#!/usr/bin/env bash
# Re-computes the parity-bar hash lock (TESTING_SPEC §12.1).
#
# Run this only when a justified change to
# `crates/simulation/tests/parity-bar/` or `TESTING_SPEC.md` lands.
# Commit the resulting `.locked-hashes` change in a separate commit
# titled `parity-bar: update lock` per §12.1.

set -euo pipefail

ROOT="${1:-$(git -C "$(dirname "$0")/.." rev-parse --show-toplevel 2>/dev/null \
    || ( cd "$(dirname "$0")/.." && pwd ) )}"

PARITY_DIR="$ROOT/crates/simulation/tests/parity-bar"
SPEC="$ROOT/crates/simulation/TESTING_SPEC.md"
LOCK_FILE="$PARITY_DIR/.locked-hashes"

if [[ ! -d "$PARITY_DIR" ]]; then
    echo "update-parity-lock: parity-bar directory missing: $PARITY_DIR" >&2
    exit 1
fi
if [[ ! -f "$SPEC" ]]; then
    echo "update-parity-lock: TESTING_SPEC.md missing: $SPEC" >&2
    exit 1
fi

DIGEST=$({
    find "$PARITY_DIR" -type f ! -name '.locked-hashes' -print0 \
        | sort -z \
        | xargs -0 sha256sum
    sha256sum "$SPEC"
} | sed -E "s|$ROOT/||" | sha256sum | awk '{print $1}')

cat > "$LOCK_FILE" <<EOF
# Parity-bar hash lock — TESTING_SPEC §12.1.
#
# Generated by scripts/update-parity-lock.sh from
#   crates/simulation/tests/parity-bar/   (all files except .locked-hashes)
#   crates/simulation/TESTING_SPEC.md
#
# Do NOT edit by hand. Re-run the script after a justified change
# and commit the diff in a separate commit titled:
#   parity-bar: update lock
$DIGEST
EOF

echo "update-parity-lock: wrote $DIGEST"