#include "Exception.hpp"
#include "Print.hpp"
#include "BoundingBox.hpp"
#include "Brim.hpp"
#include "ClipperUtils.hpp"
#include "Extruder.hpp"
#include "Flow.hpp"
#include "Geometry.hpp"
#include "I18N.hpp"
#include "ShortestPath.hpp"
#include "SupportMaterial.hpp"
#include "Thread.hpp"
#include "GCode.hpp"
#include "GCode/WipeTower.hpp"
#include "Utils.hpp"

#include <float.h>

#include <algorithm>
#include <limits>
#include <unordered_set>
#include <boost/filesystem/path.hpp>
#include <boost/format.hpp>
#include <boost/log/trivial.hpp>

// Mark string for localization and translate.
#define L(s) Slic3r::I18N::translate(s)

namespace Slic3r {

template class PrintState<PrintStep, psCount>;
template class PrintState<PrintObjectStep, posCount>;

PrintRegion::PrintRegion(const PrintRegionConfig &config) : PrintRegion(config, config.hash()) {}
PrintRegion::PrintRegion(PrintRegionConfig &&config) : PrintRegion(std::move(config), config.hash()) {}

void Print::clear() 
{
	tbb::mutex::scoped_lock lock(this->state_mutex());
    // The following call should stop background processing if it is running.
    this->invalidate_all_steps();
	for (PrintObject *object : m_objects)
		delete object;
	m_objects.clear();
    m_print_regions.clear();
    m_model.clear_objects();
}

// Called by Print::apply().
// This method only accepts PrintConfig option keys.
bool Print::invalidate_state_by_config_options(const ConfigOptionResolver & /* new_config */, const std::vector<t_config_option_key> &opt_keys)
{
    if (opt_keys.empty())
        return false;

    // Cache the plenty of parameters, which influence the G-code generator only,
    // or they are only notes not influencing the generated G-code.
    static std::unordered_set<std::string> steps_gcode = {
        "avoid_crossing_perimeters",
        "avoid_crossing_perimeters_max_detour",
        "bed_shape",
        "bed_temperature",
        "before_layer_gcode",
        "between_objects_gcode",
        "bridge_acceleration",
        "bridge_fan_speed",
        "colorprint_heights",
        "cooling",
        "default_acceleration",
        "deretract_speed",
        "disable_fan_first_layers",
        "duplicate_distance",
        "end_gcode",
        "end_filament_gcode",
        "extrusion_axis",
        "extruder_clearance_height",
        "extruder_clearance_radius",
        "extruder_colour",
        "extruder_offset",
        "extrusion_multiplier",
        "fan_always_on",
        "fan_below_layer_time",
        "full_fan_speed_layer",
        "filament_colour",
        "filament_diameter",
        "filament_density",
        "filament_notes",
        "filament_cost",
        "filament_spool_weight",
        "first_layer_acceleration",
        "first_layer_bed_temperature",
        "gcode_comments",
        "gcode_label_objects",
        "infill_acceleration",
        "layer_gcode",
        "min_fan_speed",
        "max_fan_speed",
        "max_print_height",
        "min_print_speed",
        "max_print_speed",
        "max_volumetric_speed",
#ifdef HAS_PRESSURE_EQUALIZER
        "max_volumetric_extrusion_rate_slope_positive",
        "max_volumetric_extrusion_rate_slope_negative",
#endif /* HAS_PRESSURE_EQUALIZER */
        "notes",
        "only_retract_when_crossing_perimeters",
        "output_filename_format",
        "perimeter_acceleration",
        "post_process",
        "printer_notes",
        "retract_before_travel",
        "retract_before_wipe",
        "retract_layer_change",
        "retract_length",
        "retract_length_toolchange",
        "retract_lift",
        "retract_lift_above",
        "retract_lift_below",
        "retract_restart_extra",
        "retract_restart_extra_toolchange",
        "retract_speed",
        "single_extruder_multi_material_priming",
        "slowdown_below_layer_time",
        "standby_temperature_delta",
        "start_gcode",
        "start_filament_gcode",
        "toolchange_gcode",
        "threads",
        "use_firmware_retraction",
        "use_relative_e_distances",
        "use_volumetric_e",
        "variable_layer_height",
        "wipe"
    };

    static std::unordered_set<std::string> steps_ignore;

    std::vector<PrintStep> steps;
    std::vector<PrintObjectStep> osteps;
    bool invalidated = false;

    for (const t_config_option_key &opt_key : opt_keys) {
        if (steps_gcode.find(opt_key) != steps_gcode.end()) {
            // These options only affect G-code export or they are just notes without influence on the generated G-code,
            // so there is nothing to invalidate.
            steps.emplace_back(psGCodeExport);
        } else if (steps_ignore.find(opt_key) != steps_ignore.end()) {
            // These steps have no influence on the G-code whatsoever. Just ignore them.
        } else if (
               opt_key == "skirts"
            || opt_key == "skirt_height"
            || opt_key == "draft_shield"
            || opt_key == "skirt_distance"
            || opt_key == "min_skirt_length"
            || opt_key == "ooze_prevention"
            || opt_key == "wipe_tower_x"
            || opt_key == "wipe_tower_y"
            || opt_key == "wipe_tower_rotation_angle") {
            steps.emplace_back(psSkirt);
        } else if (
               opt_key == "nozzle_diameter"
            || opt_key == "resolution"
            // Spiral Vase forces different kind of slicing than the normal model:
            // In Spiral Vase mode, holes are closed and only the largest area contour is kept at each layer.
            // Therefore toggling the Spiral Vase on / off requires complete reslicing.
            || opt_key == "spiral_vase") {
            osteps.emplace_back(posSlice);
        } else if (
               opt_key == "complete_objects"
            || opt_key == "filament_type"
            || opt_key == "first_layer_temperature"
            || opt_key == "filament_loading_speed"
            || opt_key == "filament_loading_speed_start"
            || opt_key == "filament_unloading_speed"
            || opt_key == "filament_unloading_speed_start"
            || opt_key == "filament_toolchange_delay"
            || opt_key == "filament_cooling_moves"
            || opt_key == "filament_minimal_purge_on_wipe_tower"
            || opt_key == "filament_cooling_initial_speed"
            || opt_key == "filament_cooling_final_speed"
            || opt_key == "filament_ramming_parameters"
            || opt_key == "filament_max_volumetric_speed"
            || opt_key == "gcode_flavor"
            || opt_key == "high_current_on_filament_swap"
            || opt_key == "infill_first"
            || opt_key == "single_extruder_multi_material"
            || opt_key == "temperature"
            || opt_key == "wipe_tower"
            || opt_key == "wipe_tower_width"
            || opt_key == "wipe_tower_brim_width"
            || opt_key == "wipe_tower_bridging"
            || opt_key == "wipe_tower_no_sparse_layers"
            || opt_key == "wiping_volumes_matrix"
            || opt_key == "parking_pos_retraction"
            || opt_key == "cooling_tube_retraction"
            || opt_key == "cooling_tube_length"
            || opt_key == "extra_loading_move"
            || opt_key == "travel_speed"
            || opt_key == "first_layer_speed"
            || opt_key == "z_offset") {
            steps.emplace_back(psWipeTower);
            steps.emplace_back(psSkirt);
        } else if (opt_key == "filament_soluble") {
            steps.emplace_back(psWipeTower);
            // Soluble support interface / non-soluble base interface produces non-soluble interface layers below soluble interface layers.
            // Thus switching between soluble / non-soluble interface layer material may require recalculation of supports.
            //FIXME Killing supports on any change of "filament_soluble" is rough. We should check for each object whether that is necessary.
            osteps.emplace_back(posSupportMaterial);
        } else if (
               opt_key == "first_layer_extrusion_width" 
            || opt_key == "min_layer_height"
            || opt_key == "max_layer_height") {
            osteps.emplace_back(posPerimeters);
            osteps.emplace_back(posInfill);
            osteps.emplace_back(posSupportMaterial);
            steps.emplace_back(psSkirt);
            steps.emplace_back(psBrim);
        } else {
            // for legacy, if we can't handle this option let's invalidate all steps
            //FIXME invalidate all steps of all objects as well?
            invalidated |= this->invalidate_all_steps();
            // Continue with the other opt_keys to possibly invalidate any object specific steps.
        }
    }

