const runApiExtractor = (
  log: ToolingLog,
  folder: string,
  acceptChanges: boolean = false
): ExtractorResult => {
  const config = apiExtractorConfig(folder);
  const options = {
    // Indicates that API Extractor is running as part of a local build,
    // e.g. on developer's machine. For example, if the *.api.ts output file
    // has differences, it will be automatically overwritten for a
    // local build, whereas this should report an error for a production build.
    localBuild: acceptChanges,
    messageCallback: (message: ExtractorMessage) => {
      if (message.messageId === 'console-api-report-not-copied') {
        // ConsoleMessageId.ApiReportNotCopied
        log.warning(`You have changed the signature of the ${folder} Core API`);
        log.warning(
          'To accept these changes run `node scripts/check_core_api_changes.js --accept` and then:\n' +
            "\t 1. Commit the updated documentation and API review file '" +
            config.reportFilePath +
            "' \n" +
            "\t 2. Describe the change in your PR including whether it's a major, minor or patch"
        );
        message.handled = true;
      } else if (message.messageId === 'console-api-report-copied') {
        // ConsoleMessageId.ApiReportCopied
        log.warning(`You have changed the signature of the ${folder} Core API`);
        log.warning(
          "Please commit the updated API documentation and the review file in '" +
            config.reportFilePath
        );
        message.handled = true;
      } else if (message.messageId === 'console-api-report-unchanged') {
        // ConsoleMessageId.ApiReportUnchanged
        log.info(`Core ${folder} API: no changes detected ✔`);
        message.handled = true;
      }
    },
  };

  return Extractor.invoke(config, options);
};

export function runMain(
    tsConfig: string, entryPoint: string, dtsBundleOut?: string, apiReviewFolder?: string,
    acceptApiUpdates = false): 1|0 {
  const [parsedConfig, errors] = parseTsconfig(tsConfig);
  if (errors && errors.length) {
    console.error(format('', errors));

    return 1;
  }

  const pkgJson = path.resolve(path.dirname(entryPoint), 'package.json');
  if (!fs.existsSync(pkgJson)) {
    fs.writeFileSync(pkgJson, JSON.stringify({
      'name': 'GENERATED-BY-BAZEL',
      'version': '0.0.0',
      'description': 'This is a dummy package.json as API Extractor always requires one.',
    }));
  }

  // API extractor doesn't always support the version of TypeScript used in the repo
  // example: at the moment it is not compatable with 3.2
  // to use the internal TypeScript we shall not create a program but rather pass a parsed tsConfig.
  const parsedTsConfig = parsedConfig !.config as any;
  const compilerOptions = parsedTsConfig.compilerOptions;
  for (const [key, values] of Object.entries<string[]>(compilerOptions.paths)) {
    if (key === '*') {
      continue;
    }

    // we shall not pass ts files as this will need to be parsed, and for example rxjs,
    // cannot be compiled with our tsconfig, as ours is more strict
    // hence amend the paths to point always to the '.d.ts' files.
    compilerOptions.paths[key] = values.map(path => {
      const pathSuffix = /(\*|index)$/.test(path) ? '.d.ts' : '/index.d.ts';

      return path + pathSuffix;
    });
  }

  const extractorOptions: IExtractorOptions = {
    localBuild: acceptApiUpdates,
    customLogger: DEBUG ? undefined : {
      // don't log verbose messages when not in debug mode
      logVerbose: _message => {}
    }
  };

  const extractorConfig: IExtractorConfig = {
    compiler: {
      configType: 'tsconfig',
      overrideTsconfig: parsedTsConfig,
      rootFolder: path.resolve(path.dirname(tsConfig))
    },
    project: {
      entryPointSourceFile: path.resolve(entryPoint),
    },
    apiReviewFile: {
      enabled: !!apiReviewFolder,
      apiReviewFolder: apiReviewFolder && path.resolve(apiReviewFolder),
    },
    apiJsonFile: {
      enabled: false,
    },
    policies: {
      namespaceSupport: 'permissive',
    },
    validationRules: {
      missingReleaseTags: ExtractorValidationRulePolicy.allow,
    },
    dtsRollup: {
      enabled: !!dtsBundleOut,
      publishFolder: dtsBundleOut && path.resolve(path.dirname(dtsBundleOut)),
      mainDtsRollupPath: dtsBundleOut && path.basename(dtsBundleOut),
    },
    tsdocMetadata: {
      enabled: false,
    }
  };

  const extractor = new Extractor(extractorConfig, extractorOptions);
  const isSuccessful = extractor.processProject();

  // API extractor errors are emitted by it's logger.
  return isSuccessful ? 0 : 1;
}