//! `wai.neural.int_hyper` and the keyframe of `wai.video.int_hyper` through the integer
//! operator set: their lowering `whm1/1` (`extensions/integer-operators.md` §13.2; `h_s`,
//! then `g_s` with the RGB8 step of §13.0) and the certificate of every committed set
//! (§8.5), as this crate loads them (`int_ops`, `int_hyper_synth::ops`).
//!
//! The lowered graphs and certificates are committed under `ops-conformance/certificates/`,
//! where `wai-verify` and the independent checker (`tools/wai_ops_check.py`) each
//! reproduce them byte for byte (`wai-ops.yml`). Here the lowering this crate runs, from
//! the models it parses (`int_ops::whm1_net`), must write those same bytes, and the load a
//! sink makes must give the verdict the certificate records.

use std::path::PathBuf;

use serde_json::Value;
use wai::int_hyper_synth::{self as hyper, IntModel};
use wai_ops::Profile;

const CAPS: [&str; 2] = ["wai.neural.int_hyper", "wai.video.int_hyper"];

fn wai() -> PathBuf {
    PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("..")
}

fn read(rel: &str) -> Vec<u8> {
    std::fs::read(wai().join(rel)).unwrap_or_else(|e| panic!("{rel}: {e}"))
}

fn json(rel: &str) -> Value {
    serde_json::from_slice(&read(rel)).unwrap_or_else(|e| panic!("{rel}: {e}"))
}

fn sha256(b: &[u8]) -> String {
    wai_ops::sha256::sha256(b).iter().map(|x| format!("{x:02x}")).collect()
}

/// A committed set of one of the two capabilities, as `ops-conformance/certificates/index.json`
/// lists it: its name, capability, members (name, path below `wai/`), digest and lowered
/// graphs (`h_s`, then `g_s`).
struct Indexed {
    name: String,
    cap: String,
    members: Vec<(String, String)>,
    digest: String,
    roles: [String; 2],
}

fn indexed() -> Vec<Indexed> {
    json("ops-conformance/certificates/index.json")["sets"]
        .as_array()
        .unwrap()
        .iter()
        .filter(|s| CAPS.contains(&s["capability"].as_str().unwrap()))
        .map(|s| {
            assert_eq!(s["lowering"], "whm1/1");
            let roles = s["roles"].as_array().unwrap();
            assert_eq!(roles.len(), 2, "whm1/1 lowers a conditional codec's set to two graphs, h_s and g_s");
            let members = s["members"].as_object().unwrap().iter().map(|(k, v)| (k.clone(), v.as_str().unwrap().to_string())).collect();
            Indexed {
                name: s["name"].as_str().unwrap().to_string(),
                cap: s["capability"].as_str().unwrap().to_string(),
                members,
                digest: s["set_sha256"].as_str().unwrap().to_string(),
                roles: [roles[0].as_str().unwrap().to_string(), roles[1].as_str().unwrap().to_string()],
            }
        })
        .collect()
}

impl Indexed {
    fn member(&self, name: &str) -> Vec<u8> {
        read(&self.members.iter().find(|(k, _)| k == name).unwrap_or_else(|| panic!("{}: no {name}", self.name)).1)
    }
}

/// The two graphs this crate lowers from the models it parses (`int_hyper_synth::ops::lower`),
/// whose conversion (`int_ops::whm1_net`) must give the networks `wai-ops` parses from the
/// bytes.
fn lowered_from_the_parsed_models(g_s: &[u8], h_s: &[u8]) -> (wai_ops::Graph, wai_ops::Graph) {
    let (g, h) = (IntModel::from_bytes(g_s).unwrap(), IntModel::from_bytes(h_s).unwrap());
    for (m, b) in [(&g, g_s), (&h, h_s)] {
        let net = wai::int_ops::whm1_net(m).expect("a model parsed from bytes converts");
        assert!(net == wai_ops::lower::parse_whm1(b).unwrap(), "the converted model is the one wai-ops parses from the bytes");
    }
    hyper::ops::lower(&g, &h).expect("the set lowers")
}

