#!/bin/sh
set -eu

script_dir="$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)"
cd "${script_dir}"

usage() {
  echo "Usage: $0 [--build]" >&2
}

build_image=false
case "${1:-}" in
  "")
    ;;
  --build)
    build_image=true
    ;;
  *)
    usage
    exit 2
    ;;
esac

if [ "$#" -gt 1 ]; then
  usage
  exit 2
fi

if [ -f "docker-compose.yml" ]; then
  compose_file="docker-compose.yml"
elif [ -f "compose.yaml" ]; then
  compose_file="compose.yaml"
else
  echo "No supported Compose file found." >&2
  exit 1
fi

compose_backup="${compose_file}.bak"

if [ ! -f "${compose_backup}" ]; then
  echo "Missing deployment Compose backup: ${compose_backup}" >&2
  exit 1
fi

if ! cmp -s "${compose_backup}" "${compose_file}"; then
  echo "${compose_file} differs from ${compose_backup}; refusing to republish." >&2
  diff -u "${compose_backup}" "${compose_file}" >&2 || true
  exit 1
fi

# Restore the deployment-specific Compose file even if a Git operation fails.
restore_compose() {
  cp "${compose_backup}" "${compose_file}"
}
trap restore_compose EXIT

git restore -- "${compose_file}"
git fetch --all --prune
git pull --ff-only

restore_compose
trap - EXIT

docker compose down -v
if [ "${build_image}" = true ]; then
  docker compose up -d --build
else
  docker compose up -d
fi