import { unit } from "../primitives/unit.js";
import { capitalizeFirstLetter } from "../util/util.js";
import { newProduct, getLeft, getRight } from "./product.js";

export const makeConstructor = nParams => {
  const internal = (nParams, ret) => {
    if (nParams === 0) {
      const result = ret(unit);
      return result;
    }
    return nextParam => {
      const wrappedName = 'wrapped_' + ret.name;
      const newRet = {
        [wrappedName]: inner => newProduct(nextParam)(ret(inner)),
      }[wrappedName];
      return internal(nParams-1, newRet);
    }
  };
  const id = x => x;
  return internal(nParams, id);
};

export const makeGetters = fieldNames => {
  if (fieldNames.length === 0) {
    return [];
  }
  const [fieldName, ...rest] = fieldNames;
  const getterName = `get${capitalizeFirstLetter(fieldName)}`;
  return [
    { [getterName]: obj => getLeft(obj) }[getterName],
    ...makeGetters(rest).map(getter => ({[getter.name]: obj => getter(getRight(obj))}[getter.name])),
  ];
};