/// Gate 1 of the migration: every committed set of `wai.neural.int_hyper` and
/// `wai.video.int_hyper` lowers to its committed graphs, from its members' bytes
/// (`lower::int_hyper`) and from the models this crate parses; the certificate beside them
/// is those graphs'; and loading each graph under the capability's profile gives the
/// certificate's verdict. The sets carry `check` ranges (§13.2), so they meet `acc64` by
/// construction and not `acc32`; the first `acc32` failure is `h_s`'s input range, at 53
/// bits for the conformance set `tiny` (Appendix C's prediction) and 52 for the synthetic
/// one. The tiny set's JSON models, the form the tools write beside the binary one,
/// convert to the same networks and lower to the same graphs.
#[test]
fn every_committed_set_lowers_to_its_committed_graphs_and_verdict() {
    let sets = indexed();
    let names: Vec<(&str, &str)> = sets.iter().map(|s| (s.cap.as_str(), s.name.as_str())).collect();
    assert_eq!(names, [(CAPS[0], "tiny"), (CAPS[1], "tiny"), (CAPS[0], "hyper")], "the committed int_hyper sets");
    for s in &sets {
        let (name, cap) = (&s.name, &s.cap);
        let (g_s, h_s, ent) = (s.member("g_s.whm"), s.member("h_s.whm"), s.member("entropy.json"));
        let members = vec![("entropy.json", ent.clone()), ("g_s.whm", g_s.clone()), ("h_s.whm", h_s.clone())];
        assert_eq!(wai_ops::generate::sets::set_digest(&members), s.digest, "{name}: the set's digest");
        // The entropy tables are the stage operators' data, not lowered; the set's must load.
        hyper::CondEntropy::try_from_value(&serde_json::from_slice(&ent).unwrap()).unwrap_or_else(|e| panic!("{name}: entropy.json: {e}"));
        let lowered = wai_ops::lower::int_hyper(&h_s, &g_s).unwrap_or_else(|r| panic!("{name}: does not lower: {r:?}"));
        let roles: Vec<&str> = lowered.roles.iter().map(|(r, _)| *r).collect();
        assert_eq!(roles, ["h_s", "g_s"], "{name}");
        let (h, g) = lowered_from_the_parsed_models(&g_s, &h_s);
        let cert = json(&format!("ops-conformance/certificates/{cap}/{}.json", s.digest));
        assert_eq!(cert["set_sha256"].as_str(), Some(s.digest.as_str()), "{name}");
        assert_eq!(cert["capability"].as_str(), Some(cap.as_str()), "{name}");
        assert_eq!(cert["lowering"], "whm1/1", "{name}");
        for (k, (role, ours)) in [("h_s", &h), ("g_s", &g)].into_iter().enumerate() {
            let from_bytes = lowered.get(role).unwrap();
            // The verdict first: the load a sink makes.
            let loaded = wai::int_ops::load(from_bytes).unwrap_or_else(|r| panic!("{name} {role}: refused under acc64: {r:?}"));
            assert!(!loaded.meets(Profile::Acc32), "{name} {role}: a graph with check ranges inside it does not meet acc32");
            // Then the committed bytes: the graph, both ways, and the certificate's record of it.
            let graph = from_bytes.to_bytes();
            assert!(graph == read(&s.roles[k]), "{name}: the lowering of the bytes differs from the committed {}", s.roles[k]);
            assert!(ours.to_bytes() == graph, "{name}: the lowering of the parsed models differs from the committed {role}");
            let c = &cert["graphs"][k];
            assert_eq!(c["name"].as_str(), Some(role), "{name}");
            assert_eq!(c["graph_sha256"].as_str(), Some(sha256(&graph).as_str()), "{name} {role}: the certificate is the graph's");
            // The input's check range is the lowering's X_0 for the network's first layer (§13.2).
            let x0 = &c["inputs"][0];
            let t = &from_bytes.tensors[0];
            assert_eq!((x0["policy"].as_str(), x0["lo"].as_str(), x0["hi"].as_str()), (Some("check"), Some(t.lo.to_string().as_str()), Some(t.hi.to_string().as_str())), "{name} {role}");
            assert!(t.hi > 0 && t.lo == -t.hi, "{name} {role}: a symmetric check range");
        }
        let v = &cert["verdict"];
        assert_eq!((v["acc64"].as_bool(), v["acc32"].as_bool()), (Some(true), Some(false)), "{name}: the certificate's verdict");
        let bits = if name == "tiny" { "53" } else { "52" };
        let first = &v["acc32_first_failure"];
        assert_eq!(
            (first["graph"].as_str(), first["where"].as_str(), first["index"].as_str(), first["key"].as_str(), first["bits"].as_str()),
            (Some("h_s"), Some("input"), Some("0"), Some("range"), Some(bits)),
            "{name}: the first acc32 failure"
        );
        // The decode's own load: both networks, h_s first.
        let (gm, hm) = (IntModel::from_bytes(&g_s).unwrap(), IntModel::from_bytes(&h_s).unwrap());
        let nets = hyper::ops::load(&gm, &hm).unwrap_or_else(|r| panic!("{name}: {r}"));
        assert!(nets.h_s.graph() == lowered.get("h_s").unwrap() && nets.g_s.graph() == lowered.get("g_s").unwrap(), "{name}: the decode loads the committed graphs");
    }
    // The tiny set's JSON models, which the byte-exact keyframe golden and the browser's
    // debug decode read, convert to the networks of its binary models.
    let dir = "wai-rs/tests/vectors/int_hyper";
    let from_json = |f: &str| IntModel::try_from_json(&json(&format!("{dir}/{f}"))).unwrap();
    let (g, h) = hyper::ops::lower(&from_json("tiny_g_s.json"), &from_json("tiny_h_s.json")).unwrap();
    let (gb, hb) = lowered_from_the_parsed_models(&read(&format!("{dir}/tiny_g_s.bin")), &read(&format!("{dir}/tiny_h_s.bin")));
    assert!(g == gb && h == hb, "the tiny set's JSON and binary models lower alike");
}