    sort_remove_duplicates(steps);
    for (PrintStep step : steps)
        invalidated |= this->invalidate_step(step);
    sort_remove_duplicates(osteps);
    for (PrintObjectStep ostep : osteps)
        for (PrintObject *object : m_objects)
            invalidated |= object->invalidate_step(ostep);
    return invalidated;
}

bool Print::invalidate_step(PrintStep step)
{
	bool invalidated = Inherited::invalidate_step(step);
    // Propagate to dependent steps.
    if (step == psSkirt)
		invalidated |= Inherited::invalidate_step(psBrim);
    if (step != psGCodeExport)
        invalidated |= Inherited::invalidate_step(psGCodeExport);
    return invalidated;
}

// returns true if an object step is done on all objects
// and there's at least one object
bool Print::is_step_done(PrintObjectStep step) const
{
    if (m_objects.empty())
        return false;
    tbb::mutex::scoped_lock lock(this->state_mutex());
    for (const PrintObject *object : m_objects)
        if (! object->is_step_done_unguarded(step))
            return false;
    return true;
}

// returns 0-based indices of used extruders
std::vector<unsigned int> Print::object_extruders() const
{
    std::vector<unsigned int> extruders;
    extruders.reserve(m_print_regions.size() * m_objects.size() * 3);
    for (const PrintObject *object : m_objects)
		for (const PrintRegion &region : object->all_regions())
        	region.collect_object_printing_extruders(*this, extruders);
    sort_remove_duplicates(extruders);
    return extruders;
}

// returns 0-based indices of used extruders
std::vector<unsigned int> Print::support_material_extruders() const
{
    std::vector<unsigned int> extruders;
    bool support_uses_current_extruder = false;
    auto num_extruders = (unsigned int)m_config.nozzle_diameter.size();

    for (PrintObject *object : m_objects) {
        if (object->has_support_material()) {
        	assert(object->config().support_material_extruder >= 0);
            if (object->config().support_material_extruder == 0)
                support_uses_current_extruder = true;
            else {
            	unsigned int i = (unsigned int)object->config().support_material_extruder - 1;
                extruders.emplace_back((i >= num_extruders) ? 0 : i);
            }
        	assert(object->config().support_material_interface_extruder >= 0);
            if (object->config().support_material_interface_extruder == 0)
                support_uses_current_extruder = true;
            else {
            	unsigned int i = (unsigned int)object->config().support_material_interface_extruder - 1;
                extruders.emplace_back((i >= num_extruders) ? 0 : i);
            }
        }
    }

    if (support_uses_current_extruder)
        // Add all object extruders to the support extruders as it is not know which one will be used to print supports.
        append(extruders, this->object_extruders());
    
    sort_remove_duplicates(extruders);
    return extruders;
}

// returns 0-based indices of used extruders
std::vector<unsigned int> Print::extruders() const
{
    std::vector<unsigned int> extruders = this->object_extruders();
    append(extruders, this->support_material_extruders());
    sort_remove_duplicates(extruders);
    return extruders;
}

unsigned int Print::num_object_instances() const
{
	unsigned int instances = 0;
    for (const PrintObject *print_object : m_objects)
        instances += (unsigned int)print_object->instances().size();
    return instances;
}

double Print::max_allowed_layer_height() const
{
    double nozzle_diameter_max = 0.;
    for (unsigned int extruder_id : this->extruders())
        nozzle_diameter_max = std::max(nozzle_diameter_max, m_config.nozzle_diameter.get_at(extruder_id));
    return nozzle_diameter_max;
}

std::vector<ObjectID> Print::print_object_ids() const 
{ 
    std::vector<ObjectID> out; 
    // Reserve one more for the caller to append the ID of the Print itself.
    out.reserve(m_objects.size() + 1);
    for (const PrintObject *print_object : m_objects)
        out.emplace_back(print_object->id());
    return out;
}

bool Print::has_infinite_skirt() const
{
    return (m_config.draft_shield && m_config.skirts > 0) || (m_config.ooze_prevention && this->extruders().size() > 1);
}

bool Print::has_skirt() const
{
    return (m_config.skirt_height > 0 && m_config.skirts > 0) || this->has_infinite_skirt();
}

bool Print::has_brim() const
{
    return std::any_of(m_objects.begin(), m_objects.end(), [](PrintObject *object) { return object->has_brim(); });
}

static inline bool sequential_print_horizontal_clearance_valid(const Print &print)
{
	Polygons convex_hulls_other;
	std::map<ObjectID, Polygon> map_model_object_to_convex_hull;
	for (const PrintObject *print_object : print.objects()) {
	    assert(! print_object->model_object()->instances.empty());
	    assert(! print_object->instances().empty());
	    ObjectID model_object_id = print_object->model_object()->id();
	    auto it_convex_hull = map_model_object_to_convex_hull.find(model_object_id);
        // Get convex hull of all printable volumes assigned to this print object.
        ModelInstance *model_instance0 = print_object->model_object()->instances.front();
	    if (it_convex_hull == map_model_object_to_convex_hull.end()) {
	        // Calculate the convex hull of a printable object. 
	        // Grow convex hull with the clearance margin.
	        // FIXME: Arrangement has different parameters for offsetting (jtMiter, limit 2)
	        // which causes that the warning will be showed after arrangement with the
	        // appropriate object distance. Even if I set this to jtMiter the warning still shows up.
#if ENABLE_ALLOW_NEGATIVE_Z
            it_convex_hull = map_model_object_to_convex_hull.emplace_hint(it_convex_hull, model_object_id,
                offset(print_object->model_object()->convex_hull_2d(
                    Geometry::assemble_transform({ 0.0, 0.0, model_instance0->get_offset().z() }, model_instance0->get_rotation(), model_instance0->get_scaling_factor(), model_instance0->get_mirror())),
                    // Shrink the extruder_clearance_radius a tiny bit, so that if the object arrangement algorithm placed the objects
                    // exactly by satisfying the extruder_clearance_radius, this test will not trigger collision.
                    float(scale_(0.5 * print.config().extruder_clearance_radius.value - EPSILON)),
                    jtRound, float(scale_(0.1))).front());
#else
	        it_convex_hull = map_model_object_to_convex_hull.emplace_hint(it_convex_hull, model_object_id, 
                offset(print_object->model_object()->convex_hull_2d(
	                        Geometry::assemble_transform(Vec3d::Zero(), model_instance0->get_rotation(), model_instance0->get_scaling_factor(), model_instance0->get_mirror())),
                	// Shrink the extruder_clearance_radius a tiny bit, so that if the object arrangement algorithm placed the objects
	                // exactly by satisfying the extruder_clearance_radius, this test will not trigger collision.
	                float(scale_(0.5 * print.config().extruder_clearance_radius.value - EPSILON)),
	                jtRound, float(scale_(0.1))).front());
#endif // ENABLE_ALLOW_NEGATIVE_Z
        }
	    // Make a copy, so it may be rotated for instances.
	    Polygon convex_hull0 = it_convex_hull->second;
		double z_diff = Geometry::rotation_diff_z(model_instance0->get_rotation(), print_object->instances().front().model_instance->get_rotation());
		if (std::abs(z_diff) > EPSILON)
			convex_hull0.rotate(z_diff);
	    // Now we check that no instance of convex_hull intersects any of the previously checked object instances.
	    for (const PrintInstance &instance : print_object->instances()) {
	        Polygon convex_hull = convex_hull0;
	        // instance.shift is a position of a centered object, while model object may not be centered.
	        // Conver the shift from the PrintObject's coordinates into ModelObject's coordinates by removing the centering offset.
	        convex_hull.translate(instance.shift - print_object->center_offset());
	        if (! intersection(convex_hulls_other, (Polygons)convex_hull).empty())
	            return false;
	        convex_hulls_other.emplace_back(std::move(convex_hull));
	    }
	}
	return true;
}

