import { ChevronDown, ChevronUp, Info, X } from "lucide-react";
import { useMemo, useState } from "react";

import Code from "~/components/Code";
import Input from "~/components/Input";
import Link from "~/components/link";
import PageError from "~/components/page-error";
import Tooltip from "~/components/Tooltip";
import { Capabilities } from "~/server/web/roles";
import cn from "~/utils/cn";
import { mapNodes, sortNodeTags } from "~/utils/node-info";

import type { Route } from "./+types/overview";
import MachineRow from "./components/machine-row";
import NewMachine from "./dialogs/new";
import { machineAction } from "./machine-actions";

export async function loader({ request, context }: Route.LoaderArgs) {
  const principal = await context.auth.require(request);

  if (!context.auth.can(principal, Capabilities.read_machines)) {
    throw new Error(
      "You do not have permission to view this page. Please contact your administrator.",
    );
  }

  const writablePermission = context.auth.can(principal, Capabilities.write_machines);

  const api = context.hsApi.getRuntimeClient(
    context.auth.getHeadscaleApiKey(principal, context.oidc?.apiKey),
  );
  const [nodes, users] = await Promise.all([api.getNodes(), api.getUsers()]);

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

  const stats = await context.agents?.lookup(nodes.map((node) => node.nodeKey));
  const populatedNodes = mapNodes(nodes, stats);
  const supportsNodeOwnerChange = !context.hsApi.clientHelpers.isAtleast("0.28.0-beta.1");

  return {
    agent: context.agents?.agentID(),
    headscaleUserId: principal.kind === "oidc" ? principal.user.headscaleUserId : undefined,
    magic,
    nodes,
    populatedNodes,
    preAuth: context.auth.can(principal, Capabilities.generate_authkeys),
    publicServer: context.config.headscale.public_url,
    server: context.config.headscale.url,
    supportsNodeOwnerChange: supportsNodeOwnerChange,
    users,
    writable: writablePermission,
  };
}

export const action = machineAction;

type SortField = "name" | "ip" | "version" | "lastSeen";

export default function Page({ loaderData }: Route.ComponentProps) {
  const [searchQuery, setSearchQuery] = useState("");
  const [sortField, setSortField] = useState<SortField>("name");
  const [sortDirection, setSortDirection] = useState<"asc" | "desc">("asc");

  const filteredAndSortedNodes = useMemo(() => {
    const query = searchQuery.toLowerCase().trim();

    let nodes = loaderData.populatedNodes.filter((node) => {
      if (!query) {
        return true;
      }
      if (node.givenName.toLowerCase().includes(query)) {
        return true;
      }
      if (node.ipAddresses.some((ip) => ip.toLowerCase().includes(query))) {
        return true;
      }
      return false;
    });

    nodes = [...nodes].toSorted((a, b) => {
      let comparison = 0;

      switch (sortField) {
        case "name": {
          comparison = a.givenName.localeCompare(b.givenName);
          break;
        }
        case "ip": {
          const getIPv4 = (addresses: string[]) =>
            addresses.find((ip) => !ip.includes(":")) || addresses[0] || "";
          const ipA = getIPv4(a.ipAddresses);
          const ipB = getIPv4(b.ipAddresses);

          if (!ipA.includes(":") && !ipB.includes(":")) {
            const octetsA = ipA.split(".").map(Number);
            const octetsB = ipB.split(".").map(Number);
            for (let i = 0; i < 4; i++) {
              if (octetsA[i] !== octetsB[i]) {
                comparison = octetsA[i] - octetsB[i];
                break;
              }
            }
          } else {
            comparison = ipA.localeCompare(ipB);
          }
          break;
        }
        case "version": {
          const versionA = a.hostInfo?.IPNVersion?.split("-")[0] || "0";
          const versionB = b.hostInfo?.IPNVersion?.split("-")[0] || "0";
          const partsA = versionA.split(".").map(Number);
          const partsB = versionB.split(".").map(Number);
          const maxLen = Math.max(partsA.length, partsB.length);

