/**
 * Copyright 2019 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.
 */

import * as fs from 'fs';
import {helper, assert} from './helper';
import {LifecycleWatcher, PuppeteerLifeCycleEvent} from './LifecycleWatcher';
import {TimeoutError} from './Errors';
import {JSHandle, ElementHandle} from './JSHandle';
import {ExecutionContext} from './ExecutionContext';
import {TimeoutSettings} from './TimeoutSettings';
import {MouseButtonInput} from './Input';
import {FrameManager, Frame} from './FrameManager';

const readFileAsync = helper.promisify(fs.readFile);

export interface WaitForSelectorOptions {
  visible?: boolean;
  hidden?: boolean;
  timeout?: number;
}

export class DOMWorld {
  _frameManager: FrameManager;
  _frame: Frame;
  _timeoutSettings: TimeoutSettings;
  _documentPromise?: Promise<ElementHandle> = null;
  _contextPromise?: Promise<ExecutionContext> = null;

  _contextResolveCallback?: (x?: ExecutionContext) => void = null;

  _detached = false;
  _waitTasks = new Set<WaitTask>();

  constructor(frameManager: FrameManager, frame: Frame, timeoutSettings: TimeoutSettings) {
    this._frameManager = frameManager;
    this._frame = frame;
    this._timeoutSettings = timeoutSettings;
    this._setContext(null);
  }

  frame(): Frame {
    return this._frame;
  }

  /**
   * @param {?ExecutionContext} context
   */
  _setContext(context?: ExecutionContext): void {
    if (context) {
      this._contextResolveCallback.call(null, context);
      this._contextResolveCallback = null;
      for (const waitTask of this._waitTasks)
        waitTask.rerun();
    } else {
      this._documentPromise = null;
      this._contextPromise = new Promise(fulfill => {
        this._contextResolveCallback = fulfill;
      });
    }
  }

  _hasContext(): boolean {
    return !this._contextResolveCallback;
  }

  _detach(): void {
    this._detached = true;
    for (const waitTask of this._waitTasks)
      waitTask.terminate(new Error('waitForFunction failed: frame got detached.'));
  }

  /**
   * @return {!Promise<!ExecutionContext>}
   */
  executionContext(): Promise<ExecutionContext> {
    if (this._detached)
      throw new Error(`Execution Context is not available in detached frame "${this._frame.url()}" (are you trying to evaluate?)`);
    return this._contextPromise;
  }

  /**
   * @param {Function|string} pageFunction
   * @param {!Array<*>} args
   * @return {!Promise<!JSHandle>}
   */
  async evaluateHandle(pageFunction: Function | string, ...args: unknown[]): Promise<JSHandle> {
    const context = await this.executionContext();
    return context.evaluateHandle(pageFunction, ...args);
  }

  /**
   * @param {Function|string} pageFunction
   * @param {!Array<*>} args
   * @return {!Promise<*>}
   */
  async evaluate<ReturnType extends any>(pageFunction: Function | string, ...args: unknown[]): Promise<ReturnType> {
    const context = await this.executionContext();
    return context.evaluate<ReturnType>(pageFunction, ...args);
  }

  /**
   * @param {string} selector
   * @return {!Promise<?ElementHandle>}
   */
  async $(selector: string): Promise<ElementHandle | null> {
    const document = await this._document();
    const value = await document.$(selector);
    return value;
  }

  async _document(): Promise<ElementHandle> {
    if (this._documentPromise)
      return this._documentPromise;
    this._documentPromise = this.executionContext().then(async context => {
      const document = await context.evaluateHandle('document');
      return document.asElement();
    });
    return this._documentPromise;
  }

  async $x(expression: string): Promise<ElementHandle[]> {
    const document = await this._document();
    const value = await document.$x(expression);
    return value;
  }

  async $eval<ReturnType extends any>(selector: string, pageFunction: Function | string, ...args: unknown[]): Promise<ReturnType> {
    const document = await this._document();
    return document.$eval<ReturnType>(selector, pageFunction, ...args);
  }

  async $$eval<ReturnType extends any>(selector: string, pageFunction: Function | string, ...args: unknown[]): Promise<ReturnType> {
    const document = await this._document();
    const value = await document.$$eval<ReturnType>(selector, pageFunction, ...args);
    return value;
  }

