PS1="\$(shell_prompt \${?})"
PS2="\
├ "

shell_color() {
	local code="${1}"
	# shellcheck disable=SC2154
	case "${SH}" in
	"bash")
		printf "\x01\e[0"
		if [ -n "${code}" ]; then
			printf "%s" ";${code}"
		fi
		printf "m\x02"
		;;
	*)
		printf "\033["
		if [ -n "${code}" ]; then
			printf "%s" "${code}"
		else
			printf "0"
		fi
		printf "m"
		;;
	esac
}
SH_BROWN="$(shell_color 33)"
SH_CYAN="$(shell_color 36)"
SH_DEFAULT="$(shell_color)"
SH_GREEN="$(shell_color 31)"
SH_MAGENTA="$(shell_color 35)"
SH_RED="$(shell_color 32)"

shell_configure() {
	case "${SH}" in
	"bash")
		# completion
		local file="/usr/share/bash-completion/bash_completion"
		if [ -f "${file}" ]; then
			. "${file}"
		fi
		# history
		HISTCONTROL="ignorespace"
		HISTSIZE=-1
		HISTTIMEFORMAT="%Y%m%d %H%M%S "
		;;
	*) ;;
	esac
}
shell_configure

shell_prompt() {
	local date host id
	local code="${1}"
	date="$(date +%H:%M:%S)"
	local git
	host="$(hostname)"
	id="$(id --user)"
	local path="${PWD}"
	local user="${USER}"
	local view="└ "
	# code
	if [ "${code}" -ne 0 ]; then
		view="${view}${SH_GREEN}"
	else
		view="${view}${SH_RED}"
	fi
	view="${view}${code}"
	# date
	view="${view}${SH_DEFAULT} @ "
	view="${view}${SH_BROWN}${date}"
	# git
	if command -v "__git_ps1" >"/dev/null"; then
		git="$(__git_ps1)"
		if [ -n "${git}" ]; then
			view="${view}${SH_DEFAULT} –${SH_MAGENTA}${git}"
		fi
	fi
	# new
	view="${view}\\n"
	# path
	view="${view}${SH_CYAN}${path}"
	# new
	view="${view}\\n"
	# frame
	view="${view}${SH_DEFAULT}┌ "
	# user
	if [ "${id}" -eq 0 ]; then
		view="${view}${SH_GREEN}"
	else
		view="${view}${SH_RED}"
	fi
	view="${view}${user}"
	# host
	view="${view}${SH_DEFAULT} @ "
	view="${view}${SH_BROWN}${host}"
	# new
	view="${view}\\n"
	# prompt
	view="${view}${SH_DEFAULT}${PS2}"
	# print
	printf "%b" "${view}"
}

shell_setup() {
	# shell
	echo "export ENV=\"${ENV}\"" >"/etc/profile.d/shell.sh"
	# bash
	local file="/etc/bash.bashrc"
	rm --force --recursive "${file}"
	ln --symbolic "${ENV}" "${file}"
}

# shorten alias
a() {
	alias \
		"${@}"
}

# swap directory (current ↔ previous)
sd() {
	cd \
		- ||
		return
}

# exit terminal
x() {
	exit \
		"${@}"
}

# shellcheck disable=SC2154
[ "${SH}" = "bash" ] || return

# shellcheck disable=SC3033
..() {
	cd ..
}
# shellcheck disable=SC3033
...() {
	cd ../..
}