/**
 * 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 * as fs from 'fs';
import * as path from 'path';
import * as playwright from '../../..';
import * as util from 'util';
import { ScreenshotGenerator } from './screenshotGenerator';
import { readTraceFile, TraceModel } from './traceModel';
import type { TraceEvent } from '../../trace/traceTypes';
import { SnapshotServer } from './snapshotServer';

const fsReadFileAsync = util.promisify(fs.readFile.bind(fs));

type TraceViewerDocument = {
  resourcesDir: string;
  model: TraceModel;
};

const emptyModel: TraceModel = {
  contexts: [
    {
      startTime: 0,
      endTime: 1,
      created: {
        timestamp: Date.now(),
        type: 'context-created',
        browserName: 'none',
        contextId: '<empty>',
        deviceScaleFactor: 1,
        isMobile: false,
        viewportSize: { width: 800, height: 600 },
      },
      destroyed: {
        timestamp: Date.now(),
        type: 'context-destroyed',
        contextId: '<empty>',
      },
      name: '<empty>',
      filePath: '',
      pages: [],
      resourcesByUrl: new Map()
    }
  ]
};

class TraceViewer {
  private _document: TraceViewerDocument | undefined;

  async load(traceDir: string) {
    const resourcesDir = path.join(traceDir, 'resources');
    const model = { contexts: [] };
    this._document = {
      model,
      resourcesDir,
    };

    for (const name of fs.readdirSync(traceDir)) {
      if (!name.endsWith('.trace'))
        continue;
      const filePath = path.join(traceDir, name);
      const traceContent = await fsReadFileAsync(filePath, 'utf8');
      const events = traceContent.split('\n').map(line => line.trim()).filter(line => !!line).map(line => JSON.parse(line)) as TraceEvent[];
      readTraceFile(events, model, filePath);
    }
  }

  async show() {
    const browser = await playwright.chromium.launch({ headless: false });
    const server = await SnapshotServer.create(
        path.join(__dirname, '..', '..', 'web'),
        this._document ? this._document.resourcesDir : undefined,
        this._document ? this._document.model : emptyModel,
        this._document ? new ScreenshotGenerator(this._document.resourcesDir, this._document.model) : undefined);
    const uiPage = await browser.newPage({ viewport: null });
    uiPage.on('close', () => process.exit(0));
    await uiPage.goto(server.traceViewerUrl('traceViewer/index.html'));
  }
}

export async function showTraceViewer(traceDir: string) {
  const traceViewer = new TraceViewer();
  if (traceDir)
    await traceViewer.load(traceDir);
  await traceViewer.show();
}