#!/usr/bin/env bash
# Recompute sha256sums for a PKGBUILD, single- or multi-arch.
#
#   usage: update-checksums.sh [--remote] [package-dir]
#
#     --remote   also re-download and re-hash remote sources.
#                Without it only local repo files (.desktop, icons) are
#                re-hashed, which needs no network and is what lets a
#                hand-edited repo self-correct on every nightly run.
#
# sha256 only: sha1sums/md5sums are retired and actively removed.
#
# Why this does not shell out to `makepkg -g` / `updpkgsums`: those generate
# every arch array in one pass and download all arches into a single directory.
# When two arches rename to the same target (`foo.AppImage::url-amd64`,
# `foo.AppImage::url-arm64`) the second arch finds the first arch's file
# already present, skips the download, and emits an sha256sums_aarch64
# identical to sha256sums_x86_64 -- silently wrong. Overriding CARCH does not
# help; makepkg.conf resets it, and --config still downloads every arch.

set -euo pipefail

_here="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
# shellcheck source=common.sh
source "${_here}/common.sh"

refresh_remote=0
if [ "${1-}" = "--remote" ]; then refresh_remote=1; shift; fi

pkgdir="${1:-.}"
pkgbuild="${pkgdir}/PKGBUILD"
[ -f "$pkgbuild" ] || die "no PKGBUILD in ${pkgdir}"

export DL_CACHE="${DL_CACHE:-$(mktemp -d)}"

mapfile -t arches < <(pkgbuild_array "$pkgbuild" arch)

# Build the work list: every source array present, paired with its sums array.
# Single-arch is just the degenerate case of the same loop -- no special path.
pairs=()
if pkgbuild_has_array "$pkgbuild" source; then
  pairs+=("source:sha256sums")
fi
for a in "${arches[@]}"; do
  [ "$a" = "any" ] && continue
  if pkgbuild_has_array "$pkgbuild" "source_${a}"; then
    pairs+=("source_${a}:sha256sums_${a}")
  fi
done

[ "${#pairs[@]}" -gt 0 ] || die "PKGBUILD declares no source arrays"

for pair in "${pairs[@]}"; do
  src_arr="${pair%%:*}"
  sum_arr="${pair##*:}"

  mapfile -t entries < <(pkgbuild_array "$pkgbuild" "$src_arr")
  [ "${#entries[@]}" -gt 0 ] || continue

  mapfile -t existing < <(pkgbuild_array "$pkgbuild" "$sum_arr")

  # If the existing sums don't line up with the sources we cannot reuse any of
  # them by index, so everything must be recomputed.
  reuse=1
  if [ "${#existing[@]}" -ne "${#entries[@]}" ]; then reuse=0; fi

  log "${src_arr} -> ${sum_arr} (${#entries[@]} source(s))"

  sums=()
  for i in "${!entries[@]}"; do
    entry="${entries[$i]}"
    loc="$(source_loc "$entry")"

    if is_vcs "$entry"; then
      sum="SKIP"
      info "$(source_name "$entry") SKIP (vcs)"
    elif is_remote "$entry"; then
      if [ "$refresh_remote" -eq 1 ] || [ "$reuse" -eq 0 ] \
         || [ -z "${existing[$i]:-}" ] || [ "${existing[$i]}" = "SKIP" ]; then
        path="$(download_cached "$loc")"
        sum="$(sha256sum "$path" | awk '{print $1}')"
        info "$(source_name "$entry") ${sum}"
      else
        sum="${existing[$i]}"
        info "$(source_name "$entry") ${sum} (kept)"
      fi
    else
      # A file that lives in the package repo itself.
      [ -f "${pkgdir}/${loc}" ] || die "local source '${loc}' not found in ${pkgdir}"
      sum="$(sha256sum "${pkgdir}/${loc}" | awk '{print $1}')"
      info "${loc} ${sum} (local)"
    fi
    sums+=("$sum")
  done

  replace_array "$pkgbuild" "$sum_arr" "${sums[@]}"
done

# Retire the legacy digests wherever they still appear.
for a in "" "${arches[@]}"; do
  suffix="${a:+_$a}"
  for algo in sha1sums md5sums sha224sums sha384sums sha512sums b2sums; do
    remove_array "$pkgbuild" "${algo}${suffix}"
  done
done