/// The set of the pretrained model (`mbt2018_mean`, exported to integers) is too large to
/// commit, so its certificate is committed by the set's digest and checked against the
/// regenerated set in `wai-sota-vectors.yml`, where `tests/int_hyper_synth.rs` also holds
/// this crate's lowering of it to the graphs the certificate records. Its verdict is
/// Appendix C's: `acc64`, first failing `acc32` at `h_s`'s input range, 41 bits.
#[test]
fn the_pretrained_sets_certificate_is_the_one_appendix_c_predicts() {
    let ext = json("ops-conformance/certificates/external.json");
    let s = ext["sets"].as_array().unwrap().iter().find(|s| s["capability"] == CAPS[0]).expect("the pretrained set is listed");
    assert_eq!((s["lowering"].as_str(), s["profile"].as_str()), (Some("whm1/1"), Some("acc64")));
    let digest = s["set_sha256"].as_str().unwrap();
    let cert = json(&format!("ops-conformance/certificates/{}/{digest}.json", CAPS[0]));
    let names: Vec<&str> = cert["graphs"].as_array().unwrap().iter().map(|g| g["name"].as_str().unwrap()).collect();
    assert_eq!(names, ["h_s", "g_s"]);
    let v = &cert["verdict"];
    assert_eq!((v["acc64"].as_bool(), v["acc32"].as_bool()), (Some(true), Some(false)));
    let first = &v["acc32_first_failure"];
    assert_eq!(
        (first["graph"].as_str(), first["where"].as_str(), first["key"].as_str(), first["bits"].as_str()),
        (Some("h_s"), Some("input"), Some("range"), Some("41"))
    );
}

/// The typed form of a parsed `WIH1` payload.
fn stream<'a>(k: &'a wai::int_wire::Wih1<'a>) -> hyper::CondStream<'a> {
    hyper::CondStream {
        m: k.m as usize, sh: k.sh as usize, sw: k.sw as usize, n_z: k.n_z as usize, zh: k.zh as usize, zw: k.zw as usize,
        z_rans: k.z_rans, rans: k.rans,
    }
}

/// A committed set's three members, parsed: `g_s`, `h_s` and the entropy tables.
fn set_of(v: &Value) -> (IntModel, IntModel, hyper::CondEntropy) {
    let m = |k: &str| read(v["set"][k].as_str().unwrap());
    let ent = hyper::CondEntropy::try_from_value(&serde_json::from_slice(&m("entropy.json")).unwrap()).unwrap();
    (IntModel::from_bytes(&m("g_s.whm")).unwrap(), IntModel::from_bytes(&m("h_s.whm")).unwrap(), ent)
}

fn hex(b: &[u8]) -> String {
    b.iter().map(|x| format!("{x:02x}")).collect()
}

/// Every frame's SHA-256 and the clip's, against the sidecar entry `key` of
/// `int_video/sha256.json`; every frame's FNV-1a and the clip's, against `conf`.
fn assert_clip(frames: &[Vec<u8>], key: &str, conf: &Value) {
    use sha2::Digest;
    let side = json("wai-rs/tests/vectors/int_video/sha256.json");
    let (want, fnv) = (side[key]["frames_sha256"].as_array().unwrap(), conf["frame_hashes"].as_array().unwrap());
    assert_eq!((want.len(), fnv.len()), (frames.len(), frames.len()), "{key}: frame count");
    let (mut all, mut all_fnv) = (Vec::new(), Vec::new());
    for (i, f) in frames.iter().enumerate() {
        let d = sha2::Sha256::digest(f);
        assert_eq!(hex(&d), want[i].as_str().unwrap(), "{key}: frame {i}");
        let h = format!("{:016x}", wai::int_video::fnv1a(f));
        assert_eq!(h, fnv[i].as_str().unwrap(), "{key}: frame {i}'s FNV-1a");
        all.extend_from_slice(&d);
        all_fnv.extend((0..8).map(|j| u8::from_str_radix(&h[2 * j..2 * j + 2], 16).unwrap()));
    }
    assert_eq!(hex(&sha2::Sha256::digest(&all)), side[key]["clip_sha256"].as_str().unwrap(), "{key}: the clip's SHA-256");
    assert_eq!(format!("{:016x}", wai::int_video::fnv1a(&all_fnv)), conf["clip_hash"].as_str().unwrap(), "{key}: the clip's FNV-1a");
}

