#include "libslic3r/libslic3r.h"

#include "Camera.hpp"
#if !ENABLE_THUMBNAIL_GENERATOR
#include "3DScene.hpp"
#endif // !ENABLE_THUMBNAIL_GENERATOR
#include "GUI_App.hpp"
#include "AppConfig.hpp"

#include <GL/glew.h>

static const float GIMBALL_LOCK_THETA_MAX = 180.0f;

// phi / theta angles to orient the camera.
static const float VIEW_DEFAULT[2] = { 45.0f, 45.0f };
static const float VIEW_LEFT[2] = { 90.0f, 90.0f };
static const float VIEW_RIGHT[2] = { -90.0f, 90.0f };
static const float VIEW_TOP[2] = { 0.0f, 0.0f };
static const float VIEW_BOTTOM[2] = { 0.0f, 180.0f };
static const float VIEW_FRONT[2] = { 0.0f, 90.0f };
static const float VIEW_REAR[2] = { 180.0f, 90.0f };

namespace Slic3r {
namespace GUI {

const double Camera::DefaultDistance = 1000.0;
#if ENABLE_THUMBNAIL_GENERATOR
const double Camera::DefaultZoomToBoxMarginFactor = 1.025;
const double Camera::DefaultZoomToVolumesMarginFactor = 1.025;
#endif // ENABLE_THUMBNAIL_GENERATOR
double Camera::FrustrumMinZRange = 50.0;
double Camera::FrustrumMinNearZ = 100.0;
double Camera::FrustrumZMargin = 10.0;
double Camera::MaxFovDeg = 60.0;

Camera::Camera()
    : phi(45.0f)
    , requires_zoom_to_bed(false)
    , inverted_phi(false)
    , m_type(Perspective)
    , m_target(Vec3d::Zero())
    , m_theta(45.0f)
    , m_zoom(1.0)
    , m_distance(DefaultDistance)
    , m_gui_scale(1.0)
    , m_view_matrix(Transform3d::Identity())
    , m_projection_matrix(Transform3d::Identity())
{
}

std::string Camera::get_type_as_string() const
{
    switch (m_type)
    {
    case Unknown:
        return "unknown";
    case Perspective:
        return "perspective";
    default:
    case Ortho:
        return "orthographic";
    };
}

void Camera::set_type(EType type)
{
    if (m_type != type)
    {
        m_type = type;
        wxGetApp().app_config->set("use_perspective_camera", (m_type == Perspective) ? "1" : "0");
        wxGetApp().app_config->save();
    }
}

void Camera::set_type(const std::string& type)
{
    if (type == "1")
        set_type(Perspective);
    else
        set_type(Ortho);
}

void Camera::select_next_type()
{
    unsigned char next = (unsigned char)m_type + 1;
    if (next == (unsigned char)Num_types)
        next = 1;

    set_type((EType)next);
}

void Camera::set_target(const Vec3d& target)
{
    BoundingBoxf3 test_box = m_scene_box;
    test_box.translate(-m_scene_box.center());
    // We may let this factor be customizable
    static const double ScaleFactor = 1.5;
    test_box.scale(ScaleFactor);
    test_box.translate(m_scene_box.center());

    m_target(0) = clamp(test_box.min(0), test_box.max(0), target(0));
    m_target(1) = clamp(test_box.min(1), test_box.max(1), target(1));
    m_target(2) = clamp(test_box.min(2), test_box.max(2), target(2));
}

void Camera::set_theta(float theta, bool apply_limit)
{
    if (apply_limit)
        m_theta = clamp(0.0f, GIMBALL_LOCK_THETA_MAX, theta);
    else
    {
        m_theta = fmod(theta, 360.0f);
        if (m_theta < 0.0f)
            m_theta += 360.0f;
    }
}

void Camera::update_zoom(double delta_zoom)
{
    set_zoom(m_zoom / (1.0 - std::max(std::min(delta_zoom, 4.0), -4.0) * 0.1));
}

void Camera::set_zoom(double zoom)
{
    // Don't allow to zoom too far outside the scene.
    double zoom_min = calc_zoom_to_bounding_box_factor(m_scene_box, (int)m_viewport[2], (int)m_viewport[3]);
    if (zoom_min > 0.0)
        zoom = std::max(zoom, zoom_min * 0.7);

