package DB;
use DBI;
use Carp;
use Moose::Role;
use Modern::Perl;

has 'db'      => ( is => 'rw', isa => 'Str',     lazy => 1, default => '', trigger => \&_switch_db );  
has 'dbh'     => ( is => 'rw', isa => 'DBI::db', lazy => 1, builder => '_db_connect' );
has 'dsn'     => ( is => 'rw', isa => 'Str',     lazy => 1, default => 'DBI:mysql:host=127.0.0.1');
has 'db_user' => ( is => 'rw', isa => 'Str',     lazy => 1, default => 'root' );
has 'db_pass' => ( is => 'rw', isa => 'Str',     lazy => 1, default => 'mypass' );
has 'db_host' => ( is => 'rw', isa => 'Str',     lazy => 1, default => '127.0.0.1' );
has 'db_type' => ( is => 'rw', isa => 'Str',     lazy => 1, default => 'mysql' );

sub _db_connect {
  my $self = shift;
  my $db   = shift;

  $self->_set_dsn($db);
  return DBI->connect($self->dsn, $self->db_user, $self->db_pass) || logf("Can't connect to database $db");
}

sub _set_dsn {
  my $self = shift;
  my $db = shift;

  logd('setting database');

  my $dsn = 'DBI:' . $self->db_type . ':host:' . $self->db_host;
  $dsn .= ";database=$db" if $db;
  $self->dsn($dsn);
}

sub _switch_db {
  my $self = shift;
  logd('switching db');
  $self->dbh($self->_db_connect($self->db));
}