#!/usr/bin/perl

$chapter_digits = $ENV{chapter_digits} || 2;
$chapter = 0;
start_chapter();

while (defined ($_=<STDIN>)) {
	if (/<!--Section Begins-->/ && !$before_chapter_heading) {
		next_chapter();
		$before_chapter_heading=1;
	}
	if (/> *Chapter (\d+) *</) {
		my $chapter_heading_num = $1;
		if ($before_chapter_heading) {
			$before_chapter_heading = 0;
		} else {
			next_chapter();
		}
		if ($chapter ne $chapter_heading_num) {
			warn "chapter number mismatch: $chapter_heading_num : $chapter";
		}
	}
	print OUT $_;
}

sub next_chapter {
	close OUT;
	++$chapter;
	start_chapter();
}

sub start_chapter {
	open OUT, ">ch".sprintf("%0${chapter_digits}d", $chapter).".html";
}