    // Don't allow to zoom too close to the scene.
    m_zoom = std::min(zoom, 100.0);
}

bool Camera::select_view(const std::string& direction)
{
    const float* dir_vec = nullptr;

    if (direction == "iso")
        dir_vec = VIEW_DEFAULT;
    else if (direction == "left")
        dir_vec = VIEW_LEFT;
    else if (direction == "right")
        dir_vec = VIEW_RIGHT;
    else if (direction == "top")
        dir_vec = VIEW_TOP;
    else if (direction == "bottom")
        dir_vec = VIEW_BOTTOM;
    else if (direction == "front")
        dir_vec = VIEW_FRONT;
    else if (direction == "rear")
        dir_vec = VIEW_REAR;

    if (dir_vec != nullptr)
    {
        phi = dir_vec[0];
        set_theta(dir_vec[1], false);
        return true;
    }
    else
        return false;
}

double Camera::get_fov() const
{
    switch (m_type)
    {
    case Perspective:
        return 2.0 * Geometry::rad2deg(std::atan(1.0 / m_projection_matrix.matrix()(1, 1)));
    default:
    case Ortho:
        return 0.0;
    };
}

void Camera::apply_viewport(int x, int y, unsigned int w, unsigned int h) const
{
    glsafe(::glViewport(0, 0, w, h));
    glsafe(::glGetIntegerv(GL_VIEWPORT, m_viewport.data()));
}

void Camera::apply_view_matrix() const
{
    double theta_rad = Geometry::deg2rad(-(double)m_theta);
    double phi_rad = Geometry::deg2rad((double)phi);
    double sin_theta = ::sin(theta_rad);
    Vec3d camera_pos = m_target + m_distance * Vec3d(sin_theta * ::sin(phi_rad), sin_theta * ::cos(phi_rad), ::cos(theta_rad));

    glsafe(::glMatrixMode(GL_MODELVIEW));
    glsafe(::glLoadIdentity());

    glsafe(::glRotatef(-m_theta, 1.0f, 0.0f, 0.0f)); // pitch
    glsafe(::glRotatef(phi, 0.0f, 0.0f, 1.0f));      // yaw

    glsafe(::glTranslated(-camera_pos(0), -camera_pos(1), -camera_pos(2))); 

    glsafe(::glGetDoublev(GL_MODELVIEW_MATRIX, m_view_matrix.data()));
}

void Camera::apply_projection(const BoundingBoxf3& box, double near_z, double far_z) const
{
    set_distance(DefaultDistance);

    double w = 0.0;
    double h = 0.0;

    while (true)
    {
        m_frustrum_zs = calc_tight_frustrum_zs_around(box);

        if (near_z > 0.0)
            m_frustrum_zs.first = std::min(m_frustrum_zs.first, near_z);

        if (far_z > 0.0)
            m_frustrum_zs.second = std::max(m_frustrum_zs.second, far_z);

        w = 0.5 * (double)m_viewport[2];
        h = 0.5 * (double)m_viewport[3];

        if (m_zoom != 0.0)
        {
            double inv_zoom = 1.0 / m_zoom;
            w *= inv_zoom;
            h *= inv_zoom;
        }

        switch (m_type)
        {
        default:
        case Ortho:
        {
            m_gui_scale = 1.0;
            break;
        }
        case Perspective:
        {
            // scale near plane to keep w and h constant on the plane at z = m_distance
            double scale = m_frustrum_zs.first / m_distance;
            w *= scale;
            h *= scale;
            m_gui_scale = scale;
            break;
        }
        }

        if (m_type == Perspective)
        {
            double fov_deg = Geometry::rad2deg(2.0 * std::atan(h / m_frustrum_zs.first));

