#include "Layer.hpp"
#include "BridgeDetector.hpp"
#include "ClipperUtils.hpp"
#include "PerimeterGenerator.hpp"
#include "Print.hpp"
#include "Surface.hpp"
#include "BoundingBox.hpp"
#include "SVG.hpp"

#include <string>
#include <map>

namespace Slic3r {

LayerRegion::LayerRegion(Layer *layer, PrintRegion *region)
:   _layer(layer),
    _region(region)
{
}

LayerRegion::~LayerRegion()
{
}

Layer*
LayerRegion::layer()
{
    return this->_layer;
}

Flow
LayerRegion::flow(FlowRole role, bool bridge, double width) const
{
    return this->_region->flow(
        role,
        this->_layer->height,
        bridge,
        this->_layer->id() == 0,
        width,
        *this->_layer->object()
    );
}

// Fill in layerm->fill_surfaces by trimming the layerm->slices by the cummulative layerm->fill_surfaces.
void LayerRegion::slices_to_fill_surfaces_clipped()
{
    // Note: this method should be idempotent, but fill_surfaces gets modified 
    // in place. However we're now only using its boundaries (which are invariant)
    // so we're safe. This guarantees idempotence of prepare_infill() also in case
    // that combine_infill() turns some fill_surface into VOID surfaces.
//    Polygons fill_boundaries = to_polygons(STDMOVE(this->fill_surfaces));
    Polygons fill_boundaries = to_polygons(this->fill_expolygons);
    this->fill_surfaces.surfaces.clear();
    for (Surfaces::const_iterator surface = this->slices.surfaces.begin(); surface != this->slices.surfaces.end(); ++ surface)
        this->fill_surfaces.append(
            intersection_ex(to_polygons(surface->expolygon), fill_boundaries),
            surface->surface_type);
}

void
LayerRegion::make_perimeters(const SurfaceCollection &slices, SurfaceCollection* fill_surfaces)
{
    this->perimeters.clear();
    this->thin_fills.clear();
    
    PerimeterGenerator g(
        // input:
        &slices,
        this->layer()->height,
        this->flow(frPerimeter),
        &this->region()->config,
        &this->layer()->object()->config,
        &this->layer()->object()->print()->config,
        
        // output:
        &this->perimeters,
        &this->thin_fills,
        fill_surfaces
    );
    
    if (this->layer()->lower_layer != NULL)
        // Cummulative sum of polygons over all the regions.
        g.lower_slices = &this->layer()->lower_layer->slices;
    
    g.layer_id              = this->layer()->id();
    g.ext_perimeter_flow    = this->flow(frExternalPerimeter);
    g.overhang_flow         = this->region()->flow(frPerimeter, -1, true, false, -1, *this->layer()->object());
    g.solid_infill_flow     = this->flow(frSolidInfill);
    
    g.process();
}

//#define EXTERNAL_SURFACES_OFFSET_PARAMETERS ClipperLib::jtMiter, 3.
//#define EXTERNAL_SURFACES_OFFSET_PARAMETERS ClipperLib::jtMiter, 1.5
#define EXTERNAL_SURFACES_OFFSET_PARAMETERS ClipperLib::jtSquare, 0.

void
LayerRegion::process_external_surfaces(const Layer* lower_layer)
{
    const Surfaces &surfaces = this->fill_surfaces.surfaces;
    const double margin = scale_(EXTERNAL_INFILL_MARGIN);
    
#ifdef SLIC3R_DEBUG_SLICE_PROCESSING
    export_region_fill_surfaces_to_svg_debug("3_process_external_surfaces-initial");
#endif /* SLIC3R_DEBUG_SLICE_PROCESSING */

    // 1) Collect bottom and bridge surfaces, each of them grown by a fixed 3mm offset
    // for better anchoring.
    // Bottom surfaces, grown.
    Surfaces                    bottom;
    // Bridge surfaces, initialy not grown.
    Surfaces                    bridges;
    // Top surfaces, grown.
    Surfaces                    top;
    // Internal surfaces, not grown.
    Surfaces                    internal;
    // Areas, where an infill of various types (top, bottom, bottom bride, sparse, void) could be placed.
    //FIXME if non zero infill, then fill_boundaries could be cheaply initialized from layerm->fill_expolygons.
    Polygons                    fill_boundaries;

