import * as fs from 'fs-extra';
import * as path from 'path';

import { IEnvironment } from '../types/environment';

const dirs: {[key: string]: string} = {
  configurationPath: 'configs',
  pluginsPath: 'plugins',
  repositoryPath: 'repos',
};

/**
 * Load a Squeebot environment from a file
 * @param enviroFile Environment JSON file
 * @param chroot Change bot root to this instead of the path in the environment
 * @returns Squeebot environment
 */
export async function loadEnvironment(enviroFile = 'squeebot.env.json', chroot?: string): Promise<IEnvironment> {
  if (!await fs.pathExists(enviroFile)) {
    throw new Error('Environment file does not exist.');
  }

  const env = await fs.readJson(enviroFile);
  if (!env.path && !chroot) {
    throw new Error('Root path is unspecified.');
  }

  let root = env.path;
  if (chroot) {
    root = chroot;
    env.path = chroot;
  }

  if (!await fs.pathExists(root)) {
    throw new Error('Root path does not exist.');
  }

  // Ensure necessary directories exist
  for (const opt in dirs) {
    if (!env[opt]) {
      env[opt] = dirs[opt];
    }
    env[opt] = path.resolve(root, dirs[opt]);
    await fs.ensureDir(env[opt]);
  }

  return env;
}