############
# poe musician using distributed probabability
#
# 
# it should be pretty easy to get one musician to write a random
# head, and get the others to jam along. 
#
# Author: Steve McNabb (steve@justsomeguy.com)


package POE::Framework::MIDI::Musician::Probability;
use POE::Framework::MIDI::Musician;
use POE::Framework::MIDI::Bar;
use POE::Framework::MIDI::Note;
use POE::Framework::MIDI::Rest;

use vars qw/@ISA $VERSION/;
$VERSION = 0.1;
@ISA = qw(POE::Framework::MIDI::Musician);

sub new
{
        my($self,$class) = ({},shift);
        $self->{cfg} = shift;
        bless($self,$class);
        $self->set_weights;
        return $self;
}

sub make_bar
{
	my $self = shift;
	my $barnum = shift;
	my $interval = rand_dist_weighted($weights);
	my $bar = new POE::Framework::MIDI::Bar( { number => $barnum } );
	for(1..4)
	{
		
		my $name = rand_dist_weighted($self->{cfg}->{note_weights});
		my $duration = rand_dist_weighted($self->{cfg}->{duration_weights});
				
		my $note = new POE::Framework::MIDI::Note(
			{
			name => $name,
			duration => $duration,
			}
		);
		print "make $_ in $barnum: $name $duration " .$self->name ." \n" if $self->{cfg}->{debug};		
		$bar->add_event($note);			
	}
	return $bar; 
}

# ripped off from m.a.w.p.
#   $selection = rand_dist_weighted( \%dist, \@key_order, $total_weight )
#   Select an element from %dist.  The total of the weights, and the
#   keys sorted by their weights can be provided, or else they are
#   computed.

sub rand_dist_weighted {
    my( $dist, $key_order, $total_weight ) = @_;
    my $running_weight;

    $key_order = [ sort { $dist->{$a} <=> $dist->{$b} } keys %$dist ]
        unless $key_order;
    unless ( $total_weight ) {
        foreach (@$key_order) { $total_weight += $dist->{$_} }
    }

    # Get a random value.
    my $rand = rand( $total_weight );

    # Use it to determine a key.
    foreach my $key (@$key_order) {
        return $key if ($running_weight += $dist->{$key}) >= $rand;
    }
}

sub set_weights
{
	my $self = shift;
	# set some default weights just in case
	$self->{cfg}->{note_weights} =
	{
		C 	=> 1,
		Cs 	=> 1,
		D 	=> 1,
		Ds	=> 1,
		E	=> 1,
		F 	=> 1,
		Fs	=> 1,
		G	=> 1,
		Gs	=> 1,
		A	=> 1,
		As	=> 1,
		B	=> 1,	
	} unless $self->{cfg}->{note_weights};

	# some default octave weights.  how often to switch octaves randomly
	$self->{cfg}->{octave_weights} =
	{
		same => 10,
		up	=> 3,
		down	=> 3	
	} unless $self->{cfg}->{octave_weights};
	
	$self->{cfg}->{duration_weights} =
	{
		qn => 5,
		en => 12,
		sn => 10,
		tsn => 11,
		wn => 8,
			
	} unless $self->{cfg}->{duration_weights};	
}

1;