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

# CASAN Plan-16 SEC-25 (SC-07, offline) — build-artifact attestation (tested==deployed).
#
# Proves (no network):
#   * an artifact attested + verified passes (tested == deployed),
#   * modifying the artifact after attestation -> MISMATCH (deployed != tested) REFUSED,
#   * a forged attestation (signed by a different key) is REFUSED,
#   * a missing or UNSIGNED attestation fails CLOSED.
#
# Deterministic; hermetic; uses openssl (skip-aware).

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$SCRIPT_DIR/../scripts/bash/casan-paths.sh"
PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
AA="$CASAN_HARNESS_ROOT/scripts/bash/artifact-attest.sh"
WORK="$(mktemp -d)"
trap '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; }

command -v openssl >/dev/null 2>&1 || { echo "SKIP: openssl unavailable"; exit 0; }

echo "===== Plan-16 SEC-25: build-artifact attestation (offline) ====="

openssl genrsa -out "$WORK/build.priv.pem" 2048 2>/dev/null
openssl rsa -in "$WORK/build.priv.pem" -pubout -out "$WORK/build.pub.pem" 2>/dev/null
openssl genrsa -out "$WORK/atk.priv.pem" 2048 2>/dev/null

printf 'tested release artifact v1\n' > "$WORK/app.tar"

# --- attest + verify -> OK ---
bash "$AA" attest "$WORK/app.tar" "$WORK/build.priv.pem" >/dev/null 2>&1
[[ "$(rc_of bash "$AA" verify "$WORK/app.tar" "$WORK/app.tar.att" "$WORK/build.pub.pem")" -eq 0 ]] \
  && pass "attested artifact verifies (tested==deployed)" || fail "attested artifact rejected"

# --- deployed != tested -> MISMATCH ---
cp "$WORK/app.tar" "$WORK/app2.tar"
bash "$AA" attest "$WORK/app2.tar" "$WORK/build.priv.pem" >/dev/null 2>&1
printf 'SWAPPED malicious artifact\n' > "$WORK/app2.tar"   # different deploy than tested
[[ "$(rc_of bash "$AA" verify "$WORK/app2.tar" "$WORK/app2.tar.att" "$WORK/build.pub.pem")" -eq 2 ]] \
  && pass "swapped artifact (deployed!=tested) REFUSED" || fail "artifact swap not detected"

# --- forged attestation (wrong key) -> REFUSED ---
cp "$WORK/app.tar" "$WORK/app3.tar"
bash "$AA" attest "$WORK/app3.tar" "$WORK/atk.priv.pem" >/dev/null 2>&1   # signed by attacker
[[ "$(rc_of bash "$AA" verify "$WORK/app3.tar" "$WORK/app3.tar.att" "$WORK/build.pub.pem")" -eq 2 ]] \
  && pass "forged attestation (wrong key) REFUSED" || fail "forged attestation accepted"

# --- missing attestation -> fail-closed ---
printf 'unattested\n' > "$WORK/app4.tar"
[[ "$(rc_of bash "$AA" verify "$WORK/app4.tar" "$WORK/app4.tar.att" "$WORK/build.pub.pem")" -eq 3 ]] \
  && pass "missing attestation fails CLOSED" || fail "missing attestation not refused"

# --- unsigned attestation -> fail-closed ---
cp "$WORK/app.tar" "$WORK/app5.tar"
bash "$AA" attest "$WORK/app5.tar" "$WORK/build.priv.pem" >/dev/null 2>&1
rm -f "$WORK/app5.tar.att.sig"   # strip signature
[[ "$(rc_of bash "$AA" verify "$WORK/app5.tar" "$WORK/app5.tar.att" "$WORK/build.pub.pem")" -eq 3 ]] \
  && pass "UNSIGNED attestation fails CLOSED" || fail "unsigned attestation not refused"

echo ""
echo "===== SEC-25 SUMMARY: PASS=$PASS FAIL=$FAIL ====="
[[ "$FAIL" -eq 0 ]] || exit 1