import { createHash } from "node:crypto";
import { useEffect, useState } from "react";

import type { Machine, User } from "~/types";

import { Capabilities } from "~/server/web/roles";
import cn from "~/utils/cn";

import type { Route } from "./+types/overview";

import ManageBanner from "./components/manage-banner";
import UserRow from "./components/user-row";
import { userAction } from "./user-actions";

interface UserMachine extends User {
  machines: Machine[];
}

export async function loader({ request, context }: Route.LoaderArgs) {
  const session = await context.sessions.auth(request);
  const check = await context.sessions.check(request, Capabilities.read_users);
  if (!check) {
    // Not authorized to view this page
    throw new Error(
      "You do not have permission to view this page. Please contact your administrator.",
    );
  }

  const writablePermission = await context.sessions.check(request, Capabilities.write_users);

  const api = context.hsApi.getRuntimeClient(session.api_key);
  const [nodes, apiUsers] = await Promise.all([api.getNodes(), api.getUsers()]);

  const users = apiUsers.map((user) => ({
    ...user,
    machines: nodes.filter((node) => node.user?.id === user.id),
    profilePicUrl:
      context.config.oidc?.profile_picture_source === "gravatar"
        ? (() => {
            if (!user.email) {
              return undefined;
            }

            const emailHash = user.email.trim().toLowerCase();
            const hash = createHash("sha256").update(emailHash).digest("hex");
            return `https://www.gravatar.com/avatar/${hash}?s=200&d=identicon&r=x`;
          })()
        : user.profilePicUrl,
  }));

  const roles = await Promise.all(
    users
      .sort((a, b) => a.name.localeCompare(b.name))
      .map(async (user) => {
        if (user.provider !== "oidc") {
          return "no-oidc";
        }

        if (user.provider === "oidc" && user.providerId) {
          // For some reason, headscale makes providerID a url where the
          // last component is the subject, so we need to strip that out
          const subject = user.providerId.split("/").pop();
          if (!subject) {
            return "invalid-oidc";
          }

          const role = await context.sessions.roleForSubject(subject);
          return role ?? "no-role";
        }

        // No role means the user is not registered in Headplane, but they
        // are in Headscale. We also need to handle what happens if someone
        // logs into the UI and they don't have a Headscale setup.
        return "no-role";
      }),
  );

  let magic: string | undefined;
  if (context.hs.readable()) {
    if (context.hs.c?.dns.magic_dns) {
      magic = context.hs.c.dns.base_domain;
    }
  }

  return {
    writable: writablePermission, // whether the user can write to the API
    oidc: context.config.oidc
      ? {
          issuer: context.config.oidc.issuer,
        }
      : undefined,
    roles,
    magic,
    users,
  };
}

export const action = userAction;

export default function Page({ loaderData }: Route.ComponentProps) {
  const [users, setUsers] = useState<UserMachine[]>(loaderData.users);

  // This useEffect is entirely for the purpose of updating the users when the
  // drag and drop changes the machines between users. It's pretty hacky, but
  // the idea is to treat data.users as the source of truth and update the
  // local state when it changes.
  useEffect(() => {
    setUsers(loaderData.users);
  }, [loaderData.users]);

  return (
    <>
      <h1 className="mb-1.5 text-2xl font-medium">Users</h1>
      <p className="text-md mb-8">Manage the users in your network and their permissions.</p>
      <ManageBanner isDisabled={!loaderData.writable} oidc={loaderData.oidc} />
      <div className="overflow-x-auto">
        <table className="w-full min-w-[640px] table-auto rounded-lg">
          <thead className="text-headplane-600 dark:text-headplane-300">
            <tr className="px-0.5 text-left">
              <th className="pb-2 text-xs font-bold uppercase">User</th>
              <th className="pb-2 text-xs font-bold uppercase">Role</th>
              <th className="pb-2 text-xs font-bold uppercase">Created At</th>
              <th className="pb-2 text-xs font-bold uppercase">Last Seen</th>
            </tr>
          </thead>
          <tbody
            className={cn(
              "divide-y divide-headplane-100 dark:divide-headplane-800 align-top",
              "border-t border-headplane-100 dark:border-headplane-800",
            )}
          >
            {users
              .sort((a, b) => a.name.localeCompare(b.name))
              .map((user) => (
                <UserRow key={user.id} role={loaderData.roles[users.indexOf(user)]} user={user} />
              ))}
          </tbody>
        </table>
      </div>
    </>
  );
}