#!/bin/sh
#
# pre-push hook — mirrors the trunk branch and tags to the Gitea fallback.
#
# Installed via `scripts/install-git-hooks.sh` (git core.hooksPath = scripts/hooks).
# Git has no client-side post-push hook, so the mirror runs here: the refs are
# already committed locally, so whether Gitea or GitHub receives them first makes
# no difference. A Gitea outage prints a warning and never blocks the push.
#
# stdin receives one line per ref being pushed:
#   <local-ref> <local-sha> <remote-ref> <remote-sha>
#
# args: $1 = remote name, $2 = remote URL

remote_url="${2:-}"

# Only react to pushes of the canonical GitHub remote.
case "$remote_url" in
  *github.com*) ;;
  *) exit 0 ;;
esac

# Don't recurse when the mirror script itself is pushing to Gitea.
if [ "${GRIDLINE_MIRROR_RUNNING:-}" = "1" ]; then
  exit 0
fi

mirror_needed=0
while read -r _local_ref local_sha remote_ref _remote_sha; do
  # Ignore deletions (all-zero object id).
  case "$local_sha" in
    0000000000000000000000000000000000000000) continue ;;
  esac
  case "$remote_ref" in
    refs/heads/prod|refs/heads/main|refs/tags/*) mirror_needed=1 ;;
  esac
done

[ "$mirror_needed" = "1" ] || exit 0

root="$(git rev-parse --show-toplevel)" || exit 0
GRIDLINE_MIRROR_RUNNING=1 sh "$root/scripts/mirror-gitea.sh" ||
  echo "pre-push: warning: Gitea mirror was not updated (continuing with the push)" >&2

# Never block the push to GitHub because of a mirror problem.
exit 0