import { defineConfig } from 'vite';
import react from '@vitejs/plugin-react';
import { VitePWA } from 'vite-plugin-pwa';
import { readFileSync } from 'node:fs';
import { fileURLToPath } from 'node:url';
import { generateLearnPages, lessonInputs } from './scripts/learn-pages';

const pkg = JSON.parse(readFileSync(new URL('./package.json', import.meta.url), 'utf-8')) as {
  version: string;
};

// Write a static `learn/<slug>/index.html` shell per lesson (from the lesson `.md`
// frontmatter) before the inputs below reference them. Regenerated whenever Vite
// (re)loads its config — every dev start and build — so a newly added lesson needs a
// dev restart to get its page; the generated dirs are git-ignored.
generateLearnPages();

export default defineConfig({
  resolve: {
    alias: {
      '@': fileURLToPath(new URL('./src', import.meta.url)),
      '@core': fileURLToPath(new URL('./src/core', import.meta.url)),
    },
  },
  define: {
    __APP_VERSION__: JSON.stringify(pkg.version),
  },
  build: {
    rollupOptions: {
      // Multi-page: the marketing landing is served at `/` (index.html → the
      // lightweight `src/landing` entry); the app at `/app/` (app/index.html →
      // src/main.tsx). The app is hash-routed, so it runs unchanged under /app/.
      // `/learn/` is the deep-dive learning section — another light marketing
      // entry (src/learn), reusing core + the landing's chart embed only. Its index
      // is `learn/index.html`; each lesson is its own page (`learn/<slug>/`) from a
      // generated shell, added to the inputs here via `lessonInputs()`.
      input: {
        main: fileURLToPath(new URL('./index.html', import.meta.url)),
        app: fileURLToPath(new URL('./app/index.html', import.meta.url)),
        learn: fileURLToPath(new URL('./learn/index.html', import.meta.url)),
        ...lessonInputs(),
      },
      output: {
        // Split the heavy vendors so the chunk graph stays legible and the PWA
        // can precache/update them independently of app code. Monaco and the
        // Vega stack are each multi-MB; isolating them keeps app rebuilds small.
        manualChunks: {
          monaco: ['monaco-editor'],
          vega: ['vega', 'vega-lite', 'vega-embed'],
        },
      },
    },
  },
  plugins: [
    react(),
    VitePWA({
      registerType: 'prompt',
      // The app lives at /app/; scope the service worker there so it never
      // controls the marketing landing at / (which stays uncontrolled and
      // always-fresh). A /sw.js narrowing its scope to /app/ needs no
      // Service-Worker-Allowed header — narrowing is always permitted.
      scope: '/app/',
      includeAssets: ['favicon.svg', 'icon-maskable.svg', 'icon-mono.svg', 'apple-touch-icon.png'],
      manifest: {
        id: '/app/',
        name: 'Astrolabe',
        short_name: 'Astrolabe',
        scope: '/app/',
        start_url: '/app/',
        description: 'A browser-based snippet manager for Vega-Lite visualizations.',
        // theme_color tints the OS/browser chrome; background_color is the splash
        // behind the icon. theme_color is the app accent (`--accent`, light theme);
        // background_color matches the light `--bg` the app boots into.
        theme_color: '#0e7490',
        background_color: '#ffffff',
        display: 'standalone',
        // SVG marks scale to any size — Chrome/Edge/desktop install accept SVG
        // icons. maskable = Android adaptive; monochrome = tinted mark. Safari
        // ignores SVG and the manifest both, so the 180×180 PNG covers the one
        // touch surface we target — iPad add-to-home-screen (Astrolabe is a
        // desktop/tablet tool, not a phone app). It's linked as
        // <link rel="apple-touch-icon"> in index.html, where Safari reads it; the
        // PNG is the favicon art rasterized full-bleed (no self-rounding — iOS
        // masks its own corners).
        icons: [
          { src: 'favicon.svg', sizes: 'any', type: 'image/svg+xml', purpose: 'any' },
          { src: 'icon-maskable.svg', sizes: 'any', type: 'image/svg+xml', purpose: 'maskable' },
          { src: 'icon-mono.svg', sizes: 'any', type: 'image/svg+xml', purpose: 'monochrome' },
          { src: 'apple-touch-icon.png', sizes: '180x180', type: 'image/png', purpose: 'any' },
        ],
      },
      workbox: {
        // Client-side navigations under /app/ fall back to the app shell when
        // offline; the SW's /app/ scope means / (the landing) is never matched.
        navigateFallback: '/app/index.html',
        // Precache the app, plus the font woff2 the offline-first UI and the
        // common chart path need:
        //  - the bare `latin` subset of every family (`*-latin-[0-9]*` — the
        //    weight digit excludes `latin-ext`), the common chart case;
        //  - every subset of the UI fonts (IBM Plex Sans + Mono) — these are
        //    capability: the chrome must render any script (incl. latin-ext,
        //    Cyrillic, Greek) offline. The Sans brace-list names the subsets so
        //    it matches the UI Sans but not `ibm-plex-sans-condensed-*`, a roster
        //    chart font that stays latin-only like the rest.
        // Every other subset (the roster's latin-ext and non-latin scripts) is
        // decoration with per-glyph fallback: left out of the precache and
        // runtime-cached on first use below, so the install stays small while the
        // roster still works offline once a script has been seen. (Default
        // globPatterns omit woff2 entirely — without this the first offline load
        // silently falls back to system fonts.)
        globPatterns: [
          '**/*.{js,css,html,ico,png,svg}',
          '**/*-latin-[0-9]*.woff2',
          '**/ibm-plex-sans-{latin,latin-ext,cyrillic,cyrillic-ext,greek,greek-ext,vietnamese}-*.woff2',
          '**/ibm-plex-mono-*.woff2',
        ],
        // Monaco and Vega vendor chunks exceed Workbox's 2 MiB default; raise the
        // ceiling so the whole app (offline is a core requirement) is precached.
        maximumFileSizeToCacheInBytes: 6 * 1024 * 1024,
        runtimeCaching: [
          {
            // Chart-roster non-latin font subsets: not precached, so fetch on
            // demand and keep them offline-after-first-use. Precached woff2
            // (latin + Plex) are served from the precache and never reach here.
            urlPattern: /\.woff2$/,
            handler: 'CacheFirst',
            options: {
              cacheName: 'chart-font-subsets',
              expiration: { maxEntries: 120, maxAgeSeconds: 60 * 60 * 24 * 365 },
              cacheableResponse: { statuses: [0, 200] },
            },
          },
        ],
      },
    }),
  ],
  // Vitest config (shares this file)
  test: {
    globals: true,
    environment: 'happy-dom',
    include: ['src/**/*.test.{ts,tsx}'],
  },
} as Parameters<typeof defineConfig>[0]);
