#include <map>

#include <gtest/gtest.h>

#include "libslic3r/libslic3r.h"
#include "libslic3r/Format/OBJ.hpp"
#include "libslic3r/SLAPrint.hpp"
#include "libslic3r/TriangleMesh.hpp"
#include "libslic3r/SLA/SLAPad.hpp"
#include "libslic3r/SLA/SLASupportTreeBuilder.hpp"
#include "libslic3r/SLA/SLASupportTreeAlgorithm.hpp"
#include "libslic3r/SLA/SLAAutoSupports.hpp"
#include "libslic3r/MTUtils.hpp"

#include "libslic3r/SVG.hpp"

#if defined(WIN32) || defined(_WIN32) 
#define PATH_SEPARATOR "\\" 
#else 
#define PATH_SEPARATOR "/" 
#endif

namespace  {
using namespace Slic3r;

TriangleMesh load_model(const std::string &obj_filename)
{
    TriangleMesh mesh;
    auto fpath = std::string(TEST_DATA_DIR PATH_SEPARATOR) + obj_filename;
    load_obj(fpath.c_str(), &mesh);
    return mesh;
}

enum e_validity {
    ASSUME_NO_EMPTY = 1,
    ASSUME_MANIFOLD = 2,
    ASSUME_NO_REPAIR = 4
};

void check_validity(const TriangleMesh &input_mesh,
                    int flags = ASSUME_NO_EMPTY | ASSUME_MANIFOLD |
                                ASSUME_NO_REPAIR)
{
    TriangleMesh mesh{input_mesh};
    
    if (flags & ASSUME_NO_EMPTY) {
        ASSERT_FALSE(mesh.empty());
    } else if (mesh.empty()) 
        return; // If it can be empty and it is, there is nothing left to do.
    
    ASSERT_TRUE(stl_validate(&mesh.stl));
    
    bool do_update_shared_vertices = false;
    mesh.repair(do_update_shared_vertices);
    
    if (flags & ASSUME_NO_REPAIR) {
        ASSERT_FALSE(mesh.needed_repair());
    }
    
    if (flags & ASSUME_MANIFOLD) {
        mesh.require_shared_vertices();
        if (!mesh.is_manifold()) mesh.WriteOBJFile("non_manifold.obj");
        ASSERT_TRUE(mesh.is_manifold());
    }
}

struct PadByproducts
{
    ExPolygons   model_contours;
    ExPolygons   support_contours;
    TriangleMesh mesh;
};

void test_pad(const std::string &   obj_filename,
              const sla::PadConfig &padcfg,
              PadByproducts &       out)
{
    ASSERT_TRUE(padcfg.validate().empty());
    
    TriangleMesh mesh = load_model(obj_filename);
    
    ASSERT_FALSE(mesh.empty());
    
    // Create pad skeleton only from the model
    Slic3r::sla::pad_blueprint(mesh, out.model_contours);
    
    ASSERT_FALSE(out.model_contours.empty());
    
    // Create the pad geometry the model contours only
    Slic3r::sla::create_pad({}, out.model_contours, out.mesh, padcfg);
    
    check_validity(out.mesh);
    
    auto bb = out.mesh.bounding_box();
    ASSERT_DOUBLE_EQ(bb.max.z() - bb.min.z(),
                     padcfg.full_height());
}

void test_pad(const std::string &   obj_filename,
              const sla::PadConfig &padcfg = {})
{
    PadByproducts byproducts;
    test_pad(obj_filename, padcfg, byproducts);
}

struct SupportByproducts
{
    std::vector<float>      slicegrid;
    std::vector<ExPolygons> model_slices;
    sla::SupportTreeBuilder supporttree;
};

const constexpr float CLOSING_RADIUS = 0.005f;

void check_support_tree_integrity(const sla::SupportTreeBuilder &stree,
                                  const sla::SupportConfig &cfg)
{
    double gnd  = stree.ground_level;
    double H1   = cfg.max_solo_pillar_height_mm;
    double H2   = cfg.max_dual_pillar_height_mm;

    for (const sla::Pillar &pillar : stree.pillars()) {
        if (std::abs(pillar.endpoint().z() - gnd) < EPSILON) {
            double h = pillar.height;
            
            if (h > H1) ASSERT_GE(pillar.links, 1);
            else if(h > H2) { ASSERT_GE(pillar.links, 2); }    
        }
        
