#include "client/render/camera.hh"

namespace client {
namespace render {
namespace camera {

float& get_xfov() noexcept {
    static float xfov = 100.0f;
    return xfov;
}

glm::vec3& get_pos() noexcept {
    static glm::vec3 pos{0.0f, 0.0f, 0.0f};
    return pos;
}

glm::vec3& get_front() noexcept {
    static glm::vec3 front{0.0f, 0.0f, 0.0f};
    return front;
}

glm::vec3& get_up() noexcept {
    static glm::vec3 front{0.0f, 1.0f, 0.0f};
    return front;
}

static glm::mat4 make_view() noexcept {
    const glm::vec3& pos = get_pos();
    return glm::lookAt(pos, pos + get_front(), get_up());
}

glm::mat4& get_view() noexcept {
    static glm::mat4 view = make_view();
    return view;
}

static glm::mat4 make_proj() noexcept {
    const glm::vec2& window = client::render::get_window_size();
    return glm::perspective(glm::radians(get_yfov()), window.x / window.y,
                            get_znear(), get_zfar());
}

glm::mat4& get_proj() noexcept {
    static glm::mat4 proj = make_proj();
    return proj;
}

static frustum make_frustum() noexcept {
    const glm::mat4 matrix = get_proj() * get_view();
    const glm::vec4 row_x = glm::row(matrix, 0);
    const glm::vec4 row_y = glm::row(matrix, 1);
    const glm::vec4 row_z = glm::row(matrix, 2);
    const glm::vec4 row_w = glm::row(matrix, 3);

    frustum ret{row_w + row_x, row_w - row_x, row_w + row_y,
                row_w - row_y, row_w + row_z, row_w - row_z};
    std::ranges::transform(ret, std::begin(ret), [](const auto& matrix) {
        return glm::normalize(matrix);
    });
    return ret;
}

frustum& get_frustum() noexcept {
    static frustum ret = make_frustum();
    return ret;
}

float& get_znear() noexcept {
    static float znear = 0.1f;
    return znear;
}

float& get_zfar() noexcept {
    static float zfar = 1024.0f;
    return zfar;
}

float get_yfov() noexcept {
    const glm::vec2& window = client::render::get_window_size();
    const float yfov =
        2.0f * std::atan((window.y / window.x) *
                         std::tan(glm::radians(get_xfov()) / 2.0f));
    return glm::degrees(yfov);
}

void update() noexcept {
    get_view() = make_view(); // specific order here!
    get_proj() = make_proj();
    get_frustum() = make_frustum();
}

} // namespace camera

} // namespace render

} // namespace client