import { FileKey2 } from "lucide-react";
import { useMemo, useState } from "react";
import { Link as RemixLink } from "react-router";

import Code from "~/components/Code";
import Link from "~/components/Link";
import Notice from "~/components/Notice";
import Select from "~/components/Select";
import TableList from "~/components/TableList";
import { Capabilities } from "~/server/web/roles";
import log from "~/utils/log";
import { filterUsersWithValidIds, getUserDisplayName } from "~/utils/user";

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

import { authKeysAction } from "./actions";
import AuthKeyRow from "./auth-key-row";
import AddAuthKey from "./dialogs/add-auth-key";

export async function loader({ request, context }: Route.LoaderArgs) {
  const session = await context.sessions.auth(request);
  const api = context.hsApi.getRuntimeClient(session.api_key);

  const users = await api.getUsers();
  const preAuthKeys = await Promise.all(
    filterUsersWithValidIds(users).map(async (user) => {
      try {
        const preAuthKeys = await api.getPreAuthKeys(user.id);
        return {
          success: true,
          user,
          preAuthKeys,
        };
      } catch (error) {
        log.error("api", "GET /v1/preauthkey for %s: %o", user.name, error);
        return {
          success: false,
          user,
          error,
          preAuthKeys: [],
        };
      }
    }),
  );

  const keys = preAuthKeys
    .filter(({ success }) => success)
    .map(({ user, preAuthKeys }) => ({
      user,
      preAuthKeys,
    }));

  const missing = preAuthKeys
    .filter(({ success }) => !success)
    .map(({ user, error }) => ({
      user,
      error,
    }));

  return {
    keys,
    missing,
    users,
    access: await context.sessions.check(request, Capabilities.generate_authkeys),
    url: context.config.headscale.public_url ?? context.config.headscale.url,
  };
}

export const action = authKeysAction;

type Status = "all" | "active" | "expired" | "reusable" | "ephemeral";
export default function Page({
  loaderData: { keys, missing, users, url, access },
}: Route.ComponentProps) {
  const [selectedUser, setSelectedUser] = useState("__headplane_all");
  const [status, setStatus] = useState<Status>("active");
  const isDisabled = !access || keys.flatMap(({ preAuthKeys }) => preAuthKeys).length === 0;

  const filteredKeys = useMemo(() => {
    const now = new Date();
    return keys
      .filter(({ user }) => {
        if (selectedUser === "__headplane_all") {
          return true;
        }

        return user.id === selectedUser;
      })
      .flatMap(({ preAuthKeys }) => preAuthKeys)
      .filter((key) => {
        if (status === "all") {
          return true;
        }

        if (status === "ephemeral") {
          return key.ephemeral;
        }

        if (status === "reusable") {
          return key.reusable;
        }

        const expiry = new Date(key.expiration);
        if (status === "expired") {
          // Expired keys are either used or expired
          // BUT only used if they are not reusable
          if (key.used && !key.reusable) {
            return true;
          }

          return expiry < now;
        }

        if (status === "active") {
          // Active keys are either not expired or reusable
          if (expiry < now) {
            return false;
          }

          if (!key.used) {
            return true;
          }

          return key.reusable;
        }

        return false;
      });
  }, [keys, selectedUser, status]);

  return (
    <div className="flex flex-col md:w-2/3">
      <p className="text-md mb-8">
        <RemixLink className="font-medium" to="/settings">
          Settings
        </RemixLink>
        <span className="mx-2">/</span> Pre-Auth Keys
      </p>
      {!access ? (
        <Notice title="Pre-auth key permissions restricted" variant="warning">
          You do not have the necessary permissions to generate pre-auth keys. Please contact your
          administrator to request access or to generate a pre-auth key for you.
        </Notice>
      ) : missing.length > 0 ? (
        <Notice title="Missing authentication keys" variant="error">
          An error occurred while fetching the authentication keys for the following users:{" "}
          {missing.map(({ user }, index) => (
            <>
              <Code key={user.id}>{getUserDisplayName(user)}</Code>
              {index < missing.length - 1 ? ", " : ". "}
            </>
          ))}
          Their keys may not be listed correctly. Please check the server logs for more information.
        </Notice>
      ) : undefined}
      <h1 className="mb-2 text-2xl font-medium">Pre-Auth Keys</h1>
      <p className="mb-4">
        Headscale fully supports pre-authentication keys in order to easily add devices to your
        Tailnet. To learn more about using pre-authentication keys, visit the{" "}
        <Link
          name="Tailscale Auth Keys documentation"
          to="https://tailscale.com/kb/1085/auth-keys/"
        >
          Tailscale documentation
        </Link>
      </p>
      <AddAuthKey url={url} users={users} />
      <div className="mt-4 flex items-center gap-4">
        <Select
          className="w-full"
          defaultSelectedKey="__headplane_all"
          isDisabled={isDisabled}
          label="User"
          onSelectionChange={(value) => setSelectedUser(value?.toString() ?? "")}
          placeholder="Select a user"
        >
          {[
            <Select.Item key="__headplane_all">All</Select.Item>,
            ...keys.map(({ user }) => (
              <Select.Item key={user.id}>{getUserDisplayName(user)}</Select.Item>
            )),
          ]}
        </Select>
        <Select
          className="w-full"
          defaultSelectedKey="active"
          isDisabled={isDisabled}
          label="Status"
          onSelectionChange={(value) => setStatus((value?.toString() ?? "active") as Status)}
          placeholder="Select a status"
        >
          <Select.Item key="all">All</Select.Item>
          <Select.Item key="active">Active</Select.Item>
          <Select.Item key="expired">Used/Expired</Select.Item>
          <Select.Item key="reusable">Reusable</Select.Item>
          <Select.Item key="ephemeral">Ephemeral</Select.Item>
        </Select>
      </div>
      <TableList className="mt-4">
        {keys.flatMap(({ preAuthKeys }) => preAuthKeys).length === 0 ? (
          <TableList.Item className="flex flex-col items-center gap-2.5 py-4 opacity-70">
            <FileKey2 />
            <p className="font-semibold">No pre-auth keys have been created yet.</p>
          </TableList.Item>
        ) : filteredKeys.length === 0 ? (
          <TableList.Item className="flex flex-col items-center gap-2.5 py-4 opacity-70">
            <FileKey2 />
            <p className="font-semibold">No pre-auth keys match the selected filters.</p>
          </TableList.Item>
        ) : (
          filteredKeys.map((key) => {
            // TODO: Why is Headscale using email as the user ID here?
            // https://github.com/juanfont/headscale/issues/2520
            const user = users.find((user) => user.id === key.user.id);
            if (!user) {
              return null;
            }

            return (
              <TableList.Item key={key.id}>
                <AuthKeyRow authKey={key} user={user} />
              </TableList.Item>
            );
          })
        )}
      </TableList>
    </div>
  );
}