/**
 * Copyright (c) Microsoft Corporation. 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 path from 'path';
import { canAccessFile } from '../../utils/utils';

function darwin(channel: string): string[] | undefined {
  switch (channel) {
    case 'chrome': return ['/Applications/Google Chrome.app/Contents/MacOS/Google Chrome'];
    case 'chrome-beta': return ['/Applications/Google Chrome Beta.app/Contents/MacOS/Google Chrome Beta'];
    case 'chrome-dev': return ['/Applications/Google Chrome Dev.app/Contents/MacOS/Google Chrome Dev'];
    case 'chrome-canary': return ['/Applications/Google Chrome Canary.app/Contents/MacOS/Google Chrome Canary'];
    case 'msedge': return ['/Applications/Microsoft Edge.app/Contents/MacOS/Microsoft Edge'];
    case 'msedge-beta': return ['/Applications/Microsoft Edge Beta.app/Contents/MacOS/Microsoft Edge Beta'];
    case 'msedge-dev': return ['/Applications/Microsoft Edge Dev.app/Contents/MacOS/Microsoft Edge Dev'];
    case 'msedge-canary': return ['/Applications/Microsoft Edge Canary.app/Contents/MacOS/Microsoft Edge Canary'];
  }
}

function linux(channel: string): string[] | undefined {
  switch (channel) {
    case 'chrome': return ['/opt/google/chrome/chrome'];
    case 'chrome-beta': return ['/opt/google/chrome-beta/chrome'];
    case 'chrome-dev': return ['/opt/google/chrome-unstable/chrome'];
    case 'msedge-dev': return ['/opt/microsoft/msedge-dev/msedge'];
    case 'msedge-beta': return ['/opt/microsoft/msedge-beta/msedge'];
  }
}

function win32(channel: string): string[] | undefined {
  let suffix: string | undefined;
  switch (channel) {
    case 'chrome': suffix = `\\Google\\Chrome\\Application\\chrome.exe`; break;
    case 'chrome-beta': suffix = `\\Google\\Chrome Beta\\Application\\chrome.exe`; break;
    case 'chrome-dev': suffix = `\\Google\\Chrome Dev\\Application\\chrome.exe`; break;
    case 'chrome-canary': suffix = `\\Google\\Chrome SxS\\Application\\chrome.exe`; break;
    case 'msedge': suffix = `\\Microsoft\\Edge\\Application\\msedge.exe`; break;
    case 'msedge-beta': suffix = `\\Microsoft\\Edge Beta\\Application\\msedge.exe`; break;
    case 'msedge-dev': suffix = `\\Microsoft\\Edge Dev\\Application\\msedge.exe`; break;
    case 'msedge-canary': suffix = `\\Microsoft\\Edge SxS\\Application\\msedge.exe`; break;
  }
  if (!suffix)
    return;
  const prefixes = [
    process.env.LOCALAPPDATA, process.env.PROGRAMFILES, process.env['PROGRAMFILES(X86)']
  ].filter(Boolean) as string[];
  return prefixes.map(prefix => path.join(prefix, suffix!));
}

export function findChromiumChannel(channel: string): string {
  let installationPaths: string[] | undefined;
  if (process.platform === 'linux')
    installationPaths = linux(channel);
  else if (process.platform === 'win32')
    installationPaths = win32(channel);
  else if (process.platform === 'darwin')
    installationPaths = darwin(channel);

  if (!installationPaths)
    throw new Error(`Chromium distribution '${channel}' is not supported on ${process.platform}`);

  let result: string | undefined;
  installationPaths.forEach(chromePath => {
    if (canAccessFile(chromePath))
      result = chromePath;
  });
  if (result)
    return result;
  throw new Error(`Chromium distribution is not installed on the system: ${channel}`);
}