# constants

SH_MAIN_NAME="main.sh"
SH_NAME="sh"

SH_ROOT="/etc/${SH_NAME}"

SH_MAIN="${SH_ROOT}/${SH_MAIN_NAME}"

# variables

SH_SHELL="$(cat "/proc/${$}/comm")"
SH_USER="${HOME}/${SH_NAME}"

# private

_sh_ifs_new() {
	SH_IFS="${IFS}"
	IFS="
"
}

_sh_ifs_pop() {
	IFS="${SH_IFS}"
	unset SH_IFS
}

_sh_main_log() {
	if sh_shell_interactive; then
		[ ${#} -gt 0 ] || set -- ""
		local line
		for line in "${@}"; do
			echo "${line}"
		done
	fi
}

# public

# find directory’s files by extension
sh_find_extension() {
	local extension="${1}"
	local root="${2}"
	local file="${3}"
	set -- \
		"${root}" \
		-name "*.${extension}" \
		-type "f"
	[ -n "${file}" ] &&
		set -- "${@}" \
			-not \
			-name "${file}"
	find "${@}" \
		-printf "%P\n" |
		sort
}

# find directory’s sh files
sh_find_sh() {
	sh_find_extension "sh" "${@}"
}

# get functions from file
sh_grep_functions() {
	local file="${1}"
	grep "()" "${file}" |
		cut --delimiter "(" --fields 1
}

# output help message
sh_help() {
	sh_log \
		"sh_… = shell functions" \
		"a__… = aliases" \
		"u__… = user"
}

# test if active shell is in interactive mode
sh_shell_interactive() {
	case "${-}" in
	*i*) ;;
	*) return 1 ;;
	esac
}

sh_source_directory() {
	local path="${1}"
	[ -d "${path}" ] ||
		return 1
	local cmd count module modules
	modules="$(sh_find_sh "${path}" "${SH_MAIN_NAME}")"
	_sh_ifs_new
	count=0
	_sh_main_log "" \
		". ${path}"
	for module in ${modules}; do
		count=$((count + 1))
		_sh_main_log "$(printf "%02d" "${count}") ${module%.sh}"
		module="${path}/${module}"
		# shellcheck disable=SC1090
		. "${module}"
		cmd="$(sh_grep_functions "${module}")"
		if [ -n "${cmd}" ]; then
			[ -n "${CMD}" ] && CMD="${CMD}
"
			CMD="${CMD}${cmd}"
		fi
	done
	_sh_ifs_pop
}

# main

# run initial steps
sh_main() {
	# system root
	if ! sh_source_directory "${SH_ROOT}"; then
		_sh_main_log "Not a directory: ${SH_ROOT}"
		return 1
	fi
	# user root
	sh_source_directory "${SH_USER}"
	# run interactive extras
	if sh_shell_interactive; then
		# check
		sh_log
		sh_shellcheck "${SH_ROOT}"
		# help
		sh_log
		sh_help
	fi
}

# run main function
sh_main