            // adjust camera distance to keep fov in a limited range
            if (fov_deg > MaxFovDeg)
            {
                double delta_z = h / ::tan(0.5 * Geometry::deg2rad(MaxFovDeg)) - m_frustrum_zs.first;
                if (delta_z > 0.001)
                    set_distance(m_distance + delta_z);
                else
                    break;
            }
            else
                break;
        }
        else
            break;
    }

    glsafe(::glMatrixMode(GL_PROJECTION));
    glsafe(::glLoadIdentity());

    switch (m_type)
    {
    default:
    case Ortho:
    {
        glsafe(::glOrtho(-w, w, -h, h, m_frustrum_zs.first, m_frustrum_zs.second));
        break;
    }
    case Perspective:
    {
        glsafe(::glFrustum(-w, w, -h, h, m_frustrum_zs.first, m_frustrum_zs.second));
        break;
    }
    }

    glsafe(::glGetDoublev(GL_PROJECTION_MATRIX, m_projection_matrix.data()));
    glsafe(::glMatrixMode(GL_MODELVIEW));
}

#if ENABLE_THUMBNAIL_GENERATOR
void Camera::zoom_to_box(const BoundingBoxf3& box, int canvas_w, int canvas_h, double margin_factor)
#else
void Camera::zoom_to_box(const BoundingBoxf3& box, int canvas_w, int canvas_h)
#endif // ENABLE_THUMBNAIL_GENERATOR
{
    // Calculate the zoom factor needed to adjust the view around the given box.
#if ENABLE_THUMBNAIL_GENERATOR
    double zoom = calc_zoom_to_bounding_box_factor(box, canvas_w, canvas_h, margin_factor);
#else
    double zoom = calc_zoom_to_bounding_box_factor(box, canvas_w, canvas_h);
#endif // ENABLE_THUMBNAIL_GENERATOR
    if (zoom > 0.0)
    {
        m_zoom = zoom;
        // center view around box center
        m_target = box.center();
    }
}

#if ENABLE_THUMBNAIL_GENERATOR
void Camera::zoom_to_volumes(const GLVolumePtrs& volumes, int canvas_w, int canvas_h, double margin_factor)
{
    Vec3d center;
    double zoom = calc_zoom_to_volumes_factor(volumes, canvas_w, canvas_h, center, margin_factor);
    if (zoom > 0.0)
    {
        m_zoom = zoom;
        // center view around the calculated center
        m_target = center;
    }
}
#endif // ENABLE_THUMBNAIL_GENERATOR

#if ENABLE_CAMERA_STATISTICS
void Camera::debug_render() const
{
    ImGuiWrapper& imgui = *wxGetApp().imgui();
    imgui.set_next_window_bg_alpha(0.5f);
    imgui.begin(std::string("Camera statistics"), ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoCollapse);

    std::string type = get_type_as_string();
    Vec3f position = get_position().cast<float>();
    Vec3f target = m_target.cast<float>();
    float distance = (float)get_distance();
    Vec3f forward = get_dir_forward().cast<float>();
    Vec3f right = get_dir_right().cast<float>();
    Vec3f up = get_dir_up().cast<float>();
    float nearZ = (float)m_frustrum_zs.first;
    float farZ = (float)m_frustrum_zs.second;
    float deltaZ = farZ - nearZ;
    float zoom = (float)m_zoom;
    float fov = (float)get_fov();
    float gui_scale = (float)get_gui_scale();

