#include "GLGizmo.hpp"

#include "../../libslic3r/Utils.hpp"

#include <Eigen/Dense>

#include <GL/glew.h>

#include <iostream>

static const float DEFAULT_BASE_COLOR[3] = { 0.625f, 0.625f, 0.625f };
static const float DEFAULT_DRAG_COLOR[3] = { 1.0f, 1.0f, 1.0f };
static const float DEFAULT_HIGHLIGHT_COLOR[3] = { 1.0f, 0.38f, 0.0f };

static const float RED[3] = { 1.0f, 0.0f, 0.0f };
static const float GREEN[3] = { 0.0f, 1.0f, 0.0f };
static const float BLUE[3] = { 0.0f, 0.0f, 1.0f };

namespace Slic3r {
namespace GUI {

const float GLGizmoBase::Grabber::HalfSize = 2.0f;
const float GLGizmoBase::Grabber::DraggingScaleFactor = 1.25f;

GLGizmoBase::Grabber::Grabber()
    : center(0.0, 0.0, 0.0)
    , angle_x(0.0f)
    , angle_y(0.0f)
    , angle_z(0.0f)
    , dragging(false)
{
    color[0] = 1.0f;
    color[1] = 1.0f;
    color[2] = 1.0f;
}

void GLGizmoBase::Grabber::render(bool hover) const
{
    float render_color[3];
    if (hover)
    {
        render_color[0] = 1.0f - color[0];
        render_color[1] = 1.0f - color[1];
        render_color[2] = 1.0f - color[2];
    }
    else
        ::memcpy((void*)render_color, (const void*)color, 3 * sizeof(float));

#if ENABLE_GIZMOS_3D
    render(render_color, true);
#else
    render(render_color);
#endif // ENABLE_GIZMOS_3D
}

#if ENABLE_GIZMOS_3D
void GLGizmoBase::Grabber::render(const float* render_color, bool use_lighting) const
#else
void GLGizmoBase::Grabber::render(const float* render_color) const
#endif // ENABLE_GIZMOS_3D
{
    float half_size = dragging ? HalfSize * DraggingScaleFactor : HalfSize;
#if ENABLE_GIZMOS_3D
    if (use_lighting)
        ::glEnable(GL_LIGHTING);
#else
    float min_x = -half_size;
    float max_x = +half_size;
    float min_y = -half_size;
    float max_y = +half_size;
#endif // !ENABLE_GIZMOS_3D

    ::glColor3f((GLfloat)render_color[0], (GLfloat)render_color[1], (GLfloat)render_color[2]);

    ::glPushMatrix();
    ::glTranslatef((GLfloat)center(0), (GLfloat)center(1), (GLfloat)center(2));

    float rad_to_deg = 180.0f / (GLfloat)PI;
    ::glRotatef((GLfloat)angle_x * rad_to_deg, 1.0f, 0.0f, 0.0f);
    ::glRotatef((GLfloat)angle_y * rad_to_deg, 0.0f, 1.0f, 0.0f);
    ::glRotatef((GLfloat)angle_z * rad_to_deg, 0.0f, 0.0f, 1.0f);

#if ENABLE_GIZMOS_3D
    // face min x
    ::glPushMatrix();
    ::glTranslatef(-(GLfloat)half_size, 0.0f, 0.0f);
    ::glRotatef(-90.0f, 0.0f, 1.0f, 0.0f);
    render_face(half_size);
    ::glPopMatrix();

    // face max x
    ::glPushMatrix();
    ::glTranslatef((GLfloat)half_size, 0.0f, 0.0f);
    ::glRotatef(90.0f, 0.0f, 1.0f, 0.0f);
    render_face(half_size);
    ::glPopMatrix();

    // face min y
    ::glPushMatrix();
    ::glTranslatef(0.0f, -(GLfloat)half_size, 0.0f);
    ::glRotatef(90.0f, 1.0f, 0.0f, 0.0f);
    render_face(half_size);
    ::glPopMatrix();

    // face max y
    ::glPushMatrix();
    ::glTranslatef(0.0f, (GLfloat)half_size, 0.0f);
    ::glRotatef(-90.0f, 1.0f, 0.0f, 0.0f);
    render_face(half_size);
    ::glPopMatrix();

    // face min z
    ::glPushMatrix();
    ::glTranslatef(0.0f, 0.0f, -(GLfloat)half_size);
    ::glRotatef(180.0f, 1.0f, 0.0f, 0.0f);
    render_face(half_size);
    ::glPopMatrix();

    // face max z
    ::glPushMatrix();
    ::glTranslatef(0.0f, 0.0f, (GLfloat)half_size);
    render_face(half_size);
    ::glPopMatrix();
#else
    ::glDisable(GL_CULL_FACE);
    ::glBegin(GL_TRIANGLES);
    ::glVertex3f((GLfloat)min_x, (GLfloat)min_y, 0.0f);
    ::glVertex3f((GLfloat)max_x, (GLfloat)min_y, 0.0f);
    ::glVertex3f((GLfloat)max_x, (GLfloat)max_y, 0.0f);
    ::glVertex3f((GLfloat)max_x, (GLfloat)max_y, 0.0f);
    ::glVertex3f((GLfloat)min_x, (GLfloat)max_y, 0.0f);
    ::glVertex3f((GLfloat)min_x, (GLfloat)min_y, 0.0f);
    ::glEnd();
    ::glEnable(GL_CULL_FACE);
#endif // ENABLE_GIZMOS_3D

