import {spawn} from 'child_process';
import {readdir} from 'fs/promises';
import {tmpdir} from 'os';
import {join} from 'path';

import {D} from '@flecks/core';
import commandExists from 'command-exists';

const debug = D('@flecks/repl/commands');

export default (program, flecks) => {
  const commands = {};
  commands.repl = {
    options: [
      ['-r, --rlwrap', 'use rlwrap around socat'],
    ],
    description: 'connect to REPL',
    action: async (opts) => {
      const {
        rlwrap,
      } = opts;
      try {
        await commandExists('socat');
      }
      catch (error) {
        throw new Error('socat must be installed to use REPL');
      }
      if (rlwrap) {
        try {
          await commandExists('rlwrap');
        }
        catch (error) {
          throw new Error('rlwrap must be installed to use --rlwrap');
        }
      }
      const {id} = flecks.get('@flecks/core');
      const directory = join(tmpdir(), 'flecks', id, 'repl');
      const filenames = await readdir(directory);
      const sockets = filenames.filter(
        // eslint-disable-next-line no-useless-escape
        (filename) => filename.match(new RegExp(`${id}-.*\.sock$`)),
      );
      const socket = join(
        directory,
        sockets
          .sort((l, r) => (l > r ? -1 : 1))
          .shift(),
      );
      const spawnOptions = {
        stdio: 'inherit',
      };
      const [cmd, args] = (
        rlwrap
          ? ['rlwrap', ['-C', 'qmp', 'socat', 'STDIO', `UNIX:${socket}`]]
          : ['socat', ['-', `unix-client:${socket}`]]
      );
      debug('spawning:\n%s %s', cmd, args.join(' '));
      return spawn(cmd, args, spawnOptions);
    },
  };
  return commands;
};