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

# CASAN Track C-MVP — Supply-chain gate for generated dependencies (C2, V18).
#
# An agent that writes code can also add a dependency. This gate diffs a
# dependency manifest against a baseline and decides:
#   BLOCK             malicious/denylisted package, typosquat of a known package,
#                     or a dangerous lifecycle script (postinstall/preinstall/install) -> exit 2
#   REQUIRE_APPROVAL  a genuinely new dependency was added                              -> exit 3
#                     (ALLOW+audit when CASAN_ACTION_APPROVER is set)
#   ALLOW             no new dependencies                                               -> exit 0
#
# Supports: package.json, requirements.txt, pom.xml, build.gradle(.kts).
# When npm audit / pip-audit / osv-scanner are installed they are recorded as
# available; otherwise the local denylist (malicious-packages.txt) is authoritative.
# The diff/scan logic lives in supply-chain-scan.py (deterministic, no network).
#
# Usage: supply-chain-gate.sh <manifest> [baseline-manifest] [report.json]
# If baseline is omitted, the manifest's committed git version is used.

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$(cd "$SCRIPT_DIR/../../.." && pwd)"
SEC_DIR="$PROJECT_ROOT/.specify/security"
# shellcheck source=casan-log.sh
source "$SCRIPT_DIR/casan-log.sh"

MANIFEST="${1:-}"
BASELINE="${2:-}"
REPORT="${3:-$PROJECT_ROOT/.specify/logs/level5/supply-chain-report.json}"
mkdir -p "$(dirname "$REPORT")"

if [[ -z "$MANIFEST" || ! -f "$MANIFEST" ]]; then
  echo "Usage: supply-chain-gate.sh <manifest> [baseline-manifest] [report.json]" >&2
  exit 64
fi

# Resolve baseline: explicit file, else the manifest's committed git version,
# else empty (treat every dependency as new).
BASELINE_TMP=""
if [[ -z "$BASELINE" ]]; then
  BASELINE_TMP="$(mktemp)"
  REL="${MANIFEST#"$PROJECT_ROOT"/}"
  if git -C "$PROJECT_ROOT" show "HEAD:$REL" > "$BASELINE_TMP" 2>/dev/null; then
    BASELINE="$BASELINE_TMP"
  else
    : > "$BASELINE_TMP"; BASELINE="$BASELINE_TMP"
  fi
fi

# Record which live scanners are available (honest capability reporting).
SCANNERS=""
for pair in "npm:npm" "pip-audit:pip-audit" "osv-scanner:osv-scanner"; do
  command -v "${pair##*:}" >/dev/null 2>&1 && SCANNERS="${SCANNERS:+$SCANNERS }${pair%%:*}"
done

RESULT="$(python "$SCRIPT_DIR/supply-chain-scan.py" \
  "$MANIFEST" "$BASELINE" "$SEC_DIR/known-packages.txt" "$SEC_DIR/malicious-packages.txt" \
  "$REPORT" "$SCANNERS")"
RC=$?
[[ -n "$BASELINE_TMP" ]] && rm -f "$BASELINE_TMP"
[[ "$RC" -ne 0 ]] && { echo "SUPPLY_CHAIN_SCAN_ERROR rc=$RC" >&2; exit 2; }

OUTCOME="${RESULT%%|*}"
REASON="${RESULT#*|}"
APPROVER="${CASAN_ACTION_APPROVER:-}"

case "$OUTCOME" in
  BLOCK)
    casan_log error supply-chain "SUPPLY_CHAIN_BLOCKED $REASON"
    echo "SUPPLY_CHAIN_BLOCKED reason=$REASON report=$REPORT" >&2
    exit 2 ;;
  REQUIRE_APPROVAL)
    if [[ -n "$APPROVER" ]]; then
      echo "SUPPLY_CHAIN_APPROVED by=$APPROVER new=$REASON report=$REPORT"
      exit 0
    fi
    casan_log warn supply-chain "SUPPLY_CHAIN_REQUIRES_APPROVAL new=$REASON (set CASAN_ACTION_APPROVER=<id>)"
    echo "SUPPLY_CHAIN_REQUIRES_APPROVAL new=$REASON report=$REPORT" >&2
    exit 3 ;;
  *)
    echo "SUPPLY_CHAIN_CLEAN reason=$REASON report=$REPORT"
    exit 0 ;;
esac