import * as fs from "fs";
import { Mutant } from "../types";

export function writeMutatedCode(m: Mutant) {
  fs.writeFileSync(m.sourceFile, m.mutatedSourceCode);
}

export function restoreOriginalCode(m: Mutant) {
  fs.writeFileSync(m.sourceFile, m.originalSourceCode);
}

// TODO: we can optimize this in various ways, if it seems to be a bottleneck.
// Obviously it only really matters for in-process runners, but anecdotally a
// full cache flush seems to slow down those runners by 20-30%
export function clearRequireCache() {
  Object.keys(require.cache).forEach(k => delete require.cache[k]);
}

export function makeErrorSerializable(err?: Error) {
  if (err == null) {
    return undefined;
  }

  Object.defineProperties(err, {
    stack: {
      enumerable: true,
      configurable: true,
      writable: true,
      value: err.stack,
    },
    message: {
      enumerable: true,
      configurable: true,
      writable: true,
      value: err.message,
    },
  });

  return err;
}