import { getLinkedInConfig } from "@/lib/env";

export async function refreshLinkedInAccessToken(refreshToken: string): Promise<{
  accessToken: string;
  refreshToken?: string;
  expiresAt?: string;
}> {
  const { clientId, clientSecret } = getLinkedInConfig();
  const body = new URLSearchParams({
    grant_type: "refresh_token",
    refresh_token: refreshToken,
    client_id: clientId,
    client_secret: clientSecret,
  });

  const res = await fetch("https://www.linkedin.com/oauth/v2/accessToken", {
    method: "POST",
    headers: { "Content-Type": "application/x-www-form-urlencoded" },
    body: body.toString(),
  });

  const data = (await res.json()) as {
    access_token?: string;
    refresh_token?: string;
    expires_in?: number;
    error_description?: string;
  };

  if (!res.ok || !data.access_token) {
    throw new Error(data.error_description ?? "LinkedIn token refresh failed");
  }

  return {
    accessToken: data.access_token,
    refreshToken: data.refresh_token,
    expiresAt: data.expires_in
      ? new Date(Date.now() + data.expires_in * 1000).toISOString()
      : undefined,
  };
}