/// Gate 2 of the migration: golden equality. Every committed vector of
/// `wai.neural.int_hyper` and `wai.video.int_hyper` (`int-payload-conformance/vectors.json`)
/// decodes through the lowering (`int_hyper_synth::ops`) to the image the direct decode
/// gives (`int_hyper_synth::legacy`), and to every digest the corpus commits for it:
/// - `tiny` (`WIH1`): the SHA-256 sidecar and the export's FNV-1a, from the payload, from
///   the JSON form it is converted from, and with the set's JSON models, the form the
///   byte-exact keyframe golden reads;
/// - `video_nk` (`WIV1`, keyframe 1): its nested `WIH1` keyframe, then the clip's integer
///   P-frames on it, every frame's and the clip's SHA-256 and FNV-1a.
#[test]
fn every_committed_vector_decodes_through_the_lowering_to_its_golden() {
    let index = json("int-payload-conformance/vectors.json");
    let vs: Vec<&Value> = index["vectors"].as_array().unwrap().iter().filter(|v| CAPS.contains(&v["capability"].as_str().unwrap())).collect();
    let names: Vec<&str> = vs.iter().map(|v| v["name"].as_str().unwrap()).collect();
    assert_eq!(names, ["tiny", "video_nk"], "the committed int_hyper vectors");
    let dir = "wai-rs/tests/vectors";
    // tiny: WIH1, its JSON form, and the JSON models.
    let v = vs[0];
    let (g_s, h_s, ent) = set_of(v);
    let p = read(v["payload"].as_str().unwrap());
    assert_eq!(sha256(&p), v["payload_sha256"].as_str().unwrap());
    let k = wai::int_wire::parse_wih1(&p).unwrap();
    let bs = hyper::CondBitstream::try_from_value(&json(v["converted_from"]["json"].as_str().unwrap())).unwrap();
    let from_json = |f: &str| IntModel::try_from_json(&json(&format!("{dir}/int_hyper/{f}"))).unwrap();
    let (gj, hj) = (from_json("tiny_g_s.json"), from_json("tiny_h_s.json"));
    let want_sha = json(v["sidecar"].as_str().unwrap())["tiny"]["sha256"].as_str().unwrap().to_string();
    let conf = json(&format!("{dir}/int_hyper/tiny.json"));
    for (form, g, h, st) in [("WIH1", &g_s, &h_s, stream(&k)), ("JSON", &g_s, &h_s, bs.stream()), ("JSON models", &gj, &hj, stream(&k))] {
        let ops = hyper::ops::decode(g, h, &ent, &st).unwrap_or_else(|r| panic!("tiny {form}: {r}"));
        let direct = hyper::legacy::decode_conditional_checked(g, h, &ent, &st).unwrap_or_else(|r| panic!("tiny {form}: {r}"));
        assert!(ops == direct, "tiny {form}: the decode through the lowering differs from the direct decode");
        assert_eq!((ops.1, ops.2), (16, 16), "tiny {form}");
        assert_eq!(sha256(&ops.0), want_sha, "tiny {form}: the SHA-256 sidecar");
        assert_eq!(format!("{:016x}", hyper::fnv1a(&ops.0)), conf["rgb_hash"].as_str().unwrap(), "tiny {form}: the export's FNV-1a");
    }
    // video_nk: WIV1 with keyframe 1.
    let v = vs[1];
    let (g_s, h_s, ent) = set_of(v);
    let p = read(v["payload"].as_str().unwrap());
    assert_eq!(sha256(&p), v["payload_sha256"].as_str().unwrap());
    let w = wai::int_wire::parse_wiv1(&p, Some(1)).unwrap();
    let k = wai::int_wire::parse_wih1(w.wih1.expect("keyframe 1 nests a WIH1")).unwrap();
    let (frame0, h, wd) = hyper::ops::decode(&g_s, &h_s, &ent, &stream(&k)).unwrap();
    assert!(hyper::legacy::decode_conditional_checked(&g_s, &h_s, &ent, &stream(&k)).unwrap() == (frame0.clone(), h, wd), "video_nk: the keyframe differs from the direct decode's");
    assert_eq!((h, wd), (w.h as usize, w.w as usize), "video_nk: the keyframe is the clip's size");
    let s = wai::int_video::VideoStream {
        n_frames: w.n_frames as usize, h: w.h as usize, w: w.w as usize, block: w.block as usize,
        q: w.q as i64, offset: w.offset, mv_precision: w.mv_precision, cdf: &w.cdf, mvs: &w.mvs, rans: w.rans,
    };
    let clip = wai::int_video::decode_pframes_typed(&frame0, &s).unwrap();
    assert_clip(&clip.frames, "video_nk", &json(&format!("{dir}/int_video/video_nk.json")));
}

/// The code integer-payloads §8 gives a refusal of the conditional decode.
fn code_of(r: hyper::Refused) -> &'static str {
    wai::int_payload::IntPayloadError::from(r).code()
}

/// The committed conformance set and payload (`int-payload-conformance`'s `tiny`).
const DIR: &str = "wai-rs/tests/vectors/int_hyper";

/// A typed `WIH1` payload that owns its streams, so a fixture can change any field.
#[derive(Clone)]
struct Owned {
    m: usize,
    sh: usize,
    sw: usize,
    n_z: usize,
    zh: usize,
    zw: usize,
    z_rans: Vec<u8>,
    rans: Vec<u8>,
}

impl Owned {
    fn committed() -> Owned {
        let p = read(&format!("{DIR}/tiny_bitstream.wih1"));
        let k = wai::int_wire::parse_wih1(&p).unwrap();
        Owned {
            m: k.m as usize, sh: k.sh as usize, sw: k.sw as usize, n_z: k.n_z as usize, zh: k.zh as usize, zw: k.zw as usize,
            z_rans: k.z_rans.to_vec(), rans: k.rans.to_vec(),
        }
    }
    fn st(&self) -> hyper::CondStream<'_> {
        hyper::CondStream { m: self.m, sh: self.sh, sw: self.sw, n_z: self.n_z, zh: self.zh, zw: self.zw, z_rans: &self.z_rans, rans: &self.rans }
    }
}

/// The committed set, parsed, changed by `f`: `(g_s, h_s, entropy tables)`.
fn tiny(f: impl FnOnce(&mut IntModel, &mut IntModel, &mut hyper::CondEntropy)) -> (IntModel, IntModel, hyper::CondEntropy) {
    let mut g = IntModel::from_bytes(&read(&format!("{DIR}/tiny_g_s.bin"))).unwrap();
    let mut h = IntModel::from_bytes(&read(&format!("{DIR}/tiny_h_s.bin"))).unwrap();
    let mut e = hyper::CondEntropy::try_from_value(&json(&format!("{DIR}/tiny_entropy.json"))).unwrap();
    f(&mut g, &mut h, &mut e);
    (g, h, e)
}

/// The committed payload, changed by `f`.
fn payload(f: impl FnOnce(&mut Owned)) -> Owned {
    let mut o = Owned::committed();
    f(&mut o);
    o
}

