#! /bin/bash

CONFHIST_DIR=config-history
PKG_DIR=linux-ck
BUILDFILE="$PKG_DIR/PKGBUILD"
PKG_URL=https://aur.archlinux.org/cgit/aur.git/snapshot/linux-ck.tar.gz
ARCH=x86_64

get_latest_config() {
	echo "$CONFHIST_DIR/$(ls -Art "$CONFHIST_DIR" | tail -n 1)"
}

help="$(basename "$0") [-o] [-c] [-h]

Downloads and installs new linux-ck kernel. By default will grab the
most recent config file from config-history unless the current config
is different (and exists), in which case it will be assumed more 
recent and saved in config history. If old config is used and from an
older kernel, make oldconfig will automatically run.

Options:
	-o: use the old package even if new is available
	-c: launch make nconfig
	-h: show this"

while getopts ":och" OPT; do
	case ${OPT} in
		o)
			OLD_PKG="true"
			;;
		c)
			DO_CONFIG="true"
			;;
		h)
			echo "$help"
			exit 0
			;;
		\?)
			echo "$help"
			exit 0
			;;
	esac
done

# pull old config if it exists and is not the most recent
if [ -e "$BUILDFILE" ]; then
	echo "checking for old config file"

    source "$BUILDFILE" # get pkgver
	oldconf="$PKG_DIR/src/linux-$pkgver/.config"

	if [ -e "$oldconf" ]; then
		echo "found old config"

		oldsum=$(md5sum "$oldconf" | awk '{print $1}')
		newsum=$(md5sum $(get_latest_config) | awk '{print $1}')

		if [ "$oldsum" != "$newsum" ]; then
			echo "copying old config to $CONFHIST_DIR"
			cp "$oldconf" "$CONFHIST_DIR/.config-$(date +%Y%m%d%H%M)"
		else
			echo "config file up to date. nothing to back up"
		fi
	fi
fi

if [ -z "$OLD_PKG" ]; then
	echo downloading new package

	rm -rf $PKG_DIR
	curl -O "$PKG_URL"
	tar xzf linux-ck.tar.gz

	latest_conf=$(get_latest_config)

	echo "copying conf: $latest_conf"

	cp "$latest_conf" "$PKG_DIR/config"
	updpkgsums "$BUILDFILE"
fi

cd "$PKG_DIR"
if [ -n "$DO_CONFIG" ]; then
	sed -i '/_makenconfig=/ s/$/y/' PKGBUILD
fi
makepkg -s -r -f -i
cd ..