static inline bool sequential_print_vertical_clearance_valid(const Print &print)
{
	std::vector<const PrintInstance*> print_instances_ordered = sort_object_instances_by_model_order(print);
	// Ignore the last instance printed.
	print_instances_ordered.pop_back();
	// Find the other highest instance.
	auto it = std::max_element(print_instances_ordered.begin(), print_instances_ordered.end(), [](auto l, auto r) {
		return l->print_object->height() < r->print_object->height();
	});
    return it == print_instances_ordered.end() || (*it)->print_object->height() <= scale_(print.config().extruder_clearance_height.value);
}

// Precondition: Print::validate() requires the Print::apply() to be called its invocation.
std::string Print::validate(std::string* warning) const
{
    std::vector<unsigned int> extruders = this->extruders();

    if (m_objects.empty())
        return L("All objects are outside of the print volume.");

    if (extruders.empty())
        return L("The supplied settings will cause an empty print.");

    if (m_config.complete_objects) {
    	if (! sequential_print_horizontal_clearance_valid(*this))
            return L("Some objects are too close; your extruder will collide with them.");
        if (! sequential_print_vertical_clearance_valid(*this))
	        return L("Some objects are too tall and cannot be printed without extruder collisions.");
    }

    if (m_config.spiral_vase) {
        size_t total_copies_count = 0;
        for (const PrintObject *object : m_objects)
            total_copies_count += object->instances().size();
        // #4043
        if (total_copies_count > 1 && ! m_config.complete_objects.value)
            return L("Only a single object may be printed at a time in Spiral Vase mode. "
                     "Either remove all but the last object, or enable sequential mode by \"complete_objects\".");
        assert(m_objects.size() == 1);
        if (m_objects.front()->all_regions().size() > 1)
            return L("The Spiral Vase option can only be used when printing single material objects.");
    }

    if (this->has_wipe_tower() && ! m_objects.empty()) {
        // Make sure all extruders use same diameter filament and have the same nozzle diameter
        // EPSILON comparison is used for nozzles and 10 % tolerance is used for filaments
        double first_nozzle_diam = m_config.nozzle_diameter.get_at(extruders.front());
        double first_filament_diam = m_config.filament_diameter.get_at(extruders.front());
        for (const auto& extruder_idx : extruders) {
            double nozzle_diam = m_config.nozzle_diameter.get_at(extruder_idx);
            double filament_diam = m_config.filament_diameter.get_at(extruder_idx);
            if (nozzle_diam - EPSILON > first_nozzle_diam || nozzle_diam + EPSILON < first_nozzle_diam
             || std::abs((filament_diam-first_filament_diam)/first_filament_diam) > 0.1)
                 return L("The wipe tower is only supported if all extruders have the same nozzle diameter "
                          "and use filaments of the same diameter.");
        }

        if (m_config.gcode_flavor != gcfRepRapSprinter && m_config.gcode_flavor != gcfRepRapFirmware &&
            m_config.gcode_flavor != gcfRepetier && m_config.gcode_flavor != gcfMarlinLegacy && m_config.gcode_flavor != gcfMarlinFirmware)
            return L("The Wipe Tower is currently only supported for the Marlin, RepRap/Sprinter, RepRapFirmware and Repetier G-code flavors.");
        if (! m_config.use_relative_e_distances)
            return L("The Wipe Tower is currently only supported with the relative extruder addressing (use_relative_e_distances=1).");
        if (m_config.ooze_prevention)
            return L("Ooze prevention is currently not supported with the wipe tower enabled.");
        if (m_config.use_volumetric_e)
            return L("The Wipe Tower currently does not support volumetric E (use_volumetric_e=0).");
        if (m_config.complete_objects && extruders.size() > 1)
            return L("The Wipe Tower is currently not supported for multimaterial sequential prints.");
        
        if (m_objects.size() > 1) {
            bool                                has_custom_layering = false;
            std::vector<std::vector<coordf_t>>  layer_height_profiles;
            for (const PrintObject *object : m_objects) {
                has_custom_layering = ! object->model_object()->layer_config_ranges.empty() || ! object->model_object()->layer_height_profile.empty();
                if (has_custom_layering) {
                    layer_height_profiles.assign(m_objects.size(), std::vector<coordf_t>());
                    break;
                }
            }
            const SlicingParameters &slicing_params0 = m_objects.front()->slicing_parameters();
            size_t            tallest_object_idx = 0;
            if (has_custom_layering)
                PrintObject::update_layer_height_profile(*m_objects.front()->model_object(), slicing_params0, layer_height_profiles.front());
            for (size_t i = 1; i < m_objects.size(); ++ i) {
                const PrintObject       *object         = m_objects[i];
                const SlicingParameters &slicing_params = object->slicing_parameters();
                if (std::abs(slicing_params.first_print_layer_height - slicing_params0.first_print_layer_height) > EPSILON ||
                    std::abs(slicing_params.layer_height             - slicing_params0.layer_height            ) > EPSILON)
                    return L("The Wipe Tower is only supported for multiple objects if they have equal layer heights");
                if (slicing_params.raft_layers() != slicing_params0.raft_layers())
                    return L("The Wipe Tower is only supported for multiple objects if they are printed over an equal number of raft layers");
                if (slicing_params0.gap_object_support != slicing_params.gap_object_support ||
                    slicing_params0.gap_support_object != slicing_params.gap_support_object)
                    return L("The Wipe Tower is only supported for multiple objects if they are printed with the same support_material_contact_distance");
                if (! equal_layering(slicing_params, slicing_params0))
                    return L("The Wipe Tower is only supported for multiple objects if they are sliced equally.");
                if (has_custom_layering) {
                    PrintObject::update_layer_height_profile(*object->model_object(), slicing_params, layer_height_profiles[i]);
                    if (*(layer_height_profiles[i].end()-2) > *(layer_height_profiles[tallest_object_idx].end()-2))
                        tallest_object_idx = i;
                }
            }

            if (has_custom_layering) {
                const std::vector<coordf_t> &layer_height_profile_tallest = layer_height_profiles[tallest_object_idx];
                for (size_t idx_object = 0; idx_object < m_objects.size(); ++ idx_object) {
                    if (idx_object == tallest_object_idx)
                        continue;
                    const std::vector<coordf_t> &layer_height_profile = layer_height_profiles[idx_object];

