package DBIx::Custom::Where;

use Object::Simple -base;

use Carp 'croak';

use DBIx::Custom::Util '_subname';

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

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

# Carp trust relationship

push @DBIx::Custom::CARP_NOT, __PACKAGE__;

has [qw/dbi param/],

    map => sub { {} },

    clause => sub { [] };

sub _map_param {

    my $self = shift;

    my $param = shift;

    return $param if !defined $param;

    my %map = @_;

    # Mapping

    my $map_param = {};

    foreach my $key (keys %$param) {

        my $value_cb;

        my $condition;

        my $map_key;

        # Get mapping information

        if (ref $map{$key} eq 'ARRAY') {

            foreach my $some (@{$map{$key}}) {

                $map_key = $some unless ref $some;

                $condition = $some->{if} if ref $some eq 'HASH';

                $value_cb = $some if ref $some eq 'CODE';

            }

        }

        elsif (defined $map{$key}) {

            $map_key = $map{$key};

        }

        else {

            $map_key = $key;

        }

        $value_cb ||= sub { $_[0] };

        $condition ||= $self->if || 'exists';

        # Map parameter

        my $value;

        if (ref $condition eq 'CODE') {

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

                $map_param->{$map_key} = [];

                for (my $i = 0; $i < @{$param->{$key}}; $i++) {

                    $map_param->{$map_key}->[$i]

                      = $condition->($param->{$key}->[$i]) ? $param->{$key}->[$i]

                      : $self->dbi->not_exists;

                }

            }

            else {

                $map_param->{$map_key} = $value_cb->($param->{$key})

                  if $condition->($param->{$key});

            }

        }

        elsif ($condition eq 'exists') {

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

                $map_param->{$map_key} = [];

                for (my $i = 0; $i < @{$param->{$key}}; $i++) {

                    $map_param->{$map_key}->[$i]

                      = exists $param->{$key}->[$i] ? $param->{$key}->[$i]

                      : $self->dbi->not_exists;

                }

            }

            else {

                $map_param->{$map_key} = $value_cb->($param->{$key})

                  if exists $param->{$key};

            }

        }

        else { croak qq/Condition must be code reference or "exists" / . _subname }

    }

    return $map_param;

}

sub if {

    my $self = shift;

    if (@_) {

        my $if = $_[0];

        $if = $if eq 'exists' ? $if

                : $if eq 'defined' ? sub { defined $_[0] }

                : $if eq 'length'  ? sub { length $_[0] }

                : ref $if eq 'CODE' ? $if

                : undef;

        croak "You can must specify right value to C<if> " . _subname

          unless $if;

        $self->{if} = $if;

        return $self;

    }

    $self->{if} = 'exists' unless exists $self->{if};

    return $self->{if};

}

sub new {

    my $self = shift->SUPER::new(@_);

    # Check attribute names

    my @attrs = keys %$self;

    foreach my $attr (@attrs) {

        croak qq{"$attr" is invalid attribute name (} . _subname . ")"

          unless $self->can($attr);

    }

    return $self;

}

sub to_string {

    my $self = shift;

    # Check if column name is safety character;

    my $safety = $self->dbi->safety_character;

    if (ref $self->param eq 'HASH') {

        foreach my $column (keys %{$self->param}) {

            croak qq{"$column" is not safety column name (} . _subname . ")"

              unless $column =~ /^[$safety\.]+$/;

        }

    }

    # Clause

    my $clause = $self->clause;

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

    $clause->[0] = 'and' unless @$clause;

    # Map condition

    my $if = $self->if || '';

    $if = $if eq 'exists' ? $if

            : $if eq 'defined' ? sub { defined $_[0] }

            : $if eq 'length'  ? sub { length $_[0] }

            : ref $if eq 'CODE' ? $if

            : undef;

    croak "You can must specify right value to C<if> " . _subname

      unless $if;

    $self->{_if} = $if;

    $self->{_param} = $self->_map_param($self->param, %{$self->map});

    # Parse

    my $where = [];

    my $count = {};

    $self->_parse($clause, $where, $count, 'and');

    # Stringify

    unshift @$where, 'where' if @$where;

    return join(' ', @$where);

