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

# CASAN Plan-16 SEC-23 Phase 4+5-offline (MT-04 / MT-02):
#   * 23.9 signed tenant/project registry — a valid signature verifies; a tampered,
#     forged (wrong key), or UNSIGNED registry is REFUSED (fail-closed),
#   * 23.10 per-tenant encryption at rest — tenant A's state is ciphertext on disk;
#     A can decrypt its own; tenant B (different key) CANNOT read A's plaintext.
#
# Deterministic; hermetic; uses real openssl (skip-aware if absent).

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$SCRIPT_DIR/../scripts/bash/casan-paths.sh"
PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
S="$CASAN_HARNESS_ROOT/scripts/bash"
RV="$S/tenant-registry-verify.sh"
TC="$S/tenant-crypt.sh"
WORK="$(mktemp -d)"
trap 'rm -rf "$WORK"' EXIT
export CASAN_TENANT_STATE_ROOT="$WORK/tenants"

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-23 Phase 4+5-offline: signed registry + per-tenant crypt ====="

# keys
openssl genrsa -out "$WORK/reg.priv.pem" 2048 2>/dev/null
openssl rsa -in "$WORK/reg.priv.pem" -pubout -out "$WORK/reg.pub.pem" 2>/dev/null
openssl genrsa -out "$WORK/attacker.priv.pem" 2048 2>/dev/null

# --- 23.9 registry sign/verify ---
printf '{"tenants":["alpha","beta"]}\n' > "$WORK/reg1.json"
bash "$RV" sign "$WORK/reg1.json" "$WORK/reg.priv.pem" >/dev/null 2>&1
[[ "$(rc_of bash "$RV" verify "$WORK/reg1.json" "$WORK/reg.pub.pem")" -eq 0 ]] \
  && pass "23.9 valid signed registry verifies" || fail "23.9 valid registry rejected"

cp "$WORK/reg1.json" "$WORK/reg2.json"; bash "$RV" sign "$WORK/reg2.json" "$WORK/reg.priv.pem" >/dev/null 2>&1
printf '{"tenants":["alpha","beta","evil"]}\n' > "$WORK/reg2.json"   # tamper after signing
[[ "$(rc_of bash "$RV" verify "$WORK/reg2.json" "$WORK/reg.pub.pem")" -eq 2 ]] \
  && pass "23.9 tampered registry is REFUSED" || fail "23.9 tampered registry accepted"

cp "$WORK/reg1.json" "$WORK/reg3.json"; bash "$RV" sign "$WORK/reg3.json" "$WORK/attacker.priv.pem" >/dev/null 2>&1
[[ "$(rc_of bash "$RV" verify "$WORK/reg3.json" "$WORK/reg.pub.pem")" -eq 2 ]] \
  && pass "23.9 forged (wrong-key) registry is REFUSED" || fail "23.9 forged registry accepted"

cp "$WORK/reg1.json" "$WORK/reg4.json"   # no .sig produced
[[ "$(rc_of bash "$RV" verify "$WORK/reg4.json" "$WORK/reg.pub.pem")" -eq 3 ]] \
  && pass "23.9 UNSIGNED registry fails CLOSED (refused)" || fail "23.9 unsigned registry not refused"

# --- 23.10 per-tenant encryption at rest ---
SECRET="SECRET-A-audit-line-12345"
printf '%s\n' "$SECRET" > "$WORK/pa.txt"
CASAN_TENANT_ID=alpha bash "$TC" encrypt "$WORK/pa.txt" "$WORK/ca.enc" >/dev/null 2>&1
grep -q "$SECRET" "$WORK/ca.enc" 2>/dev/null \
  && fail "23.10 plaintext leaked into ciphertext" \
  || pass "23.10 tenant A state is ciphertext on disk (no plaintext)"

CASAN_TENANT_ID=alpha bash "$TC" decrypt "$WORK/ca.enc" "$WORK/da.txt" >/dev/null 2>&1
grep -q "$SECRET" "$WORK/da.txt" 2>/dev/null \
  && pass "23.10 tenant A decrypts its own state (roundtrip)" || fail "23.10 tenant A roundtrip failed"

CASAN_TENANT_ID=beta bash "$TC" decrypt "$WORK/ca.enc" "$WORK/db.txt" >/dev/null 2>&1 || true
grep -q "$SECRET" "$WORK/db.txt" 2>/dev/null \
  && fail "23.10 tenant B read tenant A's plaintext (isolation broken)" \
  || pass "23.10 tenant B CANNOT read tenant A's plaintext (per-tenant key)"

echo ""
echo "===== SEC-23 Phase 4+5-offline SUMMARY: PASS=$PASS FAIL=$FAIL ====="
[[ "$FAIL" -eq 0 ]] || exit 1