#!/bin/bash
set -e
shopt -qu globstar
export LC_COLLATE=C
export LC_ALL=C

usage()
{
	retcode=0
	if [ -n "$1" ]; then
		exec 1>&2
		retcode=$1
	fi
	echo usage: do-rebase \$releasever
	exit $retcode
}

if ! git status | grep -q 'nothing to commit, working directory clean' ; then
	echo "Working directory is not clean, cannot rebase." 1>&2
	exit 1
fi

releasever=""
amend=""

declare -a savedargs
while [ $# -gt 0 ]; do
	case $1 in
	--help|-h|--usage|-?|-u)
		usage
		;;
	--dist=*)
		releasever=${1##--dist=}
		;;
	--dist)
		shift
		releasever=$1
		;;
	--amend)
		amend="--amend"
		;;
	*)
		savedargs[${#savedargs[@]}]="$1"
		;;
	esac
	shift
done
set -- "${savedargs[@]}"

if [ -z "${releasever}" -a $# -gt 0 ]; then
	releasever=$1
	shift
else
	dist=$(git status | grep "On branch" | cut -d\  -f3-)
	if [ -z "$dist" ]; then
		echo "Could not figure out distro release version" 1>&2
		usage 1
	fi
	case "$(eval echo \${dist})" in
	.fc*)
		releasever=$(echo ${dist} | \
			sed 's/^\.fc\([[:digit:]]\+\)$/fedora-\1/')
		;;
	.*)
		releasever=$(echo $dist | \
			sed 's/^\.\([[:alpha:]]\+\)\([[:digit:]]\+\)$/\1-\2/')
		;;
	esac
	if [ -z "${releasever}" -o "${releasever}" = "${dist}" ]; then
		echo "Could not figure out distro release version" 1>&2
		usage 1
	fi
fi

if [ -z "$releasever" ]; then
	echo "Could not figure out distro release version" 1>&2
	usage 1
fi

if [ $# -ge 1 ]; then
	echo "Unknown argument \"$1\"" 1>&2
	usage 1
fi

if ! git remote show -n github >/dev/null 2>&1 ; then
	git remote add \
		github git@github.com:vathpela/grub2-fedora.git >/dev/null 2>&1
	echo "Could not add remote: github" 1>&2
	exit 1
fi

git fetch github
remote=$(git branch --list -r "github/${releasever}" 2>/dev/null)
if [ "${remote}" != "  github/${releasever}" ]; then
	echo branch \"${releasever}\" does not appear to exist 1>&2
	exit 1
fi

unset LC_ALL
git rm -q 0*.patch
(cat <<EOF
From: Peter Jones <pjones@redhat.com>
Date:  Wed Jul 22 10:18:00 2015 -0400
Subject: Stop trying to "git format-patch" across a merge that confuses it

EOF
git diff --full-index --binary refs/tags/grub-2.02-beta3..refs/remotes/github/master
) > grub-2.02-beta3-to-origin-master.patch

patches=$(git format-patch refs/remotes/github/master..refs/remotes/github/${releasever})
echo Patch0000: grub-2.02-beta3-to-origin-master.patch > grub.patches
for x in $patches ; do
	echo Patch$(echo ${x} | cut -d- -f1): ${x} >> grub.patches
done
if [ -z "$amend" ];  then
    rpmdev-bumpspec -c "- Rebased to newer upstream for ${releasever}" grub2.spec
fi
git add 0*.patch grub2.spec grub-2.02-beta3-to-origin-master.patch grub.patches
if [ -z "$amend" ]; then
	fedpkg commit -s -c $amend
else
	git commit -m "" --amend
fi