#!/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"

arches="${ALPINE_ARCHES:-x86_64 aarch64}"
branch="${ALPINE_REGISTRY_BRANCH:-v${ALPINE_VERSION:-3.24}}"
repository="${ALPINE_REGISTRY_REPOSITORY:-${PACKAGE_NAME:-main}}"
instance_url="${INSTANCE_URL:-}"
owner="${PACKAGE_OWNER:-}"
command_name="${1:-prepare}"
registry_cache="${CI_REGISTRY_CACHE_DIR:-${repo_root}/.cache/ci-registry}"

require_registry_config() {
  local name="$1" value="$2"
  [[ -n "${value}" ]] && return
  printf 'missing required CI registry setting: %s\n' "${name}" >&2
  exit 2
}

registry_url() {
  printf '%s/api/packages/%s/alpine/%s/%s\n' \
    "${instance_url%/}" "${owner}" "${branch}" "${repository}"
}

registry_key_url() {
  printf '%s/api/packages/%s/alpine/key\n' "${instance_url%/}" "${owner}"
}

all_packages() {
  while IFS= read -r package_dir; do
    apk_package_name "${package_dir}"
  done < <(apk_all_package_dirs "${repo_root}")
}

mark_all_packages() {
  printf 'Rebuilding all packages: %s\n' "$1" >&2
  all_packages
}

diff_base() {
  local before="${GITHUB_EVENT_BEFORE:-${CI_COMMIT_BEFORE_SHA:-}}"
  local base_ref="${GITHUB_BASE_REF:-}"

  if [[ -n "${base_ref}" ]] && git rev-parse --verify "origin/${base_ref}" >/dev/null 2>&1; then
    printf '%s...HEAD\n' "origin/${base_ref}"
  elif [[ -n "${before}" && ! "${before}" =~ ^0+$ ]] && git rev-parse --verify "${before}^{commit}" >/dev/null 2>&1; then
    printf '%s..HEAD\n' "${before}"
  elif git rev-parse --verify HEAD^ >/dev/null 2>&1; then
    printf 'HEAD^..HEAD\n'
  else
    return 1
  fi
}

changed_packages() {
  local base changed_paths changed_path package
  declare -A selected=()

  if ! base="$(diff_base)"; then
    mark_all_packages "no usable git diff base"
    return
  fi
  if ! changed_paths="$(git diff --name-only "${base}")"; then
    mark_all_packages "git diff failed for ${base}"
    return
  fi

  while IFS= read -r changed_path; do
    [[ -n "${changed_path}" ]] || continue
    case "${changed_path}" in
      scripts/apk/*|.gitea/workflows/build.yml|mise.toml)
        mark_all_packages "shared build logic changed"
        return
        ;;
      packaging/alpine/local/*)
        package="${changed_path#packaging/alpine/local/}"
        selected["${package%%/*}"]=1
        ;;
    esac
  done <<< "${changed_paths}"

  for package in "${!selected[@]}"; do
    printf '%s\n' "${package}"
  done | sort
}

download_registry_metadata() {
  local arch url

  require_registry_config INSTANCE_URL "${instance_url}"
  require_registry_config PACKAGE_OWNER "${owner}"
  mkdir -p "${registry_cache}"
  url="$(registry_url)"
  for arch in ${arches}; do
    curl --fail --silent --show-error --location \
      --output "${registry_cache}/${arch}.APKINDEX.tar.gz" \
      "${url}/${arch}/APKINDEX.tar.gz"
  done
  curl --fail --silent --show-error --location \
    --output "${registry_cache}/registry.rsa.pub" \
    "$(registry_key_url)"
}

load_registry_index() {
  local arch package_name package_version
  declare -gA registry_packages=()

  for arch in ${arches}; do
    while IFS=$'\t' read -r package_name package_version; do
      [[ -n "${package_name}" && -n "${package_version}" ]] || continue
      registry_packages["${arch}|${package_name}|${package_version}"]=1
    done < <(
      tar -xOzf "${registry_cache}/${arch}.APKINDEX.tar.gz" APKINDEX | awk '
        /^P:/ { package = substr($0, 3); next }
        /^V:/ { if (package != "") print package "\t" substr($0, 3); package = "" }
      '
    )
  done
}

registry_missing_packages() {
  local package_dir package_name arch spec spec_name spec_version missing

  while IFS= read -r package_dir; do
    apk_validate_package_dir "${package_dir}"
    package_name="$(apk_package_name "${package_dir}")"
    missing=0
    for arch in ${arches}; do
      apk_package_supports_arch "${package_dir}" "${arch}" || continue
      while IFS= read -r spec; do
        spec_name="${spec%%=*}"
        spec_version="${spec#*=}"
        if [[ -z "${registry_packages[${arch}|${spec_name}|${spec_version}]:-}" ]]; then
          missing=1
          printf 'Registry miss: %s (%s, %s)\n' "${package_name}" "${arch}" "${spec}" >&2
        fi
      done < <(apk_package_versioned_names "${package_dir}" "${arch}")
    done
    [[ "${missing}" == 1 ]] && printf '%s\n' "${package_name}"
  done < <(apk_all_package_dirs "${repo_root}")
}

prepare() {
  local selected
  declare -A selected_map=()

  download_registry_metadata
  load_registry_index
  while IFS= read -r selected; do
    [[ -n "${selected}" ]] && selected_map["${selected}"]=1
  done < <(changed_packages)
  while IFS= read -r selected; do
    [[ -n "${selected}" ]] && selected_map["${selected}"]=1
  done < <(registry_missing_packages)

  ALPINE_PACKAGES="$(for selected in "${!selected_map[@]}"; do printf '%s\n' "${selected}"; done | sort | xargs)"
  if [[ -n "${ALPINE_PACKAGES}" ]]; then
    ALPINE_SKIP_BUILD=0
    printf 'Selected packages for rebuild: %s\n' "${ALPINE_PACKAGES}"
  else
    ALPINE_SKIP_BUILD=1
    printf 'No packages selected for rebuild: registry satisfies source metadata\n'
  fi

  if [[ -n "${GITHUB_ENV:-}" ]]; then
    {
      printf 'ALPINE_PACKAGES=%s\n' "${ALPINE_PACKAGES}"
      printf 'ALPINE_SKIP_BUILD=%s\n' "${ALPINE_SKIP_BUILD}"
      printf 'ALPINE_REGISTRY_URL=%s\n' "$(registry_url)"
      printf 'ALPINE_REGISTRY_KEY=%s\n' "${registry_cache}/registry.rsa.pub"
    } >> "${GITHUB_ENV}"
  fi
  if [[ -n "${GITHUB_OUTPUT:-}" ]]; then
    if [[ -n "${ALPINE_PACKAGES}" ]]; then
      printf 'packages_selected=true\n' >> "${GITHUB_OUTPUT}"
    else
      printf 'packages_selected=false\n' >> "${GITHUB_OUTPUT}"
    fi
    if [[ " ${ALPINE_PACKAGES} " == *" greptimedb "* ]]; then
      printf 'greptimedb_selected=true\n' >> "${GITHUB_OUTPUT}"
    else
      printf 'greptimedb_selected=false\n' >> "${GITHUB_OUTPUT}"
    fi
  fi
}

case "${command_name}" in
  prepare) prepare ;;
  *) printf 'usage: %s prepare\n' "$0" >&2; exit 2 ;;
esac