#!/usr/bin/env bash

set -Eeuo pipefail

die() {
  printf 'ERROR: %s\n' "$*" >&2
  exit 1
}

show_help() {
  local script_name="$1"
  local description="$2"
  printf '%s\n' "$description"
  printf 'Usage: %s -v|--version <postgresql-version>\n' "$script_name"
  printf '       %s <postgresql-version>\n' "$script_name"
  printf '       %s --help | -h\n' "$script_name"
}

parse_postgresql_version() {
  local version=""
  local positional_seen=0
  while (($#)); do
    case "$1" in
      -v|--version)
        (($# >= 2)) || die "$1 requires a PostgreSQL version"
        [[ -n "$2" ]] || die "PostgreSQL version must not be empty"
        [[ -z "$version" ]] || die "PostgreSQL version was specified more than once"
        version="$2"
        shift 2
        ;;
      --version=*)
        [[ -n "${1#*=}" ]] || die "PostgreSQL version must not be empty"
        [[ -z "$version" ]] || die "PostgreSQL version was specified more than once"
        version="${1#*=}"
        shift
        ;;
      -*)
        die "unknown option: $1"
        ;;
      *)
        (( positional_seen == 0 )) || die "unexpected argument: $1"
        [[ -z "$version" ]] || die "PostgreSQL version was specified more than once"
        version="$1"
        positional_seen=1
        shift
        ;;
    esac
  done

  [[ -n "$version" ]] || die "PostgreSQL version is required"
  validate_postgresql_version "$version"
  printf '%s\n' "$version"
}

require_tools() {
  local tool
  for tool in "$@"; do
    command -v "$tool" >/dev/null || die "$tool is required"
  done
}

validate_postgresql_version() {
  local version="$1"
  [[ "$version" =~ ^[0-9]+\.[0-9]+([.][0-9]+)?$ ]] ||
    die "invalid PostgreSQL version: $version"
}

latest_tag() {
  local repository="$1"
  local tag

  tag="$(
    curl -fsSL "https://api.github.com/repos/$repository/releases/latest" |
      sed -nE 's/^[[:space:]]*"tag_name":[[:space:]]*"([^"]+)".*/\1/p' |
      head -n 1 || true
  )"
  if [[ -n "$tag" ]]; then
    printf '%s\n' "$tag"
    return
  fi

  curl -fsSL "https://api.github.com/repos/$repository/tags?per_page=1" |
    sed -nE 's/^[[:space:]]*"name":[[:space:]]*"([^"]+)".*/\1/p' |
    head -n 1 || true
}

latest_pgaudit_tag() {
  local repository="$1"
  local major="$2"
  local tag

  tag="$(
    curl -fsSL "https://api.github.com/repos/$repository/tags?per_page=100" |
      sed -nE 's/^[[:space:]]*"name":[[:space:]]*"([^"]+)".*/\1/p' |
      grep -E "^${major//./\\.}\." |
      head -n 1 || true
  )"
  printf '%s\n' "${tag:-$(latest_tag "$repository")}"
}

reset_staging_dir() {
  local staging_dir="$1"
  [[ "$staging_dir" != "/" ]] || die "STAGING_DIR must not be the filesystem root"
  rm -rf -- "$staging_dir"
  mkdir -p "$staging_dir"
}

copy_install_source() {
  local source_directory="$1"
  local prefix="$2"
  local source_name="$3"
  local complete_version
  complete_version="$(basename -- "$prefix")"
  local sources_directory="$SCRIPT_DIR/sources/$complete_version"
  local destination="$sources_directory/$source_name"

  mkdir -p "$sources_directory"
  rm -rf -- "$destination"
  cp -a -- "$source_directory" "$destination"
  printf '%s\n' "$destination"
}

write_install_recipe() {
  local source_directory="$1"
  local postgresql_version="$2"
  local prefix="$3"
  local configure_options="${4:-}"
  local recipe="$source_directory/install_$postgresql_version.sh"

  {
    printf '#!/usr/bin/env bash\n\nset -Eeuo pipefail\n\n'
    printf 'SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"\n'
    printf 'readonly PREFIX=%q\n' "$prefix"
    printf 'readonly POSTGRES_VERSION=%q\n' "$postgresql_version"
    printf 'readonly POSTGRES_CONFIGURE_OPTIONS=%q\n' "$configure_options"
    cat <<'RECIPE_HEADER'
if [[ "${1:-}" == "--help" || "${1:-}" == "-h" ]]; then
  printf 'Re-run the saved installation steps for PostgreSQL %s.\n' "$POSTGRES_VERSION"
  printf 'Usage: %s\n' "$0"
  printf '       %s --help | -h\n' "$0"
  exit 0
fi
[[ $# -eq 0 ]] || {
  printf 'Usage: %s [--help|-h]\n' "$0" >&2
  exit 2
}

readonly PG_CONFIG="$PREFIX/bin/pg_config"
readonly JOBS="${JOBS:-$(nproc)}"

RECIPE_HEADER
    cat
  } > "$recipe"
  chmod +x "$recipe"
  printf 'Saved installation recipe: %s\n' "$recipe"
}

require_postgresql_installation() {
  local prefix="$1"
  local pg_config="$prefix/bin/pg_config"
  [[ "$prefix" != "/" ]] || die "PREFIX must not be the filesystem root"
  [[ -x "$pg_config" ]] || die "PostgreSQL is not installed at $prefix"
}

download_source() {
  local staging_dir="$1"
  local repository="$2"
  local tag="$3"
  local archive_name="$4"
  local source_dir="$5"
  local archive="$staging_dir/$archive_name"

  curl -fL --retry 3 --retry-delay 2 \
    -o "$archive" \
    "https://github.com/$repository/archive/refs/tags/$tag.tar.gz"
  tar -xzf "$archive" -C "$staging_dir"
  [[ -d "$source_dir" ]] || die "source directory was not created: $source_dir"
}

if [[ "${BASH_SOURCE[0]}" == "$0" ]]; then
  if [[ "${1:-}" == "--help" || "${1:-}" == "-h" ]]; then
    printf 'Shared helper functions used by PostgreSQL component installers.\n'
    printf 'This file is sourced by the install scripts and does not install a component.\n'
    exit 0
  fi
  printf 'This helper is not an installer; run a component installer with <postgresql-version>.\n' >&2
  printf 'Usage: %s --help | -h\n' "$0" >&2
  exit 2
fi