import type { NextApiRequestLike, NextApiResponseLike } from "./types";

/** Configuration for `exitPreview()`. */
export type ExitPreviewAPIRouteConfig = {
	/**
	 * The `req` object from a Next.js API route.
	 *
	 * @see Next.js API route docs: \<https://nextjs.org/docs/api-routes/introduction\>
	 */
	req?: NextApiRequestLike;

	/**
	 * The `res` object from a Next.js API route.
	 *
	 * @see Next.js API route docs: \<https://nextjs.org/docs/api-routes/introduction\>
	 */
	res: NextApiResponseLike;
};

/**
 * Ends a Prismic preview session within a Next.js app. This function should be
 * used in an API route.
 *
 * @example
 *
 * ```typescript
 * // src/pages/api/exit-preview.js
 *
 * import { exitPreview } from "@prismicio/next";
 *
 * export default function handler(_req, res) {
 * 	return exitPreview({ res });
 * }
 * ```
 */
export function exitPreview(config: ExitPreviewAPIRouteConfig): void {
	config.res.clearPreviewData();

	// `Cache-Control` header is used to prevent CDN-level caching.
	config.res.setHeader("Cache-Control", "no-store");

	config.res.json({ success: true });

	return;
}