/// Both decodes of a typed payload against a set: through the lowering, then directly.
fn both(set: &(IntModel, IntModel, hyper::CondEntropy), o: &Owned) -> (Result<Vec<u8>, &'static str>, Result<Vec<u8>, &'static str>) {
    let (g, h, e) = set;
    (
        hyper::ops::decode(g, h, e, &o.st()).map(|d| d.0).map_err(code_of),
        hyper::legacy::decode_conditional_checked(g, h, e, &o.st()).map(|d| d.0).map_err(code_of),
    )
}

/// Gate 3 of the migration: refusal parity, on the committed fixtures. Each fixture of
/// `int-payload-conformance` for `wai.neural.int_hyper` and `wai.video.int_hyper` is
/// refused by a sink with its code. For one that parses (`decode`), its `WIH1` (the
/// payload, or a `WIV1`'s keyframe) decodes through the lowering and directly to the same
/// image, or is refused by both with the same code: the fixture's, where the keyframe is
/// what it refuses.
#[test]
fn every_committed_refusal_fixture_keeps_its_code() {
    use std::collections::BTreeMap;
    let (mut n, mut keyframes) = (0, 0);
    for f in json("int-payload-conformance/vectors.json")["refusals"].as_array().unwrap().iter().filter(|f| CAPS.contains(&f["capability"].as_str().unwrap())) {
        let (name, cap, want) = (f["name"].as_str().unwrap(), f["capability"].as_str().unwrap(), f["code"].as_str().unwrap());
        let p = read(f["payload"].as_str().unwrap());
        let set: BTreeMap<String, Vec<u8>> = f["set"].as_object().unwrap().iter().map(|(k, v)| (k.clone(), read(v.as_str().unwrap()))).collect();
        let view: BTreeMap<String, &[u8]> = set.iter().map(|(k, v)| (k.clone(), v.as_slice())).collect();
        let params = wai::int_payload::resolve(cap, None, &[wai::pin::HeldBytes::Set { listing: b"", files: &view }], None).expect("an unpinned set resolves");
        let sink = wai::int_payload::decode_int(cap, &p, &params).map(|_| ()).map_err(|e| e.code());
        assert_eq!(sink, Err(want), "{name}: the sink's code");
        if f["layer"] == "decode" {
            let nested = if cap == CAPS[0] { p.clone() } else { wai::int_wire::parse_wiv1(&p, Some(1)).unwrap().wih1.unwrap().to_vec() };
            let k = wai::int_wire::parse_wih1(&nested).unwrap_or_else(|e| panic!("{name}: a decode fixture's keyframe parses: {e:?}"));
            let g = IntModel::from_bytes(&set["g_s.whm"]).unwrap();
            let h = IntModel::from_bytes(&set["h_s.whm"]).unwrap();
            let e = hyper::CondEntropy::try_from_value(&serde_json::from_slice(&set["entropy.json"]).unwrap()).unwrap();
            let ops = hyper::ops::decode(&g, &h, &e, &stream(&k)).map(|d| d.0).map_err(code_of);
            let direct = hyper::legacy::decode_conditional_checked(&g, &h, &e, &stream(&k)).map(|d| d.0).map_err(code_of);
            assert!(ops == direct, "{name}: the two decodes of the keyframe differ: {:?} / {:?}", ops.as_ref().err(), direct.as_ref().err());
            if cap == CAPS[0] {
                assert_eq!(ops, Err(want), "{name}: the WIH1 fixture's code, both ways");
            }
            keyframes += 1;
        }
        n += 1;
    }
    assert!(n >= 33 && keyframes >= 15, "the committed int_hyper fixtures: {n}, {keyframes} decoded");
}

