import crypto from "node:crypto";

import type { User } from "@prisma/client";
import { cookies } from "next/headers";
import { redirect } from "next/navigation";

import { SESSION_COOKIE_NAME, SESSION_TTL_DAYS } from "@/lib/constants";
import { db } from "@/server/db";
import { AppError } from "@/server/errors";

const sessionTtlMs = SESSION_TTL_DAYS * 24 * 60 * 60 * 1000;

function hashSessionToken(token: string) {
  return crypto.createHash("sha256").update(token).digest("hex");
}

function createSessionToken() {
  return crypto.randomBytes(32).toString("hex");
}

export async function createSession(userId: string) {
  const token = createSessionToken();
  const expiresAt = new Date(Date.now() + sessionTtlMs);

  await db.session.create({
    data: {
      userId,
      tokenHash: hashSessionToken(token),
      expiresAt,
    },
  });

  return { token, expiresAt };
}

export async function setSessionCookie(token: string, expiresAt: Date) {
  const cookieStore = await cookies();

  cookieStore.set(SESSION_COOKIE_NAME, token, {
    httpOnly: true,
    sameSite: "lax",
    secure: process.env.NODE_ENV === "production",
    path: "/",
    expires: expiresAt,
  });
}

export async function clearSessionCookie() {
  const cookieStore = await cookies();

  cookieStore.set(SESSION_COOKIE_NAME, "", {
    httpOnly: true,
    sameSite: "lax",
    secure: process.env.NODE_ENV === "production",
    path: "/",
    expires: new Date(0),
  });
}

export async function getSessionToken() {
  const cookieStore = await cookies();
  return cookieStore.get(SESSION_COOKIE_NAME)?.value;
}

export async function getCurrentSession() {
  const token = await getSessionToken();

  if (!token) {
    return null;
  }

  const session = await db.session.findUnique({
    where: {
      tokenHash: hashSessionToken(token),
    },
    include: {
      user: true,
    },
  });

  if (!session) {
    return null;
  }

  if (session.expiresAt <= new Date()) {
    await db.session.delete({
      where: {
        id: session.id,
      },
    });

    return null;
  }

  return session;
}

export async function getCurrentUser(): Promise<User | null> {
  const session = await getCurrentSession();
  return session?.user ?? null;
}

export async function requireCurrentUser() {
  const user = await getCurrentUser();

  if (!user) {
    redirect("/login");
  }

  return user;
}

export async function requireApiUser() {
  const user = await getCurrentUser();

  if (!user) {
    throw new AppError("أنت محتاج تسجل الدخول الأول.", 401);
  }

  return user;
}

export async function redirectIfAuthenticated() {
  const user = await getCurrentUser();

  if (user) {
    redirect("/dashboard/customers");
  }
}

export async function destroyCurrentSession() {
  const token = await getSessionToken();

  if (token) {
    const tokenHash = hashSessionToken(token);

    await db.session.deleteMany({
      where: {
        tokenHash,
      },
    });
  }

  await clearSessionCookie();
}