scrabble-game/ui/vite.config.ts

import { resolve } from 'node:path';
import { defineConfig, type Plugin } from 'vite';
import { svelte } from '@sveltejs/vite-plugin-svelte';

/**
 * stripBootDiag removes the temporary on-device boot-diagnostic block from index.html — the span
 * between the `<!-- BOOT-DIAG:START -->` and `<!-- BOOT-DIAG:END -->` markers. That block is a
 * full-screen ES5 overlay meant only for the production build shipped to the test contour, so it
 * is dropped from every non-production build: the `mock` e2e (whose first taps the overlay would
 * intercept) and the dev server. It is wired only when mode !== 'production'. Remove this plugin
 * together with the index.html block once the Android WebView diagnosis is finished — it must
 * never reach master / production.
 */
function stripBootDiag(): Plugin {
  return {
    name: 'strip-boot-diag',
    transformIndexHtml(html) {
      return html.replace(/\s*<!-- BOOT-DIAG:START[\s\S]*?BOOT-DIAG:END -->/g, '');
    },
  };
}

// The edge Connect service is scrabble.edge.v1.Gateway; the gateway serves it over
// h2c on :8081 by default. In dev we proxy the RPC path so the browser (which can
// not speak h2c directly) talks to the dev server on the same origin. In `mock`
// mode the app runs entirely against an in-memory fake transport — no gateway,
// no backend, no Postgres — which is what `pnpm start` launches.
const RPC_PREFIX = '/scrabble.edge.v1.Gateway';

export default defineConfig(({ mode }) => ({
  // Relative asset base so the one build serves under any path — the gateway maps the
  // Telegram Mini App to /telegram/ (the hash router is path-agnostic).
  base: './',
  define: {
    // App version shown on the About screen, injected at build time from `git describe`
    // via a Docker build-arg. Falls back to "dev" for a plain local/mock build,
    // so a missing build-arg never breaks the build.
    __APP_VERSION__: JSON.stringify(process.env.VITE_APP_VERSION || 'dev'),
  },
  // The boot-diagnostic overlay ships only in the production build (the test contour); it is
  // stripped from the dev server and the mock e2e build, where a full-screen overlay would
  // intercept Playwright's taps. See stripBootDiag / the index.html BOOT-DIAG block.
  plugins: [svelte(), ...(mode !== 'production' ? [stripBootDiag()] : [])],
  server: {
    port: 5173,
    proxy:
      mode === 'mock'
        ? undefined
        : {
            [RPC_PREFIX]: {
              target: process.env.GATEWAY_URL || 'http://localhost:8081',
              changeOrigin: true,
            },
          },
  },
  build: {
    // Down-level to es2019 so an old Android System WebView (seen: Telegram/VK in-app WebView on
    // Chromium 66, Android 9) can parse the bundle — esbuild lowers es2020+ syntax (?., ??, private
    // fields, static blocks, …) that Chrome 66 rejects with "Unexpected token ?", which left the SPA
    // on a white screen. esbuild lowers syntax only, not runtime APIs; the app's own source uses
    // none beyond this floor (the mock-only helpers are tree-shaken from production). Reach for
    // @vitejs/plugin-legacy if runtime-API polyfills for even older engines turn out to be needed.
    target: 'es2019',
    // Emit sourcemaps everywhere except the production build. A shipped `.map`
    // carries full `sourcesContent` — the entire TypeScript/Svelte source — and the
    // gateway/landing images serve `dist/` verbatim, so production maps would expose
    // the whole client source at the edge. Dev and the `mock` e2e build
    // (`vite build --mode mock`) keep maps for debugging; the production `vite build`
    // (the Docker image build) drops them.
    sourcemap: mode !== 'production',
    // Two entries: the game SPA (index.html, served at /app/ + /telegram/) and the
    // public landing page (landing.html, served at /). Assets are shared in dist/assets/, and
    // the relative base lets one build serve under any path.
    rollupOptions: {
      input: {
        main: resolve(import.meta.dirname, 'index.html'),
        landing: resolve(import.meta.dirname, 'landing.html'),
      },
    },
  },
}));