import { expect, test } from '@playwright/test';
import { readFile } from 'node:fs/promises';

test.use({ javaScriptEnabled: true, reducedMotion: 'reduce' });

async function probeAsset(name: string) {
  return readFile(new URL(`../../test-assets/wip-wasm/${name}`, import.meta.url));
}

test('real WASM enforces manifest byte, node and depth bounds', async ({ page }, testInfo) => {
  const base = testInfo.project.use.baseURL!;
  await page.goto(new URL('worldspace.json', base).href);
  const result = await page.evaluate(async (base) => {
    const module = await import(new URL('wip-wasm/wip_browser.js', base).href);
    await module.default();
    const root = { path: '/', name: '', displayPath: '/', title: 'Root', href: '/', html: '<p>Root</p>' };
    const attempt = (json: string) => {
      try { new module.BrowserSession(json).free(); return { error: '', trap: false }; }
      catch (error) { return { error: String(error), trap: error instanceof WebAssembly.RuntimeError }; }
    };
    // Both oversized manifests are otherwise valid; the controls prove that
    // removing a limit cannot leave this test green via unrelated validation.
    const byteLimit = 16 * 1024 * 1024;
    const empty = JSON.stringify({ nodes: [{ ...root, html: '' }] });
    const atBytes = JSON.stringify({ nodes: [{ ...root, html: 'x'.repeat(byteLimit - empty.length) }] });
    const bytesAccepted = attempt(atBytes);
    const bytes = attempt(atBytes.replace('"html":"', '"html":"x'));
    const wide = [root, ...Array.from({ length: 4096 }, (_, i) => ({
      path: `/n${i}`, name: `n${i}`, displayPath: `/n${i}`, parent: '/', title: `Node ${i}`, href: `/n${i}/`, html: '',
    }))];
    const nodesAccepted = attempt(JSON.stringify({ nodes: wide.slice(0, 4096) }));
    const nodes = attempt(JSON.stringify({ nodes: wide }));
    const deep: Record<string, string>[] = [root];
    let parent = '/';
    for (let i = 0; i < 32; i++) {
      const path = `${parent === '/' ? '' : parent}/a`;
      deep.push({ path, name: 'a', displayPath: path, parent, title: path, href: `${path}/`, html: '<p>Node</p>' });
      parent = path;
    }
    const accepted = new module.BrowserSession(JSON.stringify({ nodes: deep }));
    const deepest = JSON.parse(accepted.read(parent)).path;
    accepted.free();
    deep.push({ path: `${parent}/a`, name: 'a', displayPath: `${parent}/a`, parent, title: 'Too deep', href: `${parent}/a/`, html: '' });
    const depth = attempt(JSON.stringify({ nodes: deep }));
    return { bytes, nodes, depth, deepest, bytesAccepted, nodesAccepted, probePublished: 'panic_probe' in module.BrowserSession.prototype };
  }, base);
  expect(result.bytesAccepted).toEqual({ error: '', trap: false });
  expect(result.nodesAccepted).toEqual({ error: '', trap: false });
  expect(result.bytes).toEqual({ error: 'document JSON exceeds the input byte limit', trap: false });
  expect(result.nodes).toEqual({ error: 'document node count must be between 1 and MAX_NODES', trap: false });
  expect(result.depth).toEqual({ error: 'document hierarchy exceeds the depth limit', trap: false });
  expect(result.deepest.split('/').length - 1).toBe(32);
  expect(result.probePublished).toBe(false);
});

