/**
 * Copyright 2023 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 ProgressBar from 'progress';
import yargs from 'yargs';
import {hideBin} from 'yargs/helpers';

import {
  resolveBuildId,
  Browser,
  BrowserPlatform,
  ChromeReleaseChannel,
} from './browser-data/browser-data.js';
import {detectBrowserPlatform} from './detectPlatform.js';
import {fetch} from './fetch.js';
import {
  computeExecutablePath,
  computeSystemExecutablePath,
  launch,
} from './launcher.js';

type InstallArgs = {
  browser: {
    name: Browser;
    buildId: string;
  };
  path?: string;
  platform?: BrowserPlatform;
};

type LaunchArgs = {
  browser: {
    name: Browser;
    buildId: string;
  };
  path?: string;
  platform?: BrowserPlatform;
  detached: boolean;
  system: boolean;
};

export class CLI {
  #cachePath;

  constructor(cachePath = process.cwd()) {
    this.#cachePath = cachePath;
  }

  #defineBrowserParameter(yargs: yargs.Argv<unknown>): void {
    yargs.positional('browser', {
      description: 'The browser version',
      type: 'string',
      coerce: (opt): InstallArgs['browser'] => {
        return {
          name: this.#parseBrowser(opt),
          buildId: this.#parseBuildId(opt),
        };
      },
    });
  }

  #definePlatformParameter(yargs: yargs.Argv<unknown>): void {
    yargs.option('platform', {
      type: 'string',
      desc: 'Platform that the binary needs to be compatible with.',
      choices: Object.values(BrowserPlatform),
      defaultDescription: 'Auto-detected by default.',
    });
  }

  #definePathParameter(yargs: yargs.Argv<unknown>): void {
    yargs.option('path', {
      type: 'string',
      desc: 'Path to the root folder for the browser downloads and installation',
      default: process.cwd(),
    });
  }

  async run(argv: string[]): Promise<void> {
    await yargs(hideBin(argv))
      .command(
        'install <browser>',
        'Download and install the specified browser',
        yargs => {
          this.#defineBrowserParameter(yargs);
          this.#definePlatformParameter(yargs);
          this.#definePathParameter(yargs);
        },
        async argv => {
          const args = argv as unknown as InstallArgs;
          args.platform ??= detectBrowserPlatform();
          if (!args.platform) {
            throw new Error(`Could not resolve the current platform`);
          }
          args.browser.buildId = await resolveBuildId(
            args.browser.name,
            args.platform,
            args.browser.buildId
          );
          await fetch({
            browser: args.browser.name,
            buildId: args.browser.buildId,
            platform: args.platform,
            cacheDir: args.path ?? this.#cachePath,
            downloadProgressCallback: this.#makeProgressCallback(
              args.browser.name,
              args.browser.buildId
            ),
          });
          console.log(
            `${args.browser.name}@${
              args.browser.buildId
            } ${computeExecutablePath({
              browser: args.browser.name,
              buildId: args.browser.buildId,
              cacheDir: args.path ?? this.#cachePath,
              platform: args.platform,
            })}`
          );
        }
      )
      .command(
        'launch <browser>',
        'Launch the specified browser',
        yargs => {
          this.#defineBrowserParameter(yargs);
          this.#definePlatformParameter(yargs);
          this.#definePathParameter(yargs);
          yargs.option('detached', {
            type: 'boolean',
            desc: 'Detach the child process.',
            default: false,
          });
          yargs.option('system', {
            type: 'boolean',
            desc: 'Search for a browser installed on the system instead of the cache folder.',
            default: false,
          });
        },
        async argv => {
          const args = argv as unknown as LaunchArgs;
          const executablePath = args.system
            ? computeSystemExecutablePath({
                browser: args.browser.name,
                // TODO: throw an error if not a ChromeReleaseChannel is provided.
                channel: args.browser.buildId as ChromeReleaseChannel,
                platform: args.platform,
              })
            : computeExecutablePath({
                browser: args.browser.name,
                buildId: args.browser.buildId,
                cacheDir: args.path ?? this.#cachePath,
                platform: args.platform,
              });
          launch({
            executablePath,
            detached: args.detached,
          });
        }
      )
      .demandCommand(1)
      .help()
      .parse();
  }

  #parseBrowser(version: string): Browser {
    return version.split('@').shift() as Browser;
  }

  #parseBuildId(version: string): string {
    return version.split('@').pop() ?? 'latest';
  }

  #toMegabytes(bytes: number) {
    const mb = bytes / 1000 / 1000;
    return `${Math.round(mb * 10) / 10} MB`;
  }

  #makeProgressCallback(browser: Browser, buildId: string) {
    let progressBar: ProgressBar;
    let lastDownloadedBytes = 0;
    return (downloadedBytes: number, totalBytes: number) => {
      if (!progressBar) {
        progressBar = new ProgressBar(
          `Downloading ${browser} r${buildId} - ${this.#toMegabytes(
            totalBytes
          )} [:bar] :percent :etas `,
          {
            complete: '=',
            incomplete: ' ',
            width: 20,
            total: totalBytes,
          }
        );
      }
      const delta = downloadedBytes - lastDownloadedBytes;
      lastDownloadedBytes = downloadedBytes;
      progressBar.tick(delta);
    };
  }
}