import { readFileSync } from 'node:fs'
import { fileURLToPath } from 'node:url'
import path from 'node:path'
import react from '@vitejs/plugin-react'
import { defineConfig, type Plugin } from 'vite'

const rootDir = path.dirname(fileURLToPath(import.meta.url))
const engineDir = path.resolve(rootDir, '../engine')
const versionPath = path.resolve(rootDir, 'version.json')

// Read once per config evaluation — a dev-server restart (see restartOnVersionJsonChange below)
// re-imports this whole file, so a version bump is picked up by simply restarting, without any
// extra caching/invalidation logic here.
const version = JSON.parse(readFileSync(versionPath, 'utf-8')) as string;

// version.json isn't part of the app's module graph (nothing imports it as JS), so editing it
// doesn't trigger HMR or Vite's own config-file-triggered restart — only vite.config.ts itself is
// watched for that. This plugin explicitly watches version.json too and forces a full restart on
// change, so __APP_VERSION__ (set from `version` below) picks up a version bump without having to
// stop/start `npm run dev` by hand.
function restartOnVersionJsonChange(): Plugin {
  return {
    name: 'restart-on-version-json-change',
    configureServer(server) {
      server.watcher.add(versionPath)
      server.watcher.on('change', (file) => {
        if (path.normalize(file) === path.normalize(versionPath)) {
          server.config.logger.info('version.json changed, restarting to pick up __APP_VERSION__...', { clear: false })
          server.restart()
        }
      })
    },
  }
}

// https://vite.dev/config/
export default defineConfig({
  plugins: [react(), restartOnVersionJsonChange()],
  define: {
    __APP_VERSION__: JSON.stringify(version),
  },
  resolve: {
    // Follow the node_modules symlink to the real sibling directory, so Vite's dev server
    // watches and transforms the actual engine source files (not a frozen pre-bundled copy).
    preserveSymlinks: false,
  },
  optimizeDeps: {
    // Treat @incgame/engine as first-party source, not a vendor dependency to pre-bundle once
    // and cache — otherwise edits to the engine package wouldn't trigger HMR until a full
    // dev-server restart.
    exclude: ['@incgame/engine'],
  },
  server: {
    host: '0.0.0.0',
    port: 8877,
    fs: {
      // The engine package lives outside this project's root (a sibling directory reached
      // through a node_modules symlink); allow Vite to serve/watch files from there too.
      allow: [rootDir, engineDir],
    },
  },
})