type ComputePropertyNames<
  T,
  TKey extends keyof T & string,
  TFields extends (keyof T | string)[] = (keyof T | string)[]
> = TKey extends TFields[number]
  ? T[TKey] extends string
    ? `${TKey}_id`
    : TKey
  : TKey

/**
 * Takes an object and a list of fields to tranform in that object. If the field
 * exists on the object and its value is a string it will append `_id` to the
 * field name. This is used when allowing API calls to hold either ID or object
 * values in the payload. The method returns a new object with the
 * transformation.
 * @param obj - the object to transform
 * @param fields - the fields to apply transformation to
 * @returns the transformed object
 *
 * @example
 * ```ts
 * const obj = { test: "test", toto: 1, tata: Symbol("tata") }
 * const out = transformIdableFields(obj, ["test"]) // out: { test_id: string, toto: number, tata: symbol }
 * ```
 */
export const transformIdableFields = <
  T extends object = Record<string, unknown>,
  TFields extends (keyof T | string)[] = (keyof T | string)[],
  TOutput = {
    [P in ComputePropertyNames<T, keyof T & string, TFields>]: P extends keyof T
      ? T[P]
      : string
  }
>(
  obj: T,
  fields: TFields
): TOutput => {
  const ret = { ...obj }

  for (let key of fields) {
    key = key as string
    if (key in obj && typeof obj[key] === "string") {
      ret[`${key.toString()}_id`] = obj[key]
      delete ret[key]
    }
  }

  return ret as unknown as TOutput
}