// Reproducible proof: the wasm32 FULL CONDITIONAL codec decode is byte-identical
// to the native reference — a pretrained learned image codec (PTQ of mbt2018_mean)
// whose whole bitstream→image decode (factorized z, integer h_s, integer-σ
// entropy, integer g_s) runs in the browser engine with NO ML runtime, and whose
// RGB verifies against the native FNV-1a hash. The integer-entropy contract,
// in-browser.
//
// Run via demo/verify_int_hyper.sh (builds the nodejs-target pkg first), or:
//   node verify_int_hyper_wasm.mjs [path/to/wai_web.js] [model-dir]
// The model dir (default $WAI_SOTA_INT_DIR or /tmp/sota_int) holds the artifacts
// tools/wai_sota_int_synth_export.py emits (the g_s/h_s model JSONs are large, so
// they are NOT committed — regenerate them with the export tool).

import { readFileSync, existsSync } from 'node:fs';
import { dirname, resolve } from 'node:path';
import { fileURLToPath, pathToFileURL } from 'node:url';

const here = dirname(fileURLToPath(import.meta.url));
const pkg = resolve(here, process.argv[2] ?? './pkg-node/wai_web.js');
const named = process.argv[3] ?? process.env.WAI_SOTA_INT_DIR;
const dir = resolve(named || '/tmp/sota_int');

// The same rule as wai-rs/tests/support/require_vectors.rs: a missing artifact is a
// failure when WAI_REQUIRE_SOTA_VECTORS is on (any value but empty, 0, false, no), or
// when a directory was named (the argument or WAI_SOTA_INT_DIR); it skips only when
// neither holds and the default location lacks the artifacts.
const sw = (process.env.WAI_REQUIRE_SOTA_VECTORS ?? '').trim().toLowerCase();
const required = !['', '0', 'false', 'no'].includes(sw);
const ARTIFACTS = ['cond.json', 'cond_entropy.json', 'cond_bitstream.json', 'int_synth_sota_model.json',
  'int_hs_model.json', 'int_synth_sota_model.bin', 'int_hs_model.bin'];
const missing = ARTIFACTS.filter((f) => !existsSync(`${dir}/${f}`));
if (missing.length) {
  if (required || named) {
    console.error(`FAIL: missing in ${dir}: ${missing.join(', ')}`
      + (required ? ' (WAI_REQUIRE_SOTA_VECTORS is set)' : ' (the directory was named explicitly)'));
    process.exit(1);
  }
  console.log(`skip: artifacts not in ${dir} (run tools/wai_sota_int_synth_export.py) — NOT VERIFIED`);
  process.exit(0);
}
const wai = await import(pathToFileURL(pkg).href);
const bytes = (name) => new Uint8Array(readFileSync(`${dir}/${name}`));

// FNV-1a 64-bit — the same dependency-free checksum the export tool and the
// native Rust decode share (no domain separation; raw RGB bytes).
function fnv1a(buf) {
  const mask = (1n << 64n) - 1n;
  let h = 14695981039346656037n;
  for (let i = 0; i < buf.length; i++) h = ((h ^ BigInt(buf[i])) * 1099511628211n) & mask;
  return h.toString(16).padStart(16, '0');
}

const conf = JSON.parse(readFileSync(`${dir}/cond.json`, 'utf8'));
const ent = bytes('cond_entropy.json'); // y Gaussian-conditional + z factorized tables
const bs = bytes('cond_bitstream.json'); // z_rans + y_rans

function check(label, img) {
  const got = fnv1a(img.rgb);
  const ok = got === conf.rgb_hash
    && img.width === conf.out_w && img.height === conf.out_h
    && img.rgb.length === conf.out_w * conf.out_h * conf.out_c;
  console.log(`${ok ? 'PASS' : 'FAIL'}  ${label.padEnd(12)} ${img.width}x${img.height}  ${img.rgb.length}B  `
    + `${got.slice(0, 16)}…  ${got === conf.rgb_hash ? '== native hash' : `MISMATCH (want ${conf.rgb_hash})`}  `
    + `(${conf.psnr_cond?.toFixed?.(2) ?? '?'} dB)`);
  return ok;
}

// JSON model path and the COMPACT BINARY model path must both reproduce the
// native hash (the binary is what the browser demo downloads — ~½ the size).
const json = check('json model', wai.decodeIntHyper(
  bytes('int_synth_sota_model.json'), bytes('int_hs_model.json'), ent, bs));
const bin = check('binary model', wai.decodeIntHyperBin(
  bytes('int_synth_sota_model.bin'), bytes('int_hs_model.bin'), ent, bs));

const pass = json && bin;
console.log(pass
  ? '\n✓ wasm32 conditional-codec decode (JSON + compact-binary model) is byte-identical to the native reference — a pretrained learned codec decoded in-browser, zero JS ML runtime.'
  : '\n✗ mismatch');
process.exit(pass ? 0 : 1);