#!/bin/bash

set -euo pipefail

getStackAction() {
	local stackName=$1
	local region=$2
	local command="create"

	aws cloudformation describe-stacks \
		--stack-name "${stackName}" \
		--output text \
		--region "${region}" &> /dev/null

	# shellcheck disable=SC2181
	if [[ $? -eq 0 ]]; then
		command="update"
	fi

	echo "${command}"
}

checkError() {
	# shellcheck disable=SC2181
	if [[ $? -ne 0 ]]; then
		echo "$1"
		exit 1
	fi
}

usage() {
	cat << USAGE
Updates or creates a CloudFormation stack

Usage: $0 [--region region] template.yaml

Options:

  --region region  The region to create/update the stack in (us-west-2)
  -h|--help        Show this message

Example:
  $0 path/to/template.yaml
USAGE
}

main() {
	local cfnFile=
	local region=us-west-2

	parseArgs() {
		while [[ $# -gt 0 ]]; do
			local key="$1"
			shift

			case "${key}" in
				-h | --help)
					usage
					exit 0
					;;
				--region)
					region=$1
					shift
					;;
				*)
					if [[ -n "${cfnFile}" ]]; then
						echo "only one template file allowed"
						exit 1
					fi
					cfnFile="${key}"
					;;
			esac
		done
	}

	parseArgs "$@"

	if [[ ! -f "${cfnFile}" ]]; then
		echo "template \"${cfnFile}\" does not exist"
		exit 1
	fi

	local stackName
	stackName=$(basename "${cfnFile%.*}")

	local action
	action=$(getStackAction "${stackName}" "${region}")
	local command=
	local extraOpts=
	if [ "${action}" = "create" ]; then
		command="create-stack"
		extraOpts="--on-failure DO_NOTHING"
	else
		command="update-stack"
	fi

	local shouldContinue
	read -r -p "${action} stack ${stackName} in ${region} (profile: ${AWS_PROFILE}), continue? [y/n] " shouldContinue
	if [ "${shouldContinue}" != "y" ]; then
		echo "ok bye"
		exit
	fi

	aws cloudformation ${command} \
		--stack-name "${stackName}" \
		${extraOpts} \
		--template-body "file://${cfnFile}" \
		--region "${region}" \
		> /dev/null

	checkError "${command} failed"
	echo

	local -r tailStackEvents="node_modules/.bin/tail-stack-events"
	if [ -x "${tailStackEvents}" ]; then
		"${tailStackEvents}" --region "${region}" --stack-name "${stackName}" --die --outputs
	fi

	echo
	echo "finished in ${SECONDS}s"
}

main "$@"