        ASSERT_LE(pillar.links, cfg.pillar_cascade_neighbors);
        ASSERT_LE(pillar.bridges, cfg.max_bridges_on_pillar);
    }
    
    double max_bridgelen = 0.;
    auto chck_bridge = [&cfg](const sla::Bridge &bridge, double &max_brlen) {
        Vec3d n = bridge.endp - bridge.startp;
        double d = sla::distance(n);
        max_brlen = std::max(d, max_brlen);

        double z     = n.z();
        double polar = std::acos(z / d);
        double slope = -polar + PI / 2.;
        ASSERT_TRUE(slope >= cfg.bridge_slope || slope <= -cfg.bridge_slope);
    };
    
    for (auto &bridge : stree.bridges()) chck_bridge(bridge, max_bridgelen);
    ASSERT_LE(max_bridgelen, cfg.max_bridge_length_mm);
    
    max_bridgelen = 0;
    for (auto &bridge : stree.crossbridges()) chck_bridge(bridge, max_bridgelen);
    
    double md = cfg.max_pillar_link_distance_mm / std::cos(-cfg.bridge_slope);
    ASSERT_LE(max_bridgelen, md);
}

void test_supports(const std::string &       obj_filename,
                   const sla::SupportConfig &supportcfg,
                   SupportByproducts &       out)
{
    using namespace Slic3r;
    TriangleMesh mesh = load_model(obj_filename);
    
    ASSERT_FALSE(mesh.empty());
    
    TriangleMeshSlicer slicer{&mesh};

    auto   bb      = mesh.bounding_box();
    double zmin    = bb.min.z();
    double zmax    = bb.max.z();
    double gnd     = zmin - supportcfg.object_elevation_mm;
    auto   layer_h = 0.05f;

    out.slicegrid = grid(float(gnd), float(zmax), layer_h);
    slicer.slice(out.slicegrid , CLOSING_RADIUS, &out.model_slices, []{});
    
    // Create the special index-triangle mesh with spatial indexing which
    // is the input of the support point and support mesh generators
    sla::EigenMesh3D emesh{mesh};
    
    // Create the support point generator
    sla::SLAAutoSupports::Config autogencfg;
    autogencfg.head_diameter = float(2 * supportcfg.head_front_radius_mm);
    sla::SLAAutoSupports point_gen{emesh, out.model_slices, out.slicegrid,
                                   autogencfg, [] {}, [](int) {}};
    
    // Get the calculated support points.
    std::vector<sla::SupportPoint> support_points = point_gen.output();
    
    int validityflags = ASSUME_NO_REPAIR;
    
    // If there is no elevation, support points shall be removed from the
    // bottom of the object.
    if (supportcfg.object_elevation_mm < EPSILON) {
        sla::remove_bottom_points(support_points, zmin,
                                  supportcfg.base_height_mm); 
    } else {
        // Should be support points at least on the bottom of the model
        ASSERT_FALSE(support_points.empty());
        
        // Also the support mesh should not be empty.
        validityflags |= ASSUME_NO_EMPTY;
    }
    
    // Generate the actual support tree
    sla::SupportTreeBuilder treebuilder;
    treebuilder.build(sla::SupportableMesh{emesh, support_points, supportcfg});
    
    check_support_tree_integrity(treebuilder, supportcfg);
    
    const TriangleMesh &output_mesh = treebuilder.retrieve_mesh();
    
    check_validity(output_mesh, validityflags);
    
    // Quick check if the dimensions and placement of supports are correct
    auto obb = output_mesh.bounding_box();
    ASSERT_DOUBLE_EQ(obb.min.z(), zmin - supportcfg.object_elevation_mm);
    ASSERT_LE(obb.max.z(), zmax);
    
    // Move out the support tree into the byproducts, we can examine it further
    // in various tests.
    out.supporttree = std::move(treebuilder);
}

void test_supports(const std::string &       obj_filename,
                   const sla::SupportConfig &supportcfg = {})
{
    SupportByproducts byproducts;
    test_supports(obj_filename, supportcfg, byproducts);
}

void test_support_model_collision(
    const std::string &       obj_filename,
    const sla::SupportConfig &input_supportcfg = {})
{
    SupportByproducts byproducts;
    
    sla::SupportConfig supportcfg = input_supportcfg;
    
    // Set head penetration to a small negative value which should ensure that
    // the supports will not touch the model body.
    supportcfg.head_penetration_mm = -0.1;
    
    test_supports(obj_filename, supportcfg, byproducts);
    
    // Slice the support mesh given the slice grid of the model.
    std::vector<ExPolygons> support_slices =
        byproducts.supporttree.slice(byproducts.slicegrid, CLOSING_RADIUS);
    
