import path from 'path';
import fs from 'fs-extra';
import { normalizeOutputPath } from './path';

const memo = <T extends (...args: any[]) => any>(fn: T) => {
  const cache = new Map();

  return (...params: Parameters<T>): ReturnType<T> => {
    const stringifiedParams = JSON.stringify(params);
    const cachedResult = cache.get(stringifiedParams);

    if (cachedResult) {
      return cachedResult;
    }

    const res = fn(...params);
    cache.set(stringifiedParams, res);

    return res;
  };
};

export const createRuntimeExportsUtils = memo((pwd = '', namespace: string) => {
  const entryExportFile = path.join(
    pwd,
    `.runtime-exports/${namespace ? `${namespace}.js` : 'index.js'}`,
  );

  // const ensure = () => {
  //   if (!fs.existsSync(entryExportFile)) {
  //     fs.outputFileSync(entryExportFile, '');
  //   }
  //   fs.ensureFileSync(entryExportFile);
  // };

  const addExport = (statement: string) => {
    // eslint-disable-next-line no-param-reassign
    statement = normalizeOutputPath(statement);
    try {
      fs.ensureFileSync(entryExportFile);
      if (!fs.readFileSync(entryExportFile, 'utf8').includes(statement)) {
        fs.appendFileSync(entryExportFile, `${statement}\n`);
      }
    } catch {
      // FIXME:
    }
  };

  const getPath = () => entryExportFile;

  return {
    addExport,
    getPath,
  };
});