#!/usr/bin/perl

require 5.8.0;

use strict;
use warnings;

# Load in the modules we'll be using
use URI;
use Pod::Usage;
use Getopt::Long;
use File::Basename;

my $switches = process_switches();

# User has goofed so be concise
pod2usage(	-verbose	=> 0) unless (@ARGV >= 1 and @ARGV <= 3);

# User has asked for help so be helpful
if ($switches->{help}) {
  pod2usage(	-verbose	=> 1,
 		-message	=> "More help: cherry.pl --man\n",
 		-output		=> \*STDERR);
}

# User has asked for more help so be more helpful
if ($switches->{man}) {
  pod2usage(	-verbose	=> 2
		-output		=> \*STDERR);
}

# This is our input URI
my $uri = shift;

# Split the URI into a host / path and filename
my ($filepath, $filename) = get_file_path_name($uri);
my $filesplit = get_split($filename, $switches);
my ($min, $max) = set_limits(@ARGV, $filesplit->{digit});

# Use default precision if none was specified
unless ($switches->{precision}) {
  $switches->{precision} = length($filesplit->{digit});
  warn "Autodetected precision as $switches->{precision} digits.\n" if ($switches->{verbose});
}

if ($switches->{verbose}) {
  if ($switches->{reverse}) {
    warn "Generating sequence from $max to $min.\n" if ($switches->{verbose});
  } else {
    warn "Generating sequence from $min to $max.\n" if ($switches->{verbose});
  }
}

# Print out the sequential list...
for (my $i = $min; $i <= $max; $i++) {
  # Print the path and filename prefix
  print $filepath.$filesplit->{prefix};

  unless ($switches->{reverse}) {
    # ...in ascending order
    print (sprintf "%0$switches->{precision}d", $i);
  } else {
    # ...or in descending order
    print (sprintf "%0$switches->{precision}d", $max - $i + 1);
  }

  # Print the filename suffix
  print $filesplit->{suffix}."\n";
}

sub process_switches {
  my %switches;

  # Call Getopt::Long to handle any switches that might be present
  GetOptions (
    'help|h|?' => \$switches{help},
    'numeric-index|n:i' => \$switches{numindex},
    'precision|p:i' => \$switches{precision},
    'reverse|r' => \$switches{reverse},
    'verbose|v' => \$switches{verbose},
  );

  $switches{numindex} ||= -1;

  return \%switches;
}

sub get_file_path_name {
  # Get the URI that's been passed to the function
  my $input_uri = shift;

  # Create a new URI object based on it
  my $uri = URI->new($input_uri);

  # Extract the filename from the URI
  my ($filename) = fileparse($uri->path);

  # Slice the filename off a copy of the URI to get the full server / path
  my $filepath = $uri;
  $filepath =~ s/$filename//;

  return ($filepath, $filename);
}

sub set_limits {
  my $warn_flag = 1 if (@_ == 3);

  my $max = shift if (@_);
  my $min = shift if (@_);

  $min ||= 1;

  # Swap max and min if they're wrong
  if ($min > $max) {
    ($min, $max) = ($max, $min);
    warn "Waring: Given min is larger than max. Swapping values.\n" if ($switches->{verbose});
  }

  $min += 0;
  $max += 0;

  return ($min, $max);
}

sub get_split {
  my $filename = shift;
  my $switches = shift;

  my %filesplit;

  my @digits = $filename =~ /(\d+)/g or die "Error: Could not extract a number from filename '$filename'.\n";
   $filesplit{digit} = $digits[$switches->{numindex}];

  ### This won't work for files like 01-file01.html
  ($filesplit{prefix}, $filesplit{suffix}) = split (/$filesplit{digit}/, $filename, 2);
  ### This won't work for files like 01-file01.html

  return \%filesplit;
}