// differential.mjs: the differential's second half. examples/differential.rs writes
// modules from wasm-smith and the Rust checker's verdicts; this runs check-module.mjs on
// every one at both levels, under the caps the Rust side used, and names each verdict
// that differs.
//
//   node differential.mjs DIR
//
// DIR/verdicts.txt holds one line a module, `<name> <caps> <integer verdict> | <float
// verdict>`, the module being DIR/<name>.wasm: `<i>` for wasm-smith's i-th, `<i>-<k>` for a
// mutated copy of it, `<script>.<n>` for a module of the specification's tests
// (examples/spectest.rs). Prints each disagreement, then how the verdicts spread over held and
// the rules. Exit status 0 when every verdict agrees, 1 otherwise, 2 for an input error.
// No dependency.
import { readFileSync } from 'node:fs';
import { join } from 'node:path';
import { analyse, verdictOf, parseCaps } from './check-module.mjs';

const dir = process.argv[2];
if (!dir || process.argv.length !== 3) {
  console.error('usage: node differential.mjs DIR');
  process.exit(2);
}
let lines;
try {
  lines = readFileSync(join(dir, 'verdicts.txt'), 'utf8').split('\n').filter(Boolean);
} catch (e) {
  console.error(`differential: ${e.message}`);
  process.exit(2);
}

const spread = new Map();
const count = (k) => spread.set(k, (spread.get(k) || 0) + 1);
let differ = 0, modules = 0;
for (const line of lines) {
  const m = /^(\S+) (\S+) (.+) \| (.+)$/.exec(line);
  const caps = m && parseCaps(m[2]);
  if (!m || !caps) {
    console.error(`differential: not a verdict line: ${line}`);
    process.exit(2);
  }
  const bytes = new Uint8Array(readFileSync(join(dir, `${m[1]}.wasm`)));
  const analysis = bytes.length > caps.module_bytes ? null : analyse(bytes);
  modules++;
  for (const [level, want] of [['integer', m[3]], ['float', m[4]]]) {
    const got = verdictOf(analysis, bytes.length, level, caps);
    const kind = m[1].includes('.') ? 'spec' : m[1].includes('-') ? 'mutated' : 'wasm-smith';
    count(`${kind} ${level} ${want === 'held' ? 'held' : want.split(' ').slice(0, 2).join(' ')}`);
    if (got !== want) {
      differ++;
      if (differ <= 50) console.log(`${m[1]}.wasm ${level} ${m[2]}: the Rust checker ${want}, check-module.mjs ${got}`);
    }
  }
}
for (const k of [...spread.keys()].sort()) console.log(`  ${k}: ${spread.get(k)}`);
console.log(differ
  ? `differential: ${differ} verdicts of ${modules * 2} differ, over ${modules} modules`
  : `differential: the two checkers agree on all ${modules * 2} verdicts of ${modules} modules`);
process.exit(differ ? 1 : 0);