import { exec } from 'child_process';
import findNearestFile from 'find-nearest-file';
import * as fs from 'fs';
import * as path from 'path';
import { promisify } from 'util';
import { exitCode } from '../../common';

const execAsync = promisify(exec);

/**
 * Regex to determine version of yarn installed in project: Classic, or Modern.
 * Required to correctly build yarn command to retrieve list of installed packages.
 */
const yarnClassicVersionRegex = /^1\..*$/gim;

/**
 * Regex for Mosaic libraries.
 */
const mosaicLibraryRegex =
  /(?<prefix>@axinom\/mosaic-)(?<library>[-A-Za-z0-9]+)/gim;

/**
 * Find all Mosaic packages used in project.
 * @returns list of installed packages.
 */
const findInstalledPackages = async (): Promise<string[]> => {
  let installedMosaicLibs: string[] = [];
  const yarnVersionResult = await execAsync('yarn -v');

  if (yarnVersionResult.stderr) {
    console.log(yarnVersionResult.stderr);
  }

  if (yarnVersionResult.stdout) {
    const packagesListCommand = yarnClassicVersionRegex.test(
      yarnVersionResult.stdout,
    )
      ? 'yarn list --pattern @axinom/mosaic-* --depth=0'
      : 'yarn info @axinom/mosaic-* --recursive --all --name-only';

    const packagesListResult = await execAsync(packagesListCommand);
    if (packagesListResult.stdout) {
      installedMosaicLibs = [
        ...new Set(packagesListResult.stdout.match(mosaicLibraryRegex) ?? []),
      ];
    }
    if (packagesListResult.stderr) {
      console.log(packagesListResult.stderr);
    }
  }
  return installedMosaicLibs;
};

/**
 * Provides path to '.mosaic' configuration file.
 * Path to file provided based on the location of `yarn.lock`.
 */
export const getExtensionConfigPath = (): string => {
  const yarnLockFilePath = findNearestFile('yarn.lock');
  if (yarnLockFilePath) {
    return path.resolve(path.dirname(yarnLockFilePath), '.mosaic');
  }
  return path.resolve('.mosaic');
};

/**
 * Creates `.mosaic` configuration file with list of libraries, that provide extension for Mosaic CLI.
 */
export const createExtensionConfig = async (): Promise<void> => {
  console.log(`Starting extension configuration generation!`);
  const installedMosaicLibs = await findInstalledPackages();
  const extensions: string[] = [];
  await Promise.all(
    installedMosaicLibs.map(async (lib: string) => {
      //filter libraries, that have cli extension
      try {
        const result = await import(lib);
        if (result.cliExtension) {
          extensions.push(lib);
        }
      } catch (error) {
        //mosaic libraries, that are always(?) failing to load:
        //all `@axinom/mosaic-*-workflows`, @axinom/mosaic-portal, @axinom/mosaic-ui, @axinom/mosaic-home, @axinom/mosaic-id-link
        //todo: extend regex to exclude libraries?
        console.log(error);
        process.exit(exitCode);
      }
    }),
  );
  console.log(`Modular CLI extensions: ${extensions}`);
  //save library names, that can be used in command line
  const configFilePath = getExtensionConfigPath();
  const config = `CLI_EXTENSIONS=${extensions.join(',')}`;
  fs.writeFileSync(configFilePath, config);
  console.log(`Success! Extensions configuration file path: ${configFilePath}`);
};