#!/usr/bin/env bash

# Copyright 2020 nytpu
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

# fill out variables here
make_globals() {
	global_title="yatb"
	global_description="yet another tech blog"
	global_url="gemini://nytpu.com/gemlog/" # link to base url of blog
	global_author="nytpu"
	global_license="CC by"

	gemlog_feed="feed.rss" # filename of the rss feed
	number_of_feed_articles="50" # number of posts in rss feed
	feed_base_url="https://nytpu.com/blog/" # base url that the feed is hosted at

	index="index.gmi" # main page, not recommended to change
	
	# don't change these
	date_format_full="%a, %d %b %Y %H:%M:%S %z"
	date_format_timestamp="%Y%m%d%H%M.%S"
}

get_post_title() {
	cat "$1" | perl -lne 's/#{1,3}\s+(.*)/\1/ or next; print; exit'
}

# from bashblog (https://tildegit.org/team/bashblog)
# bashblog is licensed under the gnu gplv3
make_rss() {
	echo "Making RSS"

	rssfile="$gemlog_feed.$RANDOM"
	while [[ -f $rssfile ]]; do rssfile="feed.rss.$RANDOM"; done

	{
		pubdate=$(LC_ALL=C date +"$date_format_full")
		echo '<?xml version="1.0" encoding="UTF-8" ?>' 
		echo '<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:dc="http://purl.org/dc/elements/1.1/">' 
		echo "<channel><title>$global_title</title><link>$global_url$index</link>"
		echo "<description>$global_description</description><language>en</language>"
		echo "<lastBuildDate>$pubdate</lastBuildDate>"
		echo "<pubDate>$pubdate</pubDate>"
		echo "<atom:link href=\"$feed_base_url/$blog_feed\" rel=\"self\" type=\"application/rss+xml\">"
	
		n=0
		while IFS='' read -r i; do
			((n >= number_of_feed_articles)) && break
			echo "<item><title>" 
			get_post_title "$i"
			echo "</title><description></description><link>$global_url${i#'./'}</link>" 
			echo "<guid>$global_url${i#'./'}</guid>" 
			echo "<dc:creator>$global_author</dc:creator>" 
			echo "<pubDate>$(LC_ALL=C date -r "$i" +"$date_format_full")</pubDate></item>"
	
			n=$(( n + 1 ))
		done < <(ls -r ./[[:digit:]]*.gmi)
	
		echo '</channel></rss>'
	} 3>&1 >"$rssfile"

	mv "$rssfile" "$gemlog_feed"
	chmod 644 "$gemlog_feed"
}

# change this to what you want
build_entries() {
	echo "Building entries"
	{
		printf "# yatg (yet another tech gemlog)"
		printf "## by nytpu"

		while IFS='' read -r i; do
			post=$(basename $i)
			title=$(get_post_title "$i")
			pubdate=$(echo $i | perl -ne '/^(\d{4}-\d{2}-\d{2}).*/; print $1')
			printf "=> $global_url$post $pubdate — $title\r\n"
		done < <(ls -r [[:digit:]]*.gmi)

		printf "\r\n\r\n"
		printf "=> / go home\r\n"
		printf "\r\n"
		printf "this gemlog has an rss feed at:\r\n"
		printf "=> https://www.nytpu.com/files/feed.rss [https] https://www.nytpu.com/files/feed.rss\r\n"
		printf "\r\n"
		printf "=> /gemlog/old/ click here to view an archive of my old gemlog"
	} 3>&1 >"$index"
}

make_globals
make_rss
build_entries