    ::glPopMatrix();

#if ENABLE_GIZMOS_3D
    if (use_lighting)
        ::glDisable(GL_LIGHTING);
#endif // ENABLE_GIZMOS_3D
}

#if ENABLE_GIZMOS_3D
void GLGizmoBase::Grabber::render_face(float half_size) const
{
    ::glBegin(GL_TRIANGLES);
    ::glNormal3f(0.0f, 0.0f, 1.0f);
    ::glVertex3f(-(GLfloat)half_size, -(GLfloat)half_size, 0.0f);
    ::glVertex3f((GLfloat)half_size, -(GLfloat)half_size, 0.0f);
    ::glVertex3f((GLfloat)half_size, (GLfloat)half_size, 0.0f);
    ::glVertex3f((GLfloat)half_size, (GLfloat)half_size, 0.0f);
    ::glVertex3f(-(GLfloat)half_size, (GLfloat)half_size, 0.0f);
    ::glVertex3f(-(GLfloat)half_size, -(GLfloat)half_size, 0.0f);
    ::glEnd();
}
#endif // ENABLE_GIZMOS_3D

GLGizmoBase::GLGizmoBase()
    : m_group_id(-1)
    , m_state(Off)
    , m_hover_id(-1)
    , m_is_container(false)
{
    ::memcpy((void*)m_base_color, (const void*)DEFAULT_BASE_COLOR, 3 * sizeof(float));
    ::memcpy((void*)m_drag_color, (const void*)DEFAULT_DRAG_COLOR, 3 * sizeof(float));
    ::memcpy((void*)m_highlight_color, (const void*)DEFAULT_HIGHLIGHT_COLOR, 3 * sizeof(float));
}

void GLGizmoBase::set_hover_id(int id)
{
    if (m_is_container || (id < (int)m_grabbers.size()))
    {
        m_hover_id = id;
        on_set_hover_id();
    }
}

void GLGizmoBase::set_highlight_color(const float* color)
{
    if (color != nullptr)
        ::memcpy((void*)m_highlight_color, (const void*)color, 3 * sizeof(float));
}

void GLGizmoBase::start_dragging()
{
    for (int i = 0; i < (int)m_grabbers.size(); ++i)
    {
        m_grabbers[i].dragging = (m_hover_id == i);
    }

    on_start_dragging();
}

void GLGizmoBase::stop_dragging()
{
    for (int i = 0; i < (int)m_grabbers.size(); ++i)
    {
        m_grabbers[i].dragging = false;
    }

    on_stop_dragging();
}

void GLGizmoBase::update(const Linef3& mouse_ray)
{
    if (m_hover_id != -1)
        on_update(mouse_ray);
}

float GLGizmoBase::picking_color_component(unsigned int id) const
{
    int color = 254 - (int)id;
    if (m_group_id > -1)
        color -= m_group_id;

    return (float)color / 255.0f;
}

void GLGizmoBase::render_grabbers() const
{
    for (int i = 0; i < (int)m_grabbers.size(); ++i)
    {
        m_grabbers[i].render(m_hover_id == i);
    }
}

void GLGizmoBase::render_grabbers_for_picking() const
{
    for (int i = 0; i < (int)m_grabbers.size(); ++i)
    {
        m_grabbers[i].render_for_picking();
    }
}

const float GLGizmoRotate::Offset = 5.0f;
const unsigned int GLGizmoRotate::CircleResolution = 64;
const unsigned int GLGizmoRotate::AngleResolution = 64;
const unsigned int GLGizmoRotate::ScaleStepsCount = 72;
const float GLGizmoRotate::ScaleStepRad = 2.0f * (float)PI / GLGizmoRotate::ScaleStepsCount;
const unsigned int GLGizmoRotate::ScaleLongEvery = 2;
const float GLGizmoRotate::ScaleLongTooth = 2.0f;
const float GLGizmoRotate::ScaleShortTooth = 1.0f;
const unsigned int GLGizmoRotate::SnapRegionsCount = 8;
const float GLGizmoRotate::GrabberOffset = 5.0f;

GLGizmoRotate::GLGizmoRotate(GLGizmoRotate::Axis axis)
    : GLGizmoBase()
    , m_axis(axis)
    , m_angle(0.0f)
    , m_center(0.0, 0.0, 0.0)
    , m_radius(0.0f)
    , m_keep_initial_values(false)
{
}

void GLGizmoRotate::set_angle(float angle)
{
    if (std::abs(angle - 2.0f * PI) < EPSILON)
        angle = 0.0f;

    m_angle = angle;
}

bool GLGizmoRotate::on_init()
{
#if !ENABLE_GIZMOS_3D
    std::string path = resources_dir() + "/icons/overlay/";

    std::string filename = path + "rotate_off.png";
    if (!m_textures[Off].load_from_file(filename, false))
        return false;
    
    filename = path + "rotate_hover.png";
    if (!m_textures[Hover].load_from_file(filename, false))
        return false;
    
    filename = path + "rotate_on.png";
    if (!m_textures[On].load_from_file(filename, false))
        return false;
#endif // !ENABLE_GIZMOS_3D

    m_grabbers.push_back(Grabber());

    return true;
}

void GLGizmoRotate::on_update(const Linef3& mouse_ray)
{ 
    Vec2d mouse_pos = to_2d(mouse_position_in_local_plane(mouse_ray));

