/**
 * 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 { helper, assert, debugError } from './helper';
import { ExecutionContext } from './ExecutionContext';
import { Page } from './Page';
import { CDPSession } from './Connection';
import { KeyInput } from './USKeyboardLayout';
import { FrameManager, Frame } from './FrameManager';
import { getQueryHandlerAndSelector } from './QueryHandler';

interface BoxModel {
  content: Array<{ x: number; y: number }>;
  padding: Array<{ x: number; y: number }>;
  border: Array<{ x: number; y: number }>;
  margin: Array<{ x: number; y: number }>;
  width: number;
  height: number;
}

export function createJSHandle(
  context: ExecutionContext,
  remoteObject: Protocol.Runtime.RemoteObject
): JSHandle {
  const frame = context.frame();
  if (remoteObject.subtype === 'node' && frame) {
    const frameManager = frame._frameManager;
    return new ElementHandle(
      context,
      context._client,
      remoteObject,
      frameManager.page(),
      frameManager
    );
  }
  return new JSHandle(context, context._client, remoteObject);
}

export class JSHandle {
  _context: ExecutionContext;
  _client: CDPSession;
  _remoteObject: Protocol.Runtime.RemoteObject;
  _disposed = false;

  constructor(
    context: ExecutionContext,
    client: CDPSession,
    remoteObject: Protocol.Runtime.RemoteObject
  ) {
    this._context = context;
    this._client = client;
    this._remoteObject = remoteObject;
  }

  executionContext(): ExecutionContext {
    return this._context;
  }

  async evaluate<ReturnType extends any>(
    pageFunction: Function | string,
    ...args: unknown[]
  ): Promise<ReturnType> {
    return await this.executionContext().evaluate<ReturnType>(
      pageFunction,
      this,
      ...args
    );
  }

  async evaluateHandle(
    pageFunction: Function | string,
    ...args: unknown[]
  ): Promise<JSHandle> {
    return await this.executionContext().evaluateHandle(
      pageFunction,
      this,
      ...args
    );
  }

  async getProperty(propertyName: string): Promise<JSHandle | undefined> {
    const objectHandle = await this.evaluateHandle(
      (object: HTMLElement, propertyName: string) => {
        const result = { __proto__: null };
        result[propertyName] = object[propertyName];
        return result;
      },
      propertyName
    );
    const properties = await objectHandle.getProperties();
    const result = properties.get(propertyName) || null;
    await objectHandle.dispose();
    return result;
  }

  async getProperties(): Promise<Map<string, JSHandle>> {
    const response = await this._client.send('Runtime.getProperties', {
      objectId: this._remoteObject.objectId,
      ownProperties: true,
    });
    const result = new Map<string, JSHandle>();
    for (const property of response.result) {
      if (!property.enumerable) continue;
      result.set(property.name, createJSHandle(this._context, property.value));
    }
    return result;
  }

  async jsonValue(): Promise<{}> {
    if (this._remoteObject.objectId) {
      const response = await this._client.send('Runtime.callFunctionOn', {
        functionDeclaration: 'function() { return this; }',
        objectId: this._remoteObject.objectId,
        returnByValue: true,
        awaitPromise: true,
      });
      return helper.valueFromRemoteObject(response.result);
    }
    return helper.valueFromRemoteObject(this._remoteObject);
  }

  /* This always returns null but children can define this and return an ElementHandle */
  asElement(): ElementHandle | null {
    return null;
  }

  async dispose(): Promise<void> {
    if (this._disposed) return;
    this._disposed = true;
    await helper.releaseObject(this._client, this._remoteObject);
  }

  toString(): string {
    if (this._remoteObject.objectId) {
      const type = this._remoteObject.subtype || this._remoteObject.type;
      return 'JSHandle@' + type;
    }
    return 'JSHandle:' + helper.valueFromRemoteObject(this._remoteObject);
  }
}

export class ElementHandle extends JSHandle {
  _page: Page;
  _frameManager: FrameManager;
  constructor(
    context: ExecutionContext,
    client: CDPSession,
    remoteObject: Protocol.Runtime.RemoteObject,
    page: Page,
    frameManager: FrameManager
  ) {
    super(context, client, remoteObject);
    this._client = client;
    this._remoteObject = remoteObject;
    this._page = page;
    this._frameManager = frameManager;
  }

  asElement(): ElementHandle | null {
    return this;
  }

  async contentFrame(): Promise<Frame | null> {
    const nodeInfo = await this._client.send('DOM.describeNode', {
      objectId: this._remoteObject.objectId,
    });
    if (typeof nodeInfo.node.frameId !== 'string') return null;
    return this._frameManager.frame(nodeInfo.node.frameId);
  }

