import { lsType, setType } from "../structures/types.js";
import { pretty } from "./pretty.js";

// re-inventing the wheel:
export function deepEqual(a, b) {
  if (a === b) return true; // <- shallow equality and primitives
  if (typeof a !== 'object' || typeof b !== 'object' || a === null || b === null) {
    return false;
  }
  if (Array.isArray(a) && Array.isArray(b)) {
    if (a.length !== b.length) return false;
    for (let i = 0; i < a.length; i++) {
      if (!deepEqual(a[i], b[i])) return false;
    }
    return true;
  }
  if (a instanceof Set) {
    if (!(b instanceof Set)) {
      return false;
    }
    if (a.size !== b.size) {
      return false;
    }
    for (const entry of a) {
      if (!b.has(entry)) {
        return false;
      }
    }
    return true;
  }
  const keysA = Object.keys(a);
  const keysB = Object.keys(b);
  if (keysA.length !== keysB.length) return false;
  for (let key of keysA) {
    if (!keysB.includes(key) || !deepEqual(a[key], b[key])) {
      return false;
    }
  }
  return true;
}

// zip two arrays
export function zip(a, b) {
  return a.map((k, i) => [k, b[i]]);
}

export function capitalizeFirstLetter(val) {
  return String(val).charAt(0).toUpperCase() + String(val).slice(1);
}

const _mapRecursiveStructure = mapping => transform => root => {
  const found = mapping.get(root);
  if (found) {
    // already mapped
    // return existing result to prevent endless recursion
    return found;
  }
  // note the indirection (wrapped in lamda), this allows the user to recursively map the children (which may refer to the root) without yet having finished mapping the root.
  let memo;
  const result = () => {
    // memoization is necessary for correctness
    return memo || (memo = transform(root, _mapRecursiveStructure(mapping)(transform)));
  };
  mapping.set(root, result);
  return result;
};

export const mapRecursiveStructure = _mapRecursiveStructure(new Map());

const _transformType = mapping => transform => type => {
  const found = mapping.get(type);
  if (found) {
    return found;
  }
  const mapped = transform(type, _transformType(mapping)(transform));
  mapping.set(type, mapped);
  return mapped;
}

export const transformType = _transformType(new Map());

const __memo = () => {
  let memo;
  return fn => memo || (memo = fn());
}
export const memo = fn => {
  return __memo()(fn);
}

// let infiniteSet = mapRecursiveStructure((type, map) => {
//   const ps = [];
//   for (const p of type.params) {
//     ps.push(map(p()));
//   }
//   return setType(ps[0]);
// })(infiniteList)();
// console.log(infiniteSet);
// // while (true) {
// //   console.log(infiniteSet);
// //   infiniteSet = infiniteSet.params[0]();
// // }