botserver/packages/core.gbapp/services/GBVMService.ts

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'use strict';

import { WaterfallDialog } from 'botbuilder-dialogs';
import { GBMinInstance, IGBCoreService } from 'botlib';
import * as fs from 'fs';
import DialogClass from './GBAPIService';
import { GBDeployer } from './GBDeployer';
import { TSCompiler } from './TSCompiler';
const util = require('util');
const logger = require('../../../src/logger');
const vm = require('vm');
const UrlJoin = require('url-join');
const vb2ts = require('vbscript-to-typescript/dist/converter');

/**
 * @fileoverview Virtualization services for emulation of BASIC.
 * This alpha version is using a converter to translate BASIC to TS
 * and string replacements to emulate await code.
 * http://stevehanov.ca/blog/index.php?id=92 should be used to run it without
 * translation and enhance classic BASIC experience.
 */

export class GBVMService implements IGBCoreService {
  private readonly script = new vm.Script();

  public async loadJS(
    filename: string,
    min: GBMinInstance,
    core: IGBCoreService,
    deployer: GBDeployer,
    localPath: string
  ): Promise<void> {
    const path = 'packages/default.gbdialog';
    const file = 'bot.vbs';
    const source = UrlJoin(path, file);

    // Example when handled through fs.watch() listener
    fs.watchFile(source, async (curr, prev) => {
      await this.run(source, path, min, deployer, filename);
    });
    await this.run(source, path, min, deployer, filename);
    this.addHearDialog(min);
  }

  public async run(source: any, path: string, min: any, deployer: GBDeployer, filename: string) {
    // Converts VBS into TS.

    vb2ts.convertFile(source);

    // Convert TS into JS.
    const tsfile = `bot.ts`;
    const tsc = new TSCompiler();
    tsc.compile([UrlJoin(path, tsfile)]);

    // Run JS into the GB context.
    const jsfile = `bot.js`;
    const localPath = UrlJoin(path, jsfile);

    if (fs.existsSync(localPath)) {
      let code: string = fs.readFileSync(localPath, 'utf8');
      code = code.replace(/^.*exports.*$/gm, '');

      // Finds all hear calls.

      let parsedCode = code;
      const hearExp = /(\w+).*hear.*\(\)/;

      let match1;

      while ((match1 = hearExp.exec(code))) {
        let pos = 0;

        // Writes async body.

        const variable = match1[1]; // variable = hear();

        parsedCode = code.substring(pos, pos + match1.index);
        parsedCode += `hear (async (${variable}) => {\n`;

        // Skips old construction and point to the async block.

        pos = pos + match1.index;
        let tempCode = code.substring(pos + match1[0].length + 1);
        const start = pos;

        // Balances code blocks and checks for exits.

        let right = 0;
        let left = 1;
        let match2;
        while ((match2 = /\{|\}/.exec(tempCode))) {
          const c = tempCode.substring(match2.index, match2.index + 1);

          if (c === '}') {
            right++;
          } else if (c === '{') {
            left++;
          }

          tempCode = tempCode.substring(match2.index + 1);
          pos += match2.index + 1;

          if (left === right) {
            break;
          }
        }

        parsedCode += code.substring(start + match1[0].length + 1, pos + match1[0].length);
        parsedCode += '});\n';
        parsedCode += code.substring(pos + match1[0].length);

        // A interaction will be made for each hear.

        code = parsedCode;
      }

      parsedCode = parsedCode.replace(/("[^"]*"|'[^']*')|\btalk\b/g, ($0, $1) => {
        return $1 == undefined ? 'this.talk' : $1;
      });

      parsedCode = parsedCode.replace(/("[^"]*"|'[^']*')|\bhear\b/g, ($0, $1) => {
        return $1 == undefined ? 'this.hear' : $1;
      });

      parsedCode = parsedCode.replace(/("[^"]*"|'[^']*')|\bsendEmail\b/g, ($0, $1) => {
        return $1 == undefined ? 'this.sendEmail' : $1;
      });

      parsedCode = parsedCode.replace(/this\./gm, 'await this.');
      parsedCode = parsedCode.replace(/function/gm, 'async function');

      fs.writeFileSync(localPath, parsedCode);

      const sandbox: DialogClass = new DialogClass(min);
      const context = vm.createContext(sandbox);
      vm.runInContext(parsedCode, context);
      min.sandbox = sandbox;
      await deployer.deployScriptToStorage(min.instanceId, filename);
      logger.info(`[GBVMService] Finished loading of ${filename}`);
    }
  }

  private addHearDialog(min) {
    min.dialogs.add(
      new WaterfallDialog('/hear', [
        async step => {
          step.activeDialog.state.cbId = step.options['id'];

          return await step.prompt('textPrompt', {});
        },
        async step => {
          min.sandbox.context = step.context;
          min.sandbox.step = step;

          const cbId = step.activeDialog.state.cbId;
          const cb = min.cbMap[cbId];
          cb.bind({ step: step, context: step.context }); // TODO: Necessary or min.sandbox?

          await step.endDialog();

          return await cb(step.result);
        }
      ])
    );
  }
}