// The ops-conformance graph vectors through a browser's WebGPU.
//
// Build the page's module first:
//
//   cd wai/wai-ops-gpu/browser
//   cargo build --locked --release --target wasm32-unknown-unknown
//   wasm-bindgen --target web --out-dir pkg --out-name wai_ops_gpu_browser \
//     target/wasm32-unknown-unknown/release/wai_ops_gpu_browser.wasm
//
// then, with Playwright installed under PLAYWRIGHT_HOST:
//
//   [WAI_OPS_GPU_REQUIRE=1] [WAI_OPS_GPU_BROWSER_CHANNEL=chrome] \
//     PLAYWRIGHT_HOST=<dir with node_modules/playwright>/ node wai/wai-ops-gpu/browser/run.mjs
//
// It serves this directory and ../../ops-conformance on 127.0.0.1, opens index.html in
// a headless browser and prints the page's report. It fails on a page error, a
// mismatch or a device error, and, under WAI_OPS_GPU_REQUIRE=1, when the page found no
// adapter or the report has no `browser webgpu: key=` line with mismatches=0 errors=0.
// Headless, macOS offers a page a hardware adapter only when the browser draws through
// Metal (`--use-angle=metal`); WAI_OPS_GPU_BROWSER_ARGS (space-separated) replaces the
// launch arguments.
import http from "node:http";
import fs from "node:fs";
import path from "node:path";
import { fileURLToPath } from "node:url";
import { createRequire } from "node:module";

const HERE = path.dirname(fileURLToPath(import.meta.url));
const CORPUS = path.resolve(HERE, "../../ops-conformance");
const REQUIRE = process.env.WAI_OPS_GPU_REQUIRE === "1";
const PORT = Number(process.env.PORT || 8797);
const TIMEOUT_MS = Number(process.env.WAI_OPS_GPU_TIMEOUT_MS || 20 * 60 * 1000);
const ARGS = process.env.WAI_OPS_GPU_BROWSER_ARGS !== undefined
  ? process.env.WAI_OPS_GPU_BROWSER_ARGS.split(/\s+/).filter(Boolean)
  : (process.platform === "darwin" ? ["--use-angle=metal"] : []).concat(["--enable-unsafe-webgpu"]);
const { chromium } = createRequire(process.env.PLAYWRIGHT_HOST || HERE + "/")("playwright");

const files = ["vectors", "graphs"].flatMap((d) =>
  fs.readdirSync(path.join(CORPUS, d)).filter((f) => f.endsWith(".jsonl")).sort().map((f) => `${d}/${f}`));
const ROOTS = { "/ops-conformance/": CORPUS, "/browser/": HERE };
const MIME = { ".js": "text/javascript", ".wasm": "application/wasm", ".html": "text/html", ".json": "application/json", ".jsonl": "text/plain" };
const server = http.createServer((req, res) => {
  const url = decodeURIComponent(req.url.split("?")[0]);
  if (url === "/browser/files.json") {
    res.writeHead(200, { "content-type": "application/json" });
    return res.end(JSON.stringify(files));
  }
  const prefix = Object.keys(ROOTS).find((p) => url.startsWith(p));
  const root = prefix && ROOTS[prefix];
  const f = root && path.resolve(root, "." + url.slice(prefix.length - 1));
  if (!f || !f.startsWith(root + path.sep) || !fs.existsSync(f) || !fs.statSync(f).isFile()) {
    res.writeHead(404);
    return res.end("not found");
  }
  res.writeHead(200, { "content-type": MIME[path.extname(f)] || "application/octet-stream" });
  fs.createReadStream(f).pipe(res);
});

let browser;
try {
  if (!fs.existsSync(path.join(HERE, "pkg", "wai_ops_gpu_browser.js"))) {
    console.error("no pkg/wai_ops_gpu_browser.js; build it as this file's header says");
    process.exit(2);
  }
  await new Promise((r) => server.listen(PORT, "127.0.0.1", r));
  const channel = process.env.WAI_OPS_GPU_BROWSER_CHANNEL || undefined;
  browser = await chromium.launch({ args: ARGS, channel });
  console.log(`browser: ${channel || "chromium"} ${browser.version()} args=${ARGS.join(" ")}`);
  const page = await browser.newPage();
  const errs = [];
  page.on("pageerror", (e) => errs.push(String(e)));
  await page.goto(`http://127.0.0.1:${PORT}/browser/index.html`, { waitUntil: "domcontentloaded", timeout: 30000 });
  await page.waitForFunction(() => window.opsGpu && window.opsGpu.done === true, null, { timeout: TIMEOUT_MS, polling: 1000 });
  const report = await page.evaluate(() => window.opsGpu.report);
  const info = await page.evaluate(async () => {
    if (!navigator.gpu) return "navigator.gpu is absent";
    const a = await navigator.gpu.requestAdapter();
    if (!a) return "requestAdapter gave none";
    const i = a.info || {};
    return `vendor=${i.vendor} architecture=${i.architecture} device=${i.device} description=${i.description}`;
  });
  console.log(`adapter info (navigator.gpu): ${info}`);
  console.log(report);
  for (const e of errs) console.log(`page error: ${e}`);
  const ok = report.split("\n").some((l) => /^browser webgpu: key=\S+ .* mismatches=0 errors=0$/.test(l));
  const bad = errs.length > 0 || /MISMATCH|DEVICE ERROR|page error|did not parse/.test(report) ||
    report.split("\n").some((l) => /^browser webgpu: key=/.test(l) && !/mismatches=0 errors=0$/.test(l));
  if (bad || (REQUIRE && !ok)) process.exitCode = 1;
} finally {
  if (browser) await browser.close();
  server.close();
}