    ImGui::InputText("Type", const_cast<char*>(type.data()), type.length(), ImGuiInputTextFlags_ReadOnly);
    ImGui::Separator();
    ImGui::InputFloat3("Position", position.data(), "%.6f", ImGuiInputTextFlags_ReadOnly);
    ImGui::InputFloat3("Target", target.data(), "%.6f", ImGuiInputTextFlags_ReadOnly);
    ImGui::InputFloat("Distance", &distance, 0.0f, 0.0f, "%.6f", ImGuiInputTextFlags_ReadOnly);
    ImGui::Separator();
    ImGui::InputFloat3("Forward", forward.data(), "%.6f", ImGuiInputTextFlags_ReadOnly);
    ImGui::InputFloat3("Right", right.data(), "%.6f", ImGuiInputTextFlags_ReadOnly);
    ImGui::InputFloat3("Up", up.data(), "%.6f", ImGuiInputTextFlags_ReadOnly);
    ImGui::Separator();
    ImGui::InputFloat("Near Z", &nearZ, 0.0f, 0.0f, "%.6f", ImGuiInputTextFlags_ReadOnly);
    ImGui::InputFloat("Far Z", &farZ, 0.0f, 0.0f, "%.6f", ImGuiInputTextFlags_ReadOnly);
    ImGui::InputFloat("Delta Z", &deltaZ, 0.0f, 0.0f, "%.6f", ImGuiInputTextFlags_ReadOnly);
    ImGui::Separator();
    ImGui::InputFloat("Zoom", &zoom, 0.0f, 0.0f, "%.6f", ImGuiInputTextFlags_ReadOnly);
    ImGui::InputFloat("Fov", &fov, 0.0f, 0.0f, "%.6f", ImGuiInputTextFlags_ReadOnly);
    ImGui::Separator();
    ImGui::InputFloat("GUI scale", &gui_scale, 0.0f, 0.0f, "%.6f", ImGuiInputTextFlags_ReadOnly);
    imgui.end();
}
#endif // ENABLE_CAMERA_STATISTICS

std::pair<double, double> Camera::calc_tight_frustrum_zs_around(const BoundingBoxf3& box) const
{
    std::pair<double, double> ret;

    while (true)
    {
        // box in eye space
        BoundingBoxf3 eye_box = box.transformed(m_view_matrix);
        ret.first = -eye_box.max(2);
        ret.second = -eye_box.min(2);

        // apply margin
        ret.first -= FrustrumZMargin;
        ret.second += FrustrumZMargin;

        // ensure min size
        if (ret.second - ret.first < FrustrumMinZRange)
        {
            double mid_z = 0.5 * (ret.first + ret.second);
            double half_size = 0.5 * FrustrumMinZRange;
            ret.first = mid_z - half_size;
            ret.second = mid_z + half_size;
        }

        if (ret.first >= FrustrumMinNearZ)
            break;

        // ensure min Near Z
        set_distance(m_distance + FrustrumMinNearZ - ret.first);
    }

    return ret;
}

#if ENABLE_THUMBNAIL_GENERATOR
double Camera::calc_zoom_to_bounding_box_factor(const BoundingBoxf3& box, int canvas_w, int canvas_h, double margin_factor) const
#else
double Camera::calc_zoom_to_bounding_box_factor(const BoundingBoxf3& box, int canvas_w, int canvas_h) const
#endif // ENABLE_THUMBNAIL_GENERATOR
{
    double max_bb_size = box.max_size();
    if (max_bb_size == 0.0)
        return -1.0;

    // project the box vertices on a plane perpendicular to the camera forward axis
    // then calculates the vertices coordinate on this plane along the camera xy axes

    // ensure that the view matrix is updated
    apply_view_matrix();

    Vec3d right = get_dir_right();
    Vec3d up = get_dir_up();
    Vec3d forward = get_dir_forward();

    Vec3d bb_center = box.center();

    // box vertices in world space
    std::vector<Vec3d> vertices;
    vertices.reserve(8);
    vertices.push_back(box.min);
    vertices.emplace_back(box.max(0), box.min(1), box.min(2));
    vertices.emplace_back(box.max(0), box.max(1), box.min(2));
    vertices.emplace_back(box.min(0), box.max(1), box.min(2));
    vertices.emplace_back(box.min(0), box.min(1), box.max(2));
    vertices.emplace_back(box.max(0), box.min(1), box.max(2));
    vertices.push_back(box.max);
    vertices.emplace_back(box.min(0), box.max(1), box.max(2));

    double min_x = DBL_MAX;
    double min_y = DBL_MAX;
    double max_x = -DBL_MAX;
    double max_y = -DBL_MAX;