    Vec2d orig_dir = Vec2d::UnitX();
    Vec2d new_dir = mouse_pos.normalized();

    double theta = ::acos(clamp(-1.0, 1.0, new_dir.dot(orig_dir)));
    if (cross2(orig_dir, new_dir) < 0.0)
        theta = 2.0 * (double)PI - theta;

    // snap
    double len = mouse_pos.norm();
    double in_radius = (double)m_radius / 3.0;
    double out_radius = 2.0 * (double)in_radius;
    if ((in_radius <= len) && (len <= out_radius))
    {
        double step = 2.0 * (double)PI / (double)SnapRegionsCount;
        theta = step * (double)std::round(theta / step);
    }

    if (theta == 2.0 * (double)PI)
        theta = 0.0;

    m_angle = (float)theta;
}

void GLGizmoRotate::on_render(const BoundingBoxf3& box) const
{
#if ENABLE_GIZMOS_3D
    ::glEnable(GL_DEPTH_TEST);
#else
    ::glDisable(GL_DEPTH_TEST);
#endif // ENABLE_GIZMOS_3D

    if (!m_keep_initial_values)
    {
        m_center = box.center();
#if !ENABLE_GIZMOS_3D
        const Vec3d& size = box.size();
        m_center(2) = 0.0;
#endif // !ENABLE_GIZMOS_3D

#if ENABLE_GIZMOS_3D
        m_radius = Offset + box.radius();
#else
        m_radius = Offset + ::sqrt(sqr(0.5f * (float)size(0)) + sqr(0.5f * (float)size(1)));
#endif // ENABLE_GIZMOS_3D
        m_keep_initial_values = true;
    }

    ::glPushMatrix();
    transform_to_local();

#if ENABLE_GIZMOS_3D
    ::glLineWidth((m_hover_id != -1) ? 2.0f : 1.5f);
    ::glColor3fv((m_hover_id != -1) ? m_drag_color : m_highlight_color);
#else
    ::glLineWidth(2.0f);
    ::glColor3fv(m_drag_color);
#endif // ENABLE_GIZMOS_3D

    render_circle();
#if ENABLE_GIZMOS_3D
    if (m_hover_id != -1)
    {
#endif // ENABLE_GIZMOS_3D
        render_scale();
        render_snap_radii();
        render_reference_radius();
#if ENABLE_GIZMOS_3D
    }
#endif // ENABLE_GIZMOS_3D

    ::glColor3fv(m_highlight_color);
#if ENABLE_GIZMOS_3D
    if (m_hover_id != -1)
#endif // ENABLE_GIZMOS_3D
        render_angle();

    render_grabber();

    ::glPopMatrix();
}

void GLGizmoRotate::on_render_for_picking(const BoundingBoxf3& box) const
{
    ::glDisable(GL_DEPTH_TEST);

    ::glPushMatrix();
    transform_to_local();

    m_grabbers[0].color[0] = 1.0f;
    m_grabbers[0].color[1] = 1.0f;
    m_grabbers[0].color[2] = picking_color_component(0);

    render_grabbers_for_picking();

    ::glPopMatrix();
}

void GLGizmoRotate::render_circle() const
{
    ::glBegin(GL_LINE_LOOP);
    for (unsigned int i = 0; i < ScaleStepsCount; ++i)
    {
        float angle = (float)i * ScaleStepRad;
        float x = ::cos(angle) * m_radius;
        float y = ::sin(angle) * m_radius;
        float z = 0.0f;
        ::glVertex3f((GLfloat)x, (GLfloat)y, (GLfloat)z);
    }
    ::glEnd();
}

void GLGizmoRotate::render_scale() const
{
    float out_radius_long = m_radius + ScaleLongTooth;
    float out_radius_short = m_radius + ScaleShortTooth;

    ::glBegin(GL_LINES);
    for (unsigned int i = 0; i < ScaleStepsCount; ++i)
    {
        float angle = (float)i * ScaleStepRad;
        float cosa = ::cos(angle);
        float sina = ::sin(angle);
        float in_x = cosa * m_radius;
        float in_y = sina * m_radius;
        float in_z = 0.0f;
        float out_x = (i % ScaleLongEvery == 0) ? cosa * out_radius_long : cosa * out_radius_short;
        float out_y = (i % ScaleLongEvery == 0) ? sina * out_radius_long : sina * out_radius_short;
        float out_z = 0.0f;
        ::glVertex3f((GLfloat)in_x, (GLfloat)in_y, (GLfloat)in_z);
        ::glVertex3f((GLfloat)out_x, (GLfloat)out_y, (GLfloat)out_z);
    }
    ::glEnd();
}

void GLGizmoRotate::render_snap_radii() const
{
    float step = 2.0f * (float)PI / (float)SnapRegionsCount;

    float in_radius = m_radius / 3.0f;
    float out_radius = 2.0f * in_radius;

