CRBT-Team/Purplet

import path from 'path';
import { Logger } from '@paperdave/logger';
import { build } from 'esbuild';
import { readdir, readFile } from 'fs/promises';
import { resolveConfig } from './resolver';
import type { Config } from './types';
import { setValidatorBasePath } from './validators';
import { mkdirp } from '../utils/fs';

const searchPaths = ['purplet.config.ts', 'purplet.config.js'];

export async function loadConfig(root: string) {
  const files = await readdir(root);
  const matched = searchPaths.filter(file => files.includes(file));

  if (matched.length === 0) {
    throw new Error(
      `No configuration file found in your project. See https://purplet.js.org/docs/configuration`
    );
  }

  if (matched.length > 1) {
    throw new Error(
      `Multiple configuration files found in ${root}. Please remove one of them:\n` +
        matched.map(file => `  - ${file}`).join('\n')
    );
  }

  let configPath: string;

  if (matched[0].endsWith('.ts')) {
    const pkg = JSON.parse(await readFile(path.resolve(root, 'package.json'), 'utf8'));
    await build({
      entryPoints: [`${root}/${matched[0]}`],
      outfile: `${root}/.purplet/transpiled-config.js`,
      bundle: true,
      format: 'esm',
      logLevel: 'silent',
      external: [
        'purplet',
        ...Object.keys(pkg.dependencies ?? {}),
        ...Object.keys(pkg.devDependencies ?? {}),
        ...Object.keys(pkg.peerDependencies ?? {}),
        ...Object.keys(pkg.optionalDependencies ?? {}),
      ],
    });
    configPath = `file:///${root}/.purplet/transpiled-config.js`;
  } else {
    configPath = `file:///${root}/${matched[0]}`;
  }

  try {
    const config: Config = (await import(configPath)).default;

    setValidatorBasePath(root);

    const resolved = resolveConfig(root, config);
    await mkdirp(resolved.temp);

    return resolved;
  } catch (error) {
    Logger.error('Error while loading configuration.');
    throw error;
  }
}