package DBIx::Custom::Where;

use strict;

use warnings;

use base 'Object::Simple';

use overload 'bool' => sub {1}, fallback => 1;

use overload '""' => sub { shift->to_string }, fallback => 1;

use Carp 'croak';

__PACKAGE__->attr(clause => sub { [] });

__PACKAGE__->attr(param => sub { {} });

__PACKAGE__->attr(sql_builder => sub { {} });

sub to_string {

    my ($self, $param, $clause) = @_;

    local $self->{_where}    = '';

    local $self->{_count}    = {};

    local $self->{_op_stack} = [];

    local $self->{_param}    = $param;

    $clause = ['and', $clause] unless ref $clause eq 'ARRAY';

    $self->_forward($clause);

    return $self->{_where};

}

our %VALID_OPERATIONS = map { $_ => 1 } qw/and or or_repeat/;

sub _forward {

    my ($self, $clause) = @_;

    if (ref $clause eq 'ARRAY') {

        $self->{_where} .= '( ';

        my $op = $clause->[0] || '';

        croak qq{"$op" is invalid operation}

          unless $VALID_OPERATIONS{$op};

        push @{$self->{_op_stack}}, $op;

        for (my $i = 1; $i < @$clause; $i++) {

            $self->_forword($clause->[$i]);

        }

        pop @{$self->{_op_stack}};

        if ($self->{_where} =~ /\( $/) {

            $self->{_where} =~ s/\( $//;

            $self->{_where} .= ' ';

        }

        $self->{_where} =~ s/ $op $//;

        $self->{_where} .= ' ) ';

    }

    else {

        my $op = $self->{_op_stack}->[-1];

        my $columns = $self->sql_builder->build_query($clause)->columns;

        croak qq{each tag contains one column name: tag "$clause"}

          unless @$columns == 1;

        my $column = $columns->[0];

        my $ccount = ++$self->{_count}->{$column};

        my $param = $self->{_param};

        if (exists $param->{$column}) {

            if ($op eq 'and' || $op eq 'or') {

                if (ref $param->{$column} eq 'ARRAY') {

                    $self->{_where} .= $clause . " $op "

                      if exists $param->{$column}->[$ccount];

                }

                else {

                    $self->{_where} .= $clause . " $op "

                      if $ccount == 1;

                }

            }

            elsif ($op eq 'or_repeat') {

                if (ref $param->{$column} eq 'ARRAY') {

                    $self->{_where} .= $clause . " or "

                      for (1 .. @{$param->{$column}});

                }

                else {

                    $self->{_where} .= $clause;

                }

            }

        }

    }

}

1;

=head1 NAME

DBIx::Custom::Where - Where clause

=head1 SYNOPSYS

    $where = DBIx::Custom::Where->new;

    my $sql = "select * from book $where";

=head1 ATTRIBUTES

=head2 C<param>

    my $param = $where->param;

    $where    = $where->param({title => 'Perl',

                               date => ['2010-11-11', '2011-03-05']},

                               name => ['Ken', 'Taro']);

=head1 METHODS

=head2 C<clause>

    $where->clause(title => '{= title}', date => ['{< date}', '{> date}']);

Where clause. These clauses is joined by ' and ' at C<to_string()>

if corresponding parameter name is exists in C<param>.

=head2 C<to_string>

    $where->to_string;