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

# CASAN Plan-16 SEC-14 (M-03 / SC-03) — model-digest env-override is NOT trusted
# in enforced mode.
#
# current_digest() honored CASAN_MODEL_DIGEST unconditionally, so an attacker who
# swapped the local model could also set CASAN_MODEL_DIGEST to the pinned value
# and pass verification. Under CASAN_PROFILE=prod (or CASAN_MODEL_DIGEST_STRICT=1)
# the override is ignored and the digest must come from the live model backend.
# This proves:
#   * dev/CI: override still honored (pin + verify deterministic) — regression,
#   * dev/CI: a swapped override is a MISMATCH (control still works),
#   * prod: a forged override equal to the pin is NOT accepted (fail-closed),
#   * strict flag: same enforced behavior without a full prod profile.
#
# Deterministic; hermetic (temp pin file; live backend pointed at a dead port).

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
MDC="$PROJECT_ROOT/.specify/scripts/bash/model-digest-check.sh"
WORK="$(mktemp -d)"
trap 'rm -rf "$WORK"' EXIT

PIN="$WORK/model-digest.pin"
DEAD_OLLAMA="127.0.0.1:1"   # unreachable → live digest fetch fails deterministically

PASS=0; FAIL=0
pass() { echo "PASS: $1"; PASS=$((PASS + 1)); }
fail() { echo "FAIL: $1"; FAIL=$((FAIL + 1)); }

echo "===== Plan-16 SEC-14: model-digest env-override not trusted in enforced mode ====="

# Setup: pin an approved digest in dev mode (override honored).
CASAN_MODEL_DIGEST_PIN="$PIN" CASAN_MODEL_DIGEST="digest-approved" \
  bash "$MDC" pin ornith:9b >/dev/null 2>&1

# 1) dev/CI regression: matching override verifies OK.
rc=$(set +e; CASAN_MODEL_DIGEST_PIN="$PIN" CASAN_MODEL_DIGEST="digest-approved" \
  bash "$MDC" verify ornith:9b >/dev/null 2>&1; echo $?)
[[ "$rc" -eq 0 ]] && pass "dev: matching override verifies OK (regression)" \
  || fail "dev: matching override should verify OK (rc=$rc)"

# 2) dev/CI regression: swapped override is a MISMATCH (block).
rc=$(set +e; CASAN_MODEL_DIGEST_PIN="$PIN" CASAN_MODEL_DIGEST="digest-swapped" \
  bash "$MDC" verify ornith:9b >/dev/null 2>&1; echo $?)
[[ "$rc" -eq 2 ]] && pass "dev: swapped override detected as MISMATCH (rc=2)" \
  || fail "dev: swapped override should MISMATCH (rc=$rc)"

# 3) SEC-14 core (prod): a FORGED override equal to the pin must NOT be accepted.
#    Override is ignored; live backend is unreachable → cannot verify (rc=3), never OK.
err="$WORK/prod.err"
rc=$(set +e; CASAN_PROFILE=prod OLLAMA_HOST="$DEAD_OLLAMA" \
  CASAN_MODEL_DIGEST_PIN="$PIN" CASAN_MODEL_DIGEST="digest-approved" \
  bash "$MDC" verify ornith:9b >/dev/null 2>"$err"; echo $?)
[[ "$rc" -ne 0 ]] && pass "prod: forged override not accepted as OK (rc=$rc)" \
  || fail "prod: forged override was accepted (rc=0) — env override still trusted"
grep -q "MODEL_DIGEST_OVERRIDE_IGNORED" "$err" \
  && pass "prod: override explicitly ignored (MODEL_DIGEST_OVERRIDE_IGNORED)" \
  || fail "prod: override was not ignored (no OVERRIDE_IGNORED marker)"

# 4) strict flag: same enforced behavior without a full prod profile.
rc=$(set +e; CASAN_MODEL_DIGEST_STRICT=1 OLLAMA_HOST="$DEAD_OLLAMA" \
  CASAN_MODEL_DIGEST_PIN="$PIN" CASAN_MODEL_DIGEST="digest-approved" \
  bash "$MDC" verify ornith:9b >/dev/null 2>&1; echo $?)
[[ "$rc" -ne 0 ]] && pass "strict: forged override not accepted (rc=$rc)" \
  || fail "strict: forged override accepted (rc=0)"

echo ""
echo "===== SEC-14 SUMMARY: PASS=$PASS FAIL=$FAIL ====="
[[ "$FAIL" -eq 0 ]] || exit 1