test('a controlled release Rust panic traps, not a Protocol failure; a fresh instance recovers', async ({ page }, testInfo) => {
  const base = testInfo.project.use.baseURL!;
  await page.route('**/wip-probe/wip_browser*', async (route) => {
    const wasm = new URL(route.request().url()).pathname.endsWith('.wasm');
    await route.fulfill({ body: await probeAsset(wasm ? 'wip_browser_bg.wasm' : 'wip_browser.js'), contentType: wasm ? 'application/wasm' : 'text/javascript' });
  });
  await page.goto(new URL('worldspace.json', base).href);
  const result = await page.evaluate(async (base) => {
    const manifest = await (await fetch(new URL('worldspace.json', base))).text();
    const module = await import(new URL('wip-probe/wip_browser.js', base).href);
    await module.default();
    const session = new module.BrowserSession(manifest);
    const before = JSON.parse(session.read('/')).path;
    let trap = false, detail = '';
    try { session.panic_probe(); } catch (error) {
      trap = error instanceof WebAssembly.RuntimeError;
      detail = String(error);
    }
    // Retain the aborted wrapper too: its generated GC finalizer enters WASM.
    (window as unknown as Record<string, unknown>).__quarantinedSession = session;
    // Do not call/free the aborted Rust object: a mutable borrow was interrupted.
    // A distinct glue module creates a genuinely new WASM instance.
    const fresh = await import(`${new URL('wip-probe/wip_browser.js', base).href}?fresh`);
    await fresh.default();
    const replacement = new fresh.BrowserSession(manifest);
    const after = JSON.parse(replacement.read('/')).path;
    replacement.free();
    return { before, after, trap, detail };
  }, base);
  expect(result.before).toBe('/');
  expect(result.trap).toBe(true);
  expect(result.detail).toContain('RuntimeError');
  expect(result.after).toBe('/');
});

test('the site retires a trapped WASM session and does not replay calls on later routes', async ({ page }, testInfo) => {
  const base = testInfo.project.use.baseURL!;
  await page.route('**/wip-wasm/wip_browser.js', async (route) => {
    const source = (await probeAsset('wip_browser.js')).toString();
    await route.fulfill({ contentType: 'text/javascript', body: `${source}
BrowserSession.prototype.read = function () {
  window.__panicReadCalls = (window.__panicReadCalls || 0) + 1;
  window.__trappedSession = new WeakRef(this);
  return this.panic_probe();
};
const originalFree = BrowserSession.prototype.free;
BrowserSession.prototype.free = function () {
  window.__panicFreeCalls = (window.__panicFreeCalls || 0) + 1;
  return originalFree.call(this);
};` });
  });
  await page.route('**/wip-wasm/*.wasm', async (route) => {
    await route.fulfill({ contentType: 'application/wasm', body: await probeAsset('wip_browser_bg.wasm') });
  });
  await page.goto(base);
  const stage = page.locator('[data-landing-stage]');
  await expect(stage).toHaveAttribute('data-wip-state', 'fallback');
  expect(await page.evaluate(() => (window as Window & { __panicReadCalls?: number }).__panicReadCalls)).toBe(1);
  await page.locator('.demo-node[data-path="/book"]').click();
  await expect(page).toHaveURL(new URL('book/', base).href);
  await expect(stage).toHaveAttribute('data-wip-state', 'fallback');
  await expect(page.locator('[data-selected-content] h1')).toHaveText('Book');
  expect(await page.evaluate(() => (window as Window & { __panicReadCalls?: number }).__panicReadCalls)).toBe(1);
  // Force collection after continuations release their locals. The only test
  // reference is weak, so this catches accidentally dropping the quarantine.
  const cdp = await page.context().newCDPSession(page);
  await cdp.send('HeapProfiler.collectGarbage');
  expect(await page.evaluate(() => Boolean((window as unknown as { __trappedSession: WeakRef<object> }).__trappedSession.deref()))).toBe(true);
  await page.evaluate(() => window.dispatchEvent(new PageTransitionEvent('pagehide', { persisted: false })));
  await cdp.send('HeapProfiler.collectGarbage');
  expect(await page.evaluate(() => ({
    retained: Boolean((window as unknown as { __trappedSession: WeakRef<object> }).__trappedSession.deref()),
    frees: (window as Window & { __panicFreeCalls?: number }).__panicFreeCalls || 0,
  }))).toEqual({ retained: true, frees: 0 });
  await cdp.detach();
});