#!/usr/bin/env bash
# Print the key that names a prebuilt C++ reference build (harness/cpp/build.sh output).
#
#   v1-<upstream commit, 12 hex>-<16 hex of a sha256 over the harness inputs>
#
# The inputs are exactly what build.sh compiles into bin/cpp/lib: the pinned upstream
# commit (UPSTREAM_COMMIT in scripts/upstream-pin.env) plus
# harness/cpp/{CMakeLists.txt,build.sh,stubs/**,patches/**}. The shims
# (harness/cpp/shim/**) are compiled by crates/solidcore-ffi, not by build.sh, so they
# are not part of the key. CI (actions/cache key), .github/workflows/cpp-reference.yml
# (release tag cpp-ref-<key>) and scripts/fetch-cpp.sh all call this script, so they
# always agree. Bump the "v1" prefix when the packaging itself changes.
#
# An UPSTREAM_COMMIT environment variable overrides the pinned commit.
set -euo pipefail

ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
# The pin lives in scripts/upstream-pin.env (also read by fetch-cpp.sh, package-cpp-ref.sh,
# the site and CI); ATTRIBUTION.md / AGENTS.md / README.md quote it for humans.
PINNED="$(sed -n 's/^UPSTREAM_COMMIT=//p' "$ROOT/scripts/upstream-pin.env")"
[ -n "$PINNED" ] || { echo "cpp-ref-key.sh: no UPSTREAM_COMMIT in scripts/upstream-pin.env" >&2; exit 1; }
COMMIT="${UPSTREAM_COMMIT:-$PINNED}"

if command -v sha256sum >/dev/null 2>&1; then
  sha() { sha256sum | cut -c1-64; }
else
  sha() { shasum -a 256 | cut -c1-64; }   # macOS
fi

cd "$ROOT"
files="$(
  { printf '%s\n' harness/cpp/CMakeLists.txt harness/cpp/build.sh
    for d in harness/cpp/stubs harness/cpp/patches; do
      if [ -d "$d" ]; then find "$d" -type f; fi
    done
  } | LC_ALL=C sort
)"
hash="$(
  printf '%s\n' "$files" | while IFS= read -r f; do
    printf '%s  %s\n' "$(sha < "$f")" "$f"
  done | sha
)"
printf 'v1-%s-%s\n' "$(printf '%s' "$COMMIT" | cut -c1-12)" "$(printf '%s' "$hash" | cut -c1-16)"