#!/usr/bin/perl

###########################################
# Variable Length Markov Diddly. 
###########################################

use strict;
use constant LENGTH => 4;							# length of pattern key
use MIDI::Simple;
my %duration = (
  2 => 'qn',
  4 => 'hn',
  8 => 'wn',
  12 => 'dwn',
);

new_score;
set_tempo 500000;  # 1 qn => .5 seconds (500,000 microseconds)
patch_change 1, 77;  # Patch 76 = recorder, 77 = pan flute, 80 = whistle, 81 = Ocarina

noop "c1", "fff", "o3";  # Setup

my %probs;											# probabilities of next note

while (<DATA>) {									# read the existing tunes...
	chomp;
	my @line = split /,/;
	my @notes = ("START") x (LENGTH);				# cyclic buffer
	while (@line) {
		shift (@notes);
		push @notes, shift(@line).",".shift(@line); # "note,length"
		$probs{key(@notes)}{$notes[$#notes]}++;
	}
	shift (@notes);
	$probs{key(@notes)}{"END"}++;
}

my @notes = ("START") x LENGTH;
do {
	shift(@notes);
	my %next = %{$probs{key(@notes)}};				# array of probs
	my @next = map {($_) x $next{$_}} keys %next;	# 1 entry per 'prob'
	push @notes, $next[int(rand(@next))];
	my ($note, $dur);
	unless ($notes[$#notes] eq "END") {
    print "$notes[$#notes] ";
	  ($note, $dur) = split',',$notes[$#notes];
	  ++$note; # increment once
	  $note = uc(++$note); # increment again and then upcase it!
	  $note = $MIDI::note2number{$note};
    eval(n $duration{$dur}, $note);
	}
	
} while ($notes[$#notes] ne "END");


write_score 'markov-diddly.mid';

