#!/usr/bin/env bash

set -euo pipefail

FLAKE=
TARGET=
ON_NEXT_BOOT=
USE_SUBSTITUTES="1"
USE_REMOTE_SUDO="1"

ARGS=()
OPTS=()

while [[ $# -gt 0 ]]; do
	case $1 in
	--flake)
		FLAKE="$2"
		shift
		shift
		;;
	--target)
		TARGET="$2"
		shift
		shift
		;;
	--on-next-boot)
		ON_NEXT_BOOT="1"
		shift
		;;
	--use-substitutes)
		USE_SUBSTITUTES="1"
		shift
		;;
	--no-use-substitutes)
		USE_SUBSTITUTES=""
		shift
		;;
	--use-remote-sudo)
		USE_REMOTE_SUDO="1"
		shift
		;;
	--no-use-remote-sudo)
		USE_REMOTE_SUDO=""
		shift
		;;
	--)
		shift
		OPTS=( "$@" )
		break
		;;
	-*)
		echo "unknown option: $1"
		exit 1
		;;
	*)
		ARGS+=("$1")
		shift
		;;
	esac
done

set -- "${ARGS[@]}"

if [[ -z ${FLAKE} ]]; then
	# Flake not specified, use working directory
	FLAKE="$(pwd)"
fi

FLAKE_STORE_PATH="$(nix flake archive --json "${FLAKE}" | jq -r .path)"

if [[ "${#ARGS[@]}" -lt 1 ]]; then
	echo "Command not specified"
	exit 1
fi
COMMAND="${ARGS[0]}"

if [[ "${COMMAND}" != "apply" && "${COMMAND}" != "build" && "${COMMAND}" != "exec" ]]; then
	echo "Unsupported command: ${COMMAND}"
	exit 1
fi

if [[ "${#ARGS[1]}" -lt 2 ]]; then
	echo "Host not specified"
	exit 1
fi
HOST="${ARGS[1]}"

if [[ -z ${TARGET} ]]; then
	# Use fqdn as target
	TARGET="$(nix --extra-experimental-features "nix-command flakes" eval --raw "${FLAKE_STORE_PATH}#nixosConfigurations.${HOST}" --apply "host: host.config.networking.fqdn")"
fi

APPLY_OPTS=()

if [[ -n "${USE_SUBSTITUTES}" ]]; then
	APPLY_OPTS+=("--use-substitutes")
fi

if [[ -n "${USE_REMOTE_SUDO}" ]]; then
	APPLY_OPTS+=("--use-remote-sudo")
fi

APPLY_OPERATION="switch"

if [[ -n "${ON_NEXT_BOOT}" ]]; then
	APPLY_OPERATION="boot"
fi

case "${COMMAND}" in
apply)
	nixos-rebuild "${APPLY_OPERATION}" --flake "${FLAKE_STORE_PATH}#${HOST}" --target-host "${TARGET}" "${APPLY_OPTS[@]}"
	;;
build)
	nixos-rebuild build --flake "${FLAKE_STORE_PATH}#${HOST}"
	;;
exec)
	# shellcheck disable=SC2029
	ssh -t "${TARGET}" "${OPTS[@]}"
	;;
*)
	echo "Unsupported command: ${COMMAND}"
	exit 1
	;;
esac