#!/usr/bin/env bash
# Constitution enforcement: no amendment, no functional change.
#
# If a commit touches src/ (game behavior), it must also touch spec/ or
# DESIGN.md (the amendment). Process-only commits (AGENT.md, tools/,
# DEVLOG.md, README.md, knowledge/) are exempt.
#
# This is the local fast-feedback layer. The Tangled pipeline is the
# server-side enforcement that can't be bypassed.
set -euo pipefail

# Get staged files (added, modified, renamed, copied — not deleted)
changed=$(git diff --cached --name-only --diff-filter=ACMR HEAD)

if [ -z "$changed" ]; then
  exit 0
fi

# Check if any src/ file is in the changeset
touches_src=0
echo "$changed" | grep -q "^src/" && touches_src=1

if [ "$touches_src" -eq 0 ]; then
  # No functional changes — commit is fine
  exit 0
fi

# src/ is touched: require spec/ or DESIGN.md in the same commit
touches_spec=0
echo "$changed" | grep -qE "^spec/|^DESIGN\.md" && touches_spec=1

if [ "$touches_spec" -eq 0 ]; then
  echo ""
  echo "CONSTITUTION VIOLATION"
  echo "  This commit touches src/ (functional change) but does not touch"
  echo "  spec/ or DESIGN.md (the amendment)."
  echo ""
  echo "  AGENT.md: 'No amendment, no functional change.'"
  echo "  Either add a spec/DESIGN.md change to this commit, or restructure"
  echo "  so functional changes and their amendment ship together."
  echo ""
  echo "  If this is a false positive (e.g. generated code, test-only change),"
  echo "  bypass with: git commit --no-verify"
  echo ""
  exit 1
fi

exit 0