import {defineConfig} from 'vite';
import {readdirSync, statSync} from 'node:fs';
import {join, relative} from 'node:path';
import {createHash} from 'node:crypto';

const listFiles = dir => readdirSync(dir).flatMap(name => {
    const path = join(dir, name);
    return statSync(path).isDirectory() ? listFiles(path) : [path];
});

// Emits sw.js listing every built file, so the installed game works offline. The cache name is a
// hash of that list: a new build gets a new cache and the page offers to reload into it.
// Satellite tiles (16 MB) are not precached; they are kept as the player passes them.
function offlineServiceWorker() {
    return {
        name: 'offline-service-worker',
        apply: 'build',
        generateBundle(_, bundle) {
            const files = [...Object.keys(bundle), ...listFiles('public').map(f => relative('public', f).replaceAll('\\', '/'))]
                .filter(f => f !== 'sw.js' && !f.endsWith('.map') && !(f.startsWith('imagery/') && f.endsWith('.jpg')));
            const version = createHash('sha1').update(files.join('\n')).digest('hex').slice(0, 12);
            this.emitFile({
                type: 'asset', fileName: 'sw.js', source: `// Generated by vite.config.js — do not edit.
const CACHE = 'robot-market-${version}';
const TILES = 'robot-market-imagery';
const FILES = ${JSON.stringify(['./', ...files.map(f => `./${f}`)])};
self.addEventListener('install', event => event.waitUntil(caches.open(CACHE).then(cache => cache.addAll(FILES))));
self.addEventListener('activate', event => event.waitUntil(caches.keys().then(keys =>
    Promise.all(keys.filter(k => k.startsWith('robot-market-') && k !== CACHE && k !== TILES).map(k => caches.delete(k)))).then(() => self.clients.claim())));
self.addEventListener('message', event => event.data === 'skip-waiting' && self.skipWaiting());
self.addEventListener('fetch', event => {
    const request = event.request;
    if (request.method !== 'GET' || new URL(request.url).origin !== location.origin) return;
    // Pages: network first so updates arrive, cached page when offline. Everything else: cache first.
    if (request.mode === 'navigate') {
        event.respondWith(fetch(request).catch(() => caches.match('./')));
        return;
    }
    // Satellite tiles: cache first, and keep each one fetched so visited areas work offline.
    if (new URL(request.url).pathname.includes('/imagery/')) {
        event.respondWith(caches.open(TILES).then(cache => cache.match(request).then(hit => hit ?? fetch(request).then(response => {
            if (response.ok) cache.put(request, response.clone());
            return response;
        }))));
        return;
    }
    event.respondWith(caches.match(request, {ignoreSearch: true}).then(hit => hit ?? fetch(request)));
});
`
            });
        }
    };
}

export default defineConfig({
    // Relative assets also load under a GitHub Pages repository path.
    base: './',
    plugins: [offlineServiceWorker()],
    // Top-level await loads the building and imagery files before the world is built.
    build: {target: 'es2022'},
    server: {
        host: true,
        allowedHosts: [
            'robotmarkets.ir',
            'www.robotmarkets.ir',
        ],
    },
});