#!/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 $domain part, adding
		the required $base_url.


		Examples:

		  Get the URL for "en/about.html", when $base_url is "v2":

		    $ url-for 'about.html'
		    /v2/en/about.html


		  Get the URL for "static/favicon.svg", when $base_url is empty:

		    $ url-for 'img/link.svg'
		    /img/link.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))

. src/lib.sh

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


if [ "$FILE" = '/' ]; then
	FILE=''
fi

. src/lib/base.conf


printf '%s%s' "${base_url:-/}" "$FILE"