use strict;
use warnings;

package Test::Deep::HashKeysOnly;

use Test::Deep::Ref;

sub init
{
  my $self = shift;

  my %keys;
  @keys{@_} = ();
  $self->{val} = \%keys;
  $self->{keys} = [sort @_];
}

sub descend
{
  my $self = shift;
  my $hash = shift;

  my $data = $self->data;
  my $exp = $self->{val};
  my %got;
  @got{keys %$hash} = ();

  my @missing;
  my @extra;

  while (my ($key, $value) = each %$exp)
  {
    if (exists $got{$key})
    {
      delete $got{$key};
    }
    else
    {
      push(@missing, $key);
    }
  }

  my @diags;
  if (@missing and (not $self->ignoreMissing))
  {
    push(@diags, "Missing: ".nice_list(\@missing));
  }

  if (%got and (not $self->ignoreExtra))
  {
    push(@diags, "Extra: ".nice_list([keys %got]));
  }

  if (@diags)
  {
    $data->{diag} = join("\n", @diags);
    return 0;
  }

  return 1;
}

sub diagnostics
{
  my $self = shift;
  my ($where, $last) = @_;

  my $type = $self->{IgnoreDupes} ? "Set" : "Bag";

  my $error = $last->{diag};
  my $diag = <<EOM;
Comparing hash keys of $where
$error
EOM

  return $diag;
}

sub nice_list
{
  my $list = shift;

  return join(", ",
    (map {"'$_'"} sort @$list),
  );
}

sub ignoreMissing
{
  return 0;
}

sub ignoreExtra
{
  return 0;
}

package Test::Deep::SuperHashKeysOnly;

use base 'Test::Deep::HashKeysOnly';

sub ignoreMissing
{
  return 0;
}

sub ignoreExtra
{
  return 1;
}

package Test::Deep::SubHashKeysOnly;

use base 'Test::Deep::HashKeysOnly';

sub ignoreMissing
{
  return 1;
}

sub ignoreExtra
{
  return 0;
}

1;