          for (let i = 0; i < maxLen; i++) {
            const segA = partsA[i] || 0;
            const segB = partsB[i] || 0;
            if (segA !== segB) {
              comparison = segA - segB;
              break;
            }
          }
          break;
        }
        case "lastSeen": {
          if (a.online !== b.online) {
            comparison = a.online ? 1 : -1;
            break;
          }
          comparison = new Date(a.lastSeen).getTime() - new Date(b.lastSeen).getTime();
          break;
        }
      }

      return sortDirection === "asc" ? comparison : -comparison;
    });

    return nodes;
  }, [loaderData.populatedNodes, searchQuery, sortField, sortDirection]);

  const handleSort = (field: SortField) => {
    if (sortField === field) {
      setSortDirection((prev) => (prev === "asc" ? "desc" : "asc"));
    } else {
      setSortField(field);
      setSortDirection("asc");
    }
  };

  return (
    <>
      <div className="mb-6 flex flex-col gap-4 sm:flex-row sm:items-center sm:justify-between">
        <div className="flex flex-col">
          <h1 className="mb-2 text-2xl font-medium">Machines</h1>
          <p>
            Manage the devices connected to your Tailnet.{" "}
            <Link external styled to="https://tailscale.com/kb/1372/manage-devices">
              Learn more
            </Link>
          </p>
        </div>
        <NewMachine
          disabledKeys={loaderData.preAuth ? [] : ["pre-auth"]}
          isDisabled={!loaderData.writable}
          server={loaderData.publicServer ?? loaderData.server}
          users={loaderData.users}
        />
      </div>
      <div className="mb-4 flex items-center gap-4">
        <div className="relative w-64">
          <Input
            label="Search machines"
            labelHidden
            maxLength={100}
            onChange={(value) => setSearchQuery(value.slice(0, 100))}
            placeholder="Search by name or IP address..."
            value={searchQuery}
          />
          {searchQuery && (
            <button
              aria-label="Clear search"
              className={cn(
                "absolute right-2 top-1/2 -translate-y-1/2",
                "p-1 rounded-full",
                "text-mist-400 hover:text-mist-600",
                "dark:text-mist-500 dark:hover:text-mist-300",
                "hover:bg-mist-100 dark:hover:bg-mist-800",
              )}
              onClick={() => setSearchQuery("")}
              type="button"
            >
              <X className="h-4 w-4" />
            </button>
          )}
        </div>
        <span className="text-sm whitespace-nowrap text-mist-500">
          {searchQuery
            ? `Showing ${filteredAndSortedNodes.length} of ${loaderData.populatedNodes.length} machines`
            : `${loaderData.populatedNodes.length} machines`}
        </span>
      </div>
      <div className="overflow-x-auto">
        <table className="w-full min-w-[640px] table-auto rounded-lg">
          <thead className="text-mist-600 dark:text-mist-300">
            <tr className="px-0.5 text-left">
              <th
                aria-sort={
                  sortField === "name"
                    ? sortDirection === "asc"
                      ? "ascending"
                      : "descending"
                    : "none"
                }
                className="pb-2 text-xs font-bold uppercase"
              >
                <button
                  aria-label="Sort by name"
                  className={cn(
                    "flex items-center gap-x-1 cursor-pointer",
                    "hover:text-mist-900 dark:hover:text-mist-100",
                  )}
                  onClick={() => handleSort("name")}
                  type="button"
                >
                  Name
                  {sortField === "name" &&
                    (sortDirection === "asc" ? (
                      <ChevronUp className="h-3 w-3" />
                    ) : (
                      <ChevronDown className="h-3 w-3" />
                    ))}
                </button>
              </th>
              <th
                aria-sort={
                  sortField === "ip"
                    ? sortDirection === "asc"
                      ? "ascending"
                      : "descending"
                    : "none"
                }
                className="w-1/4 pb-2"
              >
                <div className="flex items-center gap-x-1">
                  <button
                    aria-label="Sort by IP address"
                    className={cn(
                      "flex items-center gap-x-1 cursor-pointer uppercase text-xs font-bold",
                      "hover:text-mist-900 dark:hover:text-mist-100",
                    )}
                    onClick={() => handleSort("ip")}
                    type="button"
                  >
