use strict;
use 5.010;

package FusqlFS::Backend::PgSQL::Views;
use FusqlFS::Version;
our $VERSION = $FusqlFS::Version::VERSION;
use parent 'FusqlFS::Artifact';

=head1 NAME

FusqlFS::Backend::PgSQL::Views - FusqlFS PostgreSQL database views interface

=head1 SYNOPSIS

    use FusqlFS::Backend::PgSQL::Views;

    my $views = FusqlFS::Backend::PgSQL::Views->new();
    my $list = $views->list();
    $views->create('aview');
    $views->store('aview', { 'content.sql' => 'SELECT * FROM sometable' });
    my $view = $views->get('aview');

=head1 DESCRIPTION

This is FusqlFS an interface to PostgreSQL database views. This class is not
to be used by itself.

See L<FusqlFS::Artifact> for description of interface methods,
L<FusqlFS::Backend> to learn more on backend initialization and
L<FusqlFS::Backend::Base> for more info on database backends writing.

=head1 EXPOSED STRUCTURE

=over

=item F<./content.sql>

Plain file with C<SELECT ...> SQL statement used to construct query in it. Can
be written to redefine view.

=item F<./owner>

Symlink to view's owner in F<../../roles>.

=back

=cut


use FusqlFS::Backend::PgSQL::Role::Owner;

sub init
{
    my $self = shift;

    $self->{drop_expr} = 'DROP VIEW "%s"';
    $self->{create_expr} = 'CREATE VIEW "%s" AS SELECT 1';
    $self->{store_expr} = 'CREATE OR REPLACE VIEW "%s" AS %s';
    $self->{rename_expr} = 'ALTER VIEW "%s" RENAME TO "%s"';

    $self->{get_expr} = $self->expr("SELECT definition FROM pg_catalog.pg_views WHERE viewname = ?");
    $self->{list_expr} = $self->expr("SELECT viewname FROM pg_catalog.pg_views WHERE schemaname = 'public'");

    $self->{owner} = FusqlFS::Backend::PgSQL::Role::Owner->new('v');
}

=begin testing list

cmp_set $_tobj->list(), [];

=end testing
=cut
sub list
{
    my $self = shift;
    return $self->all_col($self->{list_expr});
}

=begin testing get

is $_tobj->get('unknown'), undef;

=end testing
=cut
sub get
{
    my $self = shift;
    my ($name) = @_;
    my $result = $self->all_col($self->{get_expr}, $name);
    return unless @$result;
    return {
        'content.sql' => $result->[0],
        owner => $self->{owner},
    };
}

=begin testing rename after store

isnt $_tobj->rename('fusqlfs_view', 'new_fusqlfs_view'), undef;
is $_tobj->get('fusqlfs_view'), undef;
is_deeply $_tobj->get('new_fusqlfs_view'), { 'content.sql' => 'SELECT 2;', owner => $_tobj->{owner} };
is_deeply $_tobj->list(), [ 'new_fusqlfs_view' ];

=end testing
=cut
sub rename
{
    my $self = shift;
    my ($name, $newname) = @_;
    $self->do($self->{'rename_expr'}, [$name, $newname]);
}

=begin testing drop after rename

isnt $_tobj->drop('new_fusqlfs_view'), undef;
is_deeply $_tobj->list(), [];
is $_tobj->get('new_fusqlfs_view'), undef;

=end testing
=cut
sub drop
{
    my $self = shift;
    my ($name) = @_;
    $self->do($self->{'drop_expr'}, [$name]);
}

=begin testing create after get list

isnt $_tobj->create('fusqlfs_view'), undef;
is_deeply $_tobj->list(), [ 'fusqlfs_view' ];
is_deeply $_tobj->get('fusqlfs_view'), { 'content.sql' => 'SELECT 1;', owner => $_tobj->{owner} };

=end testing
=cut
sub create
{
    my $self = shift;
    my ($name) = @_;
    $self->do($self->{'create_expr'}, [$name]);
}

=begin testing store after create

isnt $_tobj->store('fusqlfs_view', { 'content.sql' => 'SELECT 2' }), undef;
is_deeply $_tobj->get('fusqlfs_view'), { 'content.sql' => 'SELECT 2;', owner => $_tobj->{owner} };

=end testing
=cut
sub store
{
    my $self = shift;
    my ($name, $data) = @_;
    $self->do($self->{'store_expr'}, [$name, $data->{'content.sql'}]);
}

1;

__END__

=begin testing SETUP

#!class FusqlFS::Backend::PgSQL::Test

=end testing