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

# CASAN WP-S7 — Artifact indirect injection scanner.
# Before a sub-agent reads an artifact (spec, plan, context YAML, etc.),
# this script scans its content for prompt-injection patterns.
# Untrusted content sourced from external systems or user-supplied inputs
# could carry injections that target downstream model calls.
#
# Usage:
#   artifact-scan.sh <artifact-file> [context-label]
#
# Exit:
#   0  — artifact is safe to use
#   2  — injection pattern detected in artifact (pipeline should reject/quarantine)
#   64 — usage error (file missing)

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
ARTIFACT="${1:-}"
LABEL="${2:-unknown-artifact}"

if [[ -z "$ARTIFACT" || ! -f "$ARTIFACT" ]]; then
  echo "Usage: artifact-scan.sh <artifact-file> [context-label]" >&2
  exit 64
fi

WORK="$(mktemp -d)"; trap 'rm -rf "$WORK"' EXIT
SCAN_OUT="$WORK/artifact-scan-out.txt"

# Run security-check.sh in 'input' mode on the artifact — this covers
# blocklist + normalization + semantic (if CASAN_SEMANTIC_CLASSIFY=1).
# We force semantic OFF here so the scan is fast; the caller can enable
# it for high-risk artifacts.
CASAN_SEMANTIC_CLASSIFY="${CASAN_SEMANTIC_CLASSIFY:-0}" \
  bash "$SCRIPT_DIR/security-check.sh" "$ARTIFACT" "$SCAN_OUT" input 2>/dev/null
SC_RC=$?

TIMESTAMP="$(date -u +"%Y-%m-%dT%H:%M:%SZ")"

if [[ "$SC_RC" -eq 2 ]]; then
  echo "ARTIFACT_SCAN_BLOCKED label=$LABEL file=$ARTIFACT reason=injection_detected timestamp=$TIMESTAMP"
  exit 2
elif [[ "$SC_RC" -ne 0 ]]; then
  echo "ARTIFACT_SCAN_ERROR label=$LABEL rc=$SC_RC" >&2
  exit 2  # fail closed on scan error
else
  echo "ARTIFACT_SCAN_CLEAN label=$LABEL file=$ARTIFACT timestamp=$TIMESTAMP"
  exit 0
fi