#include "scene.h"

#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <algorithm>
#include <cmath>
#include <numbers>

namespace Donut
{
    Scene::Scene()
    {
        // black-hole camera: large-scale orbital viewer outside the disk.
        sim_camera.set_camera_mode(CameraMode::Orbital);
        sim_camera.set_orbital_target(glm::vec3(0.0f));
        sim_camera.set_orbital_radius(4e11);          // ~31 r_s: outside the 12 r_s disk
        sim_camera.set_orbital_limits(2.2e11, 1.5e12);
        sim_camera.set_orbital_speed(0.01f);
        sim_camera.set_zoom_speed(3e10);
        sim_camera.set_azimuth(0.0f);
        sim_camera.set_elevation(1.25f);

        // scene camera: normal-scale orbital world-builder viewer.
        scene_camera.set_camera_mode(CameraMode::Orbital);
        scene_camera.set_orbital_target(glm::vec3(0.0f));
        scene_camera.set_orbital_radius(30.0);   // frame the hole + orbiting objects (in r_s)
        scene_camera.set_orbital_limits(3.0, 400.0);
        scene_camera.set_orbital_speed(0.01f);
        scene_camera.set_zoom_speed(2.0);
        scene_camera.set_azimuth(0.0f);
        scene_camera.set_elevation((float)std::numbers::pi / 3.0f);
        scene_camera.update_orbital();
    }

    auto Scene::reset_sim_camera() -> void
    {
        sim_camera.set_camera_mode(CameraMode::Orbital);
        sim_camera.set_orbital_radius(4e11);
        sim_camera.set_azimuth(0.0f);
        sim_camera.set_elevation(1.25f);
    }

    auto Scene::set_free_fly(bool enabled) -> void
    {
        const bool is_fps = sim_camera.get_camera_mode() == CameraMode::FPS;
        if (enabled == is_fps) return;
        if (enabled)
        {
            // seed the fly pose from the current orbital framing so the view is continuous.
            glm::vec3 pos = sim_camera.get_orbital_position();
            glm::vec3 fwd = glm::normalize(sim_camera.get_orbital_target() - pos);
            float pitch = glm::degrees(asin(glm::clamp(fwd.y, -1.0f, 1.0f)));
            float yaw   = glm::degrees(atan2(fwd.z, fwd.x));
            sim_camera.set_camera_mode(CameraMode::FPS);
            sim_camera.set_movement_speed(2.0e10f);
            sim_camera.set_mouse_sensitivity(0.15f);
            sim_camera.set_position(pos);
            sim_camera.set_rotation(glm::vec3(pitch, yaw, 0.0f));
        }
        else
        {
            sim_camera.set_camera_mode(CameraMode::Orbital);  // orbital state was left intact
        }
    }
}