/* eslint-disable @typescript-eslint/ban-ts-comment */
/* eslint-disable complexity */
'use strict';

/**
 * Deeply compares two values for equality.
 * Traverses objects, arrays, maps, sets, dates, and other types.
 *
 * @param a
 * @param b
 * @returns boolean
 */
export function deepEqual(a: unknown, b: unknown): boolean {
  if (a === b) return true;

  if (a && b && typeof a == 'object' && typeof b == 'object') {
    if (a.constructor !== b.constructor) return false;

    let length, i;
    if (Array.isArray(a)) {
      length = a.length;
      if (length != (b as unknown[]).length) return false;
      for (i = length; i-- !== 0; ) if (!deepEqual(a[i], b[i])) return false;
      return true;
    }

    if (a instanceof Map && b instanceof Map) {
      if (a.size !== b.size) return false;
      for (i of a.entries()) if (!b.has(i[0])) return false;
      for (i of a.entries()) if (!deepEqual(i[1], b.get(i[0]))) return false;
      return true;
    }

    if (a instanceof Set && b instanceof Set) {
      if (a.size !== b.size) return false;
      for (i of a.entries()) if (!b.has(i[0])) return false;
      return true;
    }

    if (a instanceof Date && b instanceof Date) {
      return a.getTime() === b.getTime();
    }

    if (ArrayBuffer.isView(a) && ArrayBuffer.isView(b)) {
      // @ts-expect-error
      length = a.length;
      // @ts-expect-error
      if (length != b.length) return false;
      for (i = length; i-- !== 0; ) if (a[i] !== b[i]) return false;
      return true;
    }

    if (a.constructor === RegExp)
      // @ts-expect-error
      return a.source === b.source && a.flags === b.flags;
    if (a.valueOf !== Object.prototype.valueOf)
      return a.valueOf() === b.valueOf();
    if (a.toString !== Object.prototype.toString)
      return a.toString() === b.toString();

    const keys = Object.keys(a);
    length = keys.length;
    if (length !== Object.keys(b).length) return false;

    for (i = length; i-- !== 0; )
      if (!Object.prototype.hasOwnProperty.call(b, keys[i])) return false;

    for (i = length; i-- !== 0; ) {
      const key = keys[i] as keyof typeof a;
      if (!deepEqual(a[key], b[key])) return false;
    }

    return true;
  }

  // true if both NaN, false otherwise
  return a !== a && b !== b;
}