/// Gate 3, beside the committed fixtures: a fixture for each refusal the direct decode
/// makes (integer-payloads §7, in its order: the set against the payload, the networks
/// planned, the shapes, then each stream and each network as it runs), each made from the
/// committed set and payload by one change. Each is refused by both decodes with the same
/// code, the one integer-payloads §8 gives that rule. The committed set and payload decode.
#[test]
fn every_refusal_of_the_direct_decode_is_refused_alike_through_the_lowering() {
    use hyper::IntLayer;
    let base = tiny(|_, _, _| {});
    let (ops, direct) = both(&base, &Owned::committed());
    assert!(ops.is_ok() && ops == direct, "the fixtures' base decodes alike");
    let same = || tiny(|_, _, _| {});
    let as_is = || payload(|_| {});
    // A hyper-latent stream that runs out: two symbols of frequency 1 in 65536 each cost
    // 16 bits, so the 8 symbols need more than the stream's 64-bit start, cut short.
    let costly_z = |e: &mut hyper::CondEntropy| {
        for k in 0..2 {
            e.z_cdfs[k] = vec![0, 1, 2, 1 << 16];
            e.z_cdf_lengths[k] = 4;
        }
    };
    let costly_z_stream = || {
        let mut enc = wai::rans::RansEncoder::new();
        for _ in 0..8 {
            assert!(enc.encode(-8, &[0, 1, 2, 1 << 16], 4, -8));
        }
        let mut s = enc.flush();
        s.truncate(s.len() - 4);
        s
    };
    let h_bias = |f: fn(&mut Vec<i64>, usize)| tiny(move |_, h, _| {
        if let IntLayer::Conv { bias, .. } = &mut h.layers[2] { f(bias, 4) }
    });
    let fixtures: Vec<(&str, &str, (IntModel, IntModel, hyper::CondEntropy), Owned)> = vec![
        ("h_s's afrac not g_s's", "model_mismatch", tiny(|_, h, _| h.afrac = 11), as_is()),
        ("the set's afrac of 0", "model_mismatch", tiny(|g, h, _| (g.afrac, h.afrac) = (0, 0)), as_is()),
        ("the set's afrac of 31", "model_mismatch", tiny(|g, h, _| (g.afrac, h.afrac) = (31, 31)), as_is()),
        ("no scale edge", "model_mismatch", tiny(|_, _, e| { e.edges.clear(); e.cdfs.clear(); e.cdf_lengths.clear(); e.offsets.clear(); }), as_is()),
        ("a latent table short", "model_mismatch", tiny(|_, _, e| { e.cdfs.pop(); }), as_is()),
        ("a hyper-latent median short", "model_mismatch", tiny(|_, _, e| { e.z_median_q.pop(); }), as_is()),
        ("a table that does not end at 2^16", "model_mismatch", tiny(|_, _, e| { let n = e.cdf_lengths[1]; e.cdfs[1][n - 1] = 65535; }), as_is()),
        ("a hyper-latent table's length past its row", "model_mismatch", tiny(|_, _, e| e.z_cdf_lengths[0] = e.z_cdfs[0].len() + 1), as_is()),
        ("a latent dimension of 0", "field_range", same(), payload(|o| o.m = 0)),
        ("more hyper-latent channels than tables", "model_mismatch", same(), payload(|o| o.n_z = 3)),
        ("a hyper-latent past 2^26", "too_large", same(), payload(|o| (o.zh, o.zw) = (1 << 13, 1 << 13))),
        ("a latent past 2^26", "too_large", same(), payload(|o| (o.sh, o.sw) = (1 << 12, 1 << 12))),
        ("an uncropped plane of h_s past 2^26", "too_large", same(), payload(|o| (o.zh, o.zw) = (1 << 11, 1 << 11))),
        ("an h_s layer's bias short", "model_mismatch", h_bias(|b, _| { b.pop(); }), as_is()),
        ("padding that leaves g_s no output", "model_mismatch", tiny(|g, _, _| if let IntLayer::ConvT { pad, .. } = &mut g.layers[2] { *pad = 1000 }), as_is()),
        ("an h_s output that is not the declared latent's shape", "geometry_mismatch", same(), payload(|o| o.sh = 5)),
        ("a g_s that gives four channels", "model_mismatch", tiny(|g, _, _| if let IntLayer::ConvT { out_ch, weight, mult, bias, .. } = &mut g.layers[2] {
            *out_ch = 4;
            *weight = vec![1; 4 * 4 * 9];
            mult.push(mult[0]);
            bias.push(0);
        }), as_is()),
        ("a hyper-latent stream too short to be one", "field_range", same(), payload(|o| o.z_rans.truncate(4))),
        ("a hyper-latent stream that runs out", "stream_exhausted", tiny(|_, _, e| costly_z(e)), payload(|o| o.z_rans = costly_z_stream())),
        ("a word left unread in the hyper-latent stream", "stream_noncanonical", same(), payload(|o| o.z_rans.extend([0, 0, 0, 0]))),
        ("a hyper-latent median at i64's end", "field_range", tiny(|_, _, e| e.z_median_q[0] = i64::MAX), as_is()),
        ("hyper-latents past h_s's range", "field_range", tiny(|_, _, e| e.z_median_q = vec![1 << 60; 2]), as_is()),
        ("a latent stream too short to be one", "field_range", same(), payload(|o| o.rans.truncate(4))),
        ("a latent stream that runs out", "stream_exhausted", same(), payload(|o| { let n = o.rans.len() / 2; o.rans.truncate(n - n % 4); })),
        ("a word left unread in the latent stream", "stream_noncanonical", same(), payload(|o| o.rans.extend([0, 0, 0, 0]))),
        ("means past g_s's range", "field_range", h_bias(|b, m| b[m..].iter_mut().for_each(|v| *v = 1 << 55)), as_is()),
        ("means near i64's end", "field_range", h_bias(|b, m| b[m..].iter_mut().for_each(|v| *v = i64::MAX - (1 << 20))), as_is()),
    ];
    for (what, want, set, o) in &fixtures {
        let (ops, direct) = both(set, o);
        assert_eq!((ops.err(), direct.err()), (Some(*want), Some(*want)), "{what}: through the lowering, then directly");
    }
}

