/**
 * Render an Admin page to static markup, outside a browser.
 *
 * The migration to the UI node tree has to be provable rather than asserted:
 * a page is rendered before it is touched, rendered again afterwards, and the
 * two are compared. This is the thing that renders it, used both to capture a
 * baseline and, from the check script, to compare against one.
 *
 *   node scripts/render-page.mjs src/pages/admin/HiredHistory.jsx out.html
 *
 * The page is loaded through a real Vite server, so `@/` aliases, Markdown
 * imports and `import.meta.glob` behave exactly as they do in the app. Queries
 * are disabled rather than mocked: every page then renders its empty state,
 * deterministically, which is all a structural comparison needs.
 */
import { createServer } from 'vite';
import { join } from 'node:path';
import { writeFileSync } from 'node:fs';
import React from 'react';
import { renderToStaticMarkup } from 'react-dom/server';
import { withSourceResolution } from './ssr-resolve.mjs';

/**
 * The design system reads `window` when its modules evaluate, which is a
 * pre-existing SSR limitation and not what any of this is testing. The shim is
 * the same one the citation tests use.
 */
export function shimWindow() {
  const had = 'window' in globalThis;
  const hadSvg = 'SVGElement' in globalThis;
  if (!had) {
    globalThis.window = {
      matchMedia: () => ({ matches: false, addEventListener() {}, removeEventListener() {} }),
      addEventListener() {}, removeEventListener() {},
    };
  }
  /* Recharts tests `instanceof SVGElement` while measuring, which is a browser
     global with no Node equivalent. A bare class is enough: nothing is ever an
     instance of it, which is the correct answer outside a browser. */
  if (!hadSvg) globalThis.SVGElement = class SVGElement {};
  return () => {
    if (!had) delete globalThis.window;
    if (!hadSvg) delete globalThis.SVGElement;
  };
}

/**
 * Render one page.
 *
 * `providers` are supplied by the caller rather than assumed here, because the
 * editing session belongs to the layout and a baseline captured before a
 * migration must be rendered without it.
 */
export async function renderPage(server, modulePath, { route = '/', wrap = null } = {}) {
  /* Imported through Node rather than the Vite graph so the instance matches
     the one the page itself resolves — loading them as SSR modules creates a
     second copy, and a second QueryClientProvider provides nothing. */
  const { QueryClient, QueryClientProvider } = await import('@tanstack/react-query');
  const { MemoryRouter } = await import('react-router-dom');

  const Page = (await server.ssrLoadModule(modulePath)).default;
  const client = new QueryClient({ defaultOptions: { queries: { retry: false, enabled: false } } });

  const inner = wrap ? wrap(React.createElement(Page)) : React.createElement(Page);

  return renderToStaticMarkup(
    React.createElement(MemoryRouter, { initialEntries: [route] },
      React.createElement(QueryClientProvider, { client }, inner))
  );
}

/**
 * Two renderings are the same page when they paint the same styled boxes, in
 * the same order, around the same words.
 *
 * Compared this way rather than byte-for-byte because a migration legitimately
 * adds `data-ui-*` identity attributes, and for components that cannot forward
 * unknown props a wrapper element carrying nothing else. Both are invisible.
 * A changed utility class, a reordered section or altered text moves one of
 * these and fails.
 */
export const classSignature = (html) => (html.match(/class="[^"]*"/g) || []).join('\n');
export const wordSignature = (html) => html.replace(/<[^>]*>/g, ' ').replace(/\s+/g, ' ').trim();

/** Tag counts, so an added element is visible and can be characterised. */
export const tagCounts = (html) => (html.match(/<\/?[a-z][a-z0-9-]*/gi) || [])
  .map((t) => t.toLowerCase())
  .reduce((acc, t) => ({ ...acc, [t]: (acc[t] || 0) + 1 }), {});

/* Run directly: capture a baseline. */
if (process.argv[1] && process.argv[1].endsWith('render-page.mjs')) {
  const [modulePath, out, route] = process.argv.slice(2);
  const restore = shimWindow();
  const server = await createServer({
    root: process.cwd(),
    server: { middlewareMode: true },
    appType: 'custom',
    logLevel: 'error',
    resolve: { alias: { 'react-hot-toast': join(process.cwd(), 'scripts/stubs/react-hot-toast.js') } },
  });
  /* The page path arrives on the command line with whatever extension it has
     today; during the TypeScript migration that may be .jsx or .tsx. */
  withSourceResolution(server, process.cwd());
  try {
    const html = await renderPage(server, `/${modulePath.replace(/^\//, '')}`, { route: route || '/' });
    writeFileSync(out, html);
    console.log(`rendered ${html.length} chars -> ${out}`);
  } catch (error) {
    console.error('RENDER FAILED:', error.message);
    process.exitCode = 1;
  } finally {
    await server.close();
    restore();
    /* `server.close()` leaves a handle open often enough that the process hangs
       without this, and a capture script that never exits is a capture script
       nobody runs. */
    process.exit(process.exitCode || 0);
  }
}