package UR::DataSource::Pg;
use strict;
use warnings;

use DBD::Pg;

require UR;
our $VERSION = "0.39"; # UR $VERSION;

UR::Object::Type->define(
    class_name => 'UR::DataSource::Pg',
    is => ['UR::DataSource::RDBMS'],
    is_abstract => 1,
);

# RDBMS API

sub driver { "Pg" }

#sub server {
#    my $self = shift->_singleton_object();
#    $self->_init_database;
#    return $self->_database_file_path;
#}

sub owner { shift->_singleton_object->login }

#sub login {
#    undef
#}
#
#sub auth {
#    undef
#}

sub _default_sql_like_escape_string { return '\\\\' };

sub _format_sql_like_escape_string {
    my $class = shift;
    my $escape = shift;
    return "E'$escape'";
}

sub can_savepoint { 1;}

sub set_savepoint {
my($self,$sp_name) = @_;

    my $dbh = $self->get_default_handle;
    $dbh->pg_savepoint($sp_name);
}

sub rollback_to_savepoint {
my($self,$sp_name) = @_;

    my $dbh = $self->get_default_handle;
    $dbh->pg_rollback_to($sp_name);
}


sub _init_created_dbh
{
    my ($self, $dbh) = @_;
    return unless defined $dbh;
    $dbh->{LongTruncOk} = 0;
    return $dbh;
}

sub _ignore_table {
    my $self = shift;
    my $table_name = shift;
    return 1 if $table_name =~ /^(pg_|sql_)/;
}


sub _get_next_value_from_sequence {
my($self,$sequence_name) = @_;

    # we may need to change how this db handle is gotten
    my $dbh = $self->get_default_handle;
    my($new_id) = $dbh->selectrow_array("SELECT nextval('$sequence_name')");

    if ($dbh->err) {
        die "Failed to prepare SQL to generate a column id from sequence: $sequence_name.\n" . $dbh->errstr . "\n";
        return;
    }

    return $new_id;
}

# The default for PostgreSQL's serial datatype is to create a sequence called
# tablename_columnname_seq
sub _get_sequence_name_for_table_and_column {
my($self,$table_name, $column_name) = @_;
    return sprintf("%s_%s_seq",$table_name, $column_name);
}


sub get_bitmap_index_details_from_data_dictionary {
    # FIXME Postgres has bitmap indexes, but we don't support them yet.  See the Oracle
    # datasource module for details about how to get it working
    return [];
}


sub get_unique_index_details_from_data_dictionary {
my($self,$table_name) = @_;

    my $sql = qq(
        SELECT c_index.relname, a.attname
        FROM pg_catalog.pg_class c_table
        JOIN pg_catalog.pg_index i ON i.indrelid = c_table.oid
        JOIN pg_catalog.pg_class c_index ON c_index.oid = i.indexrelid
        JOIN pg_catalog.pg_attribute a ON a.attrelid = c_index.oid
        WHERE c_table.relname = ?
          and (i.indisunique = 't' or i.indisprimary = 't')
          and i.indisvalid = 't'
    );
    
    my $dbh = $self->get_default_handle();
    return undef unless $dbh;

    my $sth = $dbh->prepare($sql);
    return undef unless $sth;

    #my $db_owner = $self->owner();  # We should probably do something with the owner/schema
    $sth->execute($table_name);

    my $ret;
    while (my $data = $sth->fetchrow_hashref()) {
        $ret->{$data->{'relname'}} ||= [];
        push @{ $ret->{ $data->{'relname'} } }, $data->{'attname'};
    }

    return $ret;
}

my %ur_data_type_for_vendor_data_type = (
     # DB type      UR Type
     'SMALLINT'  => ['Integer', undef],
     'BIGINT'    => ['Integer', undef],
     'SERIAL'    => ['Integer', undef],
     'TEXT'      => ['XmlBlob', undef],
     'BYTEA'     => ['Blob', undef],

     'DOUBLE PRECISION' => ['Number', undef],
);
sub ur_data_type_for_data_source_data_type {
    my($class,$type) = @_;

    my $urtype = $ur_data_type_for_vendor_data_type{uc($type)};
    unless (defined $urtype) {
        $urtype = $class->SUPER::ur_data_type_for_data_source_data_type($type);
    }
    return $urtype;
}


sub _alter_sth_for_selecting_blob_columns {
    my($self, $sth, $column_objects) = @_;

    for (my $n = 0; $n < @$column_objects; $n++) {
        next unless defined ($column_objects->[$n]);  # No metaDB info for this one
        if (uc($column_objects->[$n]->data_type) eq 'BLOB') {
            $sth->bind_param($n+1, undef, { pg_type => PG_BYTEA });
        }
    }
}

sub _value_is_null {
    my ($class,$value) = @_;
    return 1 if not defined $value;
    return 1 if $value eq '';
    return 1 if (ref($value) eq 'HASH' and $value->{operator} eq '=' and (!defied($value->{value}) or $value->{value} eq ''));
    return 0;
}   

1;

=pod

=head1 NAME

UR::DataSource::Pg - PostgreSQL specific subclass of UR::DataSource::RDBMS

=head1 DESCRIPTION

This module provides the PostgreSQL-specific methods necessary for interacting with
PostgreSQL databases

=head1 SEE ALSO

L<UR::DataSource>, L<UR::DataSource::RDBMS>

=cut