/// Gate 3, at the edge of every `check` range: for each layer of the committed `h_s` and
/// `g_s`, a network of that layer alone (with the set's header; a leaky ReLU followed by a
/// zero 1×1 transposed convolution, since a network with no layer of tag 0, 1 or 2 does
/// not lower) is lowered, and its input's `check` range is `[−X_ℓ, X_ℓ]`, the range the
/// full graph gives tensor `ℓ` (§13.2). An input whose largest magnitude is `X_ℓ` runs,
/// through the lowering and directly, to the same output; one at `X_ℓ + 1` is refused by
/// both: by the graph (`field_range`, at input 0) and by the direct decode's check of that
/// layer (`run_net_checked`, a value out of range at layer 0). So the ranges refuse exactly
/// what integer-payloads §7 *Exactness* refuses, at the same layer.
#[test]
fn every_check_range_refuses_exactly_what_the_direct_decode_refuses() {
    use hyper::{legacy::run_net_checked, IntLayer};
    use wai_ops::{Code, Site, Tensor};
    let mut seen = 0;
    for (net, rgb8) in [("tiny_h_s.bin", false), ("tiny_g_s.bin", true)] {
        let set = read(&format!("{DIR}/{net}"));
        let full = wai_ops::lower::whm1(&set, rgb8).unwrap();
        let n = wai_ops::lower::parse_whm1(&set).unwrap().layers.len();
        for l in 0..n {
            let mut one = IntModel::from_bytes(&set).unwrap();
            let layer = one.layers.swap_remove(l);
            let leaky = matches!(layer, IntLayer::Leaky { .. });
            one.layers = vec![layer];
            let c = full.tensors[l].channels;
            if leaky {
                one.layers.push(IntLayer::ConvT { out_ch: 1, k: 1, stride: 1, pad: 0, opad: 0, weight: vec![0; c as usize], mult: vec![1], bias: vec![0] });
            }
            let g = wai_ops::lower::whm1_net(&wai::int_ops::whm1_net(&one).unwrap(), false).unwrap();
            let (lo, hi) = (g.tensors[0].lo, g.tensors[0].hi);
            assert_eq!((g.tensors[0].channels, lo, hi), (c, full.tensors[l].lo, full.tensors[l].hi), "{net} layer {l}: the range of tensor {l}");
            assert!(hi > 0 && lo == -hi, "{net} layer {l}: a symmetric check range [{lo}, {hi}]");
            let loaded = wai::int_ops::load(&g).unwrap();
            let x = |v: i64| {
                let mut d = vec![0i64; c as usize * 4];
                d[c as usize * 2 + 1] = v;
                d
            };
            for v in [hi, -hi] {
                let ops = wai::int_ops::run1(&loaded, Tensor::new(c, 2, 2, x(v)), &[]).unwrap_or_else(|r| panic!("{net} layer {l}: {v} runs: {r:?}"));
                let (direct, ..) = run_net_checked(&one, &x(v), c as usize, 2, 2).unwrap_or_else(|r| panic!("{net} layer {l}: {v} runs directly: {r}"));
                assert!(ops.data == direct, "{net} layer {l}: at {v} the two differ");
            }
            for v in [hi + 1, -hi - 1] {
                let r = wai::int_ops::run1(&loaded, Tensor::new(c, 2, 2, x(v)), &[]).expect_err("one past the range");
                assert_eq!((r.code, r.at), (Code::FieldRange, Site::Input(0)), "{net} layer {l}: {v}");
                let d = run_net_checked(&one, &x(v), c as usize, 2, 2).expect_err("one past the range, directly");
                assert!(d.out_of_range && d.layer == 0, "{net} layer {l}: {v}: {d}");
            }
            seen += 1;
        }
    }
    assert_eq!(seen, 6, "every layer of the committed h_s and g_s");
}

/// Gate 5 of the migration, the whole-decoder half: the decode through the lowering under
/// the reference kernels (the interpreter computes every operator) and under each fast
/// policy (the convolutions, the transposed convolutions and the inverse GDN on this
/// crate's fast kernels, serial and threaded) gives the same image, and the same
/// refusals, on the committed vector (as `WIH1`, as its JSON form, and with the set's JSON
/// models), and on sets whose hyper-latent channel 0 lies about the edge of `h_s`'s input
/// check range (its median at `±X_0` and one past it). The per-operator half is `int_ops`' equivalence
/// tests, one of which counts the fast kernels' runs on this set.
#[test]
fn every_kernel_policy_decodes_through_the_lowering_alike() {
    use wai::int_kernels::{with_policy, Policy};
    const POLICIES: [Policy; 5] = [Policy::reference(), Policy::fast(1), Policy::fast(2), Policy::fast(5), Policy::fast(0)];
    let x0 = wai_ops::lower::whm1(&read(&format!("{DIR}/tiny_h_s.bin")), false).unwrap().tensors[0].hi;
    let base = Owned::committed();
    let bs = hyper::CondBitstream::try_from_value(&json(&format!("{DIR}/tiny_bitstream.json"))).unwrap();
    let from_json = |f: &str| IntModel::try_from_json(&json(&format!("{DIR}/{f}"))).unwrap();
    let json_models = (from_json("tiny_g_s.json"), from_json("tiny_h_s.json"), tiny(|_, _, _| {}).2);
    let json_form = Owned { m: bs.m, sh: bs.sh, sw: bs.sw, n_z: bs.n_z, zh: bs.zh, zw: bs.zw, z_rans: bs.z_rans.clone(), rans: bs.rans.clone() };
    let mut cases: Vec<(String, (IntModel, IntModel, hyper::CondEntropy), Owned)> =
        vec![("WIH1".into(), tiny(|_, _, _| {}), base.clone()), ("JSON".into(), tiny(|_, _, _| {}), json_form), ("JSON models".into(), json_models, base.clone())];
    // Channel 0's median moved to ±X_0 or one past it: its elements, the median plus each
    // symbol at 2^12, lie about the edge of h_s's input check range.
    for (what, t) in [("channel 0 at X_0", x0), ("at X_0 + 1", x0 + 1), ("at -X_0", -x0), ("at -X_0 - 1", -x0 - 1)] {
        cases.push((what.into(), tiny(move |_, _, e| e.z_median_q[0] = t), base.clone()));
    }
    for (k, (what, set, o)) in cases.iter().enumerate() {
        let (g, h, e) = set;
        let want = with_policy(POLICIES[0], || hyper::ops::decode(g, h, e, &o.st())).map(|d| d.0).map_err(code_of);
        assert!(k >= 3 || want.is_ok(), "{what}: the committed form decodes");
        for pol in &POLICIES[1..] {
            let got = with_policy(*pol, || hyper::ops::decode(g, h, e, &o.st())).map(|d| d.0).map_err(code_of);
            assert!(got == want, "{what}: {pol:?} differs from the interpreter alone");
        }
    }
}

