import fs from 'node:fs';
import path from 'node:path';
import type { PluginOption } from 'vite';
import { WebSocket } from 'ws';
import MessageInterpreter from '../interpreter';
import { BUILD_COMPLETE, LOCAL_RELOAD_SOCKET_URL } from '../constant';
import type { PluginConfig } from '../types';

const injectionsPath = path.resolve(__dirname, '..', '..', '..', 'build', 'injections');

const refreshCode = fs.readFileSync(path.resolve(injectionsPath, 'refresh.js'), 'utf-8');
const reloadCode = fs.readFileSync(path.resolve(injectionsPath, 'reload.js'), 'utf-8');

export function watchRebuildPlugin(config: PluginConfig): PluginOption {
  const { refresh, reload, id: _id, onStart } = config;
  const hmrCode = (refresh ? refreshCode : '') + (reload ? reloadCode : '');

  let ws: WebSocket | null = null;

  const id = _id ?? Math.random().toString(36);
  let reconnectTries = 0;

  function initializeWebSocket() {
    ws = new WebSocket(LOCAL_RELOAD_SOCKET_URL);

    ws.onopen = () => {
      console.log(`[HMR] Connected to dev-server at ${LOCAL_RELOAD_SOCKET_URL}`);
    };

    ws.onerror = () => {
      console.error(`[HMR] Failed to connect server at ${LOCAL_RELOAD_SOCKET_URL}`);
      console.warn('Retrying in 3 seconds...');
      ws = null;

      if (reconnectTries <= 2) {
        setTimeout(() => {
          reconnectTries++;
          initializeWebSocket();
        }, 3_000);
      } else {
        console.error(`[HMR] Cannot establish connection to server at ${LOCAL_RELOAD_SOCKET_URL}`);
      }
    };
  }

  return {
    name: 'watch-rebuild',
    writeBundle() {
      onStart?.();
      if (!ws) {
        initializeWebSocket();
        return;
      }
      /**
       * When the build is complete, send a message to the reload server.
       * The reload server will send a message to the client to reload or refresh the extension.
       */
      ws.send(MessageInterpreter.send({ type: BUILD_COMPLETE, id }));
    },
    generateBundle(_options, bundle) {
      for (const module of Object.values(bundle)) {
        if (module.type === 'chunk') {
          module.code = `(function() {let __HMR_ID = "${id}";\n` + hmrCode + '\n' + '})();' + '\n' + module.code;
        }
      }
    },
  };
}