    ::glBegin(GL_LINES);
    for (unsigned int i = 0; i < SnapRegionsCount; ++i)
    {
        float angle = (float)i * step;
        float cosa = ::cos(angle);
        float sina = ::sin(angle);
        float in_x = cosa * in_radius;
        float in_y = sina * in_radius;
        float in_z = 0.0f;
        float out_x = cosa * out_radius;
        float out_y = sina * out_radius;
        float out_z = 0.0f;
        ::glVertex3f((GLfloat)in_x, (GLfloat)in_y, (GLfloat)in_z);
        ::glVertex3f((GLfloat)out_x, (GLfloat)out_y, (GLfloat)out_z);
    }
    ::glEnd();
}

void GLGizmoRotate::render_reference_radius() const
{
    ::glBegin(GL_LINES);
    ::glVertex3f(0.0f, 0.0f, 0.0f);
    ::glVertex3f((GLfloat)(m_radius + GrabberOffset), 0.0f, 0.0f);
    ::glEnd();
}

void GLGizmoRotate::render_angle() const
{
    float step_angle = m_angle / AngleResolution;
    float ex_radius = m_radius + GrabberOffset;

    ::glBegin(GL_LINE_STRIP);
    for (unsigned int i = 0; i <= AngleResolution; ++i)
    {
        float angle = (float)i * step_angle;
        float x = ::cos(angle) * ex_radius;
        float y = ::sin(angle) * ex_radius;
        float z = 0.0f;
        ::glVertex3f((GLfloat)x, (GLfloat)y, (GLfloat)z);
    }
    ::glEnd();
}

void GLGizmoRotate::render_grabber() const
{
    float grabber_radius = m_radius + GrabberOffset;
    m_grabbers[0].center = Vec3d(::cos(m_angle) * grabber_radius, ::sin(m_angle) * grabber_radius, 0.0);
    m_grabbers[0].angle_z = m_angle;

#if ENABLE_GIZMOS_3D
    ::glColor3fv((m_hover_id != -1) ? m_drag_color : m_highlight_color);
#else
    ::glColor3fv(m_drag_color);
#endif // ENABLE_GIZMOS_3D

    ::glBegin(GL_LINES);
    ::glVertex3f(0.0f, 0.0f, 0.0f);
    ::glVertex3f((GLfloat)m_grabbers[0].center(0), (GLfloat)m_grabbers[0].center(1), (GLfloat)m_grabbers[0].center(2));
    ::glEnd();

    ::memcpy((void*)m_grabbers[0].color, (const void*)m_highlight_color, 3 * sizeof(float));
    render_grabbers();
}

void GLGizmoRotate::transform_to_local() const
{
    ::glTranslatef((GLfloat)m_center(0), (GLfloat)m_center(1), (GLfloat)m_center(2));

    switch (m_axis)
    {
    case X:
    {
        ::glRotatef(90.0f, 0.0f, 1.0f, 0.0f);
        ::glRotatef(90.0f, 0.0f, 0.0f, 1.0f);
        break;
    }
    case Y:
    {
        ::glRotatef(-90.0f, 1.0f, 0.0f, 0.0f);
        ::glRotatef(180.0f, 0.0f, 0.0f, 1.0f);
        break;
    }
    default:
    case Z:
    {
        // no rotation
        break;
    }
    }
}

Vec3d GLGizmoRotate::mouse_position_in_local_plane(const Linef3& mouse_ray) const
{
    double half_pi = 0.5 * (double)PI;

    Transform3d m = Transform3d::Identity();

    switch (m_axis)
    {
    case X:
    {
        m.rotate(Eigen::AngleAxisd(-half_pi, Vec3d::UnitZ()));
        m.rotate(Eigen::AngleAxisd(-half_pi, Vec3d::UnitY()));
        break;
    }
    case Y:
    {
        m.rotate(Eigen::AngleAxisd(-(double)PI, Vec3d::UnitZ()));
        m.rotate(Eigen::AngleAxisd(half_pi, Vec3d::UnitX()));
        break;
    }
    default:
    case Z:
    {
        // no rotation applied
        break;
    }
    }

    m.translate(-m_center);

    Eigen::Matrix<double, 3, 2> world_ray;
    Eigen::Matrix<double, 3, 2> local_ray;
    world_ray(0, 0) = mouse_ray.a(0);
    world_ray(1, 0) = mouse_ray.a(1);
    world_ray(2, 0) = mouse_ray.a(2);
    world_ray(0, 1) = mouse_ray.b(0);
    world_ray(1, 1) = mouse_ray.b(1);
    world_ray(2, 1) = mouse_ray.b(2);
    local_ray = m * world_ray.colwise().homogeneous();

    return Linef3(Vec3d(local_ray(0, 0), local_ray(1, 0), local_ray(2, 0)), Vec3d(local_ray(0, 1), local_ray(1, 1), local_ray(2, 1))).intersect_plane(0.0);
}