    // Collect top surfaces and internal surfaces.
    // Collect fill_boundaries: If we're slicing with no infill, we can't extend external surfaces over non-existent infill.
    // This loop destroys the surfaces (aliasing this->fill_surfaces.surfaces) by moving into top/internal/fill_boundaries!
    {
        // bottom_polygons are used to trim inflated top surfaces.
        fill_boundaries.reserve(number_polygons(surfaces));
        bool has_infill = this->region()->config.fill_density.value > 0.;
        for (Surfaces::iterator surface = this->fill_surfaces.surfaces.begin(); surface != this->fill_surfaces.surfaces.end(); ++surface) {
            if (surface->surface_type == stTop) {
                // Collect the top surfaces, inflate them and trim them by the bottom surfaces.
                // This gives the priority to bottom surfaces.
                surfaces_append(top, offset_ex(surface->expolygon, float(margin), EXTERNAL_SURFACES_OFFSET_PARAMETERS), *surface);
            } else if (surface->surface_type == stBottom || (surface->surface_type == stBottomBridge && lower_layer == NULL)) {
                // Grown by 3mm.
                surfaces_append(bottom, offset_ex(surface->expolygon, float(margin), EXTERNAL_SURFACES_OFFSET_PARAMETERS), *surface);
            } else if (surface->surface_type == stBottomBridge) {
                if (! surface->empty())
                    bridges.push_back(*surface);
            }
            bool internal_surface = surface->surface_type != stTop && ! surface->is_bottom();
            if (has_infill || surface->surface_type != stInternal) {
                if (internal_surface)
                    // Make a copy as the following line uses the move semantics.
                    internal.push_back(*surface);
                polygons_append(fill_boundaries, STDMOVE(surface->expolygon));
            } else if (internal_surface)
                internal.push_back(STDMOVE(*surface));
        }
    }

#if 0
    {
        static int iRun = 0;
        bridges.export_to_svg(debug_out_path("bridges-before-grouping-%d.svg", iRun ++), true);
    }
#endif

    if (bridges.empty())
    {
        fill_boundaries = union_(fill_boundaries, true);
    } else
    {
        // 1) Calculate the inflated bridge regions, each constrained to its island.
        ExPolygons               fill_boundaries_ex = union_ex(fill_boundaries, true);
        std::vector<Polygons>    bridges_grown;
        std::vector<BoundingBox> bridge_bboxes;

#ifdef SLIC3R_DEBUG_SLICE_PROCESSING
        {
            static int iRun = 0;
            SVG svg(debug_out_path("3_process_external_surfaces-fill_regions-%d.svg", iRun ++).c_str(), get_extents(fill_boundaries_ex));
            svg.draw(fill_boundaries_ex);
            svg.draw_outline(fill_boundaries_ex, "black", "blue", scale_(0.05)); 
            svg.Close();
        }

//        export_region_fill_surfaces_to_svg_debug("3_process_external_surfaces-initial");
#endif /* SLIC3R_DEBUG_SLICE_PROCESSING */
 
