package DBIx::Custom::Order;

use Object::Simple -base;

use DBIx::Custom::Util '_deprecate';

use overload

  'bool'   => sub {1},

  '""'     => sub { shift->to_string },

  fallback => 1;

has 'dbi',

  orders => sub { [] };

sub prepend {

  my $self = shift;

  for my $order (reverse @_) {

    if (ref $order eq 'ARRAY') {

      _deprecate('0.24', "prepend method receiving array reference is DEPRECATED! " .

        "use q method to quote column name.");

      my $column = shift @$order;

      $column = $self->dbi->q($column) if defined $column;

      my $derection = shift @$order;

      $order = $column;

      $order .= " $derection" if $derection;

    }

    unshift @{$self->orders}, $order;

  }

  return $self;

}

sub to_string {

  my $self = shift;

  my $exists = {};

  my @orders;

  for my $order (@{$self->orders}) {

    next unless defined $order;

    $order =~ s/^\s+//;

    $order =~ s/\s+$//;

    my ($column, $direction) = split /\s+/, $order;

    push @orders, $order unless $exists->{$column};

    $exists->{$column} = 1;

  }

  return '' unless @orders;

  return 'order by ' . join(', ', @orders);

}

1;

=head1 NAME

DBIx::Custom::Order - Order by

=head1 SYNOPSIS

  # Result

  my $order = DBIx::Custom::Order->new;

  $order->prepend('title', 'author desc');

  my $order_by = "$order";

=head1 ATTRIBUTES

=head2 C<dbi>

  my $dbi = $order->dbi;

  $order = $order->dbi($dbi);

L<DBIx::Custom> object.

=head2 C<orders>

  my $orders = $result->orders;

  $result = $result->orders(\%orders);

Parts of order by clause

=head1 METHODS

L<DBIx::Custom::Result> inherits all methods from L<Object::Simple>

and implements the following new ones.

=head2 C<prepend>

  $order->prepend('title', 'author desc');

Prepend order parts to C<orders>.

=head2 C<to_string>

  my $order_by = $order->to_string;

Create order by clause. If column name is duplicated, First one is used.

C<to_string> override stringification. so you can write the follwoing way.

  my $order_by = "$order";

=cut