                    // The comparison of the profiles is not just about element-wise equality, some layers may not be
                    // explicitely included. Always remember z and height of last reference layer that in the vector
                    // and compare to that. In case some layers are in the vectors multiple times, only the last entry is
                    // taken into account and compared.
                    size_t i = 0; // index into tested profile
                    size_t j = 0; // index into reference profile
                    coordf_t ref_z = -1.;
                    coordf_t next_ref_z = layer_height_profile_tallest[0];
                    coordf_t ref_height = -1.;
                    while (i < layer_height_profile.size()) {
                        coordf_t this_z = layer_height_profile[i];
                        // find the last entry with this z
                        while (i+2 < layer_height_profile.size() && layer_height_profile[i+2] == this_z)
                            i += 2;

                        coordf_t this_height = layer_height_profile[i+1];
                        if (ref_height < -1. || next_ref_z < this_z + EPSILON) {
                            ref_z = next_ref_z;
                            do { // one layer can be in the vector several times
                                ref_height = layer_height_profile_tallest[j+1];
                                if (j+2 >= layer_height_profile_tallest.size())
                                    break;
                                j += 2;
                                next_ref_z = layer_height_profile_tallest[j];
                            } while (ref_z == next_ref_z);
                        }
                        if (std::abs(this_height - ref_height) > EPSILON)
                            return L("The Wipe tower is only supported if all objects have the same variable layer height");
                        i += 2;
                    }
                }
            }
        }
    }
    
	{
		// Find the smallest used nozzle diameter and the number of unique nozzle diameters.
		double min_nozzle_diameter = std::numeric_limits<double>::max();
		double max_nozzle_diameter = 0;
		for (unsigned int extruder_id : extruders) {
			double dmr = m_config.nozzle_diameter.get_at(extruder_id);
			min_nozzle_diameter = std::min(min_nozzle_diameter, dmr);
			max_nozzle_diameter = std::max(max_nozzle_diameter, dmr);
		}

#if 0
        // We currently allow one to assign extruders with a higher index than the number
        // of physical extruders the machine is equipped with, as the Printer::apply() clamps them.
        unsigned int total_extruders_count = m_config.nozzle_diameter.size();
        for (const auto& extruder_idx : extruders)
            if ( extruder_idx >= total_extruders_count )
                return L("One or more object were assigned an extruder that the printer does not have.");
#endif

        auto validate_extrusion_width = [/*min_nozzle_diameter,*/ max_nozzle_diameter](const ConfigBase &config, const char *opt_key, double layer_height, std::string &err_msg) -> bool {
            // This may change in the future, if we switch to "extrusion width wrt. nozzle diameter"
            // instead of currently used logic "extrusion width wrt. layer height", see GH issues #1923 #2829.
//        	double extrusion_width_min = config.get_abs_value(opt_key, min_nozzle_diameter);
//        	double extrusion_width_max = config.get_abs_value(opt_key, max_nozzle_diameter);
            double extrusion_width_min = config.get_abs_value(opt_key, layer_height);
            double extrusion_width_max = config.get_abs_value(opt_key, layer_height);
        	if (extrusion_width_min == 0) {
        		// Default "auto-generated" extrusion width is always valid.
        	} else if (extrusion_width_min <= layer_height) {
        		err_msg = (boost::format(L("%1%=%2% mm is too low to be printable at a layer height %3% mm")) % opt_key % extrusion_width_min % layer_height).str();
				return false;
			} else if (extrusion_width_max >= max_nozzle_diameter * 3.) {
				err_msg = (boost::format(L("Excessive %1%=%2% mm to be printable with a nozzle diameter %3% mm")) % opt_key % extrusion_width_max % max_nozzle_diameter).str();
				return false;
			}
			return true;
		};
        for (PrintObject *object : m_objects) {
            if (object->has_support_material()) {
				if ((object->config().support_material_extruder == 0 || object->config().support_material_interface_extruder == 0) && max_nozzle_diameter - min_nozzle_diameter > EPSILON) {
                    // The object has some form of support and either support_material_extruder or support_material_interface_extruder
                    // will be printed with the current tool without a forced tool change. Play safe, assert that all object nozzles
                    // are of the same diameter.
                    return L("Printing with multiple extruders of differing nozzle diameters. "
                           "If support is to be printed with the current extruder (support_material_extruder == 0 or support_material_interface_extruder == 0), "
                           "all nozzles have to be of the same diameter.");
                }
                if (this->has_wipe_tower()) {
    				if (object->config().support_material_contact_distance == 0) {
    					// Soluble interface
    					if (object->config().support_material_contact_distance == 0 && ! object->config().support_material_synchronize_layers)
    						return L("For the Wipe Tower to work with the soluble supports, the support layers need to be synchronized with the object layers.");
    				} else {
    					// Non-soluble interface
    					if (object->config().support_material_extruder != 0 || object->config().support_material_interface_extruder != 0)
    						return L("The Wipe Tower currently supports the non-soluble supports only if they are printed with the current extruder without triggering a tool change. "
    							     "(both support_material_extruder and support_material_interface_extruder need to be set to 0).");
    				}
                }
            }

            // Do we have custom support data that would not be used?
            // Notify the user in that case.
            if (! object->has_support() && warning) {
                for (const ModelVolume* mv : object->model_object()->volumes) {
                    bool has_enforcers = mv->is_support_enforcer()
                        || (mv->is_model_part()
                            && ! mv->supported_facets.empty()
                            && ! mv->supported_facets.get_facets(*mv, EnforcerBlockerType::ENFORCER).indices.empty());
                    if (has_enforcers) {
                        *warning = "_SUPPORTS_OFF";
                        break;
                    }
                }
            }

            // validate first_layer_height
            assert(! m_config.first_layer_height.percent);
            double first_layer_height = m_config.first_layer_height.value;
            double first_layer_min_nozzle_diameter;
            if (object->has_raft()) {
                // if we have raft layers, only support material extruder is used on first layer
                size_t first_layer_extruder = object->config().raft_layers == 1
                    ? object->config().support_material_interface_extruder-1
                    : object->config().support_material_extruder-1;
                first_layer_min_nozzle_diameter = (first_layer_extruder == size_t(-1)) ? 
                    min_nozzle_diameter : 
                    m_config.nozzle_diameter.get_at(first_layer_extruder);
            } else {
                // if we don't have raft layers, any nozzle diameter is potentially used in first layer
                first_layer_min_nozzle_diameter = min_nozzle_diameter;
            }
            if (first_layer_height > first_layer_min_nozzle_diameter)
                return L("First layer height can't be greater than nozzle diameter");
            
