//! Cyborg is a high-performance, modern, experimental rendering engine written
//! in Rust.

use rayon::prelude::*;
use std::sync::{Arc, RwLock};
use strum::IntoEnumIterator;

pub mod handle;
pub mod pass;
pub mod phase;
pub mod scene;

use pass::*;
use phase::*;

pub struct Renderer {
    pub frames_in_flight: usize,
    pub render_passes: Vec<Box<dyn RenderPassBoxTrait>>,
}

impl Default for Renderer {
    fn default() -> Self {
        Self {
            frames_in_flight: 2,
            render_passes: Vec::new(),
        }
    }
}

impl Renderer {
    pub fn add_pass<T: 'static + RenderPass>(&mut self, pass: T) {
        let pass = Arc::new(RwLock::new(pass));
        self.add_pass_arc(pass);
    }

    pub fn add_pass_arc<T: 'static + RenderPass>(&mut self, pass: Arc<RwLock<T>>) {
        let pass = RenderPassBox::new(pass, self.frames_in_flight);
        self.add_pass_box(pass);
    }

    pub fn add_pass_box(&mut self, pass: Box<dyn RenderPassBoxTrait>) {
        self.render_passes.push(pass);
    }

    pub fn render(&mut self) {
        let frame_index = 0;

        let phase_passes = PhaseMultiMap::<usize>::default();
        let phase_passes = std::sync::Mutex::new(phase_passes);

        self.render_passes
            .par_iter_mut()
            .enumerate()
            .for_each(|(pass_index, rp)| {
                let mut phases_buf = PhaseList::default();
                phases_buf.clear();
                rp.begin_frame(frame_index, &mut phases_buf);
                phase_passes
                    .lock()
                    .unwrap()
                    .insert_multi(&phases_buf, pass_index);
            });

        let phase_passes = phase_passes.into_inner().unwrap();

        PrePhase::iter().par_bridge().for_each(|phase| {
            for pass_index in phase_passes.iter_pre(&phase) {
                let pass = &self.render_passes[*pass_index];
                let mut encoder = gpu::RenderBundleEncoder;
                pass.render_pre(phase, frame_index, &mut encoder);
            }
        });

        let viewport = ViewportData;

        ViewportPhase::iter().par_bridge().for_each(|phase| {
            for pass_index in phase_passes.iter_viewport(&phase) {
                let pass = &self.render_passes[*pass_index];
                let mut encoder = gpu::RenderBundleEncoder;
                pass.render_viewport(phase, frame_index, &viewport, &mut encoder);
            }
        });
    }
}

/// Mock GPU API (like Vulkan, WebGPU, or OpenGL) types for prototyping.
pub mod gpu {
    /// Thread-safe GPU command recorder that's later executed in a command buffer.
    ///
    /// Also known as a:
    /// - RenderBundleEncoder in WebGPU
    /// - secondary command buffer in Vulkan
    pub struct RenderBundleEncoder;
}