/**
 * Checks the body of `PATCH /api/users/me/settings` before the users route
 * trusts it.
 *
 * @module
 */

import type { UpdateSettingsRequest } from "../../shared/settings.ts";
import { isColorScheme, isStyleName } from "../../shared/theme.ts";

const VALIDATORS: Record<keyof UpdateSettingsRequest, (v: unknown) => boolean> =
  {
    style: (v) => v === null || isStyleName(v),
    colorScheme: (v) => v === null || isColorScheme(v),
    digestWeekly: (v) => typeof v === "boolean",
    digestMonthly: (v) => typeof v === "boolean",
  };

/**
 * Checks whether `obj` is an {@link UpdateSettingsRequest}: an object whose
 * every key is a setting, each with a value that setting takes. An unknown
 * key fails, so a typo doesn't pass for a change.
 */
export function isUpdateSettingsRequest(
  obj: unknown,
): obj is UpdateSettingsRequest {
  if (!obj || typeof obj !== "object" || Array.isArray(obj)) return false;
  return Object.entries(obj).every(([key, value]) =>
    key in VALIDATORS &&
    VALIDATORS[key as keyof UpdateSettingsRequest](value)
  );
}