  async _scrollIntoViewIfNeeded(): Promise<void> {
    const error = await this.evaluate<Promise<string | false>>(
      async (element: HTMLElement, pageJavascriptEnabled: boolean) => {
        if (!element.isConnected) return 'Node is detached from document';
        if (element.nodeType !== Node.ELEMENT_NODE)
          return 'Node is not of type HTMLElement';
        // force-scroll if page's javascript is disabled.
        if (!pageJavascriptEnabled) {
          element.scrollIntoView({
            block: 'center',
            inline: 'center',
            // Chrome still supports behavior: instant but it's not in the spec so TS shouts
            // We don't want to make this breaking change in Puppeteer yet so we'll ignore the line.
            // @ts-ignore
            behavior: 'instant',
          });
          return false;
        }
        const visibleRatio = await new Promise((resolve) => {
          const observer = new IntersectionObserver((entries) => {
            resolve(entries[0].intersectionRatio);
            observer.disconnect();
          });
          observer.observe(element);
        });
        if (visibleRatio !== 1.0) {
          element.scrollIntoView({
            block: 'center',
            inline: 'center',
            // Chrome still supports behavior: instant but it's not in the spec so TS shouts
            // We don't want to make this breaking change in Puppeteer yet so we'll ignore the line.
            // @ts-ignore
            behavior: 'instant',
          });
        }
        return false;
      },
      this._page._javascriptEnabled
    );

    if (error) throw new Error(error);
  }

  async _clickablePoint(): Promise<{ x: number; y: number }> {
    const [result, layoutMetrics] = await Promise.all([
      this._client
        .send('DOM.getContentQuads', {
          objectId: this._remoteObject.objectId,
        })
        .catch(debugError),
      this._client.send('Page.getLayoutMetrics'),
    ]);
    if (!result || !result.quads.length)
      throw new Error('Node is either not visible or not an HTMLElement');
    // Filter out quads that have too small area to click into.
    const { clientWidth, clientHeight } = layoutMetrics.layoutViewport;
    const quads = result.quads
      .map((quad) => this._fromProtocolQuad(quad))
      .map((quad) =>
        this._intersectQuadWithViewport(quad, clientWidth, clientHeight)
      )
      .filter((quad) => computeQuadArea(quad) > 1);
    if (!quads.length)
      throw new Error('Node is either not visible or not an HTMLElement');
    // Return the middle point of the first quad.
    const quad = quads[0];
    let x = 0;
    let y = 0;
    for (const point of quad) {
      x += point.x;
      y += point.y;
    }
    return {
      x: x / 4,
      y: y / 4,
    };
  }

  _getBoxModel(): Promise<void | Protocol.DOM.getBoxModelReturnValue> {
    return this._client
      .send('DOM.getBoxModel', {
        objectId: this._remoteObject.objectId,
      })
      .catch((error) => debugError(error));
  }

  _fromProtocolQuad(quad: number[]): Array<{ x: number; y: number }> {
    return [
      { x: quad[0], y: quad[1] },
      { x: quad[2], y: quad[3] },
      { x: quad[4], y: quad[5] },
      { x: quad[6], y: quad[7] },
    ];
  }

  _intersectQuadWithViewport(
    quad: Array<{ x: number; y: number }>,
    width: number,
    height: number
  ): Array<{ x: number; y: number }> {
    return quad.map((point) => ({
      x: Math.min(Math.max(point.x, 0), width),
      y: Math.min(Math.max(point.y, 0), height),
    }));
  }

  async hover(): Promise<void> {
    await this._scrollIntoViewIfNeeded();
    const { x, y } = await this._clickablePoint();
    await this._page.mouse.move(x, y);
  }

  async click(options: {
    delay?: number;
    button?: 'left' | 'right' | 'middle';
    clickCount?: number;
  }): Promise<void> {
    await this._scrollIntoViewIfNeeded();
    const { x, y } = await this._clickablePoint();
    await this._page.mouse.click(x, y, options);
  }

  async select(...values: string[]): Promise<string[]> {
    for (const value of values)
      assert(
        helper.isString(value),
        'Values must be strings. Found value "' +
          value +
          '" of type "' +
          typeof value +
          '"'
      );

