
    else
        zcat /proc/config.gz > .config
    fi
fi

make oldconfig $*

make $NUMJOBS
make modules $NUMJOBS
make modules_install INSTALL_MOD_PATH=$PKG

if [ -z "${HEADERS_ARCH}" ]; then
    case "$(uname -m)" in
    i?86) HEADERS_ARCH=x86 ;;
    x86_64) HEADERS_ARCH=x86 ;;
    aarch64) HEADERS_ARCH=arm64 ;;
    # Use uname -m for all other archs:
    *) HEADERS_ARCH=$(uname -m) ;;
  esac
fi
# Generate the kernel headers and clean them up:
( echo "Generating headers from the Linux kernel source tree in ${KERNEL_SOURCE}:"
  make headers_install ARCH=${HEADERS_ARCH} INSTALL_HDR_PATH=$PKG/usr
  cd $PKG/usr/include
  # You won't want these files. The ones in libdrm work better.
  rm -rf drm
  # This next part seems pretty much cosmetic, but since we've been doing this
  # for a long time (and others also do), we'll stick with it:
  mv asm asm-${HEADERS_ARCH}
  ln -sf asm-${HEADERS_ARCH} asm
  # Remove unneeded dotfiles:
  find . -name ".??*" -exec rm -f {} \+
)

VERSION=$(basename $(ls $PKG/lib/modules/ | head -n1))

mkdir -p $PKG/install
mkdir -p $PKG/boot/
cp System.map $PKG/boot/System.map-gwh-$VERSION
cp .config $PKG/boot/config-gwh-$VERSION
cp arch/${ARCH}/boot/bzImage $PKG/boot/vmlinuz-gwh-$VERSION
( cd $PKG/boot/
  ln -s vmlinuz-gwh-$VERSION vmlinuz-gwh
)

# cat <<EOF > $PKG/install/doinst.sh
# cp /boot/elilo-x86_64.efi /boot/efi/EFI/Slackware/elilo.efi
# cp /boot/vmlinuz-gwh-$VERSION /boot/efi/EFI/Slackware/vmlinuz-gwh
# if [ -e /boot/intel-ucode.cpio ]; then
#     cp /boot/intel-ucode.cpio /boot/efi/EFI/Slackware/
#     eval \$(/usr/share/mkinitrd/mkinitrd_command_generator.sh -a '-P /boot/intel-ucode.cpio' -k $VERSION -r -m crc32-pclmul:crc32c-intel:crc32_generic\$(lspci | grep -iq radeon && echo ':amdgpu:radeon'))
# else
#     eval \$(/usr/share/mkinitrd/mkinitrd_command_generator.sh -k $VERSION -r -m crc32-pclmul:crc32c-intel:crc32_generic\$(lspci | grep -iq radeon && echo ':amdgpu:radeon'))
# fi
# cp /boot/initrd.gz /boot/efi/EFI/Slackware/initrd-gwh.gz
# EOF

cat <<EOF > $PKG/install/doinst.sh
echo -n "updating grub... "
grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=grub
echo OK

[ -e /boot/initrd.gz ] && mv /boot/initrd.gz /boot/initrd.gz.orig

echo -n "building initrd... "
eval \$(/usr/share/mkinitrd/mkinitrd_command_generator.sh -k $VERSION -r)
echo OK

mv /boot/initrd.gz /boot/initrd-gwh-${VERSION}.gz
ln -s /boot/initrd-gwh-${VERSION}.gz /boot/initrd-gwh.gz

[ -e /boot/initrd.gz.orig ] && mv /boot/initrd.gz.orig /boot/initrd.gz
EOF

make clean

cat <<EOF > $PKG/install/slack-desc
$PRGNAM: $PRGNAM (kernel)
$PRGNAM:
$PRGNAM: Linux is a clone of the operating system Unix, written from scratch by
$PRGNAM: Linus Torvalds with assistance from a loosely-knit team of hackers
$PRGNAM: across the Net. It aims towards POSIX and Single UNIX Specification
$PRGNAM: compliance.
$PRGNAM:
$PRGNAM: It has all the features you would expect in a modern fully-fledged Unix
$PRGNAM:
$PRGNAM: http://www.kernel.org
$PRGNAM:
EOF

cd $PKG
rm -f $PKG/{,usr/}lib$(uname -m | grep -o 64)/*.la
/sbin/makepkg -l y -c n $OUTPUT/$PRGNAM-$(echo $VERSION | tr - _)-$ARCH-$BUILD$TAG.txz