#!/usr/bin/env bash
# Promote a tag's tree from the source repo into the PUBLIC repo working dir as one clean release
# commit + tag. Excludes .git (via git archive) and .github (private CI stays private). The public
# repo's own .git is preserved. The PUSH is done by the calling workflow (it holds the credentials).
#   usage: promote.sh <src-repo> <tag> <public-repo-dir> <commit-message>
set -euo pipefail

src="${1:?src repo required}"
tag="${2:?tag required}"
pub="${3:?public repo dir required}"
msg="${4:?commit message required}"

git -C "$src" rev-parse "$tag" >/dev/null 2>&1 || { echo "unknown tag: $tag" >&2; exit 1; }

# Fail fast BEFORE mutating the public tree if this release was already promoted — re-promoting a
# published release must be deliberate, not a silent half-commit left on the runner.
if git -C "$pub" rev-parse -q --verify "refs/tags/$tag" >/dev/null 2>&1; then
    echo "tag already promoted in public repo: $tag" >&2
    exit 1
fi

# Clear the public working tree but KEEP its .git.
find "$pub" -mindepth 1 -maxdepth 1 ! -name '.git' -exec rm -rf {} +

# Extract exactly the tag's tree (git archive omits .git automatically).
git -C "$src" archive --format=tar "$tag" | tar -x -C "$pub"

# Private CI never goes public.
rm -rf "${pub:?}/.github"

git -C "$pub" add -A
# --allow-empty: stable promotion re-tags the same source commit as the last beta, so the
# extracted tree is byte-identical and there is nothing to stage — still produce a release commit.
git -C "$pub" commit -q --allow-empty -m "$msg"
git -C "$pub" tag "$tag"