/**
 * Copyright (c) Microsoft Corporation.
 *
 * 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 { BrowserContext } from '../server/browserContext';
import { Page } from '../server/page';
import * as network from '../server/network';
import { helper, RegisteredListener } from '../server/helper';
import { debugLogger } from '../utils/debugLogger';
import { Frame } from '../server/frames';
import { SnapshotData, frameSnapshotStreamer, kSnapshotBinding, kSnapshotStreamer } from './snapshotterInjected';
import { calculateSha1 } from '../utils/utils';
import { FrameSnapshot } from './traceTypes';

export type SnapshotterResource = {
  pageId: string,
  frameId: string,
  url: string,
  contentType: string,
  responseHeaders: { name: string, value: string }[],
  sha1: string,
};

export type SnapshotterBlob = {
  buffer: Buffer,
  sha1: string,
};

export interface SnapshotterDelegate {
  onBlob(blob: SnapshotterBlob): void;
  onResource(resource: SnapshotterResource): void;
  onFrameSnapshot(frame: Frame, snapshot: FrameSnapshot, snapshotId?: string): void;
  pageId(page: Page): string;
}

export class Snapshotter {
  private _context: BrowserContext;
  private _delegate: SnapshotterDelegate;
  private _eventListeners: RegisteredListener[];

  constructor(context: BrowserContext, delegate: SnapshotterDelegate) {
    this._context = context;
    this._delegate = delegate;
    this._eventListeners = [
      helper.addEventListener(this._context, BrowserContext.Events.Page, this._onPage.bind(this)),
    ];
    this._context.exposeBinding(kSnapshotBinding, false, (source, data: SnapshotData) => {
      const snapshot: FrameSnapshot = {
        html: data.html,
        viewport: data.viewport,
        resourceOverrides: [],
        url: data.url,
      };
      for (const { url, content } of data.resourceOverrides) {
        const buffer = Buffer.from(content);
        const sha1 = calculateSha1(buffer);
        this._delegate.onBlob({ sha1, buffer });
        snapshot.resourceOverrides.push({ url, sha1 });
      }
      this._delegate.onFrameSnapshot(source.frame, snapshot, data.snapshotId);
    });
    this._context._doAddInitScript('(' + frameSnapshotStreamer.toString() + ')()');
  }

  dispose() {
    helper.removeEventListeners(this._eventListeners);
  }

  async forceSnapshot(page: Page, snapshotId: string) {
    await Promise.all([
      page.frames().forEach(async frame => {
        try {
          const context = await frame._mainContext();
          await context.evaluateInternal(({ kSnapshotStreamer, snapshotId }) => {
            // Do not block action execution on the actual snapshot.
            Promise.resolve().then(() => (window as any)[kSnapshotStreamer].forceSnapshot(snapshotId));
            return undefined;
          }, { kSnapshotStreamer, snapshotId });
        } catch (e) {
        }
      })
    ]);
  }

  private _onPage(page: Page) {
    this._eventListeners.push(helper.addEventListener(page, Page.Events.Response, (response: network.Response) => {
      this._saveResource(page, response).catch(e => debugLogger.log('error', e));
    }));
    this._eventListeners.push(helper.addEventListener(page, Page.Events.FrameAttached, async (frame: Frame) => {
      try {
        const frameElement = await frame.frameElement();
        const parent = frame.parentFrame();
        if (!parent)
          return;
        const context = await parent._mainContext();
        await context.evaluateInternal(({ kSnapshotStreamer, frameElement, frameId }) => {
          (window as any)[kSnapshotStreamer].markIframe(frameElement, frameId);
        }, { kSnapshotStreamer, frameElement, frameId: frame._id });
        frameElement.dispose();
      } catch (e) {
        // Ignore
      }
    }));
  }

  private async _saveResource(page: Page, response: network.Response) {
    const isRedirect = response.status() >= 300 && response.status() <= 399;
    if (isRedirect)
      return;

    // Shortcut all redirects - we cannot intercept them properly.
    let original = response.request();
    while (original.redirectedFrom())
      original = original.redirectedFrom()!;
    const url = original.url();

    let contentType = '';
    for (const { name, value } of response.headers()) {
      if (name.toLowerCase() === 'content-type')
        contentType = value;
    }

    const body = await response.body().catch(e => debugLogger.log('error', e));
    const sha1 = body ? calculateSha1(body) : 'none';
    const resource: SnapshotterResource = {
      pageId: this._delegate.pageId(page),
      frameId: response.frame()._id,
      url,
      contentType,
      responseHeaders: response.headers(),
      sha1,
    };
    this._delegate.onResource(resource);
    if (body)
      this._delegate.onBlob({ sha1, buffer: body });
  }
}