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

const version = process.env.TEFTER_VERSION || 'dev';

// Emits sw.js at build time with the precache list of all emitted assets,
// versioned by a hash of the file names (which themselves carry content hashes).
function serviceWorker(): Plugin {
  return {
    name: 'tefter-sw',
    apply: 'build',
    generateBundle(_opts, bundle) {
      const assets = Object.keys(bundle)
        .filter((f) => !f.endsWith('.map'))
        .map((f) => '/' + f);
      assets.push('/', '/manifest.webmanifest', '/icon-192.png', '/icon-512.png');
      const hash = createHash('sha256').update(assets.join(',') + version).digest('hex').slice(0, 12);
      const sw = `// generated by vite.config.ts — do not edit
const CACHE = 'tefter-${'${'}HASH}';
const ASSETS = ${'${'}ASSETS};

self.addEventListener('install', (e) => {
  e.waitUntil(caches.open(CACHE).then((c) => c.addAll(ASSETS)).then(() => self.skipWaiting()));
});

self.addEventListener('activate', (e) => {
  e.waitUntil(
    caches.keys()
      .then((keys) => Promise.all(keys.filter((k) => k !== CACHE).map((k) => caches.delete(k))))
      .then(() => self.clients.claim())
  );
});

self.addEventListener('fetch', (e) => {
  const url = new URL(e.request.url);
  if (e.request.method !== 'GET' || url.origin !== location.origin) return;
  if (url.pathname.startsWith('/api/')) return; // network-only; sync engine handles offline
  e.respondWith(
    caches.match(url.pathname === '/' || url.pathname === '/index.html' ? '/' : e.request).then(
      (hit) => hit || fetch(e.request)
    )
  );
});
`
        .replace('${HASH}', hash)
        .replace('${ASSETS}', JSON.stringify(assets));
      this.emitFile({ type: 'asset', fileName: 'sw.js', source: sw });
    },
  };
}

export default defineConfig({
  plugins: [svelte(), serviceWorker()],
  define: {
    __TEFTER_VERSION__: JSON.stringify(version),
  },
  build: {
    target: 'es2020',
    sourcemap: false,
  },
  server: {
    proxy: {
      '/api': 'http://127.0.0.1:8420',
    },
  },
});