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

repo_root="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
# shellcheck source=scripts/apk/package-lib.sh
. "${repo_root}/scripts/apk/package-lib.sh"

repo_name="${ALPINE_REPO_NAME:-local}"
alpine_version="${ALPINE_VERSION:-3.24}"
arches="${ALPINE_SECURITY_ARCHES:-${ALPINE_ARCHES:-x86_64}}"
reports_dir="${APK_SECURITY_REPORTS_DIR:-${repo_root}/packages/security-reports}"
trivy_bin="${TRIVY_BIN:-trivy}"

require_command() {
  command -v "$1" >/dev/null 2>&1 || {
    printf 'missing required command: %s\n' "$1" >&2
    exit 2
  }
}

platform_for_arch() {
  case "$1" in
    x86_64) printf '%s\n' 'linux/amd64' ;;
    aarch64) printf '%s\n' 'linux/arm64' ;;
    *) printf 'unsupported Alpine architecture: %s\n' "$1" >&2; return 2 ;;
  esac
}

install_rootfs() {
  local rootfs="$1"
  local arch="$2"
  shift 2
  local -a specs=("$@")
  local -a apk_args=(--root "${rootfs}/installed" --initdb --no-scripts --arch "${arch}")
  local key_dir repo_file

  key_dir="${rootfs}/keys"
  repo_file="${rootfs}/repositories"
  mkdir -p "${key_dir}"
  cp /etc/apk/keys/*.pub "${key_dir}/"
  cp "${repo_root}/packages/${repo_name}/${arch}"/*.rsa.pub "${key_dir}/"
  {
    printf 'https://dl-cdn.alpinelinux.org/alpine/v%s/main\n' "${alpine_version}"
    printf 'https://dl-cdn.alpinelinux.org/alpine/v%s/community\n' "${alpine_version}"
    printf 'file://%s/packages/%s\n' "${repo_root}" "${repo_name}"
  } > "${repo_file}"

  if [[ "$(id -u)" != 0 ]]; then
    apk_args+=(--usermode)
  fi
  apk "${apk_args[@]}" --keys-dir "${key_dir}" --repositories-file "${repo_file}" \
    add --no-cache "${specs[@]}"
}

install_rootfs_docker() {
  local rootfs="$1"
  local arch="$2"
  shift 2
  local platform

  platform="$(platform_for_arch "${arch}")"
  docker run --rm --platform "${platform}" \
    --user "$(id -u):$(id -g)" \
    -e REPO_NAME="${repo_name}" \
    -e ALPINE_ARCH="${arch}" \
    -e ALPINE_VERSION="${alpine_version}" \
    -v "${repo_root}:/work:ro" \
    -v "${rootfs}:/scan" \
    "alpine:${alpine_version}" \
    sh -ec '
      mkdir -p /scan/keys
      cp /etc/apk/keys/*.pub /scan/keys/
      cp /work/packages/"$REPO_NAME"/"$ALPINE_ARCH"/*.rsa.pub /scan/keys/
      {
        printf "https://dl-cdn.alpinelinux.org/alpine/v%s/main\\n" "$ALPINE_VERSION"
        printf "https://dl-cdn.alpinelinux.org/alpine/v%s/community\\n" "$ALPINE_VERSION"
        printf "file:///work/packages/%s\\n" "$REPO_NAME"
      } > /scan/repositories
      apk --root /scan/installed --usermode --initdb --no-scripts --arch "$ALPINE_ARCH" \
        --keys-dir /scan/keys --repositories-file /scan/repositories \
        add --no-cache "$@"
    ' security-report "$@"
}

write_summary() {
  local report="$1"
  local summary="$2"
  local package_name="$3"
  local arch="$4"
  local total

  total="$(jq '[.Results[]?.Vulnerabilities[]?] | length' "${report}")"
  {
    printf '# %s (%s) security report\n\n' "${package_name}" "${arch}"
    printf 'Installed APK rootfs scanned with Trivy. Findings are advisory.\n\n'
    printf '| Severity | Count |\n| --- | ---: |\n'
    for severity in CRITICAL HIGH MEDIUM LOW UNKNOWN; do
      printf '| %s | %s |\n' "${severity}" \
        "$(jq --arg severity "${severity}" '[.Results[]?.Vulnerabilities[]? | select(.Severity == $severity)] | length' "${report}")"
    done
    printf '\nTotal vulnerabilities: %s\n' "${total}"
  } > "${summary}"
}

print_report() {
  local report_dir="$1"
  local package_name="$2"
  local arch="$3"

  printf '\nSecurity reports for %s (%s):\n' "${package_name}" "${arch}"
  printf '  Trivy: file://%s/trivy.json\n' "${report_dir}"
  printf '  SBOM: file://%s/sbom.cdx.json\n' "${report_dir}"
  printf '  Summary: file://%s/summary.md\n' "${report_dir}"
  cat "${report_dir}/summary.md"
  printf '\n'
}

require_command "${trivy_bin}"
require_command jq

if ! command -v apk >/dev/null 2>&1; then
  require_command docker
fi

tmpdir="$(mktemp -d)"
cleanup() {
  rm -rf "${tmpdir}"
}
trap cleanup EXIT

while IFS= read -r package_dir; do
  apk_validate_package_dir "${package_dir}"
  package_name="$(apk_package_name "${package_dir}")"

  for arch in ${arches}; do
    apk_package_supports_arch "${package_dir}" "${arch}" || continue
    repo_dir="${repo_root}/packages/${repo_name}/${arch}"
    if [[ ! -f "${repo_dir}/APKINDEX.tar.gz" ]] || ! compgen -G "${repo_dir}/*.rsa.pub" >/dev/null; then
      printf 'missing signed local repository for %s: %s\n' "${package_name}" "${repo_dir}" >&2
      exit 1
    fi

    mapfile -t specs < <(
      apk_package_versioned_names "${package_dir}" "${arch}" | sed 's/=.*//'
    )
    specs=(alpine-baselayout "${specs[@]}")
    report_dir="${reports_dir}/${package_name}/${arch}"
    rootfs="${tmpdir}/${package_name}-${arch}"
    mkdir -p "${report_dir}" "${rootfs}"

    printf 'Generating security reports for %s (%s)\n' "${package_name}" "${arch}"
    if command -v apk >/dev/null 2>&1; then
      install_rootfs "${rootfs}" "${arch}" "${specs[@]}"
    else
      install_rootfs_docker "${rootfs}" "${arch}" "${specs[@]}"
    fi

    "${trivy_bin}" filesystem --distro "alpine/${alpine_version}" --scanners vuln --format json --no-progress \
      --output "${report_dir}/trivy.json" "${rootfs}/installed"
    "${trivy_bin}" filesystem --distro "alpine/${alpine_version}" --scanners vuln --format cyclonedx --no-progress \
      --output "${report_dir}/sbom.cdx.json" "${rootfs}/installed"
    jq -e 'type == "object" and has("ArtifactName")' "${report_dir}/trivy.json" >/dev/null
    jq -e '.bomFormat == "CycloneDX"' "${report_dir}/sbom.cdx.json" >/dev/null
    write_summary "${report_dir}/trivy.json" "${report_dir}/summary.md" "${package_name}" "${arch}"
    print_report "${report_dir}" "${package_name}" "${arch}"
  done
done < <(apk_package_dirs "${repo_root}")