#!/usr/bin/env perl
use strict;
use warnings FATAL => 'all';

use ExtUtils::Manifest qw(maniread);
use File::Spec;
use Getopt::Long qw(:config gnu_getopt);

GetOptions(
  'tar=s'   => \(my $tar = 'tar'),
) or die("Error in command line arguments\n");

my ($tarball, $manifest) = @ARGV;
my $type
  = $tarball =~ /\.bz2$/  ? '-j'
  : $tarball =~ /\.xz$/   ? '-J'
  : $tarball =~ /\.t?gz$/ ? '-z'
  : $tarball =~ /\.Z$/    ? '-Z'
  : '';

my @tarfiles;
{
  my $null = File::Spec->devnull;
  @tarfiles = `$tar -t $type -f "$tarball" 2>$null`;
  chomp @tarfiles;
}

{
  my $prefix;
  for my $path (@tarfiles) {
    if (!defined $prefix) {
      ($prefix) = $path =~ m{^([^/]+)};
    }
    elsif ($path !~ m{^\Q$prefix\E(?:/|$)}) {
      undef $prefix;
      last;
    }
  }
  if ($prefix) {
    s{^\Q$prefix\E/}{} for @tarfiles;
  }
}

@tarfiles = grep !m{(?:^|/)$}, @tarfiles;
my %tarfiles = map +($_ => 1), @tarfiles;

my %manifiles = %{ maniread($manifest) };

my @extra = grep { !exists $manifiles{$_} } sort keys %tarfiles;
my @missing = grep { !exists $tarfiles{$_} } sort keys %manifiles;

my $message = '';
if (@extra) {
  $message .= "$tarball has extra files:\n" . join '', map "  $_\n", @extra;
}
if (@missing) {
  $message .= "$tarball is missing files:\n" . join '', map "  $_\n", @missing;
}
if ($message) {
  die $message . <<'END_MESSAGE';

This may happen if the file attributes are not compatible with the ustar format.
END_MESSAGE
}
exit 0;