            // validate layer_height
            double layer_height = object->config().layer_height.value;
            if (layer_height > min_nozzle_diameter)
                return L("Layer height can't be greater than nozzle diameter");

            // Validate extrusion widths.
            std::string err_msg;
            if (! validate_extrusion_width(object->config(), "extrusion_width", layer_height, err_msg))
            	return err_msg;
            if ((object->has_support() || object->has_raft()) && ! validate_extrusion_width(object->config(), "support_material_extrusion_width", layer_height, err_msg))
            	return err_msg;
            for (const char *opt_key : { "perimeter_extrusion_width", "external_perimeter_extrusion_width", "infill_extrusion_width", "solid_infill_extrusion_width", "top_infill_extrusion_width" })
				for (const PrintRegion &region : object->all_regions())
            		if (! validate_extrusion_width(region.config(), opt_key, layer_height, err_msg))
		            	return err_msg;
        }
    }

    return std::string();
}

#if 0
// the bounding box of objects placed in copies position
// (without taking skirt/brim/support material into account)
BoundingBox Print::bounding_box() const
{
    BoundingBox bb;
    for (const PrintObject *object : m_objects)
        for (const PrintInstance &instance : object->instances()) {
        	BoundingBox bb2(object->bounding_box());
        	bb.merge(bb2.min + instance.shift);
        	bb.merge(bb2.max + instance.shift);
        }
    return bb;
}

// the total bounding box of extrusions, including skirt/brim/support material
// this methods needs to be called even when no steps were processed, so it should
// only use configuration values
BoundingBox Print::total_bounding_box() const
{
    // get objects bounding box
    BoundingBox bb = this->bounding_box();
    
    // we need to offset the objects bounding box by at least half the perimeters extrusion width
    Flow perimeter_flow = m_objects.front()->get_layer(0)->get_region(0)->flow(frPerimeter);
    double extra = perimeter_flow.width/2;
    
    // consider support material
    if (this->has_support_material()) {
        extra = std::max(extra, SUPPORT_MATERIAL_MARGIN);
    }
    
    // consider brim and skirt
    if (m_config.brim_width.value > 0) {
        Flow brim_flow = this->brim_flow();
        extra = std::max(extra, m_config.brim_width.value + brim_flow.width/2);
    }
    if (this->has_skirt()) {
        int skirts = m_config.skirts.value;
        if (skirts == 0 && this->has_infinite_skirt()) skirts = 1;
        Flow skirt_flow = this->skirt_flow();
        extra = std::max(
            extra,
            m_config.brim_width.value
                + m_config.skirt_distance.value
                + skirts * skirt_flow.spacing()
                + skirt_flow.width/2
        );
    }
    
    if (extra > 0)
        bb.offset(scale_(extra));
    
    return bb;
}
#endif

double Print::skirt_first_layer_height() const
{
    assert(! m_config.first_layer_height.percent);
    return m_config.first_layer_height.value;
}

Flow Print::brim_flow() const
{
    ConfigOptionFloatOrPercent width = m_config.first_layer_extrusion_width;
    if (width.value == 0) 
        width = m_print_regions.front()->config().perimeter_extrusion_width;
    if (width.value == 0) 
        width = m_objects.front()->config().extrusion_width;
    
    /* We currently use a random region's perimeter extruder.
       While this works for most cases, we should probably consider all of the perimeter
       extruders and take the one with, say, the smallest index.
       The same logic should be applied to the code that selects the extruder during G-code
       generation as well. */
    return Flow::new_from_config_width(
        frPerimeter,
		width,
        (float)m_config.nozzle_diameter.get_at(m_print_regions.front()->config().perimeter_extruder-1),
		(float)this->skirt_first_layer_height());
}

Flow Print::skirt_flow() const
{
    ConfigOptionFloatOrPercent width = m_config.first_layer_extrusion_width;
    if (width.value == 0) 
        width = m_print_regions.front()->config().perimeter_extrusion_width;
    if (width.value == 0)
        width = m_objects.front()->config().extrusion_width;
    
    /* We currently use a random object's support material extruder.
       While this works for most cases, we should probably consider all of the support material
       extruders and take the one with, say, the smallest index;
       The same logic should be applied to the code that selects the extruder during G-code
       generation as well. */
    return Flow::new_from_config_width(
        frPerimeter,
		width,
		(float)m_config.nozzle_diameter.get_at(m_objects.front()->config().support_material_extruder-1),
		(float)this->skirt_first_layer_height());
}

bool Print::has_support_material() const
{
    for (const PrintObject *object : m_objects)
        if (object->has_support_material()) 
            return true;
    return false;
}

/*  This method assigns extruders to the volumes having a material
    but not having extruders set in the volume config. */
void Print::auto_assign_extruders(ModelObject* model_object) const
{
    // only assign extruders if object has more than one volume
    if (model_object->volumes.size() < 2)
        return;
    
//    size_t extruders = m_config.nozzle_diameter.values.size();
    for (size_t volume_id = 0; volume_id < model_object->volumes.size(); ++ volume_id) {
        ModelVolume *volume = model_object->volumes[volume_id];
        //FIXME Vojtech: This assigns an extruder ID even to a modifier volume, if it has a material assigned.
        if ((volume->is_model_part() || volume->is_modifier()) && ! volume->material_id().empty() && ! volume->config.has("extruder"))
            volume->config.set("extruder", int(volume_id + 1));
    }
}

// Slicing process, running at a background thread.
void Print::process()
{
    name_tbb_thread_pool_threads();

    BOOST_LOG_TRIVIAL(info) << "Starting the slicing process." << log_memory_info();
    for (PrintObject *obj : m_objects)
        obj->make_perimeters();
    this->set_status(70, L("Infilling layers"));
    for (PrintObject *obj : m_objects)
        obj->infill();
    for (PrintObject *obj : m_objects)
        obj->ironing();
    for (PrintObject *obj : m_objects)
        obj->generate_support_material();
    if (this->set_started(psWipeTower)) {
        m_wipe_tower_data.clear();
        m_tool_ordering.clear();
        if (this->has_wipe_tower()) {
            //this->set_status(95, L("Generating wipe tower"));
            this->_make_wipe_tower();
        } else if (! this->config().complete_objects.value) {
        	// Initialize the tool ordering, so it could be used by the G-code preview slider for planning tool changes and filament switches.
        	m_tool_ordering = ToolOrdering(*this, -1, false);
            if (m_tool_ordering.empty() || m_tool_ordering.last_extruder() == unsigned(-1))
                throw Slic3r::SlicingError("The print is empty. The model is not printable with current print settings.");
        }
        this->set_done(psWipeTower);
    }
    if (this->set_started(psSkirt)) {
        m_skirt.clear();
        m_skirt_convex_hull.clear();
        m_first_layer_convex_hull.points.clear();
        if (this->has_skirt()) {
            this->set_status(88, L("Generating skirt"));
            this->_make_skirt();
        }
        this->set_done(psSkirt);
    }
	if (this->set_started(psBrim)) {
        m_brim.clear();
        m_first_layer_convex_hull.points.clear();
        if (this->has_brim()) {
            this->set_status(88, L("Generating brim"));
            Polygons islands_area;
            m_brim = make_brim(*this, this->make_try_cancel(), islands_area);
            for (Polygon &poly : union_(this->first_layer_islands(), islands_area))
                append(m_first_layer_convex_hull.points, std::move(poly.points));
        }
        // Brim depends on skirt (brim lines are trimmed by the skirt lines), therefore if
        // the skirt gets invalidated, brim gets invalidated as well and the following line is called.
        this->finalize_first_layer_convex_hull();
        this->set_done(psBrim);
    }
    BOOST_LOG_TRIVIAL(info) << "Slicing process finished." << log_memory_info();
}

