#!/bin/sh -e

main() {
	test -n "$1" || usage
	test -n "$2" || usage

	url="$1"
	head="$2"
	entries="$3"

	feed_start "$head"
	process_entries "$url" "$entries"
	feed_end ""
}

usage() {
	echo "usage:\n\t${0##*/} <header file> <entries file>" >&2
	echo "\tHeader file is tab-delimited: title, subtitle, link, name, email." >&2
	echo "\tEntries file is tab-delimited: title, link, id, updated, summary." >&2
	echo "\tPlease note that entries file will be read in reverse order." >&2
	exit 1
}

feed_start() {
	title=`cut -f 1 ${1}`
	subtitle=`cut -f 2 ${1}`
	link=`cut -f 3 ${1}`
	updated=`date "+%Y-%m-%dT%H:%M:%S.000-05:00"`
	name=`cut -f 4 ${1}`
	email=`cut -f 5 ${1}`

	printf '<?xml version="1.0" encoding="utf-8"?>\n'
	printf '<feed xmlns="http://www.w3.org/2005/Atom">\n'
	printf '\t<title>%s</title>\n' "$title"
	printf '\t<subtitle>%s</subtitle>\n' "$subtitle"
	printf '\t<link href="%s"/>\n' "$link"
	printf '\t<updated>%s</updated>\n' "$updated"
	printf '\t<author>\n'
	printf '\t\t<name>%s</name>\n' "$name"
	printf '\t\t<email>%s</email>\n' "$email"
	printf '\t</author>\n'
	printf '\t<id>%s</id>\n' "$link"
}

process_entries() {
	url=$1
	while IFS= read -r line
	do
		write_entry "$url" "$line"
	done < $2
}

write_entry() {
	url=$1
	title=`echo "$2" | cut -f 3`
	link=`echo "$2" | cut -f 2`
	updated=`echo "$2" | cut -f 1`
	summary=`echo "$2" | cut -f 4`
	
	printf '\t<entry>\n'
	printf '\t\t<title>%s</title>\n' "$title"
	printf '\t\t<link rel="alternate" href="%s%s"/>\n' "$url" "$link"
	printf '\t\t<id>%s%s</id>\n' "$url" "$link"
	printf '\t\t<updated>%sT23:58:00.000-0500</updated>\n' "$updated"
	printf '\t\t<summary>%s</summary>\n' "$summary"
	printf '\t</entry>\n'
}

feed_end() {
	printf '</feed>\n'
}

main "$@"

m4_include(website.m4)
m4_define([__title], [])
m4_define([__description], [])
m4_include(article-header.html)
<section>
$body$
</section>
m4_include(footer.html)