import type { EmailMessage, Middleware } from "../types.mjs";
/** Renderer contract. Each adapter (`react`, `jsx-email`, `mjml`) ships a
*  `Renderer` that knows which message field it owns and how to turn it
*  into HTML. Users register renderers via `withRender(...renderers)`. */
export interface Renderer {
	readonly name: string;
	/** Return `true` if this renderer can handle the message (e.g. `msg.react`
	*  is non-nullish). */
	match: (msg: EmailMessage) => boolean;
	/** Render the relevant field to HTML. May be async (React's renderAsync). */
	render: (msg: EmailMessage) => Promise<string> | string;
}
export interface WithRenderOptions {
	/** Auto-derive `msg.text` from the rendered HTML when `text` is missing.
	*  Default: true. */
	autoText?: boolean;
}
/** Middleware that resolves `msg.react`, `msg.jsx`, or `msg.mjml` into
*  `msg.html` before the driver sees the message. Registered once per
*  `createEmail` instance:
*
*  ```ts
*  import reactRenderer from "unemail/render/react"
*
*  email.use(withRender(reactRenderer()))
*  ```
*/
export declare function withRender(...renderers: Renderer[]): Middleware & {
	options: WithRenderOptions;
};