GLGizmoRotate3D::GLGizmoRotate3D()
    : GLGizmoBase()
    , m_x(GLGizmoRotate::X)
    , m_y(GLGizmoRotate::Y)
    , m_z(GLGizmoRotate::Z)
{
    m_is_container = true;

    m_x.set_group_id(0);
    m_y.set_group_id(1);
    m_z.set_group_id(2);
}

bool GLGizmoRotate3D::on_init()
{
    if (!m_x.init() || !m_y.init() || !m_z.init())
        return false;

    m_x.set_highlight_color(RED);
    m_y.set_highlight_color(GREEN);
    m_z.set_highlight_color(BLUE);

    std::string path = resources_dir() + "/icons/overlay/";

    std::string filename = path + "rotate_off.png";
    if (!m_textures[Off].load_from_file(filename, false))
        return false;

    filename = path + "rotate_hover.png";
    if (!m_textures[Hover].load_from_file(filename, false))
        return false;

    filename = path + "rotate_on.png";
    if (!m_textures[On].load_from_file(filename, false))
        return false;

    return true;
}

void GLGizmoRotate3D::on_start_dragging()
{
    switch (m_hover_id)
    {
    case 0:
    {
        m_x.start_dragging();
        break;
    }
    case 1:
    {
        m_y.start_dragging();
        break;
    }
    case 2:
    {
        m_z.start_dragging();
        break;
    }
    default:
    {
        break;
    }
    }
}

void GLGizmoRotate3D::on_stop_dragging()
{
    switch (m_hover_id)
    {
    case 0:
    {
        m_x.stop_dragging();
        break;
    }
    case 1:
    {
        m_y.stop_dragging();
        break;
    }
    case 2:
    {
        m_z.stop_dragging();
        break;
    }
    default:
    {
        break;
    }
    }
}

void GLGizmoRotate3D::on_render(const BoundingBoxf3& box) const
{
    if ((m_hover_id == -1) || (m_hover_id == 0))
        m_x.render(box);

    if ((m_hover_id == -1) || (m_hover_id == 1))
        m_y.render(box);

    if ((m_hover_id == -1) || (m_hover_id == 2))
        m_z.render(box);
}

const float GLGizmoScale::Offset = 5.0f;

GLGizmoScale::GLGizmoScale()
    : GLGizmoBase()
    , m_scale(1.0f)
    , m_starting_scale(1.0f)
{
}

bool GLGizmoScale::on_init()
{
    std::string path = resources_dir() + "/icons/overlay/";

    std::string filename = path + "scale_off.png";
    if (!m_textures[Off].load_from_file(filename, false))
        return false;

    filename = path + "scale_hover.png";
    if (!m_textures[Hover].load_from_file(filename, false))
        return false;

    filename = path + "scale_on.png";
    if (!m_textures[On].load_from_file(filename, false))
        return false;

    for (unsigned int i = 0; i < 4; ++i)
    {
        m_grabbers.push_back(Grabber());
    }

    return true;
}

void GLGizmoScale::on_start_dragging()
{
    if (m_hover_id != -1)
        m_starting_drag_position = to_2d(m_grabbers[m_hover_id].center);
}

void GLGizmoScale::on_update(const Linef3& mouse_ray)
{
    Vec2d mouse_pos = to_2d(mouse_ray.intersect_plane(0.0));
    Vec2d center(0.5 * (m_grabbers[1].center(0) + m_grabbers[0].center(0)), 0.5 * (m_grabbers[3].center(1) + m_grabbers[0].center(1)));

    double orig_len = (m_starting_drag_position - center).norm();
    double new_len = (mouse_pos - center).norm();
    double ratio = (orig_len != 0.0) ? new_len / orig_len : 1.0;

    m_scale = m_starting_scale * (float)ratio;
}

void GLGizmoScale::on_render(const BoundingBoxf3& box) const
{
    ::glDisable(GL_DEPTH_TEST);

    double min_x = box.min(0) - (double)Offset;
    double max_x = box.max(0) + (double)Offset;
    double min_y = box.min(1) - (double)Offset;
    double max_y = box.max(1) + (double)Offset;

    m_grabbers[0].center = Vec3d(min_x, min_y, 0.0);
    m_grabbers[1].center = Vec3d(max_x, min_y, 0.0);
    m_grabbers[2].center = Vec3d(max_x, max_y, 0.0);
    m_grabbers[3].center = Vec3d(min_x, max_y, 0.0);

    ::glLineWidth(2.0f);
    ::glColor3fv(m_drag_color);

    // draw outline
    ::glBegin(GL_LINE_LOOP);
    for (unsigned int i = 0; i < 4; ++i)
    {
        ::glVertex3f((GLfloat)m_grabbers[i].center(0), (GLfloat)m_grabbers[i].center(1), 0.0f);
    }
    ::glEnd();

    // draw grabbers
    for (unsigned int i = 0; i < 4; ++i)
    {
        ::memcpy((void*)m_grabbers[i].color, (const void*)m_highlight_color, 3 * sizeof(float));
    }
    render_grabbers();
}

void GLGizmoScale::on_render_for_picking(const BoundingBoxf3& box) const
{
    ::glDisable(GL_DEPTH_TEST);

    for (unsigned int i = 0; i < 4; ++i)
    {
        m_grabbers[i].color[0] = 1.0f;
        m_grabbers[i].color[1] = 1.0f;
        m_grabbers[i].color[2] = picking_color_component(i);
    }
    render_grabbers_for_picking();
}

const float GLGizmoScale3D::Offset = 5.0f;

