#!/usr/bin/perl
use strict;
use warnings;

my %css;

my $fg = 'black';	# default foreground colour.
	# You might want to change this at least for a dark background.

# part 1: Read the file (files even, in case you provide)
while (<>) {
	my  ($force, $from, $to, $name, $col, $att) =
		/^hi(?:ghlight)?
			(?:
				(!)?\s+link\s+(\w+)\s+(\w+)
				|
				\s+(\w+)\s+
					(?= .*?guifg=( [a-zA-Z]+ | \#[0-9a-fA-F]{6} ) )?
					(?= .*?gui=( \w+ ) )?
			)
		/x;
	next unless $from or $name and ($col or $att);
	
	#{
	#	no warnings 'uninitialized';
	#	print "$force, $from, $to, $name, $col, $att\n";
	#}

	if ($name) {
		$name = lc $name;
		$css{$name} = {};
		$css{$name}->{col} = $col if $col;
		$css{$name}->{col} ||= $fg;
		$css{$name}->{att} = $att if $att and uc $att ne 'NONE';
	}
	else {	# link
		next if $css{$from} and not $force;
		$from = lc $from;
		$css{$from}->{lnk} = lc $to;
	}
}

#part 2: Resolve "links".
# Does Vim handle forward declared links?
# Anyway, the code does.
my $more = keys %css;
while (--$more) {
	my $found = 0;
	for my $group (keys %css) {
		next unless $css{$group}->{lnk};
		$found = 1;
		my $to = $css{$group}->{lnk};
		if (exists $css{$to}) {
			$css{$group} = $css{$to};
		}
		else {
			$css{$group} = {col => $fg};
		}
	}
	next unless $found;
}

#part 3: Create the CSS

# Use this Vim "group" => JS className translation.
# Is Vim case sensitive on the names?
my %map = (
	quotedString => 'string',
	comment => 'comment',
	operator => 'normal',
	builtinVariable => 'identifier',
	variableSpecifier => 'identifier',
	keyword => 'keyword',
	builtinFunction => 'keyword',
	identifier => 'identifier',
	number => 'number',
);

for my $class (keys %map) {
	my $id = $map{$class};
	my $cid = $css{$id} || $css{Normal};
	my $col = lc $cid->{col} || $fg;
	my $att = $cid->{att}||q() eq 'bold' ? "\n  font-weight:bold;" : q();
	print <<EOS;
.$class
{
  color: $col;$att
}
EOS
}