import { cookie as prismicCookie, type Client, type LinkResolverFunction } from "@prismicio/client"

import type { NextRequestLike } from "./types"

export type RedirectToPreviewURLConfig = {
	/** The Prismic client configured for the preview session's repository. */
	// `Pick` is used to use the smallest possible subset of
	// `prismic.Client`. Doing this reduces the surface area for breaking
	// type changes.
	client: Pick<Client, "resolvePreviewURL">

	/**
	 * The `request` object from a Next.js Route Handler.
	 *
	 * @see Next.js Route Handler docs: \<https://nextjs.org/docs/app/building-your-application/routing/route-handlers\>
	 */
	request: NextRequestLike

	/**
	 * A Link Resolver used to resolve the previewed document's URL.
	 *
	 * @see To learn more about Link Resolver: {@link https://prismic.io/docs/core-concepts/link-resolver-route-resolver}
	 */
	linkResolver?: LinkResolverFunction

	/**
	 * The default redirect URL if a URL cannot be determined for the previewed document.
	 *
	 * **Note**: If you `next.config.js` file contains a `basePath`, the `defaultURL` option must
	 * _not_ include it. Instead, provide the `basePath` property using the `basePath` option.
	 */
	defaultURL?: string
}

export async function redirectToPreviewURL(config: RedirectToPreviewURLConfig): Promise<never> {
	const { client, request, linkResolver, defaultURL = "/" } = config

	// Need this to avoid the following Next.js build-time error:
	// You're importing a component that needs next/headers. That only works
	// in a Server Component which is not supported in the pages/ directory.
	const { cookies, draftMode } = await import("next/headers")

	// Dynamic so Node.js can load this module: the bare specifier (kept by
	// tsdown.config.ts for Next.js's server alias) is not resolvable by Node.js.
	const { redirect } = await import("next/navigation")

	const documentID = request.nextUrl.searchParams.get("documentId") ?? undefined

	// Set the initial preview cookie. Setting the cookie here is necessary
	// to support unpublished previews. Without setting it here, the page
	// will try to render without the preview cookie, leading to a
	// PrismicNotFound error.
	const cookieJar = await cookies()
	const previewToken = request.nextUrl.searchParams.get("token") ?? undefined
	if (previewToken) {
		cookieJar.set(prismicCookie.preview, previewToken, { sameSite: "none", secure: true })
	}

	const previewURL = await client.resolvePreviewURL({
		documentID,
		previewToken,
		defaultURL,
		linkResolver,
	})

	;(await draftMode()).enable()

	// Next.js uses `SameSite=Lax` in development, which cross-site iframes drop.
	cookieJar.set({
		...cookieJar.get("__prerender_bypass")!,
		httpOnly: true,
		sameSite: "none",
		secure: true,
	})

	return redirect(previewURL)
}