//! The kernels' arithmetic on the device (`wgsl/arith.wgsl`): every 64-bit and 128-bit
//! function, from 32-bit words, against the host's 128-bit integers, on the edges of
//! every width pairwise, every shift under every rounding mode, and a million SplitMix64
//! cases, on every adapter found. Then an edit of one function (a carry dropped from the
//! 32 × 32-bit product) is shown to be caught: discovery refuses the adapter.

use std::io::Write;

use wai_ops_gpu::probe::{self, ProbeIn};
use wai_ops_gpu::{blocking, kernels::Sources};

/// A result line, also appended to `WAI_OPS_GPU_REPORT` when it is set.
fn report(line: &str) {
    println!("{line}");
    if let Ok(p) = std::env::var("WAI_OPS_GPU_REPORT") {
        let mut f = std::fs::OpenOptions::new().create(true).append(true).open(&p).unwrap();
        writeln!(f, "{line}").unwrap();
    }
}

#[test]
fn the_arithmetic_is_the_hosts_on_every_adapter() {
    let d = blocking::discover();
    if d.found.is_empty() {
        println!("ops-gpu arith: SKIPPED: no adapter: {:?}", d.refused.iter().map(|(a, w)| (a.key(), w.clone())).collect::<Vec<_>>());
        assert!(std::env::var_os("WAI_OPS_GPU_REQUIRE").is_none(), "WAI_OPS_GPU_REQUIRE is set and no adapter was found");
        return;
    }
    let mut cases: Vec<ProbeIn> = probe::cases(0, 0);
    for seed in 0..16u64 {
        let c = probe::cases(65536, 0xA417_0000 + seed);
        cases.extend_from_slice(&c[c.len() - 65536..]);
    }
    for g in &d.found {
        let mut checked = 0usize;
        for chunk in cases.chunks(1 << 16) {
            let got = blocking::probe(g, chunk).unwrap_or_else(|e| panic!("{}: {e}", g.adapter().key()));
            assert_eq!(probe::first_mismatch(chunk, &got), None, "{}", g.adapter().key());
            checked += chunk.len();
        }
        report(&format!("ops-gpu arith: key={} {} cases={checked} words={} equal", g.adapter().key(), g.adapter().describe(), checked * probe::OUT_WORDS));
    }
}

#[test]
fn an_edited_product_is_caught_by_the_probe() {
    let d = blocking::discover();
    if d.found.is_empty() {
        println!("ops-gpu arith mutant: SKIPPED: no adapter");
        assert!(std::env::var_os("WAI_OPS_GPU_REQUIRE").is_none(), "WAI_OPS_GPU_REQUIRE is set and no adapter was found");
        return;
    }
    let mut src = Sources::shipped();
    let from = "let hi = p11 + (mid2 >> 16u) + ((c1 + c2) << 16u);";
    assert!(src.probe.contains(from));
    src.probe = src.probe.replace(from, "let hi = p11 + (mid2 >> 16u) + (c2 << 16u);");
    let m = blocking::discover_with(&src, "mutant: a carry dropped");
    assert!(m.found.is_empty(), "an adapter passed the probe with a carry dropped");
    for (a, why) in &m.refused {
        assert!(why.contains("probe"), "{}: refused for another reason: {why}", a.key());
        println!("ops-gpu arith mutant: key={} refused: {why}", a.key());
    }
    assert_eq!(m.refused.len(), d.found.len() + d.refused.len());
}