// G-code export process, running at a background thread.
// The export_gcode may die for various reasons (fails to process output_filename_format,
// write error into the G-code, cannot execute post-processing scripts).
// It is up to the caller to show an error message.
std::string Print::export_gcode(const std::string& path_template, GCodeProcessor::Result* result, ThumbnailsGeneratorCallback thumbnail_cb)
{
    // output everything to a G-code file
    // The following call may die if the output_filename_format template substitution fails.
    std::string path = this->output_filepath(path_template);
    std::string message;
    if (!path.empty() && result == nullptr) {
        // Only show the path if preview_data is not set -> running from command line.
        message = L("Exporting G-code");
        message += " to ";
        message += path;
    } else
        message = L("Generating G-code");
    this->set_status(90, message);

    // The following line may die for multiple reasons.
    GCode gcode;
    gcode.do_export(this, path.c_str(), result, thumbnail_cb);
    return path.c_str();
}

void Print::_make_skirt()
{
    // First off we need to decide how tall the skirt must be.
    // The skirt_height option from config is expressed in layers, but our
    // object might have different layer heights, so we need to find the print_z
    // of the highest layer involved.
    // Note that unless has_infinite_skirt() == true
    // the actual skirt might not reach this $skirt_height_z value since the print
    // order of objects on each layer is not guaranteed and will not generally
    // include the thickest object first. It is just guaranteed that a skirt is
    // prepended to the first 'n' layers (with 'n' = skirt_height).
    // $skirt_height_z in this case is the highest possible skirt height for safety.
    coordf_t skirt_height_z = 0.;
    for (const PrintObject *object : m_objects) {
        size_t skirt_layers = this->has_infinite_skirt() ?
            object->layer_count() : 
            std::min(size_t(m_config.skirt_height.value), object->layer_count());
        skirt_height_z = std::max(skirt_height_z, object->m_layers[skirt_layers-1]->print_z);
    }
    
    // Collect points from all layers contained in skirt height.
    Points points;
    for (const PrintObject *object : m_objects) {
        Points object_points;
        // Get object layers up to skirt_height_z.
        for (const Layer *layer : object->m_layers) {
            if (layer->print_z > skirt_height_z)
                break;
            for (const ExPolygon &expoly : layer->lslices)
                // Collect the outer contour points only, ignore holes for the calculation of the convex hull.
                append(object_points, expoly.contour.points);
        }
        // Get support layers up to skirt_height_z.
        for (const SupportLayer *layer : object->support_layers()) {
            if (layer->print_z > skirt_height_z)
                break;
            layer->support_fills.collect_points(object_points);
        }
        // Repeat points for each object copy.
        for (const PrintInstance &instance : object->instances()) {
            Points copy_points = object_points;
            for (Point &pt : copy_points)
                pt += instance.shift;
            append(points, copy_points);
        }
    }

    // Include the wipe tower.
    append(points, this->first_layer_wipe_tower_corners());

    if (points.size() < 3)
        // At least three points required for a convex hull.
        return;
    
    this->throw_if_canceled();
    Polygon convex_hull = Slic3r::Geometry::convex_hull(points);
    
    // Skirt may be printed on several layers, having distinct layer heights,
    // but loops must be aligned so can't vary width/spacing
    // TODO: use each extruder's own flow
    double first_layer_height = this->skirt_first_layer_height();
    Flow   flow = this->skirt_flow();
    float  spacing = flow.spacing();
    double mm3_per_mm = flow.mm3_per_mm();
    
    std::vector<size_t> extruders;
    std::vector<double> extruders_e_per_mm;
    {
        auto set_extruders = this->extruders();
        extruders.reserve(set_extruders.size());
        extruders_e_per_mm.reserve(set_extruders.size());
        for (auto &extruder_id : set_extruders) {
            extruders.push_back(extruder_id);
            extruders_e_per_mm.push_back(Extruder((unsigned int)extruder_id, &m_config).e_per_mm(mm3_per_mm));
        }
    }

    // Number of skirt loops per skirt layer.
    size_t n_skirts = m_config.skirts.value;
    if (this->has_infinite_skirt() && n_skirts == 0)
        n_skirts = 1;

    // Initial offset of the brim inner edge from the object (possible with a support & raft).
    // The skirt will touch the brim if the brim is extruded.
    auto   distance = float(scale_(m_config.skirt_distance.value) - spacing/2.);
    // Draw outlines from outside to inside.
    // Loop while we have less skirts than required or any extruder hasn't reached the min length if any.
    std::vector<coordf_t> extruded_length(extruders.size(), 0.);
    for (size_t i = n_skirts, extruder_idx = 0; i > 0; -- i) {
        this->throw_if_canceled();
        // Offset the skirt outside.
        distance += float(scale_(spacing));
        // Generate the skirt centerline.
        Polygon loop;
        {
            Polygons loops = offset(convex_hull, distance, ClipperLib::jtRound, float(scale_(0.1)));
            Geometry::simplify_polygons(loops, scale_(0.05), &loops);
			if (loops.empty())
				break;
			loop = loops.front();
        }
        // Extrude the skirt loop.
        ExtrusionLoop eloop(elrSkirt);
        eloop.paths.emplace_back(ExtrusionPath(
            ExtrusionPath(
                erSkirt,
                (float)mm3_per_mm,         // this will be overridden at G-code export time
                flow.width(),
				(float)first_layer_height  // this will be overridden at G-code export time
            )));
        eloop.paths.back().polyline = loop.split_at_first_point();
        m_skirt.append(eloop);
        if (m_config.min_skirt_length.value > 0) {
            // The skirt length is limited. Sum the total amount of filament length extruded, in mm.
            extruded_length[extruder_idx] += unscale<double>(loop.length()) * extruders_e_per_mm[extruder_idx];
            if (extruded_length[extruder_idx] < m_config.min_skirt_length.value) {
                // Not extruded enough yet with the current extruder. Add another loop.
                if (i == 1)
                    ++ i;
            } else {
                assert(extruded_length[extruder_idx] >= m_config.min_skirt_length.value);
                // Enough extruded with the current extruder. Extrude with the next one,
                // until the prescribed number of skirt loops is extruded.
                if (extruder_idx + 1 < extruders.size())
                    ++ extruder_idx;
            }
        } else {
            // The skirt lenght is not limited, extrude the skirt with the 1st extruder only.
        }
    }
    // Brims were generated inside out, reverse to print the outmost contour first.
    m_skirt.reverse();

