#!/bin/sh

BASE_URL=https://ieks.cc/
TITLE=ieks.cc
AUTHOR='Lucas Ieks'
EMAIL=lucas@ieks.cc

# TODO handle image links

STYLE='
html { font-family: "Helvetica", "Arial", "Nimbus Sans L", sans-serif; background: #181408; color: #eeeeee; }
body { max-width: 50rem; margin: 0 auto 25vh; }
main { background: #eeeeee; color: #080808; padding: 1rem; }
main a { color: darkblue; }
@media (prefers-color-scheme: dark) {
	main { background: inherit; color: inherit; a { color: lightblue; } }
}
a { color: lightblue; text-decoration: none; }
a:hover { color: grey; }
h1 a, h2 a, h3 a, sup a { color: inherit; }
nav, h1, h2, h3 { margin: 1rem 0; font-variant-caps: small-caps; }
nav { margin-left: 1rem; padding-left: 0; }
nav h1 { font-variant-caps: normal; }
nav ul { margin: 0; padding: 0; }
nav ul a::after { content: "\a0\2192"; }
small { font-size: 0.75em; }
nav ul, nav ol { list-style-type: none; padding: 0; margin: 0 0.5rem; }
h1 { font-size: 2.618rem; }
h2 { font-size: 1.618rem; }
h3 { font-size: 1rem; }
p, div, li, blockquote { line-height: 1.5; text-align: justify; hyphens: auto; }
p { margin: 0; margin-top: 0.75rem; }
blockquote { margin: 0.5rem 1rem; }
p:first-child, h1:first-child { margin-top: 0; }
pre { padding-left: 1rem; line-height: 1.5; overflow-x: auto; }
sup { line-height: 0; font-size: 0.618em; }
'

# relpath file dir
# slightly adjusted from https://stackoverflow.com/a/14914070 (CC BY-SA 3.0)
relpath () {
	current="${2:+"$1"}"
	target="${2:-"$1"}"
	[ "$target" = . ] && target=/
	target="/${target##/}"
	[ "$current" = . ] && current=/
	current="${current:="/"}"
	current="/${current##/}"
	appendix="${target##/}"
	relative=''
	while appendix="${target#"$current"/}"
		[ "$current" != '/' ] && [ "$appendix" = "$target" ]
	do
		if [ "$current" = "$appendix" ]; then
			relative="${relative:-.}"
			printf '%s\n' "${relative#/}"
			return 0
		fi
		current="${current%/*}"
		relative="$relative${relative:+/}.."
	done
	relative="$relative${relative:+${appendix:+/}}${appendix#/}"
	printf '%s\n' "$relative"
}

TABLE_OF_CONTENTS='
	function esc(i) {
		gsub(/&/, "\\&", i)
		gsub(/</, "\\&lt;", i)
		gsub(/>/, "\\&gt;", i)
		gsub(/"/, "\\&quot;", i)
		return i
	}
	function rep(i) {
		gsub(/&/, "\\&amp;", i)
		gsub(/---/, "\\&mdash;", i)
		gsub(/--/, "\\&ndash;", i)
		gsub(/->/, "\\&rightarrow;", i)
		gsub(/</, "\\&lt;", i)
		gsub(/>/, "\\&gt;", i)
		gsub(/"/, "\\&quot;", i)
		return i
	}

	BEGIN { print "<ul>" }

	MODE == "code" && /^```/ { MODE = "text"; next }
	MODE == "code" { next }
	/^```/ { MODE = "code"; next }

	/^###/ {
		sub(/^###[[:space:]]*/, "")
		if (h3 == 0) print "<li><ol>"
		h3++
		print "<li><a href=\"#" h1 "." h2 "." h3 "\">" rep($0) "</a></li>"
	}
	/^##[^#]/ {
		sub(/^##[[:space:]]*/, "")
		if (h2 == 0) print "<li><ol>"
		h2++
		if (h3 > 0) print "</ol></li>"
		h3 = 0
		print "<li><a href=\"#" h1 "." h2 "\">" rep($0) "</a></li>"
	}
	/^#[^#]/ {
		sub(/^#[[:space:]]*/, "")
		h1++
		if (h3 > 0) print "</ol></li>"
		h3 = 0
		if (h2 > 0) print "</ol></li>"
		h2 = 0
	}

	{ }

	END {
		if (h3 > 0) print "</ol></li>"
		if (h2 > 0) print "</ol></li>"
		print "</ul>"
	}
'

BODY='
	function esc(i) {
		gsub(/&/, "\\&amp;", i)
		gsub(/</, "\\&lt;", i)
		gsub(/>/, "\\&gt;", i)
		gsub(/"/, "\\&quot;", i)
		return i
	}
	function rep(i) {
		gsub(/&/, "\\&amp;", i)
		gsub(/---/, "\\&mdash;", i)
		gsub(/--/, "\\&ndash;", i)
		gsub(/->/, "\\&rightarrow;", i)
		gsub(/</, "\\&lt;", i)
		gsub(/>/, "\\&gt;", i)
		gsub(/"/, "\\&quot;", i)
		return i
	}

	BEGIN { MODE = "text" }

	MODE == "code" && /^```/ { print "</code></pre>"; MODE = "text"; next }
	MODE == "code" { print esc($0); next }
	/^```/ { if (MODE == "par") print "</p>"; printf "<pre><code>"; MODE = "code"; next }

	MODE != "list" && /^\*/ { if (MODE == "par") print "</p>"; print "<ul>"; MODE = "list" }
	/^\*/ {
		sub(/^\*[[:space:]]*/, "")
		$0 = rep($0)
		gsub(/\[[[:lower:]]+\]/, "<sup><a href=\"#" LINK ".&\">&</a></sup>")
		print "<li>" $0 "</li>"
		next
	}
	MODE == "list" { print "</ul>"; MODE = "text" }

