use std::{
    alloc::{GlobalAlloc, Layout, System},
    cell::Cell,
};
use weld_core::{Engine, Fit, Listen, Section, Settings};

struct CheckedAllocator;
thread_local! {
    static CHECK:Cell<bool>=const {Cell::new(false)};
    static OPERATIONS:Cell<usize>=const {Cell::new(0)};
}
fn record() {
    if CHECK.try_with(Cell::get).unwrap_or(false) {
        let _ = OPERATIONS.try_with(|n| n.set(n.get() + 1));
    }
}
unsafe impl GlobalAlloc for CheckedAllocator {
    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
        record();
        unsafe { System.alloc(layout) }
    }
    unsafe fn dealloc(&self, pointer: *mut u8, layout: Layout) {
        record();
        unsafe { System.dealloc(pointer, layout) }
    }
    unsafe fn realloc(&self, pointer: *mut u8, layout: Layout, size: usize) -> *mut u8 {
        record();
        unsafe { System.realloc(pointer, layout, size) }
    }
}
#[global_allocator]
static ALLOCATOR: CheckedAllocator = CheckedAllocator;

#[test]
fn processing_fits_crossfades_and_a_full_queue_do_not_allocate_or_free() {
    let mut engine = Engine::new(48000., 2).unwrap();
    let mut settings = Settings::default();
    engine.set_settings(settings).unwrap();
    let link = engine.link();
    let fits: Vec<Fit> = (0..4)
        .map(|k| Fit {
            flip: k % 2 == 1,
            count: k,
            sections: [Section {
                fc: 200. * (k + 1) as f32,
                q: 0.7,
            }; 4],
        })
        .collect();
    CHECK.with(|v| v.set(true));
    // Nothing takes blocks, so the queue fills up and later blocks are dropped.
    for i in 0..96000 {
        if i % 4800 == 0 {
            settings.output = ((i / 4800) % 5) as f32 - 2.;
            settings.listen = [Listen::Layer, Listen::Sum, Listen::SumDry][(i / 4800) % 3];
            engine.set_settings(settings).unwrap();
            link.push_fit(fits[(i / 4800) % 4]);
        }
        let t = i as f32 / 48000.;
        let x = (std::f32::consts::TAU * 55. * t).sin() * 0.5;
        std::hint::black_box(engine.process_sample([x, -x], [x * 0.5, x]));
        if i % 1600 == 0 {
            std::hint::black_box(engine.take_analyzer());
        }
    }
    engine.reset();
    CHECK.with(|v| v.set(false));
    assert_eq!(OPERATIONS.with(Cell::get), 0);
    assert!(link.dropped() > 0);
}