import { useEffect, useState } from "react";
import { Link } from "react-router-dom";
import {
  api,
  type CurrentUser,
  type IntegrationSummary,
  type TailscaleDevice,
  type TailscaleDevicesResponse,
} from "../api/client";
import { formatDateTime } from "../utils/date";
import { useSortable } from "../hooks/useSortable";
import SortableTh from "../components/SortableTh";
import { downloadCsv } from "../utils/csv";

const KEY_EXPIRY_WARN_DAYS = 30;

function keyExpiryBadge(device: TailscaleDevice) {
  if (device.keyExpiryDisabled || !device.keyExpiry) {
    return <span className="text-secondary">Never</span>;
  }
  const daysLeft = (new Date(device.keyExpiry).getTime() - Date.now()) / 86_400_000;
  const style =
    daysLeft < 0 ? "bg-red-lt text-red" : daysLeft <= KEY_EXPIRY_WARN_DAYS ? "bg-yellow-lt text-yellow" : "bg-green-lt text-green";
  return (
    <>
      {formatDateTime(new Date(device.keyExpiry))} <span className={`badge ${style} ms-1`}>{daysLeft < 0 ? "Expired" : `${Math.floor(daysLeft)}d left`}</span>
    </>
  );
}

export default function Tailscale({ user }: { user: CurrentUser }) {
  const canEdit = user.role === "admin" || user.role === "operator";

  const [integrations, setIntegrations] = useState<IntegrationSummary[] | null>(null);
  const [selectedId, setSelectedId] = useState<number | null>(null);
  const [error, setError] = useState<string | null>(null);

  const [data, setData] = useState<TailscaleDevicesResponse | null>(null);
  const [loading, setLoading] = useState(false);

  useEffect(() => {
    api.integrations
      .list()
      .then((res) => {
        const tailscaleIntegrations = res.integrations.filter((i) => i.type === "tailscale");
        setIntegrations(tailscaleIntegrations);
        if (!selectedId && tailscaleIntegrations.length > 0) setSelectedId(tailscaleIntegrations[0].id);
      })
      .catch((err) => setError(err instanceof Error ? err.message : String(err)));
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  const selected = integrations?.find((i) => i.id === selectedId) ?? null;

  function loadDevices(id: number) {
    setLoading(true);
    setError(null);
    api.integrations.tailscale
      .devices(id)
      .then((res) => setData(res))
      .catch((err) => setError(err instanceof Error ? err.message : String(err)))
      .finally(() => setLoading(false));
  }

  useEffect(() => {
    if (selected?.enabled) {
      loadDevices(selected.id);
    } else {
      setData(null);
    }
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [selectedId]);

  async function setDeviceAuthorized(device: TailscaleDevice, authorized: boolean) {
    if (!selectedId) return;
    try {
      await api.integrations.tailscale.setAuthorized(selectedId, device.id, authorized);
      loadDevices(selectedId);
    } catch (err) {
      setError(err instanceof Error ? err.message : String(err));
    }
  }

  async function removeDevice(device: TailscaleDevice) {
    if (!selectedId) return;
    if (!confirm(`Remove device "${device.label || device.hostname}" from the tailnet?`)) return;
    try {
      await api.integrations.tailscale.remove(selectedId, device.id);
      loadDevices(selectedId);
    } catch (err) {
      setError(err instanceof Error ? err.message : String(err));
    }
  }

  const { sorted, sortKey, sortDir, requestSort } = useSortable(data?.devices);

  function exportCsv() {
    if (!sorted) return;
    downloadCsv(
      "tailscale-devices.csv",
      ["Device", "Address", "OS", "Online", "Authorized", "Last seen", "Key expiry"],
      sorted.map((d) => [
        d.label || d.hostname,
        d.primaryAddress,
        d.os,
        d.online ? "yes" : "no",
        d.authorized ? "yes" : "no",
        d.lastSeen ? formatDateTime(new Date(d.lastSeen)) : "",
        d.keyExpiryDisabled ? "never" : d.keyExpiry ? formatDateTime(new Date(d.keyExpiry)) : "",
      ]),
    );
  }

  return (
    <>
      <h2 className="page-title mb-3">Tailscale</h2>
      {error && <div className="alert alert-danger">{error}</div>}

