class ViewportPanel : Panel {
    FrameBuffer frameBuffer;
    WorldCamera sceneCamera;
    EntityEnvironment env;

    float pitch = 0;
    float yaw = 0;
    float vel = 0.02f;

    void render() {
        if (!frameBuffer.isValid())
            return;
            
        int x = ImGui::getAvailableSizeX();
        int y = ImGui::getAvailableSizeY();

        if (x < 10 || y < 10)
            return;

        frameBuffer.resize(x, y);
        frameBuffer.clearRGBA(0, 0, 0, 255);

        sceneCamera.camera.aspect = float(x) / y;
        env.render(frameBuffer, sceneCamera);

        ImGui::drawFrameBufferCentered(frameBuffer, x, y);
        if (!ImGui::isPanelActive())
            return;

        if (ImGui::isMouseDragging(key::MouseRight) && !ImGui::isKeyDown(key::MouseMiddle)) {
            pitch += ImGui::getMouseDeltaY() * 0.1f;
            yaw += ImGui::getMouseDeltaX() * 0.1f;

            sceneCamera.transform.rotation.setEuler(vec3(pitch, yaw, 0));
        }

        if (ImGui::isMouseDragging(key::MouseMiddle) && !ImGui::isKeyDown(key::MouseRight)) {
            vec3 panDir = vec3();

            panDir.x -= ImGui::getMouseDeltaX();
            panDir.y += ImGui::getMouseDeltaY();

            panDir = panDir * vel * 0.4f;
            sceneCamera.transform.position = sceneCamera.transform.relative(panDir);
        }

        vec3 relDir = vec3();

        if (ImGui::isKeyDown(key::W))
            relDir.z++;
        if (ImGui::isKeyDown(key::S))
            relDir.z--;

        if (ImGui::isKeyDown(key::D))
            relDir.x++;
        if (ImGui::isKeyDown(key::A))
            relDir.x--;

        relDir = relDir * vel;
        sceneCamera.transform.position = sceneCamera.transform.relative(relDir);

        float vertically = 0;
        if (ImGui::isKeyDown(key::Space))
            vertically++;
        if (ImGui::isKeyDown(key::LeftCtrl))
            vertically--;

        sceneCamera.transform.position = sceneCamera.transform.position + vec3(0, vertically * vel, 0);
    }

    void init() {
        frameBuffer = Resource::createLoadRGBA8FrameBuffer("MainFrameBuffer", 1000, 1000);
        env = Resource::getMainEntityEnvironment();

        sceneCamera.transform.position = vec3(0, 1, -2);
        sceneCamera.camera.nearZ = 0.1;
        sceneCamera.camera.farZ = 100;
        ImGui::disablePanelPadding(true);
    }

    void menuBar() {
        if (ImGui::menuItem("Start")) {

        }

        if (ImGui::menuItem("Camera Props")) {
            ImGui::openPopup("ViewportCameraProps", any());
        }

        ImGui::simplePopup("ViewportCameraProps", SimpleFunction(this.viewportCameraProps));
    }

    void viewportCameraProps() {
        sceneCamera.camera.fov = ImGui::slider("Fov", sceneCamera.camera.fov / 3.14f * 180, 10, 160) / 180 * 3.14f;
    }
}