    // The slices originate from the same slice grid so the numbers must match
    ASSERT_EQ(support_slices.size(), byproducts.model_slices.size());
    
    bool notouch = true;
    for (size_t n = 0; notouch && n < support_slices.size(); ++n) {
        const ExPolygons &sup_slice = support_slices[n];
        const ExPolygons &mod_slice = byproducts.model_slices[n];
        
        Polygons intersections = intersection(sup_slice, mod_slice);
        notouch = notouch && intersections.empty();
    }
    
    ASSERT_TRUE(notouch);
}

const char * const BELOW_PAD_TEST_OBJECTS[] = {
    "20mm_cube.obj",
    "V.obj",
};

const char * const AROUND_PAD_TEST_OBJECTS[] = {
    "20mm_cube.obj",
    "V.obj",
    "frog_legs.obj",
    "cube_with_concave_hole_enlarged.obj",
};

const char *const SUPPORT_TEST_MODELS[] = {
    "cube_with_concave_hole_enlarged_standing.obj",
};

} // namespace

template <class I, class II> void test_pairhash()
{
    std::map<II, std::pair<I, I> > ints;
    for (I i = 0; i < 1000; ++i)
        for (I j = 0; j < 1000; ++j) {
            if (j != i) {
                II hash_ij = sla::pairhash<I, II>(i, j);
                II hash_ji = sla::pairhash<I, II>(j, i);
                ASSERT_EQ(hash_ij, hash_ji);
                
                auto it = ints.find(hash_ij);
                
                if (it != ints.end()) {
                    ASSERT_TRUE(
                        (it->second.first == i && it->second.second == j) ||
                        (it->second.first == j && it->second.second == i));
                } else ints[hash_ij] = std::make_pair(i, j);
            }
        }
}

TEST(SLASupportGeneration, PillarPairHashShouldBeUnique) {
    test_pairhash<int, long>();
    test_pairhash<unsigned, unsigned>();
    test_pairhash<unsigned, unsigned long>();
}

TEST(SLASupportGeneration, FlatPadGeometryIsValid) {
    sla::PadConfig padcfg;
    
    // Disable wings
    padcfg.wall_height_mm = .0;
    
    for (auto &fname : BELOW_PAD_TEST_OBJECTS) test_pad(fname, padcfg);
}

TEST(SLASupportGeneration, WingedPadGeometryIsValid) {
    sla::PadConfig padcfg;
    
    // Add some wings to the pad to test the cavity
    padcfg.wall_height_mm = 1.;
    
    for (auto &fname : BELOW_PAD_TEST_OBJECTS) test_pad(fname, padcfg);
}

TEST(SLASupportGeneration, FlatPadAroundObjectIsValid) {
    sla::PadConfig padcfg;
    
    // Add some wings to the pad to test the cavity
    padcfg.wall_height_mm = 0.;
    // padcfg.embed_object.stick_stride_mm = 0.;
    padcfg.embed_object.enabled = true;
    padcfg.embed_object.everywhere = true;
    
    for (auto &fname : AROUND_PAD_TEST_OBJECTS) test_pad(fname, padcfg);
}

TEST(SLASupportGeneration, WingedPadAroundObjectIsValid) {
    sla::PadConfig padcfg;
    
    // Add some wings to the pad to test the cavity
    padcfg.wall_height_mm = 1.;
    padcfg.embed_object.enabled = true;
    padcfg.embed_object.everywhere = true;
    
    for (auto &fname : AROUND_PAD_TEST_OBJECTS) test_pad(fname, padcfg);
}

TEST(SLASupportGeneration, ElevatedSupportGeometryIsValid) {
    sla::SupportConfig supportcfg;
    supportcfg.object_elevation_mm = 5.;
    
    for (auto fname : SUPPORT_TEST_MODELS) test_supports(fname);
}

TEST(SLASupportGeneration, FloorSupportGeometryIsValid) {
    sla::SupportConfig supportcfg;
    supportcfg.object_elevation_mm = 0;
    
    for (auto &fname: SUPPORT_TEST_MODELS) test_supports(fname, supportcfg);
}

TEST(SLASupportGeneration, SupportsDoNotPierceModel) {
    
    sla::SupportConfig supportcfg;

    for (auto fname : SUPPORT_TEST_MODELS)
        test_support_model_collision(fname, supportcfg);
}

int main(int argc, char **argv) {
    ::testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
}