// Jank-hunt: per-frame draw-op census. Answers "is the scene we hand to
// Skia/Mali unnecessarily big or expensive?" A scrolling 3-column grid of
// thumbnails should be a few dozen cheap ops per frame; if the counts (or
// the total drawn area, or the image upscale ratio) are large or growing,
// that explains the Mali GPU backpressure. See docs/BUGS/scroll-jank-120hz.md.
use std::sync::atomic::{AtomicU64, Ordering};

pub static SCN_RECT: AtomicU64 = AtomicU64::new(0);
pub static SCN_RECT_AREA: AtomicU64 = AtomicU64::new(0);
pub static SCN_IMG: AtomicU64 = AtomicU64::new(0);
pub static SCN_IMG_AREA: AtomicU64 = AtomicU64::new(0);
/// Max (drawn area / source area) x 100, i.e. a value of 200 = drawn at 2x
/// the source area (a 1.41x linear upscale). High values = the GPU is
/// upscaling small textures a lot (or the "source" is a tiny fallback).
pub static SCN_IMG_UP: AtomicU64 = AtomicU64::new(0);
pub static SCN_TEXT: AtomicU64 = AtomicU64::new(0);
pub static SCN_BORDER: AtomicU64 = AtomicU64::new(0);
pub static SCN_SHADOW: AtomicU64 = AtomicU64::new(0);
pub static SCN_CLIP: AtomicU64 = AtomicU64::new(0);

pub fn reset() {
    for s in [
        &SCN_RECT,
        &SCN_RECT_AREA,
        &SCN_IMG,
        &SCN_IMG_AREA,
        &SCN_IMG_UP,
        &SCN_TEXT,
        &SCN_BORDER,
        &SCN_SHADOW,
        &SCN_CLIP,
    ] {
        s.store(0, Ordering::Relaxed);
    }
}

/// Add a value to an atomic (relaxed), used by the item renderer.
#[inline]
pub fn add(slot: &AtomicU64, v: u64) {
    slot.fetch_add(v, Ordering::Relaxed);
}

#[inline]
pub fn inc(slot: &AtomicU64) {
    slot.fetch_add(1, Ordering::Relaxed);
}

#[inline]
pub fn max(slot: &AtomicU64, v: u64) {
    let _ = slot.fetch_max(v, Ordering::Relaxed);
}

pub fn report(frame: u64) {
    let rect = SCN_RECT.load(Ordering::Relaxed);
    let img = SCN_IMG.load(Ordering::Relaxed);
    let text = SCN_TEXT.load(Ordering::Relaxed);
    let border = SCN_BORDER.load(Ordering::Relaxed);
    let shadow = SCN_SHADOW.load(Ordering::Relaxed);
    let clip = SCN_CLIP.load(Ordering::Relaxed);
    let rect_area = SCN_RECT_AREA.load(Ordering::Relaxed);
    let img_area = SCN_IMG_AREA.load(Ordering::Relaxed);
    let img_up = SCN_IMG_UP.load(Ordering::Relaxed);
    let total = rect + img + text + border + shadow;
    log::info!(
        "SCN f={} rect={} rarea={} img={} iarea={} iup={} text={} border={} shadow={} clip={} total={}ops",
        frame, rect, rect_area, img, img_area, img_up, text, border, shadow, clip, total
    );
}