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

# CASAN H4 — Tool-output indirect-injection scanner (Track A, V7).
#
# A tool (shell command, file read, web fetch, sub-agent) can return content
# that is then fed back into a downstream model's context. If that content
# carries a prompt injection, the model can be hijacked even though the ORIGINAL
# user input was clean. This scans a tool-output file the same way an untrusted
# artifact is scanned, BEFORE the output is allowed to re-enter model context.
#
# It reuses security-check.sh in `input` mode (block-pattern + unicode/encoding
# normalization + secret detection) but forces the semantic/strict model path
# OFF so the scan is deterministic and needs no model backend — this is a
# pattern scan of machine output, not a user-intent classification.
#
# Usage:
#   tool-output-scan.sh <tool-output-file> [context-label]
# Exit:
#   0  — safe to reuse
#   2  — injection / secret pattern detected (caller should reject/quarantine)
#   64 — usage error (file missing)

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

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

WORK="$(mktemp -d)"; trap 'rm -rf "$WORK"' EXIT
SCAN_OUT="$WORK/tool-output-scan.txt"
TIMESTAMP="$(date -u +"%Y-%m-%dT%H:%M:%SZ")"

# Deterministic pattern scan: semantic + strict explicitly disabled here so a
# tool-output scan never depends on (or is blocked by) model availability.
CASAN_SECURITY_STRICT=0 CASAN_SEMANTIC_CLASSIFY=0 \
  bash "$SCRIPT_DIR/security-check.sh" "$OUTPUT_FILE" "$SCAN_OUT" input >/dev/null 2>&1
SC_RC=$?

if [[ "$SC_RC" -eq 2 ]]; then
  echo "TOOL_OUTPUT_SCAN_BLOCKED label=$LABEL file=$OUTPUT_FILE reason=injection_or_secret timestamp=$TIMESTAMP"
  exit 2
elif [[ "$SC_RC" -ne 0 ]]; then
  echo "TOOL_OUTPUT_SCAN_ERROR label=$LABEL rc=$SC_RC" >&2
  exit 2  # fail closed on scan error
fi

echo "TOOL_OUTPUT_SCAN_CLEAN label=$LABEL file=$OUTPUT_FILE timestamp=$TIMESTAMP"
exit 0