    // Remember the outer edge of the last skirt line extruded as m_skirt_convex_hull.
    for (Polygon &poly : offset(convex_hull, distance + 0.5f * float(scale_(spacing)), ClipperLib::jtRound, float(scale_(0.1))))
        append(m_skirt_convex_hull, std::move(poly.points));
}

Polygons Print::first_layer_islands() const
{
    Polygons islands;
    for (PrintObject *object : m_objects) {
        Polygons object_islands;
        for (ExPolygon &expoly : object->m_layers.front()->lslices)
            object_islands.push_back(expoly.contour);
        if (! object->support_layers().empty())
            object->support_layers().front()->support_fills.polygons_covered_by_spacing(object_islands, float(SCALED_EPSILON));
        islands.reserve(islands.size() + object_islands.size() * object->instances().size());
        for (const PrintInstance &instance : object->instances())
            for (Polygon &poly : object_islands) {
                islands.push_back(poly);
                islands.back().translate(instance.shift);
            }
    }
    return islands;
}

std::vector<Point> Print::first_layer_wipe_tower_corners() const
{
    std::vector<Point> corners;
    if (has_wipe_tower() && ! m_wipe_tower_data.tool_changes.empty()) {
        double width = m_config.wipe_tower_width + 2*m_wipe_tower_data.brim_width;
        double depth = m_wipe_tower_data.depth + 2*m_wipe_tower_data.brim_width;
        Vec2d pt0(-m_wipe_tower_data.brim_width, -m_wipe_tower_data.brim_width);
        for (Vec2d pt : {
                pt0,
                Vec2d(pt0.x()+width, pt0.y()      ),
                Vec2d(pt0.x()+width, pt0.y()+depth),
                Vec2d(pt0.x(),       pt0.y()+depth)
            }) {
            pt = Eigen::Rotation2Dd(Geometry::deg2rad(m_config.wipe_tower_rotation_angle.value)) * pt;
            pt += Vec2d(m_config.wipe_tower_x.value, m_config.wipe_tower_y.value);
            corners.emplace_back(Point(scale_(pt.x()), scale_(pt.y())));
        }
    }
    return corners;
}

void Print::finalize_first_layer_convex_hull()
{
    append(m_first_layer_convex_hull.points, m_skirt_convex_hull);
    if (m_first_layer_convex_hull.empty()) {
        // Neither skirt nor brim was extruded. Collect points of printed objects from 1st layer.
        for (Polygon &poly : this->first_layer_islands())
            append(m_first_layer_convex_hull.points, std::move(poly.points));
    }
    append(m_first_layer_convex_hull.points, this->first_layer_wipe_tower_corners());
    m_first_layer_convex_hull = Geometry::convex_hull(m_first_layer_convex_hull.points);
}

// Wipe tower support.
bool Print::has_wipe_tower() const
{
    return 
        ! m_config.spiral_vase.value &&
        m_config.wipe_tower.value && 
        m_config.nozzle_diameter.values.size() > 1;
}

const WipeTowerData& Print::wipe_tower_data(size_t extruders_cnt) const
{
    // If the wipe tower wasn't created yet, make sure the depth and brim_width members are set to default.
    if (! is_step_done(psWipeTower) && extruders_cnt !=0) {

        float width = float(m_config.wipe_tower_width);

        const_cast<Print*>(this)->m_wipe_tower_data.depth = (900.f/width) * float(extruders_cnt - 1);
        const_cast<Print*>(this)->m_wipe_tower_data.brim_width = m_config.wipe_tower_brim_width;
    }

    return m_wipe_tower_data;
}

void Print::_make_wipe_tower()
{
    m_wipe_tower_data.clear();
    if (! this->has_wipe_tower())
        return;

    // Get wiping matrix to get number of extruders and convert vector<double> to vector<float>:
    std::vector<float> wiping_matrix(cast<float>(m_config.wiping_volumes_matrix.values));
    // Extract purging volumes for each extruder pair:
    std::vector<std::vector<float>> wipe_volumes;
    const unsigned int number_of_extruders = (unsigned int)(sqrt(wiping_matrix.size())+EPSILON);
    for (unsigned int i = 0; i<number_of_extruders; ++i)
        wipe_volumes.push_back(std::vector<float>(wiping_matrix.begin()+i*number_of_extruders, wiping_matrix.begin()+(i+1)*number_of_extruders));

    // Let the ToolOrdering class know there will be initial priming extrusions at the start of the print.
    m_wipe_tower_data.tool_ordering = ToolOrdering(*this, (unsigned int)-1, true);

    if (! m_wipe_tower_data.tool_ordering.has_wipe_tower())
        // Don't generate any wipe tower.
        return;

    // Check whether there are any layers in m_tool_ordering, which are marked with has_wipe_tower,
    // they print neither object, nor support. These layers are above the raft and below the object, and they
    // shall be added to the support layers to be printed.
    // see https://github.com/prusa3d/PrusaSlicer/issues/607
    {
        size_t idx_begin = size_t(-1);
        size_t idx_end   = m_wipe_tower_data.tool_ordering.layer_tools().size();
        // Find the first wipe tower layer, which does not have a counterpart in an object or a support layer.
        for (size_t i = 0; i < idx_end; ++ i) {
            const LayerTools &lt = m_wipe_tower_data.tool_ordering.layer_tools()[i];
            if (lt.has_wipe_tower && ! lt.has_object && ! lt.has_support) {
                idx_begin = i;
                break;
            }
        }
        if (idx_begin != size_t(-1)) {
            // Find the position in m_objects.first()->support_layers to insert these new support layers.
            double wipe_tower_new_layer_print_z_first = m_wipe_tower_data.tool_ordering.layer_tools()[idx_begin].print_z;
            auto it_layer = m_objects.front()->support_layers().begin();
            auto it_end   = m_objects.front()->support_layers().end();
            for (; it_layer != it_end && (*it_layer)->print_z - EPSILON < wipe_tower_new_layer_print_z_first; ++ it_layer);
            // Find the stopper of the sequence of wipe tower layers, which do not have a counterpart in an object or a support layer.
            for (size_t i = idx_begin; i < idx_end; ++ i) {
                LayerTools &lt = const_cast<LayerTools&>(m_wipe_tower_data.tool_ordering.layer_tools()[i]);
                if (! (lt.has_wipe_tower && ! lt.has_object && ! lt.has_support))
                    break;
                lt.has_support = true;
                // Insert the new support layer.
                double height    = lt.print_z - (i == 0 ? 0. : m_wipe_tower_data.tool_ordering.layer_tools()[i-1].print_z);
                //FIXME the support layer ID is set to -1, as Vojtech hopes it is not being used anyway.
                it_layer = m_objects.front()->insert_support_layer(it_layer, -1, height, lt.print_z, lt.print_z - 0.5 * height);
                ++ it_layer;
            }
        }
    }
    this->throw_if_canceled();

    // Initialize the wipe tower.
    WipeTower wipe_tower(m_config, wipe_volumes, m_wipe_tower_data.tool_ordering.first_extruder());

    //wipe_tower.set_retract();
    //wipe_tower.set_zhop();

