/**

* Copyright 2020 The AMP HTML Authors. All Rights Reserved.

*

* Licensed under the Apache License, Version 2.0 (the "License");

* you may not use this file except in compliance with the License.

* You may obtain a copy of the License at

*

* http://www.apache.org/licenses/LICENSE-2.0

*

* Unless required by applicable law or agreed to in writing, software

* distributed under the License is distributed on an "AS-IS" BASIS,

* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

* See the License for the specific language governing permissions and

* limitations under the License.

*/

import { WorkerContext } from './worker';

import { WorkerDOMConfiguration } from './configuration';

import { registerPromise } from './commands/function';

import { FunctionCallToWorker, MessageType } from '../transfer/Messages';

import { TransferrableKeys } from '../transfer/TransferrableKeys';

import { TransferrableMutationType } from '../transfer/TransferrableMutation';

/**

* An ExportedWorker is returned by the upgradeElement API.

* For the most part, it delegates to the underlying Worker.

*

* It notably removes `postMessage` support and add `callFunction`.

*/

export class ExportedWorker {

workerContext_: WorkerContext;

config: WorkerDOMConfiguration;

constructor(workerContext: WorkerContext, config: WorkerDOMConfiguration) {

this.workerContext_ = workerContext;

this.config = config;

}

/**

* Calls a function in the worker and returns a promise with the result.

* @param functionIdentifer

* @param functionArguments

*/

callFunction(functionIdentifer: string, ...functionArguments: any[]): Promise<any> {

if (!this.config.executorsAllowed.includes(TransferrableMutationType.FUNCTION_CALL)) {

throw new Error(`[worker-dom]: Error calling ${functionIdentifer}. You must enable the FUNCTION_CALL executor within the config.`);

}

const { promise, index } = registerPromise();

const msg: FunctionCallToWorker = {

[TransferrableKeys.type]: MessageType.FUNCTION,

[TransferrableKeys.functionIdentifier]: functionIdentifer,

[TransferrableKeys.functionArguments]: JSON.stringify(functionArguments),

[TransferrableKeys.index]: index,

};

this.workerContext_.messageToWorker(msg);

return promise;

}

set onerror(handler: any) {

this.workerContext_.worker.onerror = handler;

}

terminate(): void {

this.workerContext_.worker.terminate();

}

}