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

PATH="/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:${PATH:-}"
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
ROOT_DIR="$(cd "${SCRIPT_DIR}/../.." && pwd)"
ENV_FILE="${ROOT_DIR}/.env"
BACKUP_DIR="${BACKUP_DIR:-/volume1/naurua_db_backups/dev}"
FILE_PREFIX="${FILE_PREFIX:-erpnaurua_dev}"
DOCKER_BIN="${DOCKER_BIN:-$(command -v docker || true)}"
DOCKER_CMD=()

if [[ ! -f "${ENV_FILE}" ]]; then
  echo "Missing environment file: ${ENV_FILE}" >&2
  exit 1
fi

set -a
# shellcheck disable=SC1090
. "${ENV_FILE}"
set +a

for required_var in DB_HOST DB_PORT DB_NAME DB_USER DB_PASSWORD; do
  if [[ -z "${!required_var:-}" ]]; then
    echo "Missing required database setting: ${required_var}" >&2
    exit 1
  fi
done

if [[ -z "${DOCKER_BIN}" || ! -x "${DOCKER_BIN}" ]]; then
  echo "Docker is required for the PostgreSQL client container." >&2
  exit 1
fi
if "${DOCKER_BIN}" info >/dev/null 2>&1; then
  DOCKER_CMD=("${DOCKER_BIN}")
elif sudo -n "${DOCKER_BIN}" info >/dev/null 2>&1; then
  DOCKER_CMD=(sudo -n "${DOCKER_BIN}")
else
  echo "Docker daemon is not accessible for this user." >&2
  exit 1
fi

mkdir -p "${BACKUP_DIR}"
timestamp="$(date +%Y%m%d_%H%M%S)"
output_file="${BACKUP_DIR}/${FILE_PREFIX}_${DB_NAME}_${timestamp}.dump"
temporary_file="${output_file}.tmp"

cleanup() { rm -f "${temporary_file}"; }
trap cleanup EXIT

export BACKUP_DIR
"${DOCKER_CMD[@]}" run --rm --network host \
  --env-file "${ENV_FILE}" \
  -e "PGHOST=${DB_HOST}" \
  -e "PGPORT=${DB_PORT}" \
  -e "PGDATABASE=${DB_NAME}" \
  -e "PGUSER=${DB_USER}" \
  -e "PGPASSWORD=${DB_PASSWORD}" \
  -v "${BACKUP_DIR}:/backup" \
  postgres:17.7-alpine \
  pg_dump --format=custom --no-owner --no-privileges --file=/backup/current.dump

if [[ ! -s "${BACKUP_DIR}/current.dump" ]]; then
  echo "Backup failed: container dump file is empty." >&2
  exit 1
fi

mv -f "${BACKUP_DIR}/current.dump" "${temporary_file}"

if [[ ! -s "${temporary_file}" ]]; then
  echo "Backup failed: dump file is empty." >&2
  exit 1
fi

mv -f "${temporary_file}" "${output_file}"
trap - EXIT

find "${BACKUP_DIR}" -maxdepth 1 -type f -name "${FILE_PREFIX}_${DB_NAME}_*.dump" \
  -printf '%T@ %p\n' | sort -nr | tail -n +21 | cut -d' ' -f2- | xargs -r rm -f

printf '%s\n' "Backup created: ${output_file}"