package DBManager;

use strict;
use warnings;
use DBI;
use Date::Manip;
use Class::Singleton;

our @ISA = qw(Class::Singleton);

1;

sub _new_instance {
    my $type = shift;
    my $class = ref $type || $type;
    
    die "DBManager::instance must be invoked as DBManager->instance" if ! defined $class;
    
    my $dbh = DBI->connect("dbi:SQLite:databasefilename", "", "");

    die "Cannot connect to database: $DBI::errstr\n"
        unless defined $dbh;
        
    $dbh->{AutoCommit} = 0;
    $dbh->{RaiseError} = 1;

    return bless {dbh => $dbh}, $class;
}


sub DESTROY {
    my $self = shift;
    
    $self->{dbh}->disconnect () if defined $self->{dbh};
}


package DBObject;

require Exporter;
our @ISA = ('Exporter');

our @EXPORT = qw(new);

sub new {
    my ($class, %params) = @_;

    die "DBObject::new must be invoked as DBObject->new"
        unless defined $class;

    die "A table definition (tableDef => ['name', 'column info'] is required by $class->new ()"
        unless 'ARRAY' eq ref $params{tableDef};

    die "database handle must be from a DBManager derived object"
        if exists $params{db} and ! $params{db}->isa ('DBManager');

    my $self = bless {%params}, $class;
    my %cols = map {s/^\s*//; s/\s*$//; /(\w+)\s*(.*)/; $1 => $2}
        split /,/, $params{tableDef}[1];

    $self->{cols} = \%cols;    
    $self->setDbh ();
    
    return $self;
}


sub DESTROY {
    my $self = shift;
    
    $self->{db} = undef;
}