#!/usr/bin/env bash
# gstack-verify-gate — Stop hook. Blocks the turn from ending until the
# project's declared verification command passes.
#
# Declare the command on one line in the project's CLAUDE.md:
#   <!-- gstack:verify: bun test -->
#
# Read-or-ask: gstack never invents this command. No declaration, no gate.
# Fails open on every absence (no CLAUDE.md, no declaration, empty value).
#
# Exit 0 = allow the turn to end, one-line reason on stdout.
# Exit 2 = block, Claude Code feeds stderr back to the agent.
#
# Remove with: gstack-settings-hook remove-source --source verify-gate
set -uo pipefail

INPUT=""
[ -t 0 ] || INPUT="$(cat)"

# Claude Code re-runs Stop hooks after a block. Never gate the same turn twice.
if printf '%s' "$INPUT" | grep -q '"stop_hook_active"[[:space:]]*:[[:space:]]*true'; then
  echo "verify-gate: gate already ran this turn, allowing."
  exit 0
fi

ROOT="${CLAUDE_PROJECT_DIR:-$PWD}"
while [ ! -f "$ROOT/CLAUDE.md" ] && [ "$ROOT" != "/" ]; do
  ROOT="$(dirname "$ROOT")"
done

if [ ! -f "$ROOT/CLAUDE.md" ]; then
  echo "verify-gate: no CLAUDE.md above $PWD, no check declared, allowing."
  exit 0
fi

CMD="$(sed -n 's/^[[:space:]]*\(<!--[[:space:]]*\)\{0,1\}gstack:verify:[[:space:]]*\(.*\)$/\2/p' "$ROOT/CLAUDE.md" | head -1)"
CMD="${CMD%%-->*}"
CMD="$(printf '%s' "$CMD" | tr -d '`' | sed 's/[[:space:]]*$//')"

if [ -z "$CMD" ]; then
  echo "verify-gate: $ROOT/CLAUDE.md declares no 'gstack:verify:' command, allowing."
  exit 0
fi

OUT="$(cd "$ROOT" && eval "$CMD" 2>&1)"
STATUS=$?

if [ "$STATUS" -eq 0 ]; then
  echo "verify-gate: declared check passed ($CMD)."
  exit 0
fi

echo "verify-gate: declared check FAILED with exit $STATUS: $CMD" >&2
printf '%s\n' "$OUT" | tail -20 >&2
echo "Fix the failure, or drop the gstack:verify line from $ROOT/CLAUDE.md." >&2
exit 2