use vulkano::command_buffer::{AutoCommandBufferBuilder, PrimaryAutoCommandBuffer};

use super::{input::InputState, render::render_context::RenderContext, timer::Timer};

pub trait Scene {
    fn loaded(&self) -> bool;
    fn load(&mut self, render_context: &RenderContext);
    fn update(&mut self, render_context: &RenderContext, input_state: &InputState, timer: &Timer);
    fn render(
        &self,
        render_context: &RenderContext,
        builder: &mut AutoCommandBufferBuilder<PrimaryAutoCommandBuffer>,
    );
    fn unload(&mut self);
}

pub struct SceneManager {
    current_scene: Option<Box<dyn Scene>>,
}

impl SceneManager {
    pub fn new() -> Self {
        Self {
            current_scene: None,
        }
    }

    pub fn load_scene_if_not_loaded(&mut self, render_context: &RenderContext) {
        if let Some(current_scene) = self.current_scene.as_mut() {
            if !current_scene.loaded() {
                current_scene.load(render_context);
            }
        }
    }

    pub fn load_scene(&mut self, scene: Box<dyn Scene>) {
        if let Some(current_scene) = self.current_scene.as_mut() {
            current_scene.unload();
        }
        self.current_scene = Some(scene);
    }

    pub fn current_scene(&self) -> Option<&Box<dyn Scene>> {
        if let Some(current_scene) = self.current_scene.as_ref() {
            if current_scene.loaded() {
                return Some(current_scene);
            }
        }
        None
    }

    pub fn current_scene_mut(&mut self) -> Option<&mut Box<dyn Scene>> {
        if let Some(current_scene) = self.current_scene.as_mut() {
            if current_scene.loaded() {
                return Some(current_scene);
            }
        }
        None
    }
}