        {
            // Bridge expolygons, grown, to be tested for intersection with other bridge regions.
            std::vector<BoundingBox> fill_boundaries_ex_bboxes = get_extents_vector(fill_boundaries_ex);
            bridges_grown.reserve(bridges.size());
            bridge_bboxes.reserve(bridges.size());
            for (size_t i = 0; i < bridges.size(); ++ i) {
                // Find the island of this bridge.
                const Point pt = bridges[i].expolygon.contour.points.front();
                int idx_island = -1;
                for (int j = 0; j < int(fill_boundaries_ex.size()); ++ j)
                    if (fill_boundaries_ex_bboxes[j].contains(pt) && 
                        fill_boundaries_ex[j].contains(pt)) {
                        idx_island = j;
                        break;
                    }
                // Grown by 3mm.
                Polygons polys = offset(to_polygons(bridges[i].expolygon), float(margin), EXTERNAL_SURFACES_OFFSET_PARAMETERS);
                if (idx_island == -1) {
                    printf("Bridge did not fall into the source region!\r\n");
                } else {
                    // Found an island, to which this bridge region belongs. Trim it,
                    polys = intersection(polys, to_polygons(fill_boundaries_ex[idx_island]));
                }
                bridge_bboxes.push_back(get_extents(polys));
                bridges_grown.push_back(STDMOVE(polys));
            }
        }

        // 2) Group the bridge surfaces by overlaps.
        std::vector<size_t> bridge_group(bridges.size(), (size_t)-1);
        size_t n_groups = 0; 
        for (size_t i = 0; i < bridges.size(); ++ i) {
            // A grup id for this bridge.
            size_t group_id = (bridge_group[i] == -1) ? (n_groups ++) : bridge_group[i];
            bridge_group[i] = group_id;
            // For all possibly overlaping bridges:
            for (size_t j = i + 1; j < bridges.size(); ++ j) {
                if (! bridge_bboxes[i].overlap(bridge_bboxes[j]))
                    continue;
                if (intersection(bridges_grown[i], bridges_grown[j], false).empty())
                    continue;
                // The two bridge regions intersect. Give them the same group id.
                if (bridge_group[j] != -1) {
                    // The j'th bridge has been merged with some other bridge before.
                    size_t group_id_new = bridge_group[j];
                    for (size_t k = 0; k < j; ++ k)
                        if (bridge_group[k] == group_id)
                            bridge_group[k] = group_id_new;
                    group_id = group_id_new;
                }
                bridge_group[j] = group_id;
            }
        }

        // 3) Merge the groups with the same group id, detect bridges.
        {
            for (size_t group_id = 0; group_id < n_groups; ++ group_id) {
                size_t n_bridges_merged = 0;
                size_t idx_last = (size_t)-1;
                for (size_t i = 0; i < bridges.size(); ++ i) {
                    if (bridge_group[i] == group_id) {
                        ++ n_bridges_merged;
                        idx_last = i;
                    }
                }
                if (n_bridges_merged == 0)
                    // This group has no regions assigned as these were moved into another group.
                    continue;
                // Collect the initial ungrown regions and the grown polygons.
                ExPolygons  initial;
                Polygons    grown;
                for (size_t i = 0; i < bridges.size(); ++ i) {
                    if (bridge_group[i] != group_id)
                        continue;
                    initial.push_back(STDMOVE(bridges[i].expolygon));
                    polygons_append(grown, bridges_grown[i]);
                }
                // detect bridge direction before merging grown surfaces otherwise adjacent bridges
                // would get merged into a single one while they need different directions
                // also, supply the original expolygon instead of the grown one, because in case
                // of very thin (but still working) anchors, the grown expolygon would go beyond them
                BridgeDetector bd(
                    initial,
                    lower_layer->slices,
                    this->flow(frInfill, true).scaled_width()
                );
                #ifdef SLIC3R_DEBUG
                printf("Processing bridge at layer " PRINTF_ZU ":\n", this->layer()->id());
                #endif
                if (bd.detect_angle()) {
                    bridges[idx_last].bridge_angle = bd.angle;
                    if (this->layer()->object()->config.support_material) {
                        polygons_append(this->bridged, bd.coverage());
                        this->unsupported_bridge_edges.append(bd.unsupported_edges()); 
                    }
                }
                // without safety offset, artifacts are generated (GH #2494)
                surfaces_append(bottom, union_ex(grown, true), bridges[idx_last]);
            }

            fill_boundaries = STDMOVE(to_polygons(fill_boundaries_ex));
        }

    #if 0
        {
            static int iRun = 0;
            bridges.export_to_svg(debug_out_path("bridges-after-grouping-%d.svg", iRun ++), true);
        }
    #endif
    }

