package # hide from PAUSE
    DBIx::Class::Relationship::HasMany;

use strict;
use warnings;

sub has_many {
  my ($class, $rel, $f_class, $cond, $attrs) = @_;

  unless (ref $cond) {
    $class->ensure_class_loaded($f_class);
    my ($pri, $too_many) = $class->primary_columns;

    $class->throw_exception(
      "has_many can only infer join for a single primary key; ".
      "${class} has more"
    ) if $too_many;

    $class->throw_exception(
      "has_many needs a primary key to infer a join; ".
      "${class} has none"
    ) if !defined $pri && (!defined $cond || !length $cond);

    my ($f_key,$guess);
    if (defined $cond && length $cond) {
      $f_key = $cond;
      $guess = "caller specified foreign key '$f_key'";
    } else {
      $class =~ /([^\:]+)$/;
      $f_key = lc $1; # go ahead and guess; best we can do
      $guess = "using our class name '$class' as foreign key";
    }

    my $f_class_loaded = eval { $f_class->columns };
    $class->throw_exception(
      "No such column ${f_key} on foreign class ${f_class} ($guess)"
    ) if $f_class_loaded && !$f_class->has_column($f_key);
      
    $cond = { "foreign.${f_key}" => "self.${pri}" };
  }

  $class->add_relationship($rel, $f_class, $cond, {
    accessor => 'multi',
    join_type => 'LEFT',
    cascade_delete => 1,
    cascade_copy => 1,
    %{$attrs||{}}
  });
}

1;
