#!/bin/sh
set -o errexit
set -o nounset

REPO='https://gn.googlesource.com/gn'

# Validate the argument
COMMIT=''
if [ "$#" = '1' ]
then
  if echo "$1" | grep -E '^[[:xdigit:]]{40}$' >/dev/null
  then
    COMMIT="$1"
  fi
elif [ "$#" = '0' ]
then
  COMMIT='main'
fi
if [ -z "${COMMIT}" ]
then
  cat 1>&2 <<EOF
Usage: $0 [COMMIT]

Parameters:
  COMMIT - full commit hash from upstream git (${REPO});
           otherwise the latest commit in main is used
EOF
  exit 1
fi

# Generate the version header
SRCDIR="$(cd "$(dirname "$0")"; pwd)"
SPEC="${SRCDIR}/gn.spec"

SPEC_COMMIT="$(
  awk '/^%global[[:blank:]]+commit[[:blank:]]+[[:xdigit:]]{40}[[:blank:]]*$/ {
    print $3; exit
  }' "${SPEC}"
)"

check_equal_commits() {
  if [ "${1}" = "${SPEC_COMMIT}" ]
  then
    cat 1>&2 <<EOF
Spec file is already up to date at ${SPEC_COMMIT}.
EOF
    exit
  fi
}

if echo "${COMMIT}" | grep -E '^[[:xdigit:]]{40}$' >/dev/null
then
  check_equal_commits "${COMMIT}"
fi

tmpd="$(mktemp -d)"
trap "rm -rf '${tmpd}'" INT TERM EXIT

cd "${tmpd}"
git clone 'https://gn.googlesource.com/gn'
cd gn
if ! echo "${COMMIT}" | grep -E '^[[:xdigit:]]{40}$' >/dev/null
then
  COMMIT="$(git rev-parse "${COMMIT}")"
  check_equal_commits "${COMMIT}"
fi
git checkout "${COMMIT}"
python3 './build/gen.py'
cp -vp './out/last_commit_position.h' "${SRCDIR}/"

cd "${SRCDIR}"

# Modify the spec file
POSITION="$(
  awk '
    $1 == "#define" && $2 == "LAST_COMMIT_POSITION_NUM" {
      print $3; exit
    }' 'last_commit_position.h'
)"

sed -r -i \
    -e 's/(%global[[:blank:]]+commit[[:blank:]]+)[[:xdigit:]]{40}[[:blank:]]*$/\1'"${COMMIT}/" \
    -e 's/(%global[[:blank:]]+access[[:blank:]]+)[[:digit:]]{8}[[:blank:]]*$/\1'"$(
      date -u '+%Y%m%d'
    )/" \
    -e 's/(Version:[[:blank:]]+)[[:digit:]]+[[:blank:]]*$/\1'"${POSITION}/" \
    "${SPEC}"

# Download the new tarball
spectool --get-files --directory "${SRCDIR}" "${SPEC}"

# Update the local git repo and upload the new source tarball
fedpkg new-sources "$(
  spectool --list-files "${SPEC}" |
    grep -E '^Source0:' |
    sed -r 's|.*/||'
)"
git add 'last_commit_position.h' gn.spec
fedpkg commit -m "Update to version ${POSITION}"

#  vim: tw=78 ts=2 sw=2 sts=2 et ai nojs