use Test::More tests => 3;
use strict;
use warnings;

BEGIN {
    use FindBin;
    use lib "$FindBin::Bin/../lib";
}

use List::Util qw(first);
use Slic3r;
use Slic3r::Test;

{
    my $config = Slic3r::Config->new_from_defaults;
    $config->set('skirts', 0);
    $config->set('solid_layers', 0);
    $config->set('bottom_solid_layers', 0);
    $config->set('top_solid_layers', 0);
    $config->set('infill_every_layers', 6);
    $config->set('layer_height', 0.06);
    $config->set('perimeters', 1);
    
    my $test = sub {
        my ($shift) = @_;
        
        my $self = Slic3r::Test::init_print('20mm_cube', config => $config);
        
        $shift /= &Slic3r::SCALING_FACTOR;
        my $scale = 4; # make room for fat infill lines with low layer height

        # Put a slope on the box's sides by shifting x and y coords by $tilt * (z / boxheight).
        # The test here is to put such a slight slope on the walls that it should
        # not trigger any extra fill on fill layers that should be empty when 
        # combine infill is enabled.
        $_->[0] += $shift * ($_->[2] / (20 / &Slic3r::SCALING_FACTOR)) for @{$self->objects->[0]->meshes->[0]->vertices};
        $_->[1] += $shift * ($_->[2] / (20 / &Slic3r::SCALING_FACTOR)) for @{$self->objects->[0]->meshes->[0]->vertices};
        $_ = [$_->[0]*$scale, $_->[1]*$scale, $_->[2]] for @{$self->objects->[0]->meshes->[0]->vertices};
                
        # copy of Print::export_gcode() up to the point 
        # after fill surfaces are combined
        $self->init_extruders;
        $_->slice for @{$self->objects};
        $_->make_perimeters for @{$self->objects};
        foreach my $layer (map @{$_->layers}, @{$self->objects}) {
            @$_ = map $_->simplify(&Slic3r::SCALED_RESOLUTION), @$_
                for $layer->slices, (map $_->slices, @{$layer->regions});
        }
        $_->detect_surfaces_type for @{$self->objects};
        $_->prepare_fill_surfaces for map @{$_->regions}, map @{$_->layers}, @{$self->objects};
        $_->process_external_surfaces for map @{$_->regions}, map @{$_->layers}, @{$self->objects};
        $_->discover_horizontal_shells for @{$self->objects};
        $_->combine_infill for @{$self->objects};

        # Only layers with id % 6 == 0 should have fill.
        my $spurious_infill = 0;
        foreach my $layer (map @{$_->layers}, @{$self->objects}) {
            ++$spurious_infill if ($layer->id % 6 && grep @{$_->fill_surfaces} > 0, @{$layer->regions});
        }

        $spurious_infill -= scalar(@{$self->objects->[0]->layers} - 1) % 6;
        
        fail "spurious fill surfaces found on layers that should have none (walls " . sprintf("%.4f", Slic3r::Geometry::rad2deg(atan2($shift, 20/&Slic3r::SCALING_FACTOR))) . " degrees off vertical)"
            unless $spurious_infill == 0;
        1;
    };
    
    # Test with mm skew offsets for the top of the 20mm-high box
    for my $shift (0, 0.0001, 1) {
        ok $test->($shift), "no spurious fill surfaces with box walls " . sprintf("%.4f",Slic3r::Geometry::rad2deg(atan2($shift, 20))) . " degrees off of vertical";
    }
}

__END__