#!/usr/bin/env bash

set -Eeuo pipefail

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

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"
}

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"
}