import { cookies } from "next/headers";
import { NextRequest, NextResponse } from "next/server";
import { requireAdmin } from "@/lib/auth";

function escapeHtml(value: unknown) {
	return String(value ?? "")
		.replaceAll("&", "&")
		.replaceAll("<", "&lt;")
		.replaceAll(">", "&gt;")
		.replaceAll('"', "&quot;")
		.replaceAll("'", "&#39;");
}

export async function GET(request: NextRequest) {
	await requireAdmin();
	const params = new URL(request.url).searchParams;
	const cookieStore = await cookies();
	const expected = cookieStore.get("youtube-oauth-state")?.value;
	cookieStore.delete("youtube-oauth-state");
	if (!expected || expected !== params.get("state"))
		return NextResponse.json(
			{ error: "Invalid OAuth state." },
			{ status: 400 },
		);
	const code = params.get("code");
	if (!code)
		return NextResponse.json(
			{ error: "No authorization code received." },
			{ status: 400 },
		);
	const response = await fetch("https://oauth2.googleapis.com/token", {
		method: "POST",
		headers: { "Content-Type": "application/x-www-form-urlencoded" },
		body: new URLSearchParams({
			code,
			client_id: process.env.YOUTUBE_CLIENT_ID ?? "",
			client_secret: process.env.YOUTUBE_CLIENT_SECRET ?? "",
			redirect_uri: `${process.env.BASE_URL}/api/auth/youtube/callback`,
			grant_type: "authorization_code",
		}),
	});
	const data = (await response.json()) as Record<string, unknown>;
	if (!response.ok || !data.refresh_token)
		return NextResponse.json(
			{ error: "YouTube token exchange failed." },
			{ status: 400 },
		);
	const html = `<!doctype html><html><body style="font-family:system-ui;max-width:720px;margin:40px auto;padding:20px"><h1>YouTube OAuth success</h1><p>Copy these values into your server environment:</p><pre>YOUTUBE_REFRESH_TOKEN=${escapeHtml(data.refresh_token)}\nYOUTUBE_ACCESS_TOKEN=${escapeHtml(data.access_token)}</pre><p>Restart the app after saving them.</p></body></html>`;
	return new NextResponse(html, { headers: { "Content-Type": "text/html" } });
}