/**
 * Copyright 2017 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 fs = require('fs');
const path = require('path');
const PROJECT_ROOT = fs.existsSync(path.join(__dirname, '..', 'package.json')) ? path.join(__dirname, '..') : path.join(__dirname, '..', '..');

/**
 * @param {Map<string, boolean>} apiCoverage
 * @param {string} className
 * @param {!Object} classType
 */
function traceAPICoverage(apiCoverage, className, classType) {
  className = className.substring(0, 1).toLowerCase() + className.substring(1);
  for (const methodName of Reflect.ownKeys(classType.prototype)) {
    const method = Reflect.get(classType.prototype, methodName);
    if (methodName === 'constructor' || typeof methodName !== 'string' || methodName.startsWith('_') || typeof method !== 'function')
      continue;
    apiCoverage.set(`${className}.${methodName}`, false);
    Reflect.set(classType.prototype, methodName, function(...args) {
      apiCoverage.set(`${className}.${methodName}`, true);
      return method.call(this, ...args);
    });
  }

  if (classType.Events) {
    for (const event of Object.values(classType.Events))
      apiCoverage.set(`${className}.emit(${JSON.stringify(event)})`, false);
    const method = Reflect.get(classType.prototype, 'emit');
    Reflect.set(classType.prototype, 'emit', function(event, ...args) {
      if (this.listenerCount(event))
        apiCoverage.set(`${className}.emit(${JSON.stringify(event)})`, true);
      return method.call(this, event, ...args);
    });
  }
}

const utils = module.exports = {
  recordAPICoverage: function(testRunner, api, disabled) {
    const coverage = new Map();
    for (const [className, classType] of Object.entries(api))
      traceAPICoverage(coverage, className, classType);
    testRunner.describe('COVERAGE', () => {
      for (const method of coverage.keys()) {
        (disabled.has(method) ? testRunner.xit : testRunner.it)(`public api '${method}' should be called`, async({page, server}) => {
          if (!coverage.get(method))
            throw new Error('NOT CALLED!');
        });
      }
    });
  },

  /**
   * @return {string}
   */
  projectRoot: function() {
    return PROJECT_ROOT;
  },

  /**
   * @return {*}
   */
  requireRoot: function(name) {
    return require(path.join(PROJECT_ROOT, name));
  },

  /**
   * @param {!Page} page
   * @param {string} frameId
   * @param {string} url
   * @return {!Puppeteer.Frame}
   */
  attachFrame: async function(page, frameId, url) {
    const handle = await page.evaluateHandle(attachFrame, frameId, url);
    return await handle.asElement().contentFrame();

    async function attachFrame(frameId, url) {
      const frame = document.createElement('iframe');
      frame.src = url;
      frame.id = frameId;
      document.body.appendChild(frame);
      await new Promise(x => frame.onload = x);
      return frame;
    }
  },

  /**
   * @param {!Page} page
   * @param {string} frameId
   */
  detachFrame: async function(page, frameId) {
    await page.evaluate(detachFrame, frameId);

    function detachFrame(frameId) {
      const frame = document.getElementById(frameId);
      frame.remove();
    }
  },

  /**
   * @param {!Page} page
   * @param {string} frameId
   * @param {string} url
   */
  navigateFrame: async function(page, frameId, url) {
    await page.evaluate(navigateFrame, frameId, url);

    function navigateFrame(frameId, url) {
      const frame = document.getElementById(frameId);
      frame.src = url;
      return new Promise(x => frame.onload = x);
    }
  },

  /**
   * @param {!Frame} frame
   * @param {string=} indentation
   * @return {string}
   */
  dumpFrames: function(frame, indentation) {
    indentation = indentation || '';
    let result = indentation + frame.url().replace(/:\d{4}\//, ':<PORT>/');
    for (const child of frame.childFrames())
      result += '\n' + utils.dumpFrames(child, '    ' + indentation);
    return result;
  },

  /**
   * @param {!EventEmitter} emitter
   * @param {string} eventName
   * @return {!Promise<!Object>}
   */
  waitEvent: function(emitter, eventName, predicate = () => true) {
    return new Promise(fulfill => {
      emitter.on(eventName, function listener(event) {
        if (!predicate(event))
          return;
        emitter.removeListener(eventName, listener);
        fulfill(event);
      });
    });
  },
};