GLGizmoScale3D::GLGizmoScale3D()
    : GLGizmoBase()
    , m_scale_x(1.0f)
    , m_scale_y(1.0f)
    , m_scale_z(1.0f)
    , m_starting_scale_x(1.0f)
    , m_starting_scale_y(1.0f)
    , m_starting_scale_z(1.0f)
{
}

bool GLGizmoScale3D::on_init()
{
    std::string path = resources_dir() + "/icons/overlay/";

    std::string filename = path + "scale_off.png";
    if (!m_textures[Off].load_from_file(filename, false))
        return false;

    filename = path + "scale_hover.png";
    if (!m_textures[Hover].load_from_file(filename, false))
        return false;

    filename = path + "scale_on.png";
    if (!m_textures[On].load_from_file(filename, false))
        return false;

    for (int i = 0; i < 10; ++i)
    {
        m_grabbers.push_back(Grabber());
    }

    float half_pi = 0.5f * (float)PI;

    // x axis
    m_grabbers[0].angle_y = half_pi;
    m_grabbers[1].angle_y = half_pi;

    // y axis
    m_grabbers[2].angle_x = half_pi;
    m_grabbers[3].angle_x = half_pi;

    return true;
}

void GLGizmoScale3D::on_start_dragging()
{
    if (m_hover_id != -1)
    {
        m_starting_drag_position = m_grabbers[m_hover_id].center;
        m_starting_center = m_box.center();
    }
}

void GLGizmoScale3D::on_update(const Linef3& mouse_ray)
{
    if ((m_hover_id == 0) || (m_hover_id == 1))
        do_scale_x(mouse_ray);
    else if ((m_hover_id == 2) || (m_hover_id == 3))
        do_scale_y(mouse_ray);
    else if ((m_hover_id == 4) || (m_hover_id == 5))
        do_scale_z(mouse_ray);
    else if (m_hover_id >= 6)
        do_scale_uniform(mouse_ray);
}

void GLGizmoScale3D::on_render(const BoundingBoxf3& box) const
{
    ::glEnable(GL_DEPTH_TEST);

    Vec3d offset_vec((double)Offset, (double)Offset, (double)Offset);

    m_box = BoundingBoxf3(box.min - offset_vec, box.max + offset_vec);
    const Vec3d& center = m_box.center();

    // x axis
    m_grabbers[0].center = Vec3d(m_box.min(0), center(1), center(2));
    m_grabbers[1].center = Vec3d(m_box.max(0), center(1), center(2));
    ::memcpy((void*)m_grabbers[0].color, (const void*)RED, 3 * sizeof(float));
    ::memcpy((void*)m_grabbers[1].color, (const void*)RED, 3 * sizeof(float));

    // y axis
    m_grabbers[2].center = Vec3d(center(0), m_box.min(1), center(2));
    m_grabbers[3].center = Vec3d(center(0), m_box.max(1), center(2));
    ::memcpy((void*)m_grabbers[2].color, (const void*)GREEN, 3 * sizeof(float));
    ::memcpy((void*)m_grabbers[3].color, (const void*)GREEN, 3 * sizeof(float));

    // z axis
    m_grabbers[4].center = Vec3d(center(0), center(1), m_box.min(2));
    m_grabbers[5].center = Vec3d(center(0), center(1), m_box.max(2));
    ::memcpy((void*)m_grabbers[4].color, (const void*)BLUE, 3 * sizeof(float));
    ::memcpy((void*)m_grabbers[5].color, (const void*)BLUE, 3 * sizeof(float));

    // uniform
    m_grabbers[6].center = Vec3d(m_box.min(0), m_box.min(1), m_box.min(2));
    m_grabbers[7].center = Vec3d(m_box.max(0), m_box.min(1), m_box.min(2));
    m_grabbers[8].center = Vec3d(m_box.max(0), m_box.max(1), m_box.min(2));
    m_grabbers[9].center = Vec3d(m_box.min(0), m_box.max(1), m_box.min(2));
    for (int i = 6; i < 10; ++i)
    {
        ::memcpy((void*)m_grabbers[i].color, (const void*)m_highlight_color, 3 * sizeof(float));
    }