 
sub key {return join("",@_[0..LENGTH-2]);}			# make space-separated key

# a bunch of common session tunes (plus one of mine <g>)
 
__DATA__
e2,4,e2,2,b2,2,e2,2,b2,2,e2,2,e2,2,b2,2,a2,2,fs2,2,d2,2,e2,4,e2,2,b2,4,cs3,2,d3,2,cs3,2,b2,2,a2,2,fs2,2,d2,2,e2,4,e2,2,b2,2,e2,2,b2,2,e2,2,e2,2,b2,2,a2,2,fs2,2,d2,2,g2,4,g2,2,fs2,2,g2,2,a2,2,b2,2,a2,2,g2,2,fs2,2,e2,2,d2,2
d2,2,g2,2,g2,2,b2,2,g2,2,g2,2,a2,2,g2,2,a2,2,b2,2,g2,2,g2,2,e3,2,g3,2,e3,2,d3,2,b2,2,g2,2,a2,2,g2,2,a2,2,b2,2,g2,2,e2,2,d2,2,g2,2,g2,2,b2,2,g2,2,g2,2,a2,2,g2,2,a2,2,b2,2,g2,2,g2,2,e3,2,g3,2,e3,2,d3,2,b2,2,g2,2,a2,2,g2,2,fs2,2,g2,6
d2,4,d2,2,a2,6,b2,2,a2,2,g2,2,a2,2,b2,2,a2,2,d2,4,d2,2,a2,6,b2,2,a2,2,g2,2,e2,2,g2,2,e2,2,d2,4,d2,2,a2,6,b2,2,a2,2,g2,2,a2,2,b2,2,c3,2,d2,2,c3,2,b2,2,c3,2,b2,2,a2,2,b2,2,a2,2,g2,2,e2,2,g2,2,e2,2
d3,2,e3,2,d3,2,b2,4,g2,2,a2,4,g2,2,e2,4,d2,2,g2,4,g2,2,g2,2,a2,2,b2,2,d3,4,b2,2,a2,6,d3,2,e3,2,d3,2,b2,4,g3,2,fs2,4,e3,2,c3,4,e3,2,d3,2,e3,2,d3,2,c3,2,b2,2,a2,2,g2,12
b2,2,g2,2,g2,2,d2,2,g2,2,g2,2,b2,2,g2,2,b2,2,d3,2,c3,2,b2,2,c3,2,a2,2,a2,2,fs2,2,a2,2,a2,2,c3,2,a2,2,c3,2,e3,2,d3,2,c3,2,b2,2,g2,2,g2,2,d2,2,g2,2,g2,2,b2,2,g2,2,b2,2,d3,2,c3,2,b2,2,c3,2,b2,2,c3,2,a2,2,d3,2,c3,2,b2,2,g2,2,g2,2,g2,2,d3,2,c3,2
fs2,4,b2,2,b2,2,cs3,2,d3,2,cs3,4,a2,2,a2,2,b2,2,cs3,2,d3,4,b2,2,b2,2,cs3,2,d3,2,e3,2,fs3,2,e3,2,d3,2,cs3,2,b2,2,fs2,4,b2,2,b2,2,cs3,2,d3,2,cs3,4,a2,2,a2,2,b2,2,cs3,2,d3,2,cs3,2,d3,2,e3,2,d3,2,e3,2,fs3,2,b2,2,b2,2,b2,6
a2,2,fs2,2,a2,2,a2,2,fs2,2,a2,2,b2,2,g2,2,b2,2,b2,2,g2,2,b2,2,a2,2,fs2,2,a2,2,a2,2,d3,2,e3,2,fs3,2,e3,2,d3,3,b2,2,d3,2,b2,2,a2,2,fs2,2,a2,2,a2,2,fs2,2,a2,2,b2,2,g2,2,b2,2,b2,2,g2,2,b2,2,d3,2,e3,2,fs3,2,a3,2,fs3,2,e3,2,fs3,2,b2,2,b2,3,b2,2,d3,2,b2,2
a2,2,d2,2,d2,2,b2,2,d2,2,d2,2,c3,6,c3,2,b2,2,a2,2,g2,2,a2,2,b2,2,a2,2,g2,2,fs2,2,g2,2,fs2,2,g2,2,e2,2,fs2,2,g2,2,a2,2,d2,2,d2,2,b2,2,d2,2,d2,2,c3,6,c3,2,b2,2,a2,2,g2,2,a2,2,b2,2,a2,2,g2,2,fs2,2,g2,12
e2,2,fs2,2,e2,2,b2,4,b2,2,b2,2,a2,2,fs2,2,d3,6,e2,2,fs2,2,e2,2,b2,4,b2,2,b2,2,a2,2,fs2,2,fs2,4,e2,2,e2,2,fs2,2,e2,2,b2,4,b2,2,b2,2,a2,2,fs2,2,d3,6,b2,2,cs3,2,d3,2,e3,4,b2,2,b2,2,a2,2,fs2,2,fs2,4,e2,2
d2,4,a2,2,fs2,4,a2,2,d2,4,a2,2,fs2,4,a2,2,d3,4,e3,2,fs3,4,e3,2,d3,4,cs3,2,b2,4,a2,2,e3,6,fs3,6,g3,6,fs3,6,e3,4,d3,2,cs3,4,b2,2,a2,2,b2,2,a2,2,g2,2,fs2,2,e2,2
d2,4,e2,2,fs2,4,g2,2,a2,4,b2,2,a2,4,fs2,2,a2,4,b2,2,a2,4,fs2,2,a2,4,b2,2,a2,4,fs2,2,d2,4,e2,2,fs2,4,g2,2,a2,4,b2,2,a2,4,d3,2,cs3,4,b2,2,a2,4,fs2,2,d2,12
g2,2,g2,2,g2,2,g2,6,g2,2,g2,2,g2,2,g2,4,d3,2,b2,4,g2,2,b2,4,d3,2,g3,4,d3,2,b2,4,g2,2,d2,2,d2,2,d2,2,d2,6,d2,2,d2,2,d2,2,d2,4,a2,2,fs2,4,d2,2,fs2,4,a2,2,c3,4,a2,2,fs2,4,d2,2
a2,6,a2,6,a2,2,fs2,2,d3,2,a2,2,fs2,2,d2,2,g2,6,g2,6,g2,2,e2,2,fs2,2,g3,2,fs2,2,e2,2,a2,6,a2,6,a2,2,fs2,2,d3,2,a2,2,fs2,2,d2,2,e2,2,fs2,2,g2,2,fs2,2,g2,2,e2,2,d2,12
a2,2,d2,2,d2,2,b2,2,d2,2,d2,2,c3,6,c3,2,b2,2,a2,2,g2,2,a2,2,b2,2,a2,2,g2,2,fs2,2,g2,2,fs2,2,g2,2,e2,2,fs2,2,g2,2,a2,2,d2,2,d2,2,b2,2,d2,2,d2,2,c3,6,c3,2,b2,2,a2,2,g2,2,a2,2,b2,2,a2,2,g2,2,fs2,2,g2,12