#!/usr/bin/perl -w
use strict;

my $total_lines = 0;   # Contains the total number of lines in all the files supplied.
my $logical_lines = 0; # Contains the number of logical lines of code in one file.
my $in_pod = 0;        # If set to 1, indicates that we are currently in the middle of
                       # a POD comment and hence shouldn't be counting lines of code.

# If the first argument specified on the command-line is '-v', we want verbose output.
my $verbose = 0;
my $first_arg = $ARGV[0];

if ($first_arg eq "-v") {
  shift @ARGV;         # Remove the first element of the @ARGV array.
  $verbose = 1;
}

# For each of the filenames supplied on the command-line, execute the following block,
# which will count up the logical lines in that file.
foreach my $file (@ARGV) {

  # Re-initialize variables to zero.
  $logical_lines = 0;
  $in_pod = 0;

  # Open the file for reading. Die if there is some kind of error.
  open(FILE, $file) or die "Could not open $file: $!";

  # Process each of the lines of the file, in sequence.
  foreach (<FILE>) {

    # A line beginning with '=cut' marks the end of a POD block.
    reject($_), $in_pod = 0, next if /^=cut/i;

    # If we are in a POD block, this is not a line of code.
    reject($_), next if $in_pod;

    # A line beginning with the '=' character marks the beginning of a POD block.
    reject($_), $in_pod = 1, next if /^=/i;

    # A line containing no alphanumerics is not counted as a line of code.
    reject($_), next unless /\w/;

    # A line beginning with whitespace and followed by a pound character is a comment.
    reject($_), next if /^\s*#/;

    # If we got here, this line is actually a line of code.
    acknowledge($_);
  }

  # Close the file.
  close(FILE);

  # Print the results for this file and add to $total_lines.
  print "$file contains $logical_lines logical lines of code.\n";
  $total_lines += $logical_lines;
}

# Print the final result.
print "$total_lines logical lines of code in ", scalar(@ARGV), " files.\n";

# The function that gets called whenever we determine that
# the current line is a logical line of code.
sub acknowledge {
  my $line = shift;
  $logical_lines++;
  print "+ $line" if $verbose;
}

# The function that gets called whenever we determine that
# the current line isn't a logical line of code.
sub reject {
  my $line = shift;
  print "- $line" if $verbose;
}