#!/bin/sh
set -eu

. src/development/lib.sh

usage() {
	cat <<-'EOF'
		Usage:
		  md2html.sh -T TITLE [-D TOC_DEPTH] < FILE.md
		  md2html.sh -h
	EOF
}

help() {
	cat <<-'EOF'


		Options:
		  -T TITLE        the required title of the generated HTML
		                  document
		  -D TOC_DEPTH    the depth of the generated table of
		                  contents (default: 2)
		  -h, --help      show this message


		Read markdown text from STDIN and emit HTML to STDOUT.


		Examples:

		  Generate the HTML from markdown using the default:

		    $ md2html.sh -T 'Homepage' < index.md > index.html


		  Pick a different TOC depth:

		    $ md2html.sh -D3 -T 'TODOs' < TODOs.md > TODOs.html
	EOF
}


for flag in "$@"; do
	case "$flag" in
		--)
			break
			;;
		--help)
			usage
			help
			exit
			;;
		*)
			;;
	esac
done

TOC_DEPTH=2
while getopts 'T:D:h' flag; do
	case "$flag" in
		T)
			TITLE="$OPTARG"
			;;
		D)
			TOC_DEPTH="$OPTARG"
			;;
		h)
			usage
			help
			exit
			;;
		*)
			usage >&2
			exit 2
			;;
	esac
done
shift $((OPTIND - 1))

eval "$(assert_arg "${TITLE:-}" '-T TITLE')"


HEAD="$(mkstemp)"
trap 'rm -f "$HEAD"' EXIT

cat <<-'EOF' > "$HEAD"
	<link rel="icon"       href="favicon.svg" type="image/svg+xml" />
	<link rel="stylesheet" href="style.css"   type="text/css" />
EOF

pandoc \
	-s \
	--toc                     \
	--toc-depth="$TOC_DEPTH"  \
	--metadata lang=pt        \
	--metadata title="$TITLE" \
	-H "$HEAD"