#!/bin/sh
set -eu

usage() {
	cat <<-'EOF'
		Usage:
		  url-for [CONTENT...]
		  url-for -h
	EOF
}

help() {
	cat <<-'EOF'

		Options:
		  -h, --help    show this message

		  CONTENT       literal strings to be transformed into URLs


		Build an URL without the $domain part, adding the required
		$base_url.  If CONTENT is not given, get data from STDIN.


		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:

		    $ echo 'img/link.svg' | url-for
		    /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/base.conf


url() {
	sed \
		-e "s|^$CONTENT_PREFIX/||" \
		-e 's|\.md|.html|'   \
		-e 's|\.page|.html|' \
		-e 's|^/||' |
	printf '%s%s\n' "${base_url:-/}" "$(cat -)"
}

if [ $# = 0 ]; then
	url
else
	for f in "$@"; do
		if [ "$f" = '/' ]; then
			f=''
		fi
		printf '%s\n' "$f" | url
	done
fi