    ::glLineWidth((m_hover_id != -1) ? 2.0f : 1.5f);

    if (m_hover_id == -1)
    {
        ::glColor3fv(m_base_color);
        // draw box
        render_box();
        // draw grabbers
        render_grabbers();
    }
    else if ((m_hover_id == 0) || (m_hover_id == 1))
    {
        ::glColor3fv(m_grabbers[0].color);
        // draw connection
        render_grabbers_connection(0, 1);
        // draw grabbers
        m_grabbers[0].render(true);
        m_grabbers[1].render(true);
    }
    else if ((m_hover_id == 2) || (m_hover_id == 3))
    {
        ::glColor3fv(m_grabbers[2].color);
        // draw connection
        render_grabbers_connection(2, 3);
        // draw grabbers
        m_grabbers[2].render(true);
        m_grabbers[3].render(true);
    }
    else if ((m_hover_id == 4) || (m_hover_id == 5))
    {
        ::glColor3fv(m_grabbers[4].color);
        // draw connection
        render_grabbers_connection(4, 5);
        // draw grabbers
        m_grabbers[4].render(true);
        m_grabbers[5].render(true);
    }
    else if (m_hover_id >= 6)
    {
        ::glColor3fv(m_drag_color);
        // draw box
        render_box();
        // draw grabbers
        for (int i = 6; i < 10; ++i)
        {
            m_grabbers[i].render(true);
        }
    }
}

void GLGizmoScale3D::on_render_for_picking(const BoundingBoxf3& box) const
{
    ::glDisable(GL_DEPTH_TEST);

    for (unsigned int i = 0; i < (unsigned int)m_grabbers.size(); ++i)
    {
        m_grabbers[i].color[0] = 1.0f;
        m_grabbers[i].color[1] = 1.0f;
        m_grabbers[i].color[2] = picking_color_component(i);
    }

    render_grabbers_for_picking();
}

void GLGizmoScale3D::render_box() const
{
    // bottom face
    ::glBegin(GL_LINE_LOOP);
    ::glVertex3f((GLfloat)m_box.min(0), (GLfloat)m_box.min(1), (GLfloat)m_box.min(2));
    ::glVertex3f((GLfloat)m_box.min(0), (GLfloat)m_box.max(1), (GLfloat)m_box.min(2));
    ::glVertex3f((GLfloat)m_box.max(0), (GLfloat)m_box.max(1), (GLfloat)m_box.min(2));
    ::glVertex3f((GLfloat)m_box.max(0), (GLfloat)m_box.min(1), (GLfloat)m_box.min(2));
    ::glEnd();

    // top face
    ::glBegin(GL_LINE_LOOP);
    ::glVertex3f((GLfloat)m_box.min(0), (GLfloat)m_box.min(1), (GLfloat)m_box.max(2));
    ::glVertex3f((GLfloat)m_box.min(0), (GLfloat)m_box.max(1), (GLfloat)m_box.max(2));
    ::glVertex3f((GLfloat)m_box.max(0), (GLfloat)m_box.max(1), (GLfloat)m_box.max(2));
    ::glVertex3f((GLfloat)m_box.max(0), (GLfloat)m_box.min(1), (GLfloat)m_box.max(2));
    ::glEnd();

    // vertical edges
    ::glBegin(GL_LINES);
    ::glVertex3f((GLfloat)m_box.min(0), (GLfloat)m_box.min(1), (GLfloat)m_box.min(2)); ::glVertex3f((GLfloat)m_box.min(0), (GLfloat)m_box.min(1), (GLfloat)m_box.max(2));
    ::glVertex3f((GLfloat)m_box.min(0), (GLfloat)m_box.max(1), (GLfloat)m_box.min(2)); ::glVertex3f((GLfloat)m_box.min(0), (GLfloat)m_box.max(1), (GLfloat)m_box.max(2));
    ::glVertex3f((GLfloat)m_box.max(0), (GLfloat)m_box.max(1), (GLfloat)m_box.min(2)); ::glVertex3f((GLfloat)m_box.max(0), (GLfloat)m_box.max(1), (GLfloat)m_box.max(2));
    ::glVertex3f((GLfloat)m_box.max(0), (GLfloat)m_box.min(1), (GLfloat)m_box.min(2)); ::glVertex3f((GLfloat)m_box.max(0), (GLfloat)m_box.min(1), (GLfloat)m_box.max(2));
    ::glEnd();
}

void GLGizmoScale3D::render_grabbers_connection(unsigned int id_1, unsigned int id_2) const
{
    unsigned int grabbers_count = (unsigned int)m_grabbers.size();
    if ((id_1 < grabbers_count) && (id_2 < grabbers_count))
    {
        ::glBegin(GL_LINES);
        ::glVertex3f((GLfloat)m_grabbers[id_1].center(0), (GLfloat)m_grabbers[id_1].center(1), (GLfloat)m_grabbers[id_1].center(2));
        ::glVertex3f((GLfloat)m_grabbers[id_2].center(0), (GLfloat)m_grabbers[id_2].center(1), (GLfloat)m_grabbers[id_2].center(2));
        ::glEnd();
    }
}

