#!/bin/sh
set -eu


usage() {
	cat <<-'EOF'
		Usage:
		  url-for FILE
		  url-for -h
	EOF
}

help() {
	cat <<-'EOF'

		Options:
		  -h, --help    show this message

		  FILE          the path for the URL to be constructed


		Build an URL for the given FILE, without the FQDN part, adding
		the required BASE_URL.


		Examples:

		  Get the URL for "static/style.css", when BASE_URL is empty:

		    $ url-for 'static/style.css'
		    /static/style.css


		  Get the URL for "static/favicon.svg", when BASE_URL is "v2":

		    $ url-for 'static/favicon.svg'
		    /v2/static/favicon.svg
	EOF
}


for flag in "$@"; do
	case "$flag" in
		--)
			break
			;;
		--help)
			usage
			help
			exit
			;;
		*)
			;;
	esac
done

while getopts 'h' flag; do
	case "$flag" in
		h)
			usage
			help
			exit
			;;
		*)
			usage >&2
			exit 2
			;;
	esac
done
shift $((OPTIND - 1))

FILE="${1:-}"
eval "$(assert-arg "$FILE" 'FILE')"

. src/development/config.env

printf '%s/%s' "$BASE_URL" "$FILE"