}

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

sub _parse {

    my ($self, $clause, $where, $count, $op) = @_;

    # Array

    if (ref $clause eq 'ARRAY') {

        # Start

        push @$where, '(';

        # Operation

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

        croak qq{First argument must be "and" or "or" in where clause } .

              qq{"$op" is passed} . _subname . ")"

          unless $VALID_OPERATIONS{$op};

        my $pushed_array;

        # Parse internal clause

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

            my $pushed = $self->_parse($clause->[$i], $where, $count, $op);

            push @$where, $op if $pushed;

            $pushed_array = 1 if $pushed;

        }

        pop @$where if $where->[-1] eq $op;

        # Undo

        if ($where->[-1] eq '(') {

            pop @$where;

            pop @$where if ($where->[-1] || '') eq $op;

        }

        # End

        else { push @$where, ')' }

        return $pushed_array;

    }

    # String

    else {

        # Pushed

        my $pushed;

        # Column

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

        if (@$columns == 0) {

            push @$where, $clause;

            $pushed = 1;

            return $pushed;

        }

        elsif (@$columns != 1) {

            croak qq{Each part contains one column name: "$clause" (}

                  . _subname . ")";

        }

        # Remove quote

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

        if (my $q = $self->dbi->_quote) {

            $q = quotemeta($q);

            $column =~ s/[$q]//g;

        }

        # Check safety

        my $safety = $self->dbi->safety_character;

        croak qq{"$column" is not safety column name (} . _subname . ")"

          unless $column =~ /^[$safety\.]+$/;

        # Column count up

        my $count = ++$count->{$column};

        # Push

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

        if (ref $param eq 'HASH') {

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

                my $if = $self->{_if};

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

                    $pushed = 1 if exists $param->{$column}->[$count - 1]

                      && ref $param->{$column}->[$count - 1] ne 'DBIx::Custom::NotExists'

                }

                elsif ($count == 1) { $pushed = 1 }

            }

            push @$where, $clause if $pushed;

        }

        elsif (!defined $param) {

            push @$where, $clause;

            $pushed = 1;

        }

        else {

            croak "Parameter must be hash reference or undfined value ("

                . _subname . ")"

        }

        return $pushed;

    }

    return;

}

1;

=head1 NAME

DBIx::Custom::Where - Where clause

=head1 SYNOPSYS

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

    my $string_where = "$where";

=head1 ATTRIBUTES

=head2 C<clause>

    my $clause = $where->clause;

    $where = $where->clause(

        ['and',

            'title = :title', 

            ['or', 'date < :date', 'date > :date']

        ]

    );

Where clause. Above one is expanded to the following SQL by to_string

If all parameter names is exists.

    "where ( title = :title and ( date < :date or date > :date ) )"

=head2 C<map EXPERIMENTAL>

Mapping parameter key and value when C<to_stirng> method is executed.

    $where->map({

        'id' => 'book.id',

        'author' => ['book.author' => sub { '%' . $_[0] . '%' }],

        'price' => [

            'book.price', {if => sub { length $_[0] }

        ]

    });

The following option is available.

=over 4

=item * C<if>

By default, if parameter key is exists, mapping is done.

    if => 'exists';

In case C<defined> is specified, if the value is defined,

mapping is done.

    if => 'defined';

In case C<length> is specified, the value is defined

and the length is bigger than 0, mappting is done.

    if => 'length';

You can also subroutine like C<sub { defined $_[0] }> for mappging.

    if => sub { defined $_[0] }

=back

=head2 C<param>

    my $param = $where->param;

    $where = $where->param({

        title => 'Perl',

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

    });

=head2 C<dbi>

    my $dbi = $where->dbi;

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

L<DBIx::Custom> object.

=head1 METHODS

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

and implements the following new ones.

=head2 C<if EXPERIMENTAL>

    my $if = $where->if($condition);

    $where->if($condition);

C<if> is default of C<map> method C<if> option.

=head2 C<to_string>

    $where->to_string;

Convert where clause to string.

double quote is override to execute C<to_string> method.

    my $string_where = "$where";

=cut