Linef3 transform(const Linef3& line, const Transform3d& t)
{
    Eigen::Matrix<double, 3, 2> world_line;
    Eigen::Matrix<double, 3, 2> local_line;
    world_line(0, 0) = line.a(0);
    world_line(1, 0) = line.a(1);
    world_line(2, 0) = line.a(2);
    world_line(0, 1) = line.b(0);
    world_line(1, 1) = line.b(1);
    world_line(2, 1) = line.b(2);
    local_line = t * world_line.colwise().homogeneous();

    return Linef3(Vec3d(local_line(0, 0), local_line(1, 0), local_line(2, 0)), Vec3d(local_line(0, 1), local_line(1, 1), local_line(2, 1)));
}

void GLGizmoScale3D::do_scale_x(const Linef3& mouse_ray)
{
    double ratio = calc_ratio(1, mouse_ray, m_starting_center);

    if (ratio > 0.0)
        m_scale_x = m_starting_scale_x * (float)ratio;
}

void GLGizmoScale3D::do_scale_y(const Linef3& mouse_ray)
{
    double ratio = calc_ratio(2, mouse_ray, m_starting_center);

    if (ratio > 0.0)
        m_scale_x = m_starting_scale_y * (float)ratio;
//        m_scale_y = m_starting_scale_y * (float)ratio;
}

void GLGizmoScale3D::do_scale_z(const Linef3& mouse_ray)
{
    double ratio = calc_ratio(1, mouse_ray, m_starting_center);

    if (ratio > 0.0)
        m_scale_x = m_starting_scale_z * (float)ratio;
//        m_scale_z = m_starting_scale_z * (float)ratio;
}

void GLGizmoScale3D::do_scale_uniform(const Linef3& mouse_ray)
{
    Vec3d center = m_starting_center;
    center(2) = m_box.min(2);
    double ratio = calc_ratio(0, mouse_ray, center);

    if (ratio > 0.0)
    {
        m_scale_x = m_starting_scale_x * (float)ratio;
        m_scale_y = m_starting_scale_y * (float)ratio;
        m_scale_z = m_starting_scale_z * (float)ratio;
    }
}

double GLGizmoScale3D::calc_ratio(unsigned int preferred_plane_id, const Linef3& mouse_ray, const Vec3d& center) const
{
    double ratio = 0.0;

    Vec3d starting_vec = m_starting_drag_position - center;
    double len_starting_vec = starting_vec.norm();
    if (len_starting_vec == 0.0)
        return ratio;

    Vec3d starting_vec_dir = starting_vec.normalized();
    Vec3d mouse_dir = mouse_ray.unit_vector();
    unsigned int plane_id = preferred_plane_id;

    // 1st try to see if the mouse direction is close enough to the preferred plane normal
    double dot_to_normal = 0.0;
    switch (plane_id)
    {
    case 0:
    {
        dot_to_normal = std::abs(mouse_dir.dot(Vec3d::UnitZ()));
        break;
    }
    case 1:
    {
        dot_to_normal = std::abs(mouse_dir.dot(-Vec3d::UnitY()));
        break;
    }
    case 2:
    {
        dot_to_normal = std::abs(mouse_dir.dot(Vec3d::UnitX()));
        break;
    }
    }

    if (dot_to_normal < 0.1)
    {
        // if not, select the plane who's normal is closest to the mouse direction

        typedef std::map<double, unsigned int> ProjsMap;
        ProjsMap projs_map;

        projs_map.insert(ProjsMap::value_type(std::abs(mouse_dir.dot(Vec3d::UnitZ())), 0));  // plane xy
        projs_map.insert(ProjsMap::value_type(std::abs(mouse_dir.dot(-Vec3d::UnitY())), 1)); // plane xz
        projs_map.insert(ProjsMap::value_type(std::abs(mouse_dir.dot(Vec3d::UnitX())), 2));  // plane yz
        plane_id = projs_map.rbegin()->second;
    }

    switch (plane_id)
    {
    case 0:
    {
        // calculates the intersection of the mouse ray with the plane parallel to plane XY and passing through the given center
        Transform3d m = Transform3d::Identity();
        m.translate(-center);
        Vec2d mouse_pos_2d = to_2d(transform(mouse_ray, m).intersect_plane(0.0));

        // ratio is given by the projection of the calculated intersection on the starting vector divided by the starting vector length
        ratio = starting_vec_dir.dot(Vec3d(mouse_pos_2d(0), mouse_pos_2d(1), 0.0)) / len_starting_vec;
        break;
    }
    case 1:
    {
        // calculates the intersection of the mouse ray with the plane parallel to plane XZ and passing through the given center
        Transform3d m = Transform3d::Identity();
        m.rotate(Eigen::AngleAxisd(-0.5 * (double)PI, Vec3d::UnitX()));
        m.translate(-center);
        Vec2d mouse_pos_2d = to_2d(transform(mouse_ray, m).intersect_plane(0.0));

        // ratio is given by the projection of the calculated intersection on the starting vector divided by the starting vector length
        ratio = starting_vec_dir.dot(Vec3d(mouse_pos_2d(0), 0.0, mouse_pos_2d(1))) / len_starting_vec;
        break;
    }
    case 2:
    {
        // calculates the intersection of the mouse ray with the plane parallel to plane YZ and passing through the given center
        Transform3d m = Transform3d::Identity();
        m.rotate(Eigen::AngleAxisd(-0.5f * (double)PI, Vec3d::UnitY()));
        m.translate(-center);
        Vec2d mouse_pos_2d = to_2d(transform(mouse_ray, m).intersect_plane(0.0));

        // ratio is given by the projection of the calculated intersection on the starting vector divided by the starting vector length
        ratio = starting_vec_dir.dot(Vec3d(0.0, mouse_pos_2d(1), -mouse_pos_2d(0))) / len_starting_vec;
        break;
    }
    }

    return ratio;
}

} // namespace GUI
} // namespace Slic3r