#if !ENABLE_THUMBNAIL_GENERATOR
    // margin factor to give some empty space around the box
    double margin_factor = 1.25;
#endif // !ENABLE_THUMBNAIL_GENERATOR

    for (const Vec3d& v : vertices)
    {
        // project vertex on the plane perpendicular to camera forward axis
        Vec3d pos = v - bb_center;
        Vec3d proj_on_plane = pos - pos.dot(forward) * forward;

        // calculates vertex coordinate along camera xy axes
        double x_on_plane = proj_on_plane.dot(right);
        double y_on_plane = proj_on_plane.dot(up);

        min_x = std::min(min_x, x_on_plane);
        min_y = std::min(min_y, y_on_plane);
        max_x = std::max(max_x, x_on_plane);
        max_y = std::max(max_y, y_on_plane);
    }

    double dx = max_x - min_x;
    double dy = max_y - min_y;
    if ((dx <= 0.0) || (dy <= 0.0))
        return -1.0f;

    double med_x = 0.5 * (max_x + min_x);
    double med_y = 0.5 * (max_y + min_y);

    dx *= margin_factor;
    dy *= margin_factor;

    return std::min((double)canvas_w / dx, (double)canvas_h / dy);
}

#if ENABLE_THUMBNAIL_GENERATOR
double Camera::calc_zoom_to_volumes_factor(const GLVolumePtrs& volumes, int canvas_w, int canvas_h, Vec3d& center, double margin_factor) const
{
    if (volumes.empty())
        return -1.0;

    // project the volumes vertices on a plane perpendicular to the camera forward axis
    // then calculates the vertices coordinate on this plane along the camera xy axes

    // ensure that the view matrix is updated
    apply_view_matrix();

    Vec3d right = get_dir_right();
    Vec3d up = get_dir_up();
    Vec3d forward = get_dir_forward();

    BoundingBoxf3 box;
    for (const GLVolume* volume : volumes)
    {
        box.merge(volume->transformed_bounding_box());
    }
    center = box.center();

    double min_x = DBL_MAX;
    double min_y = DBL_MAX;
    double max_x = -DBL_MAX;
    double max_y = -DBL_MAX;

    for (const GLVolume* volume : volumes)
    {
        const Transform3d& transform = volume->world_matrix();
        const TriangleMesh* hull = volume->convex_hull();
        if (hull == nullptr)
            continue;

        for (const Vec3f& vertex : hull->its.vertices)
        {
            Vec3d v = transform * vertex.cast<double>();

            // project vertex on the plane perpendicular to camera forward axis
            Vec3d pos = v - center;
            Vec3d proj_on_plane = pos - pos.dot(forward) * forward;

            // calculates vertex coordinate along camera xy axes
            double x_on_plane = proj_on_plane.dot(right);
            double y_on_plane = proj_on_plane.dot(up);

            min_x = std::min(min_x, x_on_plane);
            min_y = std::min(min_y, y_on_plane);
            max_x = std::max(max_x, x_on_plane);
            max_y = std::max(max_y, y_on_plane);
        }
    }

    center += 0.5 * (max_x + min_x) * right + 0.5 * (max_y + min_y) * up;

    double dx = margin_factor * (max_x - min_x);
    double dy = margin_factor * (max_y - min_y);

    if ((dx <= 0.0) || (dy <= 0.0))
        return -1.0f;

    return std::min((double)canvas_w / dx, (double)canvas_h / dy);
}
#endif // ENABLE_THUMBNAIL_GENERATOR

void Camera::set_distance(double distance) const
{
    m_distance = distance;
    apply_view_matrix();
}

} // GUI
} // Slic3r