                    Addresses
                    {sortField === "ip" &&
                      (sortDirection === "asc" ? (
                        <ChevronUp className="h-3 w-3" />
                      ) : (
                        <ChevronDown className="h-3 w-3" />
                      ))}
                  </button>
                  {loaderData.magic ? (
                    <Tooltip>
                      <Info className="h-4 w-4" />
                      <Tooltip.Body className="font-normal">
                        Since MagicDNS is enabled, you can access devices based on their name and
                        also at{" "}
                        <Code>
                          [name].
                          {loaderData.magic}
                        </Code>
                      </Tooltip.Body>
                    </Tooltip>
                  ) : undefined}
                </div>
              </th>
              {/* We only want to show the version column if there are agents */}
              {loaderData.agent !== undefined ? (
                <th
                  aria-sort={
                    sortField === "version"
                      ? sortDirection === "asc"
                        ? "ascending"
                        : "descending"
                      : "none"
                  }
                  className="pb-2 text-xs font-bold uppercase"
                >
                  <button
                    aria-label="Sort by version"
                    className={cn(
                      "flex items-center gap-x-1 cursor-pointer",
                      "hover:text-mist-900 dark:hover:text-mist-100",
                    )}
                    onClick={() => handleSort("version")}
                    type="button"
                  >
                    Version
                    {sortField === "version" &&
                      (sortDirection === "asc" ? (
                        <ChevronUp className="h-3 w-3" />
                      ) : (
                        <ChevronDown className="h-3 w-3" />
                      ))}
                  </button>
                </th>
              ) : undefined}
              <th
                aria-sort={
                  sortField === "lastSeen"
                    ? sortDirection === "asc"
                      ? "ascending"
                      : "descending"
                    : "none"
                }
                className="pb-2 text-xs font-bold uppercase"
              >
                <button
                  aria-label="Sort by last seen"
                  className={cn(
                    "flex items-center gap-x-1 cursor-pointer",
                    "hover:text-mist-900 dark:hover:text-mist-100",
                  )}
                  onClick={() => handleSort("lastSeen")}
                  type="button"
                >
                  Last Seen
                  {sortField === "lastSeen" &&
                    (sortDirection === "asc" ? (
                      <ChevronUp className="h-3 w-3" />
                    ) : (
                      <ChevronDown className="h-3 w-3" />
                    ))}
                </button>
              </th>
              <th className="w-12 pb-2">
                <span className="sr-only">Actions</span>
              </th>
            </tr>
          </thead>
          <tbody
            className={cn(
              "divide-y divide-mist-100 dark:divide-mist-800 align-top",
              "border-t border-mist-100 dark:border-mist-800",
            )}
          >
            {filteredAndSortedNodes.length === 0 ? (
              <tr>
                <td
                  className="py-8 text-center text-mist-500"
                  colSpan={loaderData.agent !== undefined ? 6 : 5}
                >
                  No machines found matching "{searchQuery}"
                </td>
              </tr>
            ) : (
              filteredAndSortedNodes.map((node) => (
                <MachineRow
                  existingTags={sortNodeTags(loaderData.nodes)}
                  isAgent={loaderData.agent ? loaderData.agent === node.nodeKey : undefined}
                  isDisabled={
                    loaderData.writable
                      ? false // If the user has write permissions, they can edit all machines
                      : node.user?.id !== loaderData.headscaleUserId
                  }
                  key={node.id}
                  magic={loaderData.magic}
                  node={node}
                  users={loaderData.users}
                  supportsNodeOwnerChange={loaderData.supportsNodeOwnerChange}
                />
              ))
            )}
          </tbody>
        </table>
      </div>
    </>
  );
}

export function ErrorBoundary({ error }: Route.ErrorBoundaryProps) {
  return <PageError error={error} page="Machines" />;
}