#!/bin/sh

# MIT License

# Copyright (c) 2023 Bradley Taunt
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

set -eu
MARKDOWN=lowdown
MARKDOWN_OPTS="--html-no-skiphtml	--html-no-escapehtml"
IFS='	'

# Create tab separated file with filename, title, creation date, last update
index_tsv() {
	for f in "$1"/*.md
	do
		title=$(sed -n '/^# /{s/# //p; q}' "$f")
		printf '%s\t%s\t%s\t%s\n' "$f" "${title:="No Title"}"
	done
}

index_html() {
	# Print header
	title=$(sed -n '/^# /{s/# //p; q}' index.md)
	sed "s/{{TITLE}}/$title/" header.html

	# Intro text
	$MARKDOWN $MARKDOWN_OPTS index.md

	# Posts
	while read -r f title created; do
		link=$(echo "$f" | sed -E 's|.*/(.*).md|\1/|')
		created=$(echo $(head -3 "$f" | tail -1))
	 	echo "<span class='created'>$created &mdash; <a href=\"$link\">$title</a></span>"
	done < "$1" | sort -r

	# Print footer after post list
	cat footer.html
}

atom_xml() {
	uri=$(sed -rn '/atom.xml/ s/.*href="([^"]*)".*/\1/ p' header.html)
	domain=$(echo "$uri" | sed 's/atom.xml//g' | sed 's|/[^/]*$||')
	first_commit_date=$(git log --pretty='format:%ai' . | cut -d ' ' -f1 | tail -1)

	cat <<EOF
<?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://www.w3.org/2005/Atom">
	<title>$(sed -n '/^# /{s/# //p; q}' index.md)</title>
	<link href="$domain/atom.xml" rel="self" />
	<updated>$(date +%FT%TZ)</updated>
	<author>
		<name>$(git config user.name)</name>
	</author>
	<id>$domain,$first_commit_date:default-atom-feed/</id>
EOF

	while read -r f title created; do

		content=$($MARKDOWN $MARKDOWN_OPTS "$f" | sed 's/&/\&amp;/g; s/</\&lt;/g; s/>/\&gt;/g; s/"/\&quot;/g; s/'"'"'/\&#39;/g')
		post_link=$(echo "$f" | sed -E 's|posts/(.*).md|\1|')
		basic_date=$(echo $(head -3 "$f" | tail -1))
		published_date=$(date -d $basic_date -u +%Y-%m-%dT10:%M:%SZ)

		cat <<EOF
	<entry>
		<title>$title</title>
		<content type="html">$content</content>
		<link href="$domain/$post_link"/>
		<id>$domain/$post_link</id>
		<updated>$published_date</updated>
		<published>$published_date</published>
	</entry>
EOF
	done < "$1"

	echo '</feed>'
}

write_page() {
	filename=$1
	directory=$(echo $(basename "$filename" .md))
	$(mkdir -p build/$directory)
	target=$(echo "$filename" | sed -r 's|\w+/(.*).md|build/\1/index.html|')
	created=$(echo $(head -3 "$filename" | tail -1))
	title=$2

	$MARKDOWN $MARKDOWN_OPTS "$filename" | \
		cat header.html - |\
		sed "s|{{TITLE}}|$title|" \
		> "$target" && cat footer.html >> "$target"
}

rm -fr build && mkdir build

# Blog posts
index_tsv posts | sort -rt "	" -k 3 > build/posts.tsv
index_html build/posts.tsv > build/index.html
atom_xml build/posts.tsv > build/atom.xml
while read -r f title created; do
	write_page "$f" "$title" "$created"
done < build/posts.tsv

# Pages
index_tsv pages > build/pages.tsv
while read -r f title created; do
	write_page "$f" "$title" "$created"
done < build/pages.tsv