import type { EmailMessage } from "../types.mjs";
/** A compiled template — a function that takes typed variables and
*  returns a partial `EmailMessage` ready to splat into `email.send()`. */
export type TemplateFn<
	Vars,
	Output extends Partial<EmailMessage>
> = (vars: Vars) => Output;
/** Declare a template with compile-time-checked variables.
*
*  ```ts
*  const welcome = defineTemplate<{ name: string }>(({ name }) => ({
*    subject: `Welcome, ${name}!`,
*    react: <Welcome name={name} />,
*  }))
*
*  await email.send({ from, to, ...welcome({ name: "Ada" }) })
*  ```
*
*  Pass `render` as a function that produces whichever shape you want
*  (`{ react }`, `{ jsx }`, `{ mjml }`, or direct `{ html }`) — all of
*  them land as a typed `Partial<EmailMessage>`.
*/
export declare function defineTemplate<Vars = void>(render: (vars: Vars) => Partial<EmailMessage>): TemplateFn<Vars, Partial<EmailMessage>>;