/**
 * Copyright 2018 Google Inc. 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.
 */
const EventEmitter = require('events');
const {debugError} = require('./helper');
const {ExecutionContext} = require('./ExecutionContext');
const {JSHandle} = require('./JSHandle');

class Worker extends EventEmitter {
  /**
   * @param {Puppeteer.CDPSession} client
   * @param {string} url
   * @param {function(string, !Array<!JSHandle>, Protocol.Runtime.StackTrace=):void} consoleAPICalled
   * @param {function(!Protocol.Runtime.ExceptionDetails):void} exceptionThrown
   */
  constructor(client, url, consoleAPICalled, exceptionThrown) {
    super();
    this._client = client;
    this._url = url;
    this._executionContextPromise = new Promise(x => this._executionContextCallback = x);
    /** @type {function(!Protocol.Runtime.RemoteObject):!JSHandle} */
    let jsHandleFactory;
    this._client.once('Runtime.executionContextCreated', /* async */ event => {return (fn => {
  const gen = fn.call(this);
  return new Promise((resolve, reject) => {
    function step(key, arg) {
      let info, value;
      try {
        info = gen[key](arg);
        value = info.value;
      } catch (error) {
        reject(error);
        return;
      }
      if (info.done) {
        resolve(value);
      } else {
        return Promise.resolve(value).then(
            value => {
              step('next', value);
            },
            err => {
              step('throw', err);
            });
      }
    }
    return step('next');
  });
})(function*(){
      jsHandleFactory = remoteObject => new JSHandle(executionContext, client, remoteObject);
      const executionContext = new ExecutionContext(client, event.context, null);
      this._executionContextCallback(executionContext);
    });});
    // This might fail if the target is closed before we recieve all execution contexts.
    this._client.send('Runtime.enable', {}).catch(debugError);

    this._client.on('Runtime.consoleAPICalled', event => consoleAPICalled(event.type, event.args.map(jsHandleFactory), event.stackTrace));
    this._client.on('Runtime.exceptionThrown', exception => exceptionThrown(exception.exceptionDetails));
  }

  /**
   * @return {string}
   */
  url() {
    return this._url;
  }

  /**
   * @return {!Promise<ExecutionContext>}
   */
  /* async */ executionContext() {return (fn => {
  const gen = fn.call(this);
  return new Promise((resolve, reject) => {
    function step(key, arg) {
      let info, value;
      try {
        info = gen[key](arg);
        value = info.value;
      } catch (error) {
        reject(error);
        return;
      }
      if (info.done) {
        resolve(value);
      } else {
        return Promise.resolve(value).then(
            value => {
              step('next', value);
            },
            err => {
              step('throw', err);
            });
      }
    }
    return step('next');
  });
})(function*(){
    return this._executionContextPromise;
  });}

  /**
   * @param {Function|string} pageFunction
   * @param {!Array<*>} args
   * @return {!Promise<*>}
   */
  /* async */ evaluate(pageFunction, ...args) {return (fn => {
  const gen = fn.call(this);
  return new Promise((resolve, reject) => {
    function step(key, arg) {
      let info, value;
      try {
        info = gen[key](arg);
        value = info.value;
      } catch (error) {
        reject(error);
        return;
      }
      if (info.done) {
        resolve(value);
      } else {
        return Promise.resolve(value).then(
            value => {
              step('next', value);
            },
            err => {
              step('throw', err);
            });
      }
    }
    return step('next');
  });
})(function*(){
    return ((yield this._executionContextPromise)).evaluate(pageFunction, ...args);
  });}

  /**
   * @param {Function|string} pageFunction
   * @param {!Array<*>} args
   * @return {!Promise<!JSHandle>}
   */
  /* async */ evaluateHandle(pageFunction, ...args) {return (fn => {
  const gen = fn.call(this);
  return new Promise((resolve, reject) => {
    function step(key, arg) {
      let info, value;
      try {
        info = gen[key](arg);
        value = info.value;
      } catch (error) {
        reject(error);
        return;
      }
      if (info.done) {
        resolve(value);
      } else {
        return Promise.resolve(value).then(
            value => {
              step('next', value);
            },
            err => {
              step('throw', err);
            });
      }
    }
    return step('next');
  });
})(function*(){
    return ((yield this._executionContextPromise)).evaluateHandle(pageFunction, ...args);
  });}
}

module.exports = {Worker};