  /**
   * @param {string} selector
   * @return {!Promise<!Array<!ElementHandle>>}
   */
  async $$(selector: string): Promise<ElementHandle[]> {
    const document = await this._document();
    const value = await document.$$(selector);
    return value;
  }

  async content(): Promise<string> {
    return await this.evaluate(() => {
      let retVal = '';
      if (document.doctype)
        retVal = new XMLSerializer().serializeToString(document.doctype);
      if (document.documentElement)
        retVal += document.documentElement.outerHTML;
      return retVal;
    });
  }

  async setContent(html: string, options: {timeout?: number; waitUntil?: PuppeteerLifeCycleEvent | PuppeteerLifeCycleEvent[]} = {}): Promise<void> {
    const {
      waitUntil = ['load'],
      timeout = this._timeoutSettings.navigationTimeout(),
    } = options;
    // We rely upon the fact that document.open() will reset frame lifecycle with "init"
    // lifecycle event. @see https://crrev.com/608658
    await this.evaluate(html => {
      document.open();
      document.write(html);
      document.close();
    }, html);
    const watcher = new LifecycleWatcher(this._frameManager, this._frame, waitUntil, timeout);
    const error = await Promise.race([
      watcher.timeoutOrTerminationPromise(),
      watcher.lifecyclePromise(),
    ]);
    watcher.dispose();
    if (error)
      throw error;
  }

  /**
   * @param {!{url?: string, path?: string, content?: string, type?: string}} options
   * @return {!Promise<!ElementHandle>}
   */
  async addScriptTag(options: {url?: string; path?: string; content?: string; type?: string}): Promise<ElementHandle> {
    const {
      url = null,
      path = null,
      content = null,
      type = ''
    } = options;
    if (url !== null) {
      try {
        const context = await this.executionContext();
        return (await context.evaluateHandle(addScriptUrl, url, type)).asElement();
      } catch (error) {
        throw new Error(`Loading script from ${url} failed`);
      }
    }

    if (path !== null) {
      let contents = await readFileAsync(path, 'utf8');
      contents += '//# sourceURL=' + path.replace(/\n/g, '');
      const context = await this.executionContext();
      return (await context.evaluateHandle(addScriptContent, contents, type)).asElement();
    }

    if (content !== null) {
      const context = await this.executionContext();
      return (await context.evaluateHandle(addScriptContent, content, type)).asElement();
    }

    throw new Error('Provide an object with a `url`, `path` or `content` property');

    async function addScriptUrl(url: string, type: string): Promise<HTMLElement> {
      const script = document.createElement('script');
      script.src = url;
      if (type)
        script.type = type;
      const promise = new Promise((res, rej) => {
        script.onload = res;
        script.onerror = rej;
      });
      document.head.appendChild(script);
      await promise;
      return script;
    }

    function addScriptContent(content: string, type = 'text/javascript'): HTMLElement {
      const script = document.createElement('script');
      script.type = type;
      script.text = content;
      let error = null;
      script.onerror = e => error = e;
      document.head.appendChild(script);
      if (error)
        throw error;
      return script;
    }
  }

  async addStyleTag(options: {url?: string; path?: string; content?: string}): Promise<ElementHandle> {
    const {
      url = null,
      path = null,
      content = null
    } = options;
    if (url !== null) {
      try {
        const context = await this.executionContext();
        return (await context.evaluateHandle(addStyleUrl, url)).asElement();
      } catch (error) {
        throw new Error(`Loading style from ${url} failed`);
      }
    }

    if (path !== null) {
      let contents = await readFileAsync(path, 'utf8');
      contents += '/*# sourceURL=' + path.replace(/\n/g, '') + '*/';
      const context = await this.executionContext();
      return (await context.evaluateHandle(addStyleContent, contents)).asElement();
    }

    if (content !== null) {
      const context = await this.executionContext();
      return (await context.evaluateHandle(addStyleContent, content)).asElement();
    }

    throw new Error('Provide an object with a `url`, `path` or `content` property');

    async function addStyleUrl(url: string): Promise<HTMLElement> {
      const link = document.createElement('link');
      link.rel = 'stylesheet';
      link.href = url;
      const promise = new Promise((res, rej) => {
        link.onload = res;
        link.onerror = rej;
      });
      document.head.appendChild(link);
      await promise;
      return link;
    }

    async function addStyleContent(content: string): Promise<HTMLElement> {
      const style = document.createElement('style');
      style.type = 'text/css';
      style.appendChild(document.createTextNode(content));
      const promise = new Promise((res, rej) => {
        style.onload = res;
        style.onerror = rej;
      });
      document.head.appendChild(style);
      await promise;
      return style;
    }
  }

