#!/bin/bash

if [ "x$1" != "x" ] && ! [ -d "$1" ]; then
  echo "Usage: $0 [git_reference_dir_to_speed_up]"
  exit 1
fi

# Variables to set up for a new GTS update.
# The latest GTS supported on this branch.
gts_major=15
# Tests that need to be synced in for this change.  These are required to sync
# in adjustments to tests due to changes to pretty printer output.
# Occasionally, a test adjustment may be due to an ABI change, in which case
# the test may fail with the system gcc, since we do not backport ABI changes.
# This is expected, in which case we adjust back the expected output for the
# test to match the system libstdc++ ABI in a subsequent, hand-written patch to
# the tests.
tests="
filesystem-ts.cc
compat.cc
cxx11.cc
cxx17.cc
libfundts.cc
"

system_major=`sed -n 's/^%global gcc_major //p' gcc.spec`
systemrev=`sed -n 's/^%global gitrev //p' gcc.spec`

if [ $gts_major -eq $system_major ]; then echo "GTS same version as system, nothing to do."; exit 1; fi
if ! [ -f gcc.spec ]; then echo Must be run in the directory with gcc.spec file.; exit 1; fi
branch=`git branch --show-current`

if ! [[ $branch =~ ^c[0-9]+s$ ]]; then echo "Must be run on a valid centos stream branch, not '$branch'"; exit 1; fi

gtsrev=`curl -s https://gitlab.com/redhat/centos-stream/rpms/gcc-toolset-$gts_major-gcc/-/raw/$(git branch --show-current)/gcc-toolset-15-gcc.spec?ref_type=heads | sed -n 's/^%global gitrev //p'`

echo "system at $systemrev and GTS at $gtsrev on the vendor branch"

cwd=$PWD
cleanup() {
  rm -rf $cwd/gcc-dir.tmp
}

trap cleanup EXIT

# Get vendor branch contents from upstream.  git-fetch doesn't have the
# --reference feature, so do a full clone referencing a local upstream repo if
# present.  Otherwise fetch only those specific refs.
url=https://gcc.gnu.org/git/gcc.git
echo -n "Getting sources from $url"
if [ "$#" -eq 1 ]; then
  echo " (using $1 as cache)"
  git clone -q --dissociate --reference $1 $url gcc-dir.tmp
  pushd gcc-dir.tmp
else
  echo
  mkdir gcc-dir.tmp
  pushd gcc-dir.tmp
  git init -q
  git remote add origin $url
fi

pp_patchfile=gcc$system_major-libstdc++-prettyprinter-update-$gts_major.patch
tests_patchfile=gcc$system_major-libstdc++-prettyprinter-update-$gts_major-tests.patch
git fetch -q origin $systemrev $gtsrev
# We limit the update to just the printer, retain the system gcc hook and
# make-foo.
git diff --stat --patch $systemrev..$gtsrev -- libstdc++-v3/python/libstdcxx > ../$pp_patchfile
echo "Updated $pp_patchfile"

testfiles=$(echo "$tests" | awk '/.+/{printf "libstdc++-v3/testsuite/libstdc++-prettyprinters/%s ", $1}')
git diff --stat --patch $systemrev..$gtsrev -- $testfiles > ../$tests_patchfile
echo "Updated $tests_patchfile"

popd