#!/usr/bin/perl -w

# Check a LaTeX file (stdin) for floats that aren't referenced.

my %refs = ();
my @labs = ();
my @spans = ();
my $infig = 0;
my $inspan = 0;
my $hadlab = 0;

local $/ = "\n\n";              # Paragraph mode
while (<>) {
  my $pgh = $_;

  $pgh =~ s/%.+\n//g;		# Discard comments

  while ($pgh =~ /\\ref{/) {
    if ($pgh =~ /\\ref{([^}]+)}\s+to\s+\\ref{([^}]+)}/) {
      push @spans, "$1, $2";
      #	print "|pgh before removal of span $spans[-1]| = |$pgh|\n";
      $pgh =~ s/\\ref{.+?}\s+to\s+\\ref{.+?}//;
      #	print "|pgh after removal of span $spans[-1]| = |$pgh|\n";
    } elsif ($pgh =~ /\\ref{([^}]+)/) {
      ++$refs{$1};
      #	print "|pgh before removal of ref $1| = |$pgh|\n";
      $pgh =~ s/\\ref{.+?}//;
      #	print "|pgh after removal of ref| = |$pgh|\n";
    }
  }

  foreach (split /\n/, $pgh) {
    if (/\\begin{(figure|table)}/) {
      $infig = 1;
    }

    if ($infig && /\\label{([^}]+)/) {
      my $lab = $1;
      my $hasref = 0;

      push @labs, $lab;
      print "lab: $1";
      foreach my $span (@spans){
	if($span =~ /^$lab, /){
	  $inspan = $span;
	  $hasref = 1;
	} elsif($span =~ /, $lab$/){
	  $inspan = 0;
	  $hasref = 1;
	} elsif($inspan){
	  print " supposedly referred to by span $inspan";
	  $hasref = 1;
	}
      }
#      print "\nspan ref = $hasref\n";
      $hasref |= grep(/^$lab$/, keys %refs);
#      print "|ref lab| = |$refs{$lab}|\n" if(defined($refs{$lab}));
#      print "grep ref = $hasref\n";
#      foreach my $k (keys %refs){
#	print "k: $k\t";
#      }
      print " defined before reference." unless($hasref);
      print "\n";
      $hadlab = 1;
    }

    if (/\\end{(figure|table)}/) {
      $infig = 0;
      unless($hadlab){
	print "Float ending at paragraph $. has no label.\n";
	$hadlab = 0;
      }
    }
  }
}

foreach my $span (@spans){
  my ($spanstart, $spanend) = split /, /, $span;

  my $inspan = 0;
  foreach my $lab (@labs){
    $inspan = 1 if($lab eq $spanstart);
    if($inspan){
      ++$refs{$lab};
    }
    last if($lab eq $spanend);
  }
}

print "\n    Label\t\tNo. of refs\n";
print "    -----\t\t-----------\n";
foreach my $l (@labs){
    print "$l\t\t";
    if(defined($refs{$l})){
	print "$refs{$l}\n";
    }
    else{
	print "No references found!\n";
    }
}