Implement lyrics lookup

There is now a generic mechanism for loading lyrics,
or any other arbitrary content related to songs.

info/10-azlyrics.pl

@@ -0,0 +1,43 @@
+#!/usr/bin/env perl
+# 10-azlyrics.pl: nncmpp info plugin to fetch song lyrics on AZLyrics
+#
+# Copyright (c) 2022, Přemysl Eric Janouch <p@janouch.name>
+# SPDX-License-Identifier: 0BSD
+#
+# Inspired by a similar ncmpc plugin.
+
+use warnings;
+use strict;
+use utf8;
+use open ':std', ':utf8';
+unless (@ARGV) {
+	print "Look up on AZLyrics\n";
+	exit;
+}
+
+use Encode;
+my ($title, $artist, $album) = map {decode_utf8($_)} @ARGV;
+
+# TODO: An upgrade would be transliteration with, e.g., Text::Unidecode.
+use Unicode::Normalize;
+$artist = lc(NFD($artist) =~ s/^the\s+//ir =~ s/[^A-Za-z0-9]//gr);
+$title  = lc(NFD($title)  =~ s/\(.*?\)//gr =~ s/[^A-Za-z0-9]//gr);
+
+# TODO: Consider caching the results in a location like
+# $XDG_CACHE_HOME/nncmpp/info/azlyrics/$artist-$title
+my $found = 0;
+if ($title ne '') {
+	open(my $curl, '-|', 'curl', '-sA', 'nncmpp/2.0',
+		"https://www.azlyrics.com/lyrics/$artist/$title.html") or die $!;
+	while (<$curl>) {
+		next unless /^<div>/ .. /^<\/div>/; s/<!--.*?-->//g; s/\s+$//gs;
+
+		$found = 1;
+		s/<\/?b>/\x01/g; s/<\/?i>/\x02/g; s/<br>/\n/; s/<.+?>//g;
+		s/&lt;/</g; s/&gt;/>/g; s/&quot;/"/g; s/&apos;/'/g; s/&amp;/&/g;
+		print;
+	}
+	close($curl) or die $?;
+}
+
+print "No lyrics have been found.\n" unless $found;