    Surfaces new_surfaces;
    {
        // Merge top and bottom in a single collection.
        surfaces_append(top, STDMOVE(bottom));
        // Intersect the grown surfaces with the actual fill boundaries.
        Polygons bottom_polygons = to_polygons(bottom);
        for (size_t i = 0; i < top.size(); ++ i) {
            Surface &s1 = top[i];
            if (s1.empty())
                continue;
            Polygons polys;
            polygons_append(polys, STDMOVE(s1));
            for (size_t j = i + 1; j < top.size(); ++ j) {
                Surface &s2 = top[j];
                if (! s2.empty() && surfaces_could_merge(s1, s2)) {
                    polygons_append(polys, STDMOVE(s2));
                    s2.clear();
                }
            }
            if (s1.surface_type == stTop)
                // Trim the top surfaces by the bottom surfaces. This gives the priority to the bottom surfaces.
                polys = diff(polys, bottom_polygons);
            surfaces_append(
                new_surfaces,
                // Don't use a safety offset as fill_boundaries were already united using the safety offset.
                STDMOVE(intersection_ex(polys, fill_boundaries, false)),
                s1);
        }
    }
    
    // Subtract the new top surfaces from the other non-top surfaces and re-add them.
    Polygons new_polygons = to_polygons(new_surfaces);
    for (size_t i = 0; i < internal.size(); ++ i) {
        Surface &s1 = internal[i];
        if (s1.empty())
            continue;
        Polygons polys;
        polygons_append(polys, STDMOVE(s1));
        for (size_t j = i + 1; j < internal.size(); ++ j) {
            Surface &s2 = internal[j];
            if (! s2.empty() && surfaces_could_merge(s1, s2)) {
                polygons_append(polys, STDMOVE(s2));
                s2.clear();
            }
        }
        ExPolygons new_expolys = diff_ex(polys, new_polygons);
        polygons_append(new_polygons, to_polygons(new_expolys));
        surfaces_append(new_surfaces, STDMOVE(new_expolys), s1);
    }
    
    this->fill_surfaces.surfaces = STDMOVE(new_surfaces);

#ifdef SLIC3R_DEBUG_SLICE_PROCESSING
    export_region_fill_surfaces_to_svg_debug("3_process_external_surfaces-final");
#endif /* SLIC3R_DEBUG_SLICE_PROCESSING */
}

void
LayerRegion::prepare_fill_surfaces()
{
#ifdef SLIC3R_DEBUG_SLICE_PROCESSING
    export_region_slices_to_svg_debug("2_prepare_fill_surfaces-initial");
    export_region_fill_surfaces_to_svg_debug("2_prepare_fill_surfaces-initial");
#endif /* SLIC3R_DEBUG_SLICE_PROCESSING */ 

    /*  Note: in order to make the psPrepareInfill step idempotent, we should never
        alter fill_surfaces boundaries on which our idempotency relies since that's
        the only meaningful information returned by psPerimeters. */
    
    // if no solid layers are requested, turn top/bottom surfaces to internal
    if (this->region()->config.top_solid_layers == 0) {
        for (Surfaces::iterator surface = this->fill_surfaces.surfaces.begin(); surface != this->fill_surfaces.surfaces.end(); ++surface)
            if (surface->surface_type == stTop)
                surface->surface_type = (this->layer()->object()->config.infill_only_where_needed) ? 
                    stInternalVoid : stInternal;
    }
    if (this->region()->config.bottom_solid_layers == 0) {
        for (Surfaces::iterator surface = this->fill_surfaces.surfaces.begin(); surface != this->fill_surfaces.surfaces.end(); ++surface) {
            if (surface->surface_type == stBottom || surface->surface_type == stBottomBridge)
                surface->surface_type = stInternal;
        }
    }
        