  async click(selector: string, options: {delay?: number; button?: MouseButtonInput; clickCount?: number}): Promise<void> {
    const handle = await this.$(selector);
    assert(handle, 'No node found for selector: ' + selector);
    await handle.click(options);
    await handle.dispose();
  }

  async focus(selector: string): Promise<void> {
    const handle = await this.$(selector);
    assert(handle, 'No node found for selector: ' + selector);
    await handle.focus();
    await handle.dispose();
  }

  async hover(selector: string): Promise<void> {
    const handle = await this.$(selector);
    assert(handle, 'No node found for selector: ' + selector);
    await handle.hover();
    await handle.dispose();
  }

  async select(selector: string, ...values: string[]): Promise<string[]> {
    const handle = await this.$(selector);
    assert(handle, 'No node found for selector: ' + selector);
    const result = await handle.select(...values);
    await handle.dispose();
    return result;
  }

  async tap(selector: string): Promise<void> {
    const handle = await this.$(selector);
    assert(handle, 'No node found for selector: ' + selector);
    await handle.tap();
    await handle.dispose();
  }

  async type(selector: string, text: string, options?: {delay: number}): Promise<void> {
    const handle = await this.$(selector);
    assert(handle, 'No node found for selector: ' + selector);
    await handle.type(text, options);
    await handle.dispose();
  }

  waitForSelector(selector: string, options: WaitForSelectorOptions): Promise<ElementHandle | null> {
    return this._waitForSelectorOrXPath(selector, false, options);
  }

  waitForXPath(xpath: string, options: WaitForSelectorOptions): Promise<ElementHandle | null> {
    return this._waitForSelectorOrXPath(xpath, true, options);
  }

  waitForFunction(pageFunction: Function | string, options: {polling?: string | number; timeout?: number} = {}, ...args: unknown[]): Promise<JSHandle> {
    const {
      polling = 'raf',
      timeout = this._timeoutSettings.timeout(),
    } = options;
    return new WaitTask(this, pageFunction, 'function', polling, timeout, ...args).promise;
  }

  async title(): Promise<string> {
    return this.evaluate(() => document.title);
  }

  private async _waitForSelectorOrXPath(selectorOrXPath: string, isXPath: boolean, options: WaitForSelectorOptions = {}): Promise<ElementHandle | null> {
    const {
      visible: waitForVisible = false,
      hidden: waitForHidden = false,
      timeout = this._timeoutSettings.timeout(),
    } = options;
    const polling = waitForVisible || waitForHidden ? 'raf' : 'mutation';
    const title = `${isXPath ? 'XPath' : 'selector'} "${selectorOrXPath}"${waitForHidden ? ' to be hidden' : ''}`;
    const waitTask = new WaitTask(this, predicate, title, polling, timeout, selectorOrXPath, isXPath, waitForVisible, waitForHidden);
    const handle = await waitTask.promise;
    if (!handle.asElement()) {
      await handle.dispose();
      return null;
    }
    return handle.asElement();

    /**
     * @param {string} selectorOrXPath
     * @param {boolean} isXPath
     * @param {boolean} waitForVisible
     * @param {boolean} waitForHidden
     * @return {?Node|boolean}
     */
    function predicate(selectorOrXPath: string, isXPath: boolean, waitForVisible: boolean, waitForHidden: boolean): Node | null | boolean {
      const node = isXPath
        ? document.evaluate(selectorOrXPath, document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue
        : document.querySelector(selectorOrXPath);
      if (!node)
        return waitForHidden;
      if (!waitForVisible && !waitForHidden)
        return node;
      const element = (node.nodeType === Node.TEXT_NODE ? node.parentElement : node as Element);

      const style = window.getComputedStyle(element);
      const isVisible = style && style.visibility !== 'hidden' && hasVisibleBoundingBox();
      const success = (waitForVisible === isVisible || waitForHidden === !isVisible);
      return success ? node : null;

      function hasVisibleBoundingBox(): boolean {
        const rect = element.getBoundingClientRect();
        return !!(rect.top || rect.bottom || rect.width || rect.height);
      }
    }
  }
}

class WaitTask {
  _domWorld: DOMWorld;
  _polling: string | number;
  _timeout: number;
  _predicateBody: string;
  _args: unknown[];
  _runCount = 0;
  promise: Promise<JSHandle>;
  _resolve: (x: JSHandle) => void;
  _reject: (x: Error) => void;
  _timeoutTimer?: NodeJS.Timeout;
  _terminated = false;