    // Set the extruder & material properties at the wipe tower object.
    for (size_t i = 0; i < number_of_extruders; ++ i)
        wipe_tower.set_extruder(i, m_config);

    m_wipe_tower_data.priming = Slic3r::make_unique<std::vector<WipeTower::ToolChangeResult>>(
        wipe_tower.prime((float)this->skirt_first_layer_height(), m_wipe_tower_data.tool_ordering.all_extruders(), false));

    // Lets go through the wipe tower layers and determine pairs of extruder changes for each
    // to pass to wipe_tower (so that it can use it for planning the layout of the tower)
    {
        unsigned int current_extruder_id = m_wipe_tower_data.tool_ordering.all_extruders().back();
        for (auto &layer_tools : m_wipe_tower_data.tool_ordering.layer_tools()) { // for all layers
            if (!layer_tools.has_wipe_tower) continue;
            bool first_layer = &layer_tools == &m_wipe_tower_data.tool_ordering.front();
            wipe_tower.plan_toolchange((float)layer_tools.print_z, (float)layer_tools.wipe_tower_layer_height, current_extruder_id, current_extruder_id, false);
            for (const auto extruder_id : layer_tools.extruders) {
                if ((first_layer && extruder_id == m_wipe_tower_data.tool_ordering.all_extruders().back()) || extruder_id != current_extruder_id) {
                    float volume_to_wipe = wipe_volumes[current_extruder_id][extruder_id];             // total volume to wipe after this toolchange
                    // Not all of that can be used for infill purging:
                    volume_to_wipe -= (float)m_config.filament_minimal_purge_on_wipe_tower.get_at(extruder_id);

                    // try to assign some infills/objects for the wiping:
                    volume_to_wipe = layer_tools.wiping_extrusions().mark_wiping_extrusions(*this, current_extruder_id, extruder_id, volume_to_wipe);

                    // add back the minimal amount toforce on the wipe tower:
                    volume_to_wipe += (float)m_config.filament_minimal_purge_on_wipe_tower.get_at(extruder_id);

                    // request a toolchange at the wipe tower with at least volume_to_wipe purging amount
                    wipe_tower.plan_toolchange((float)layer_tools.print_z, (float)layer_tools.wipe_tower_layer_height,
                                               current_extruder_id, extruder_id, volume_to_wipe);
                    current_extruder_id = extruder_id;
                }
            }
            layer_tools.wiping_extrusions().ensure_perimeters_infills_order(*this);
            if (&layer_tools == &m_wipe_tower_data.tool_ordering.back() || (&layer_tools + 1)->wipe_tower_partitions == 0)
                break;
        }
    }

    // Generate the wipe tower layers.
    m_wipe_tower_data.tool_changes.reserve(m_wipe_tower_data.tool_ordering.layer_tools().size());
    wipe_tower.generate(m_wipe_tower_data.tool_changes);
    m_wipe_tower_data.depth = wipe_tower.get_depth();
    m_wipe_tower_data.brim_width = wipe_tower.get_brim_width();

    // Unload the current filament over the purge tower.
    coordf_t layer_height = m_objects.front()->config().layer_height.value;
    if (m_wipe_tower_data.tool_ordering.back().wipe_tower_partitions > 0) {
        // The wipe tower goes up to the last layer of the print.
        if (wipe_tower.layer_finished()) {
            // The wipe tower is printed to the top of the print and it has no space left for the final extruder purge.
            // Lift Z to the next layer.
            wipe_tower.set_layer(float(m_wipe_tower_data.tool_ordering.back().print_z + layer_height), float(layer_height), 0, false, true);
        } else {
            // There is yet enough space at this layer of the wipe tower for the final purge.
        }
    } else {
        // The wipe tower does not reach the last print layer, perform the pruge at the last print layer.
        assert(m_wipe_tower_data.tool_ordering.back().wipe_tower_partitions == 0);
        wipe_tower.set_layer(float(m_wipe_tower_data.tool_ordering.back().print_z), float(layer_height), 0, false, true);
    }
    m_wipe_tower_data.final_purge = Slic3r::make_unique<WipeTower::ToolChangeResult>(
        wipe_tower.tool_change((unsigned int)(-1)));

    m_wipe_tower_data.used_filament = wipe_tower.get_used_filament();
    m_wipe_tower_data.number_of_toolchanges = wipe_tower.get_number_of_toolchanges();
}

// Generate a recommended G-code output file name based on the format template, default extension, and template parameters
// (timestamps, object placeholders derived from the model, current placeholder prameters and print statistics.
// Use the final print statistics if available, or just keep the print statistics placeholders if not available yet (before G-code is finalized).
std::string Print::output_filename(const std::string &filename_base) const 
{ 
    // Set the placeholders for the data know first after the G-code export is finished.
    // These values will be just propagated into the output file name.
    DynamicConfig config = this->finished() ? this->print_statistics().config() : this->print_statistics().placeholders();
    config.set_key_value("num_extruders", new ConfigOptionInt((int)m_config.nozzle_diameter.size()));
    return this->PrintBase::output_filename(m_config.output_filename_format.value, ".gcode", filename_base, &config);
}

DynamicConfig PrintStatistics::config() const
{
    DynamicConfig config;
    std::string normal_print_time = short_time(this->estimated_normal_print_time);
    std::string silent_print_time = short_time(this->estimated_silent_print_time);
    config.set_key_value("print_time", new ConfigOptionString(normal_print_time));
    config.set_key_value("normal_print_time", new ConfigOptionString(normal_print_time));
    config.set_key_value("silent_print_time", new ConfigOptionString(silent_print_time));
    config.set_key_value("used_filament",             new ConfigOptionFloat(this->total_used_filament / 1000.));
    config.set_key_value("extruded_volume",           new ConfigOptionFloat(this->total_extruded_volume));
    config.set_key_value("total_cost",                new ConfigOptionFloat(this->total_cost));
    config.set_key_value("total_toolchanges",         new ConfigOptionInt(this->total_toolchanges));
    config.set_key_value("total_weight",              new ConfigOptionFloat(this->total_weight));
    config.set_key_value("total_wipe_tower_cost",     new ConfigOptionFloat(this->total_wipe_tower_cost));
    config.set_key_value("total_wipe_tower_filament", new ConfigOptionFloat(this->total_wipe_tower_filament));
    return config;
}

DynamicConfig PrintStatistics::placeholders()
{
    DynamicConfig config;
    for (const std::string &key : { 
        "print_time", "normal_print_time", "silent_print_time", 
        "used_filament", "extruded_volume", "total_cost", "total_weight", 
        "total_toolchanges", "total_wipe_tower_cost", "total_wipe_tower_filament"})
        config.set_key_value(key, new ConfigOptionString(std::string("{") + key + "}"));
    return config;
}

std::string PrintStatistics::finalize_output_path(const std::string &path_in) const
{
    std::string final_path;
    try {
        boost::filesystem::path path(path_in);
        DynamicConfig cfg = this->config();
        PlaceholderParser pp;
        std::string new_stem = pp.process(path.stem().string(), 0, &cfg);
        final_path = (path.parent_path() / (new_stem + path.extension().string())).string();
    } catch (const std::exception &ex) {
        BOOST_LOG_TRIVIAL(error) << "Failed to apply the print statistics to the export file name: " << ex.what();
        final_path = path_in;
    }
    return final_path;
}

} // namespace Slic3r
