use gui::{UIRenderNode, primitive::Primitives};
use pollster::FutureExt;
use std::sync::Arc;
use wgpu::util::StagingBelt;
use winit::{dpi::PhysicalSize, window::Window};

pub const CLEAR_COLOR: wgpu::Color = wgpu::Color::BLACK;

pub struct Renderer {
    window: Arc<Window>,
    surface: wgpu::Surface<'static>,
    device: wgpu::Device,
    queue: wgpu::Queue,
    config: wgpu::SurfaceConfiguration,
    encoder: wgpu::CommandEncoder,
    staging_belt: StagingBelt,
    ui_node: UIRenderNode,
}

impl Renderer {
    pub fn update(&mut self, primitives: Option<&Primitives>) {
        self.ui_node.update(&self.device, &self.queue, primitives);
    }

    pub fn draw(&mut self) {
        let output = self.surface.get_current_texture().unwrap();
        let view = output
            .texture
            .create_view(&wgpu::TextureViewDescriptor::default());

        let mut encoder = std::mem::replace(&mut self.encoder, Self::create_encoder(&self.device));
        {
            let render_pass = &mut encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
                color_attachments: &[Some(wgpu::RenderPassColorAttachment {
                    view: &view,
                    resolve_target: None,
                    ops: wgpu::Operations {
                        load: wgpu::LoadOp::Clear(CLEAR_COLOR),
                        store: wgpu::StoreOp::Store,
                    },
                    depth_slice: None,
                })],
                ..Default::default()
            });
            self.ui_node.draw(render_pass);
        }

        self.queue.submit(std::iter::once(encoder.finish()));
        self.staging_belt.finish();
        output.present();
        self.staging_belt.recall();
    }

    pub fn resize(&mut self, size: &PhysicalSize<u32>) {
        self.config.width = size.width;
        self.config.height = size.height;
        self.surface.configure(&self.device, &self.config);
        self.ui_node.resize(size, &self.queue);
    }

    fn create_encoder(device: &wgpu::Device) -> wgpu::CommandEncoder {
        device.create_command_encoder(&wgpu::CommandEncoderDescriptor {
            label: Some("Render Encoder"),
        })
    }

    pub fn new(window: Arc<Window>) -> Self {
        let size = window.inner_size();

        let instance = wgpu::Instance::new(&wgpu::InstanceDescriptor {
            backends: wgpu::Backends::PRIMARY,
            ..Default::default()
        });

        let surface = instance
            .create_surface(window.clone())
            .expect("Could not create window surface!");

        let adapter = instance
            .request_adapter(&wgpu::RequestAdapterOptions {
                power_preference: wgpu::PowerPreference::default(),
                compatible_surface: Some(&surface),
                force_fallback_adapter: false,
            })
            .block_on()
            .expect("Could not get adapter!");

        let (device, queue) = adapter
            .request_device(&wgpu::DeviceDescriptor {
                required_features: wgpu::Features::empty(),
                required_limits: wgpu::Limits::default(),
                ..Default::default()
            })
            .block_on()
            .expect("Could not get device!");

        let surface_caps = surface.get_capabilities(&adapter);
        let surface_format = surface_caps
            .formats
            .iter()
            .copied()
            .find(|f| f.is_srgb())
            .unwrap_or(surface_caps.formats[0]);

        let config = wgpu::SurfaceConfiguration {
            usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
            format: surface_format,
            width: size.width,
            height: size.height,
            present_mode: wgpu::PresentMode::AutoVsync,
            alpha_mode: surface_caps.alpha_modes[0],
            desired_maximum_frame_latency: 2,
            view_formats: vec![],
        };

        surface.configure(&device, &config);

        let staging_belt = StagingBelt::new(4096 * 4);
        let encoder = Self::create_encoder(&device);

        let shape_pipeline = UIRenderNode::new(&device, &config);

        Self {
            surface,
            device,
            queue,
            config,
            encoder,
            staging_belt,
            ui_node: shape_pipeline,
            window,
        }
    }

    pub fn window(&self) -> &Window {
        self.window.as_ref()
    }
}