    /* TODO(jacktfranklin@): once ExecutionContext is TypeScript, and
     * its evaluate function is properly typed with generics we can
     * return here and remove the typecasting
     */
    return this.evaluate((element: HTMLSelectElement, values: string[]) => {
      if (element.nodeName.toLowerCase() !== 'select')
        throw new Error('Element is not a <select> element.');

      const options = Array.from(element.options);
      element.value = undefined;
      for (const option of options) {
        option.selected = values.includes(option.value);
        if (option.selected && !element.multiple) break;
      }
      element.dispatchEvent(new Event('input', { bubbles: true }));
      element.dispatchEvent(new Event('change', { bubbles: true }));
      return options
        .filter((option) => option.selected)
        .map((option) => option.value);
    }, values);
  }

  async uploadFile(...filePaths: string[]): Promise<void> {
    const isMultiple = await this.evaluate<boolean>(
      (element: HTMLInputElement) => element.multiple
    );
    assert(
      filePaths.length <= 1 || isMultiple,
      'Multiple file uploads only work with <input type=file multiple>'
    );

    // This import is only needed for `uploadFile`, so keep it scoped here to avoid paying
    // the cost unnecessarily.
    // eslint-disable-next-line @typescript-eslint/no-var-requires
    const path = require('path');
    // eslint-disable-next-line @typescript-eslint/no-var-requires
    const fs = require('fs');
    // eslint-disable-next-line @typescript-eslint/no-var-requires
    const { promisify } = require('util');
    const access = promisify(fs.access);

    // Locate all files and confirm that they exist.
    const files = await Promise.all(
      filePaths.map(async (filePath) => {
        const resolvedPath: string = path.resolve(filePath);
        try {
          await access(resolvedPath, fs.constants.R_OK);
        } catch (error) {
          if (error.code === 'ENOENT')
            throw new Error(`${filePath} does not exist or is not readable`);
        }

        return resolvedPath;
      })
    );
    const { objectId } = this._remoteObject;
    const { node } = await this._client.send('DOM.describeNode', { objectId });
    const { backendNodeId } = node;

    // The zero-length array is a special case, it seems that DOM.setFileInputFiles does
    // not actually update the files in that case, so the solution is to eval the element
    // value to a new FileList directly.
    if (files.length === 0) {
      await this.evaluate((element: HTMLInputElement) => {
        element.files = new DataTransfer().files;

        // Dispatch events for this case because it should behave akin to a user action.
        element.dispatchEvent(new Event('input', { bubbles: true }));
        element.dispatchEvent(new Event('change', { bubbles: true }));
      });
    } else {
      await this._client.send('DOM.setFileInputFiles', {
        objectId,
        files,
        backendNodeId,
      });
    }
  }

  async tap(): Promise<void> {
    await this._scrollIntoViewIfNeeded();
    const { x, y } = await this._clickablePoint();
    await this._page.touchscreen.tap(x, y);
  }

  async focus(): Promise<void> {
    await this.evaluate((element) => element.focus());
  }

  async type(text: string, options?: { delay: number }): Promise<void> {
    await this.focus();
    await this._page.keyboard.type(text, options);
  }

  async press(
    key: KeyInput,
    options?: { delay?: number; text?: string }
  ): Promise<void> {
    await this.focus();
    await this._page.keyboard.press(key, options);
  }

  async boundingBox(): Promise<{
    x: number;
    y: number;
    width: number;
    height: number;
  }> {
    const result = await this._getBoxModel();

    if (!result) return null;

    const quad = result.model.border;
    const x = Math.min(quad[0], quad[2], quad[4], quad[6]);
    const y = Math.min(quad[1], quad[3], quad[5], quad[7]);
    const width = Math.max(quad[0], quad[2], quad[4], quad[6]) - x;
    const height = Math.max(quad[1], quad[3], quad[5], quad[7]) - y;

    return { x, y, width, height };
  }

  /**
   * @return {!Promise<?BoxModel>}
   */
  async boxModel(): Promise<BoxModel | null> {
    const result = await this._getBoxModel();

    if (!result) return null;

    const { content, padding, border, margin, width, height } = result.model;
    return {
      content: this._fromProtocolQuad(content),
      padding: this._fromProtocolQuad(padding),
      border: this._fromProtocolQuad(border),
      margin: this._fromProtocolQuad(margin),
      width,
      height,
    };
  }

  async screenshot(options = {}): Promise<string | Buffer> {
    let needsViewportReset = false;

    let boundingBox = await this.boundingBox();
    assert(boundingBox, 'Node is either not visible or not an HTMLElement');

    const viewport = this._page.viewport();

    if (
      viewport &&
      (boundingBox.width > viewport.width ||
        boundingBox.height > viewport.height)
    ) {
      const newViewport = {
        width: Math.max(viewport.width, Math.ceil(boundingBox.width)),
        height: Math.max(viewport.height, Math.ceil(boundingBox.height)),
      };
      await this._page.setViewport(Object.assign({}, viewport, newViewport));