	/^###/ {
		sub(/^###[[:space:]]*/, "")
		h3++
		LINK = h1 "." h2 "." h3
		print "<h3 id=\"" LINK "\"><a href=\"#" LINK "\">" rep($0) "</a></h3>"
		next
	}
	/^##[^#]/ { sub(/^##[[:space:]]*/, "")
		h2++
		h3 = 0
		LINK = h1 "." h2
		print "<h2 id=\"" LINK "\"><a href=\"#" LINK "\">" rep($0) "</a></h2>"
		next
	}
	/^#[^#]/ { sub(/^#[[:space:]]*/, "")
		h1++
		h2 = 0
		LINK = h1
		print "<h1 id=\"" LINK "\"><a href=\"#" LINK "\">" rep($0) "</a></h1>"
		next
	}

	/^[[:space:]]*$/ { if (MODE == "par") print "</p>"; MODE = "text"; next }

	/^>/ {
		if (MODE == "par") print "</p>"
		sub(/^>[[:space:]]*/, "")
		print "<blockquote>" rep($0) "</blockquote>"
		MODE = "text"
		next
	}

	MODE == "par" { print "<br>" }
	MODE == "text" { printf "<p>"; MODE = "par" }

	/^\[[[:lower:]]+\]/ {
		match($0, /\[[[:lower:]]+\]/)
		letter = substr($0, RSTART, RLENGTH)
		printf "<small id=\"%s.%s\">%s</small>", LINK, letter, rep($0)
		next
	}
	/^---/ { printf "<cite>%s</cite>", rep($0); next }
	/^=>/ {
		href = esc($2)
		if (href !~ /^gemini:\/\//) sub(/\.gmi$/, ".html", href)
		sub(/^=>[[:space:]]*[^[:space:]]+[[:space:]]*/, "")
		if (match($0, /\[[[:lower:]]+\]/)) {
			letter = substr($0, RSTART, RLENGTH)
			$0 = "<small id=\"" LINK "." letter "\">" rep($0) "</small>"
		} else if (/^---/) {
			$0 = "<cite>" rep($0) "</cite>"
		} else {
			$0 = rep($0)
		}
		print "<a href=\"" href "\">" $0 "</a>"
		next
	}
	{
		$0 = rep($0)
		gsub(/\[[[:lower:]]+\]/, "<sup><a href=\"#" LINK ".&\">&</a></sup>")
		printf "%s", $0
		MODE = "par"
	}

	END { if (MODE == "par") print "</p>" }
'

find . ! \( -path '*/.*' -prune \) -name '*.gmi' -type f | while read file; do
	printf 'convert %s\n' "${file%.gmi}.html"
	(
		printf '<!DOCTYPE html><html><head><meta charset="utf-8">'
		printf '<meta name="viewport" content="width=device-width,initial-scale=1">\n'
		printf '<link rel="alternate" type="application/atom+xml" title="%s" href="%s">\n' "$TITLE" "${BASE_URL}atom.xml"
		printf '<title>%s</title>\n' "$(sed -n 's/^#[^#][[:space:]]*//p' "$file" | head -1)"
		printf '<style>%s</style><body lang=en>' "$STYLE"
		printf '<nav>'
		printf '<h1><a href="/">%s</a></h1>' "$TITLE"
		if [ "$(basename "$file")" != index.gmi ]; then
			printf '<ul><li><a href="index.html">Up</a></li></ul>'
		elif [ "$(dirname "$file")" != . ]; then
			printf '<ul><li><a href="../">Up</a></li></ul>'
		fi
		awk "$TABLE_OF_CONTENTS" "$file"
		printf '</nav>'
		printf '<main>'
		awk "$BODY" "$file"
		printf '</main>'
	) > "${file%.gmi}.html"
done

printf '<?xml version="1.0" encoding="utf-8"?>' > atom.xml
printf '<feed xmlns="http://www.w3.org/2005/Atom">' >> atom.xml
printf '<id>%s</id>' "$BASE_URL" >> atom.xml
printf '<title>%s</title>' "$TITLE" >> atom.xml
printf '<updated>%s</updated>' "$(date -Iseconds)" >> atom.xml
printf '<link href="%s" rel="self"/>' "${BASE_URL}atom.xml" >> atom.xml
printf '<author>' >> atom.xml
printf '<name>%s</name>' "$AUTHOR" >> atom.xml
printf '<email>%s</email>' "$EMAIL" >> atom.xml
printf '</author>' >> atom.xml
printf '<generator uri="%s">%s</generator>' "${BASE_URL}$(relpath "$PWD" "$(realpath "$0")")" "$0" >> atom.xml

find . ! \( -path '*/.*' -prune \) -name '*.gmi' -type f | while read file; do
	published=$(sed -n 's/^Written:[[:space:]]*//p' "$file")
	updated=$(sed -n 's/^Revised:[[:space:]]*//p' "$file")
	[ "$updated" ] || updated=$published
	url="${BASE_URL}$(relpath "$PWD" "$(realpath "${file%.gmi}.html")")"

	[ "$published" ] || continue

	printf 'atom %s\n' "$file"
	printf '<entry>' >> atom.xml
	printf '<title>%s</title>' "$(sed -n 's/^#[^#][[:space:]]*//p' "$file" | head -1)" >> atom.xml
	printf '<link href="%s"></link>' "$url" >> atom.xml
	printf '<id>%s</id>' "$url" >> atom.xml
	printf '<published>%s</published>' "$(date -Iseconds -d "$published")" >> atom.xml
	printf '<updated>%s</updated>' "$(date -Iseconds -d "$updated")" >> atom.xml
	printf '</entry>' >> atom.xml
done

printf '</feed>' >> atom.xml