package Slic3r::Fill::Concentric;
use Moo;

extends 'Slic3r::Fill::Base';

use Slic3r::ExtrusionPath ':roles';
use Slic3r::Geometry qw(scale unscale X1 Y1 X2 Y2);

sub fill_surface {
    my $self = shift;
    my ($surface, %params) = @_;
    
    # no rotation is supported for this infill pattern
    
    my $expolygon = $surface->expolygon;
    my $bounding_box = [ $expolygon->bounding_box ];
    
    my $min_spacing = scale $params{flow_spacing};
    my $distance = $min_spacing / $params{density};
    
    my $flow_spacing = $params{flow_spacing};
    if ($params{density} == 1) {
        $distance = $self->adjust_solid_spacing(
            width       => $bounding_box->[X2] - $bounding_box->[X1],
            distance    => $distance,
        );
        $flow_spacing = unscale $distance;
    }
    
    my @contour_loops = ();
    my @hole_loops = ();
    my @last_offsets = ($expolygon->offset_ex($distance));
    while (@last_offsets) {
        my @new_offsets = ();
        foreach my $last_expolygon (@last_offsets) {
            my @offsets = $last_expolygon->offset_ex(-$distance);
            foreach my $offset (@offsets) {
                push @new_offsets, $offset;
                push @contour_loops, $offset->contour;
                push @hole_loops, $offset->holes;
            }
        }
        @last_offsets = @new_offsets;
    }
    
    my @loops = (@contour_loops, reverse @hole_loops);
    
    # make paths
    my @paths = ();
    my $cur_pos = Slic3r::Point->new(
        ($bounding_box->[X1] + $bounding_box->[X2]) / 2,
        ($bounding_box->[Y1] + $bounding_box->[Y2]) / 2,
    );
    foreach my $loop (map Slic3r::ExtrusionLoop->new(polygon => $_, role => EXTR_ROLE_FILL), @loops) {
        # extrude all loops ccw
        $loop->polygon->make_counter_clockwise;
        
        # find the point of the loop that is closest to the current extruder position
        my $index = $loop->nearest_point_index_to($cur_pos);
        $cur_pos = $loop->polygon->[0];
        
        # split the loop at the starting point and make a path
        my $path = $loop->split_at_index($index);
        
        # clip the path to avoid the extruder to get exactly on the first point of the loop
        $path->clip_end(($self->layer ? $self->layer->flow->scaled_spacing : $Slic3r::flow->scaled_spacing) * &Slic3r::LOOP_CLIPPING_LENGTH_OVER_SPACING);
        
        push @paths, $path->points if @{$path->points};
    }
    
    return { flow_spacing => $flow_spacing }, @paths;
}

1;