      needsViewportReset = true;
    }

    await this._scrollIntoViewIfNeeded();

    boundingBox = await this.boundingBox();
    assert(boundingBox, 'Node is either not visible or not an HTMLElement');
    assert(boundingBox.width !== 0, 'Node has 0 width.');
    assert(boundingBox.height !== 0, 'Node has 0 height.');

    const {
      layoutViewport: { pageX, pageY },
    } = await this._client.send('Page.getLayoutMetrics');

    const clip = Object.assign({}, boundingBox);
    clip.x += pageX;
    clip.y += pageY;

    const imageData = await this._page.screenshot(
      Object.assign(
        {},
        {
          clip,
        },
        options
      )
    );

    if (needsViewportReset) await this._page.setViewport(viewport);

    return imageData;
  }

  async $(selector: string): Promise<ElementHandle | null> {
    const defaultHandler = (element: Element, selector: string) =>
      element.querySelector(selector);
    const { updatedSelector, queryHandler } = getQueryHandlerAndSelector(
      selector,
      defaultHandler
    );

    const handle = await this.evaluateHandle(queryHandler, updatedSelector);
    const element = handle.asElement();
    if (element) return element;
    await handle.dispose();
    return null;
  }

  async $$(selector: string): Promise<ElementHandle[]> {
    const defaultHandler = (element: Element, selector: string) =>
      element.querySelectorAll(selector);
    const { updatedSelector, queryHandler } = getQueryHandlerAndSelector(
      selector,
      defaultHandler
    );

    const arrayHandle = await this.evaluateHandle(
      queryHandler,
      updatedSelector
    );
    const properties = await arrayHandle.getProperties();
    await arrayHandle.dispose();
    const result = [];
    for (const property of properties.values()) {
      const elementHandle = property.asElement();
      if (elementHandle) result.push(elementHandle);
    }
    return result;
  }

  async $eval<ReturnType extends any>(
    selector: string,
    pageFunction: Function | string,
    ...args: unknown[]
  ): Promise<ReturnType> {
    const elementHandle = await this.$(selector);
    if (!elementHandle)
      throw new Error(
        `Error: failed to find element matching selector "${selector}"`
      );
    const result = await elementHandle.evaluate<ReturnType>(
      pageFunction,
      ...args
    );
    await elementHandle.dispose();
    return result;
  }

  async $$eval<ReturnType extends any>(
    selector: string,
    pageFunction: Function | string,
    ...args: unknown[]
  ): Promise<ReturnType> {
    const defaultHandler = (element: Element, selector: string) =>
      Array.from(element.querySelectorAll(selector));
    const { updatedSelector, queryHandler } = getQueryHandlerAndSelector(
      selector,
      defaultHandler
    );

    const arrayHandle = await this.evaluateHandle(
      queryHandler,
      updatedSelector
    );
    const result = await arrayHandle.evaluate<ReturnType>(
      pageFunction,
      ...args
    );
    await arrayHandle.dispose();
    return result;
  }

  async $x(expression: string): Promise<ElementHandle[]> {
    const arrayHandle = await this.evaluateHandle((element, expression) => {
      const document = element.ownerDocument || element;
      const iterator = document.evaluate(
        expression,
        element,
        null,
        XPathResult.ORDERED_NODE_ITERATOR_TYPE
      );
      const array = [];
      let item;
      while ((item = iterator.iterateNext())) array.push(item);
      return array;
    }, expression);
    const properties = await arrayHandle.getProperties();
    await arrayHandle.dispose();
    const result = [];
    for (const property of properties.values()) {
      const elementHandle = property.asElement();
      if (elementHandle) result.push(elementHandle);
    }
    return result;
  }

  async isIntersectingViewport(): Promise<boolean> {
    return await this.evaluate<Promise<boolean>>(async (element) => {
      const visibleRatio = await new Promise((resolve) => {
        const observer = new IntersectionObserver((entries) => {
          resolve(entries[0].intersectionRatio);
          observer.disconnect();
        });
        observer.observe(element);
      });
      return visibleRatio > 0;
    });
  }
}

function computeQuadArea(quad: Array<{ x: number; y: number }>): number {
  // Compute sum of all directed areas of adjacent triangles
  // https://en.wikipedia.org/wiki/Polygon#Simple_polygons
  let area = 0;
  for (let i = 0; i < quad.length; ++i) {
    const p1 = quad[i];
    const p2 = quad[(i + 1) % quad.length];
    area += (p1.x * p2.y - p2.x * p1.y) / 2;
  }
  return Math.abs(area);
}