import { cookies } from "next/headers";
import { auth } from "@/auth";

const COOKIE_NAME = "ayrismail_creds";

export interface MailSessionData {
  email: string;
  password: string;
  ownerId: string; // Dashboard user ID who owns this mail session
}

/**
 * Encode credentials to base64 (in production, use proper encryption
 * with AES-256-GCM and AUTH_SECRET as key).
 */
function encode(data: MailSessionData): string {
  return Buffer.from(JSON.stringify(data)).toString("base64");
}

function decode(token: string): MailSessionData | null {
  try {
    return JSON.parse(Buffer.from(token, "base64").toString("utf-8"));
  } catch {
    return null;
  }
}

/** Save mail credentials to cookie */
export async function setMailSession(data: Omit<MailSessionData, "ownerId">): Promise<void> {
  const session = await auth();
  if (!session?.user?.id) {
    throw new Error("Cannot set mail session without dashboard session");
  }

  const cookieStore = await cookies();
  const sessionData: MailSessionData = {
    ...data,
    ownerId: session.user.id,
  };

  cookieStore.set(COOKIE_NAME, encode(sessionData), {
    httpOnly: true,
    secure: process.env.NODE_ENV === "production",
    sameSite: "lax",
    maxAge: 60 * 60 * 24, // 24 hours
    path: "/",
  });
}

/** Get mail credentials from cookie */
export async function getMailSession(): Promise<MailSessionData | null> {
  const session = await auth();
  if (!session?.user?.id) return null;

  const cookieStore = await cookies();
  const cookie = cookieStore.get(COOKIE_NAME);
  if (!cookie?.value) return null;

  const data = decode(cookie.value);
  if (!data) return null;

  // Verify that this mail session belongs to the current dashboard user
  if (data.ownerId !== session.user.id) {
    // Session belongs to another user, clear it for safety
    await clearMailSession();
    return null;
  }

  return data;
}

/** Clear mail credentials cookie */
export async function clearMailSession(): Promise<void> {
  const cookieStore = await cookies();
  cookieStore.delete(COOKIE_NAME);
}