#!/usr/bin/env bash
set -euo pipefail

SCRIPT_DIR=$(cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd)
cd "${SCRIPT_DIR}"

if [[ ! -v XEN_REPO_DIR ]]; then
	XEN_REPO_DIR="${HOME}/repos/xen"
fi

XEN_VERSION="${1}"
OUR_PATCHES_VERSION="${2}"

XEN_VER_COMPONENTS=( ${XEN_VERSION//./ } )
XEN_MAJOR_MINOR_VERSION="${XEN_VER_COMPONENTS[0]}.${XEN_VER_COMPONENTS[1]}"


git -C "${XEN_REPO_DIR}" fetch origin

readarray -d '' CURRENT_PATCHES < <(find . -maxdepth 1 -type f -name "*.patch" -print0)
if [[ ${#CURRENT_PATCHES[@]} -gt 0 ]]; then
	git rm -f *.patch
fi

PATCH_RANGE_START="RELEASE-${XEN_VERSION}"
PATCH_RANGE_END="staging-${XEN_MAJOR_MINOR_VERSION}"
git -C "${XEN_REPO_DIR}" format-patch \
	-o "${SCRIPT_DIR}" \
	${PATCH_RANGE_START}..origin/${PATCH_RANGE_END}

XEN_NEXT_PATCHLEVEL=$((XEN_VER_COMPONENTS[2]+1))
XEN_NEXT_VERSION="${XEN_MAJOR_MINOR_VERSION}.${XEN_NEXT_PATCHLEVEL}"

PATCH_RANGE_START_ID=$(git -C "${XEN_REPO_DIR}" rev-parse ${PATCH_RANGE_START})
PATCH_RANGE_END_ID=$(git -C "${XEN_REPO_DIR}" rev-parse ${PATCH_RANGE_END})

cat <<EOF > "info.txt"
Xen upstream patchset #${OUR_PATCHES_VERSION} for ${XEN_NEXT_VERSION}-pre

Containing patches from
$PATCH_RANGE_START ($PATCH_RANGE_START_ID)
to
$PATCH_RANGE_END ($PATCH_RANGE_END_ID)
EOF

git add \
	info.txt \
	*.patch

TAG="${XEN_NEXT_VERSION}-pre-patchset-${OUR_PATCHES_VERSION}"
DESCRIPTION="Xen ${TAG}"

git commit \
	--signoff \
	-m "${DESCRIPTION}"

git tag \
	-s \
	-m "${DESCRIPTION}" \
	"${TAG}"