    // turn too small internal regions into solid regions according to the user setting
    if (this->region()->config.fill_density.value > 0) {
        // scaling an area requires two calls!
        double min_area = scale_(scale_(this->region()->config.solid_infill_below_area.value));
        for (Surfaces::iterator surface = this->fill_surfaces.surfaces.begin(); surface != this->fill_surfaces.surfaces.end(); ++surface) {
            if (surface->surface_type == stInternal && surface->area() <= min_area)
                surface->surface_type = stInternalSolid;
        }
    }

#ifdef SLIC3R_DEBUG_SLICE_PROCESSING
    export_region_slices_to_svg_debug("2_prepare_fill_surfaces-final");
    export_region_fill_surfaces_to_svg_debug("2_prepare_fill_surfaces-final");
#endif /* SLIC3R_DEBUG_SLICE_PROCESSING */
}

double
LayerRegion::infill_area_threshold() const
{
    double ss = this->flow(frSolidInfill).scaled_spacing();
    return ss*ss;
}


void LayerRegion::export_region_slices_to_svg(const char *path)
{
    BoundingBox bbox;
    for (Surfaces::const_iterator surface = this->slices.surfaces.begin(); surface != this->slices.surfaces.end(); ++surface)
        bbox.merge(get_extents(surface->expolygon));
    Point legend_size = export_surface_type_legend_to_svg_box_size();
    Point legend_pos(bbox.min.x, bbox.max.y);
    bbox.merge(Point(std::max(bbox.min.x + legend_size.x, bbox.max.x), bbox.max.y + legend_size.y));

    SVG svg(path, bbox);
    const float transparency = 0.5f;
    for (Surfaces::const_iterator surface = this->slices.surfaces.begin(); surface != this->slices.surfaces.end(); ++surface)
        svg.draw(surface->expolygon, surface_type_to_color_name(surface->surface_type), transparency);
    for (Surfaces::const_iterator surface = this->fill_surfaces.surfaces.begin(); surface != this->fill_surfaces.surfaces.end(); ++surface)
        svg.draw(surface->expolygon.lines(), surface_type_to_color_name(surface->surface_type));
    export_surface_type_legend_to_svg(svg, legend_pos);
    svg.Close();
}

// Export to "out/LayerRegion-name-%d.svg" with an increasing index with every export.
void LayerRegion::export_region_slices_to_svg_debug(const char *name)
{
    static std::map<std::string, size_t> idx_map;
    size_t &idx = idx_map[name];
    this->export_region_slices_to_svg(debug_out_path("LayerRegion-slices-%s-%d.svg", name, idx ++).c_str());
}

void LayerRegion::export_region_fill_surfaces_to_svg(const char *path) 
{
    BoundingBox bbox;
    for (Surfaces::const_iterator surface = this->fill_surfaces.surfaces.begin(); surface != this->fill_surfaces.surfaces.end(); ++surface)
        bbox.merge(get_extents(surface->expolygon));
    Point legend_size = export_surface_type_legend_to_svg_box_size();
    Point legend_pos(bbox.min.x, bbox.max.y);
    bbox.merge(Point(std::max(bbox.min.x + legend_size.x, bbox.max.x), bbox.max.y + legend_size.y));

    SVG svg(path, bbox);
    const float transparency = 0.5f;
    for (Surfaces::const_iterator surface = this->fill_surfaces.surfaces.begin(); surface != this->fill_surfaces.surfaces.end(); ++surface) {
        svg.draw(surface->expolygon, surface_type_to_color_name(surface->surface_type), transparency);
        svg.draw_outline(surface->expolygon, "black", "blue", scale_(0.05)); 
    }
    export_surface_type_legend_to_svg(svg, legend_pos);
    svg.Close();
}

// Export to "out/LayerRegion-name-%d.svg" with an increasing index with every export.
void LayerRegion::export_region_fill_surfaces_to_svg_debug(const char *name)
{
    static std::map<std::string, size_t> idx_map;
    size_t &idx = idx_map[name];
    this->export_region_fill_surfaces_to_svg(debug_out_path("LayerRegion-fill_surfaces-%s-%d.svg", name, idx ++).c_str());
}

}