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

# CASAN Plan-16 SEC-24 (SC-05/06, offline) — supply-chain build-file integrity.
#
# Proves (no network):
#   * image-pin: a Dockerfile/workflow using a floating tag (`:latest`, `:20`, or no
#     tag) is a violation; digest-pinned (`@sha256:`) and `scratch`/build-stage names
#     are OK,
#   * sign/verify: a signed workflow verifies; tampered/forged/UNSIGNED is REFUSED.
#
# Deterministic; hermetic; uses openssl (skip-aware).

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$SCRIPT_DIR/../scripts/bash/casan-paths.sh"
PROJECT_ROOT="$CASAN_APP_ROOT"
SCI="$CASAN_HARNESS_ROOT/scripts/bash/supply-chain-integrity.sh"
WORK="$(mktemp -d)"
trap 'rm -rf "$WORK"' EXIT
DIG="sha256:$(printf 'a%.0s' {1..64})"

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; }

echo "===== Plan-16 SEC-24: supply-chain build-file integrity (offline) ====="

# --- image-pin: floating tag -> violation ---
printf 'FROM ubuntu:latest\nRUN echo hi\n' > "$WORK/Dockerfile.bad"
[[ "$(rc_of bash "$SCI" image-pin "$WORK/Dockerfile.bad")" -eq 2 ]] \
  && pass "floating tag (:latest) flagged as unpinned" || fail "floating tag not flagged"

printf 'FROM node:20\n' > "$WORK/Dockerfile.tag"
[[ "$(rc_of bash "$SCI" image-pin "$WORK/Dockerfile.tag")" -eq 2 ]] \
  && pass "version tag without digest flagged" || fail "version tag not flagged"

# --- image-pin: digest-pinned + scratch + build stage -> OK ---
printf 'FROM scratch\nFROM ubuntu@%s AS base\nFROM base\nRUN echo ok\n' "$DIG" > "$WORK/Dockerfile.ok"
[[ "$(rc_of bash "$SCI" image-pin "$WORK/Dockerfile.ok")" -eq 0 ]] \
  && pass "digest-pinned + scratch + build-stage accepted (no false positive)" || fail "pinned Dockerfile wrongly flagged"

# --- workflow image ---
printf 'jobs:\n  build:\n    image: node:20\n' > "$WORK/wf.bad.yml"
[[ "$(rc_of bash "$SCI" image-pin "$WORK/wf.bad.yml")" -eq 2 ]] \
  && pass "workflow floating image flagged" || fail "workflow floating image not flagged"
printf 'jobs:\n  build:\n    image: node@%s\n' "$DIG" > "$WORK/wf.ok.yml"
[[ "$(rc_of bash "$SCI" image-pin "$WORK/wf.ok.yml")" -eq 0 ]] \
  && pass "workflow digest-pinned image accepted" || fail "workflow pinned image wrongly flagged"

# --- sign / verify workflow ---
command -v openssl >/dev/null 2>&1 || { echo "(openssl absent — skipping sign/verify)"; echo "===== SEC-24 SUMMARY: PASS=$PASS FAIL=$FAIL ====="; [[ "$FAIL" -eq 0 ]] || exit 1; exit 0; }
openssl genrsa -out "$WORK/wf.priv.pem" 2048 2>/dev/null
openssl rsa -in "$WORK/wf.priv.pem" -pubout -out "$WORK/wf.pub.pem" 2>/dev/null
openssl genrsa -out "$WORK/atk.priv.pem" 2048 2>/dev/null

cp "$WORK/wf.ok.yml" "$WORK/wf1.yml"; bash "$SCI" sign "$WORK/wf1.yml" "$WORK/wf.priv.pem" >/dev/null 2>&1
[[ "$(rc_of bash "$SCI" verify "$WORK/wf1.yml" "$WORK/wf.pub.pem")" -eq 0 ]] \
  && pass "signed workflow verifies" || fail "signed workflow rejected"

cp "$WORK/wf.ok.yml" "$WORK/wf2.yml"; bash "$SCI" sign "$WORK/wf2.yml" "$WORK/wf.priv.pem" >/dev/null 2>&1
printf 'jobs:\n  build:\n    image: evil:latest\n' > "$WORK/wf2.yml"   # tamper after signing
[[ "$(rc_of bash "$SCI" verify "$WORK/wf2.yml" "$WORK/wf.pub.pem")" -eq 2 ]] \
  && pass "tampered workflow REFUSED" || fail "tampered workflow accepted"

cp "$WORK/wf.ok.yml" "$WORK/wf3.yml"   # no signature produced
[[ "$(rc_of bash "$SCI" verify "$WORK/wf3.yml" "$WORK/wf.pub.pem")" -eq 3 ]] \
  && pass "UNSIGNED workflow fails CLOSED" || fail "unsigned workflow not refused"

echo ""
echo "===== SEC-24 SUMMARY: PASS=$PASS FAIL=$FAIL ====="
[[ "$FAIL" -eq 0 ]] || exit 1