import { parse } from "convex-helpers/validators";
import type { Validator, Infer } from "convex/values";

export const assertExhaustive = (value: never): never => {
  throw new Error(`Unhandled event type: ${value as string}`);
};

export const iife = <T>(fn: () => T): T => fn();

/**
 * Generic function to attempt parsing with proper TypeScript type narrowing
 */
export function attemptToParse<T extends Validator<any, any, any>>(
  validator: T,
  value: unknown,
): { kind: "success"; data: Infer<T> } | { kind: "error"; error: unknown } {
  try {
    return {
      kind: "success",
      data: parse(validator, value),
    };
  } catch (error) {
    return {
      kind: "error",
      error,
    };
  }
}

/**
 * This is one is intentionally kept simple and only allows - and _ as special characters
 * since Resend does not specify what pattern a label must follow, the documentation
 * only says "any string": https://resend.com/docs/dashboard/emails/send-test-emails#using-labels-effectively
 * and a full RFC-5322 compliant regex would be way too long.
 */
const RESEND_TEST_EMAIL_REGEX =
  /^(delivered|bounced|complained)(\+[a-zA-Z0-9_-]*)?@resend\.dev$/;

/**
 * Check if the given e-mail address is a valid test e-mail for Resend.
 * @param email
 */
export function isValidResendTestEmail(email: string): boolean {
  return RESEND_TEST_EMAIL_REGEX.test(email);
}