//! (d) of IRIS_TODO.md's "Benchmarks" item: 1,000 image rows, checking that
//! standalone-image bind-group *creation* -- a real `wgpu` resource, unlike
//! the counters in `benches/message_lazy_span.rs` -- goes to zero once every
//! image has loaded. This needs an actual `wgpu` device (`GpuTextures`,
//! `UiRenderNode`), so unlike the rest of the suite it cannot run as a
//! plain binary; run it through `iris/run-headless.sh bench_images`, which
//! gives it a real (headless, GPU-accelerated) compositor and surface. See
//! `run-bench.sh` for the wrapper that greps its output into one line.
//!
//! Each `RedrawRequested` prints the frame number and
//! `UiRenderNode::take_image_bind_group_creates()` for that frame, then
//! requests another redraw (nothing else marks the scene dirty, so without
//! this the app would only ever draw once). The first frame is expected to
//! report 1,000 (one create per image, on first load); the steady state
//! IRIS_TODO.md asks this scenario to prove is every frame after settling
//! down to 0.
//!
//! After `SETTLE_FRAMES` it appends one *new* image row (a transcript
//! receiving one more message) and keeps counting -- a chat transcript's
//! real access pattern is "one more image arrives," not "reload the whole
//! list," so the steady-state question that actually matters is the
//! *incremental* cost of that one append, not just whether an untouched
//! scene costs zero. It exits after `FRAMES`.

use iris::prelude::*;

const ROWS: usize = 1000;
const SETTLE_FRAMES: usize = 4;
const FRAMES: usize = 6;

#[derive(DefaultUiState)]
struct State {
    ui_state: DefaultUiState,
    span: WeakWidget<Span>,
    frame: usize,
    appended: bool,
}

impl DefaultAppState for State {
    fn new(
        mut ui_state: DefaultUiState,
        rsc: &mut DefaultRsc<Self>,
        _: Proxy<Self::Event>,
    ) -> Self {
        let mut span = Span::empty(Dir::DOWN);
        for _ in 0..ROWS {
            let img = image::DynamicImage::new_rgba8(32, 32);
            let widget = image::<DefaultRsc<Self>>(img)(rsc);
            let widget = rsc.ui.widgets.add_strong(widget);
            span.push(widget.any());
        }
        let span = rsc.ui.widgets.add_strong(span);
        let span_weak = span.weak();
        let root = rsc
            .ui
            .widgets
            .add_strong(ScrollArea::new(span.any(), Axis::Y, Pin::End));
        ui_state.set_root(root.any());
        Self {
            ui_state,
            span: span_weak,
            frame: 0,
            appended: false,
        }
    }

    fn window_event(
        &mut self,
        event: winit::event::WindowEvent,
        rsc: &mut DefaultRsc<Self>,
        _render: &mut UiRenderState,
    ) {
        if !matches!(event, winit::event::WindowEvent::RedrawRequested) {
            return;
        }
        self.frame += 1;
        let creates = self.ui_state.renderer.ui.take_image_bind_group_creates();
        println!(
            "BENCH_IMAGES frame={} bind_group_creates={creates}",
            self.frame
        );
        if self.frame == SETTLE_FRAMES && !self.appended {
            self.appended = true;
            let img = image::DynamicImage::new_rgba8(32, 32);
            let widget = image::<DefaultRsc<Self>>(img)(rsc);
            let widget = rsc.ui.widgets.add_strong(widget);
            rsc.ui
                .widgets
                .get_mut(&self.span)
                .unwrap()
                .push(widget.any());
            println!("BENCH_IMAGES appended one image after settling");
        }
        if self.frame < FRAMES {
            self.ui_state.window.request_redraw();
        } else {
            std::process::exit(0);
        }
    }
}

fn main() {
    DefaultApp::<State>::run();
}