  constructor(domWorld: DOMWorld, predicateBody: Function | string, title: string, polling: string | number, timeout: number, ...args: unknown[]) {
    if (helper.isString(polling))
      assert(polling === 'raf' || polling === 'mutation', 'Unknown polling option: ' + polling);
    else if (helper.isNumber(polling))
      assert(polling > 0, 'Cannot poll with non-positive interval: ' + polling);
    else
      throw new Error('Unknown polling options: ' + polling);

    this._domWorld = domWorld;
    this._polling = polling;
    this._timeout = timeout;
    this._predicateBody = helper.isString(predicateBody) ? 'return (' + predicateBody + ')' : 'return (' + predicateBody + ')(...args)';
    this._args = args;
    this._runCount = 0;
    domWorld._waitTasks.add(this);
    this.promise = new Promise<JSHandle>((resolve, reject) => {
      this._resolve = resolve;
      this._reject = reject;
    });
    // Since page navigation requires us to re-install the pageScript, we should track
    // timeout on our end.
    if (timeout) {
      const timeoutError = new TimeoutError(`waiting for ${title} failed: timeout ${timeout}ms exceeded`);
      this._timeoutTimer = setTimeout(() => this.terminate(timeoutError), timeout);
    }
    this.rerun();
  }

  terminate(error: Error): void {
    this._terminated = true;
    this._reject(error);
    this._cleanup();
  }

  async rerun(): Promise<void> {
    const runCount = ++this._runCount;
    /** @type {?JSHandle} */
    let success = null;
    let error = null;
    try {
      success = await (await this._domWorld.executionContext()).evaluateHandle(waitForPredicatePageFunction, this._predicateBody, this._polling, this._timeout, ...this._args);
    } catch (error_) {
      error = error_;
    }

    if (this._terminated || runCount !== this._runCount) {
      if (success)
        await success.dispose();
      return;
    }

    // Ignore timeouts in pageScript - we track timeouts ourselves.
    // If the frame's execution context has already changed, `frame.evaluate` will
    // throw an error - ignore this predicate run altogether.
    if (!error && await this._domWorld.evaluate(s => !s, success).catch(() => true)) {
      await success.dispose();
      return;
    }

    // When the page is navigated, the promise is rejected.
    // We will try again in the new execution context.
    if (error && error.message.includes('Execution context was destroyed'))
      return;

    // We could have tried to evaluate in a context which was already
    // destroyed.
    if (error && error.message.includes('Cannot find context with specified id'))
      return;

    if (error)
      this._reject(error);
    else
      this._resolve(success);

    this._cleanup();
  }

  _cleanup(): void {
    clearTimeout(this._timeoutTimer);
    this._domWorld._waitTasks.delete(this);
  }
}

async function waitForPredicatePageFunction(predicateBody: string, polling: string, timeout: number, ...args: unknown[]): Promise<unknown> {
  const predicate = new Function('...args', predicateBody);
  let timedOut = false;
  if (timeout)
    setTimeout(() => timedOut = true, timeout);
  if (polling === 'raf')
    return await pollRaf();
  if (polling === 'mutation')
    return await pollMutation();
  if (typeof polling === 'number')
    return await pollInterval(polling);

  /**
   * @return {!Promise<*>}
   */
  function pollMutation(): Promise<unknown> {
    const success = predicate(...args);
    if (success)
      return Promise.resolve(success);

    let fulfill;
    const result = new Promise(x => fulfill = x);
    const observer = new MutationObserver(() => {
      if (timedOut) {
        observer.disconnect();
        fulfill();
      }
      const success = predicate(...args);
      if (success) {
        observer.disconnect();
        fulfill(success);
      }
    });
    observer.observe(document, {
      childList: true,
      subtree: true,
      attributes: true
    });
    return result;
  }

  function pollRaf(): Promise<unknown> {
    let fulfill;
    const result = new Promise(x => fulfill = x);
    onRaf();
    return result;

    function onRaf(): void {
      if (timedOut) {
        fulfill();
        return;
      }
      const success = predicate(...args);
      if (success)
        fulfill(success);
      else
        requestAnimationFrame(onRaf);
    }
  }

  function pollInterval(pollInterval: number): Promise<unknown> {
    let fulfill;
    const result = new Promise(x => fulfill = x);
    onTimeout();
    return result;

    function onTimeout(): void {
      if (timedOut) {
        fulfill();
        return;
      }
      const success = predicate(...args);
      if (success)
        fulfill(success);
      else
        setTimeout(onTimeout, pollInterval);
    }
  }
}