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#!/usr/bin/env perl
# rainmidi3000.pl - an example Algorithm::Gutter script, where random
# holes in a gutter either produce MIDI note events or toggle other
# holes on or off over time, as fed by changing amounts of rainfall.
# There are lots of things to TWEAK.
use v5.26.0;
use Algorithm::Gutter 0.02;
use Data::Dumper;
use List::Util 'shuffle';
use MIDI;

my $out_file = shift // 'out.midi';
my $ch       = 0;                     # MIDI channel (9 for drums)
my $tick     = 32;                    # default duration (dtime)

# So you can figure out how things were wired up if you actually get
# good results from this thing, unless you are on OpenBSD, or this code
# is somehow incorrect.
my $seed = shift;
if ( defined $seed ) {
    srand $seed;
} else {
    say "SEED ", srand;
}

# See MIDI::Event and the MIDI specification.
my @events = (
    [ text_event => 0, 'RAIN-MIDI 3000 ][' ],
    #[ patch_change => 0, $ch, 11 ],
    [ set_tempo => 0, 450_000 ],
);

my $gobj  = Algorithm::Gutter->new( rain => \&water );
my $glist = $gobj->gutter;

# The 'undef' are replaced with togglers, while the numbers are used to
# generate MIDI events with the given pitch number. Random pitches
# better suit random drum soundfonts. TWEAK
my $nbuckets = 32;
my @pitches  = shuffle( (undef) x 5, map getapitch(), 1 .. 13 );
#my @pitches = shuffle( (undef) x 5,
#    55, 56, 60, 61, 65, 67, 68, 72, 73, 77, 79, 80, 84 );
die "too many pitches\n" if @pitches > $nbuckets;
my $nholes = @pitches;

# Randomly allocate the toggler and pitch-generating cells. Planning
# where these go might get you better results?
{
    my $total  = $nbuckets;
    my $remain = $nholes;
    my $id     = 0;
    for ( 1 .. $nbuckets ) {
        my $cell = Algorithm::Gutter::Cell->new( amount => 0, id => $id++ );
        push @$glist, $cell;
        if ( rand(1.0) < ( $remain / $total ) ) {
            $cell->enabled = 1;
            die "not enough pitches??\n" unless @pitches;
            my $p = shift @pitches;
            if ( defined $p ) {
                $cell->update = \&pitch;
                # TWEAK larger values need more rainfall to trigger
                $cell->threshold = 4 + int( rand 6 + rand 6 + rand 6 );
                $cell->context->{pitch} = $p;
            } else {
                $cell->update    = \&toggle;
                $cell->threshold = 4 + int( rand 2 + rand 2 + rand 2 );
            }
            last if $remain-- <= 0;
        }
        $total--;
    }
}

# Wire up the togglers to toggle a random toggler or pitch generator
# cell, if possible.
my @targets = shuffle grep { $_->enabled } @$glist;
for my $cell ( shuffle @$glist ) {
    unless ( defined $cell->context ) {
        if (@targets) {
            $cell->context->{toggles} = shift @targets;
            $cell->enabled = coinflip();
        } else {
            ( $cell->enabled, $cell->threshold, $cell->update ) =
              ( 0, ~0, undef );
        }
    }
}

# What thing did we wire up? Some way to visualize this over time might
# also help direct one towards better wirings?
show_wiring($glist);

{
    # TWEAK fewer slosh iterations makes the fluid more viscous and thus
    # less able to spread out to adjacent cells
    #my $slosh_iters;
    my $slosh_iters = 2;
    my %slosh;