/// Every committed `WIH1` payload, alone or inside another file (a `WIV1`'s keyframe, an
/// envelope, a staged base, a counting fixture): each occurrence of the magic in the
/// corpora that hold integer payloads whose bytes from there parse as a `WIH1` of exactly
/// the length its header and stream lengths give. Returns `(where, payload)` pairs.
fn committed_wih1_payloads() -> Vec<(String, Vec<u8>)> {
    fn files(d: &std::path::Path, out: &mut Vec<PathBuf>) {
        let mut es: Vec<_> = std::fs::read_dir(d).unwrap().filter_map(|e| e.ok()).map(|e| e.path()).collect();
        es.sort();
        for p in es {
            if p.is_dir() { files(&p, out) } else { out.push(p) }
        }
    }
    let mut all = Vec::new();
    for d in ["int-payload-conformance", "staged-conformance", "staged-measure-conformance", "http-conformance/objects", "wai-rs/tests/vectors"] {
        files(&wai().join(d), &mut all);
    }
    let u32_at = |b: &[u8], i: usize| b.get(i..i + 4).map(|s| u32::from_le_bytes(s.try_into().unwrap()) as usize);
    let mut v = Vec::new();
    for f in all {
        let b = std::fs::read(&f).unwrap();
        for i in (0..b.len().saturating_sub(3)).filter(|&i| &b[i..i + 4] == b"WIH1") {
            let Some(lz) = u32_at(&b, i + 32) else { continue };
            let Some(ly) = i.checked_add(36 + lz).and_then(|j| u32_at(&b, j)) else { continue };
            let end = i + 40 + lz + ly;
            if let Some(p) = b.get(i..end).filter(|p| wai::int_wire::parse_wih1(p).is_ok()) {
                v.push((format!("{}@{i}", f.strip_prefix(wai()).unwrap().display()), p.to_vec()));
            }
        }
    }
    v
}

/// The scan for the load rules the switch brings (integer-operators §15.3 item 3): no
/// committed set or payload is affected. Every committed set of either capability has a
/// layer of tag 0, 1 or 2 in each network, header shifts under 128, no bias of magnitude
/// `2^63 − 1` or more, and its two networks lower and load under `acc64`; every committed
/// `WIH1` payload, wherever it is carried, decodes through the lowering to the bytes the
/// direct decode gives, or is refused by both with the same code, against the set every
/// committed one is decoded with (`tiny`). (The other files that hold the magic are code:
/// the browser crate's recorded build, its demo page and its scripts.)
#[test]
fn the_new_load_rules_affect_no_committed_set_or_payload() {
    use wai_ops::lower::NetLayer as N;
    for s in indexed() {
        for (role, rgb8) in [("h_s.whm", false), ("g_s.whm", true)] {
            let b = s.member(role);
            let net = wai_ops::lower::parse_whm1(&b).unwrap();
            assert!(net.layers.iter().any(|l| matches!(l, N::ConvT { .. } | N::Conv { .. } | N::Igdn { .. })), "{} {role}: no layer of tag 0, 1 or 2", s.name);
            assert!(net.shift < 128 && net.gf < 128, "{} {role}: a header shift of 128 or more", s.name);
            for l in &net.layers {
                if let N::ConvT { bias, .. } | N::Conv { bias, .. } = l {
                    assert!(bias.iter().all(|b| b.unsigned_abs() < i64::MAX as u64), "{} {role}: a bias of magnitude 2^63 - 1 or more", s.name);
                }
            }
            let g = wai_ops::lower::whm1(&b, rgb8).unwrap_or_else(|r| panic!("{} {role}: does not lower: {r:?}", s.name));
            assert!(wai::int_ops::load(&g).is_ok(), "{} {role}: does not load under acc64", s.name);
        }
    }
    let set = tiny(|_, _, _| {});
    let (mut decoded, mut refused) = (0, 0);
    let payloads = committed_wih1_payloads();
    for (at, p) in &payloads {
        let k = wai::int_wire::parse_wih1(p).unwrap();
        let o = Owned { m: k.m as usize, sh: k.sh as usize, sw: k.sw as usize, n_z: k.n_z as usize, zh: k.zh as usize, zw: k.zw as usize, z_rans: k.z_rans.to_vec(), rans: k.rans.to_vec() };
        let (ops, direct) = both(&set, &o);
        assert!(ops == direct, "{at}: the decode through the lowering differs from the direct decode");
        if ops.is_ok() { decoded += 1 } else { refused += 1 }
    }
    let staged = payloads.iter().filter(|(at, _)| at.starts_with("staged-conformance")).count();
    assert!(decoded >= 10 && refused >= 5 && staged >= 5, "the committed WIH1 payloads, at least those of this revision: {decoded} decoded, {refused} refused, {staged} staged");
}