      {integrations?.length === 0 ? (
        <div className="card">
          <div className="card-body text-secondary">
            No Tailscale integration configured yet.{" "}
            <Link to="/integrations">Add one under Integrations</Link>.
          </div>
        </div>
      ) : (
        <>
          {integrations && integrations.length > 1 && (
            <div className="mb-3" style={{ maxWidth: 320 }}>
              <select
                className="form-select"
                value={selectedId ?? ""}
                onChange={(e) => setSelectedId(Number(e.target.value))}
              >
                {integrations.map((i) => (
                  <option key={i.id} value={i.id} disabled={!i.enabled}>
                    {i.name}
                    {!i.enabled ? " — disabled" : ""}
                  </option>
                ))}
              </select>
            </div>
          )}

          {selected && !selected.enabled ? (
            <div className="card">
              <div className="card-body text-secondary">
                "{selected.name}" is disabled. Enable it under Integrations → Manage integrations to see its
                devices.
              </div>
            </div>
          ) : (
            <div className="card">
              <div className="card-header">
                <h3 className="card-title">
                  Devices
                  {data && (
                    <span className="text-secondary fw-normal ms-2">
                      {data.summary.online}/{data.summary.total} online
                      {data.summary.unauthorized > 0 && `, ${data.summary.unauthorized} awaiting authorization`}
                      {data.summary.expiringSoon > 0 && `, ${data.summary.expiringSoon} key(s) expiring soon`}
                    </span>
                  )}
                </h3>
                <div className="card-actions">
                  <button className="btn btn-sm btn-outline-secondary" onClick={exportCsv} disabled={!sorted || sorted.length === 0}>
                    Export CSV
                  </button>
                  <button
                    className="btn btn-sm btn-outline-secondary"
                    onClick={() => selected && loadDevices(selected.id)}
                    disabled={loading}
                  >
                    {loading ? "Refreshing…" : "Refresh"}
                  </button>
                </div>
              </div>
              <div className="table-responsive">
                <table className="table table-vcenter card-table">
                  <thead>
                    <tr>
                      <SortableTh<TailscaleDevice> label="Device" sortKeyName="label" activeKey={sortKey} direction={sortDir} onSort={requestSort} />
                      <SortableTh<TailscaleDevice>
                        label="Address"
                        sortKeyName="primaryAddress"
                        activeKey={sortKey}
                        direction={sortDir}
                        onSort={requestSort}
                      />
                      <SortableTh<TailscaleDevice> label="OS" sortKeyName="os" activeKey={sortKey} direction={sortDir} onSort={requestSort} />
                      <SortableTh<TailscaleDevice> label="Status" sortKeyName="online" activeKey={sortKey} direction={sortDir} onSort={requestSort} />
                      <SortableTh<TailscaleDevice>
                        label="Last seen"
                        sortKeyName="lastSeen"
                        activeKey={sortKey}
                        direction={sortDir}
                        onSort={requestSort}
                      />
                      <SortableTh<TailscaleDevice>
                        label="Key expiry"
                        sortKeyName="keyExpiry"
                        activeKey={sortKey}
                        direction={sortDir}
                        onSort={requestSort}
                      />
                      {canEdit && <th className="w-1">Actions</th>}
                    </tr>
                  </thead>
                  <tbody>
                    {sorted?.map((d) => (
                      <tr key={d.id}>
                        <td>
                          {d.label || d.hostname}
                          {d.isExitNode && <span className="badge bg-purple-lt ms-2">Exit node</span>}
                        </td>
                        <td className="text-secondary">{d.primaryAddress}</td>
                        <td>{d.os || "—"}</td>
                        <td>
                          {d.online ? (
                            <span className="badge bg-green-lt text-green me-1">Online</span>
                          ) : (
                            <span className="badge bg-secondary-lt text-secondary me-1">Offline</span>
                          )}
                          {!d.authorized && <span className="badge bg-yellow-lt text-yellow">Unauthorized</span>}
                        </td>
                        <td className="text-secondary">{d.lastSeen ? formatDateTime(new Date(d.lastSeen)) : "—"}</td>
                        <td>{keyExpiryBadge(d)}</td>
                        {canEdit && (
                          <td>
                            <div className="btn-list flex-nowrap">
                              {d.authorized ? (
                                <button className="btn btn-sm" onClick={() => setDeviceAuthorized(d, false)}>
                                  Deauthorize
                                </button>
                              ) : (
                                <button className="btn btn-sm btn-primary" onClick={() => setDeviceAuthorized(d, true)}>
                                  Authorize
                                </button>
                              )}
                              <button className="btn btn-sm btn-outline-danger" onClick={() => removeDevice(d)}>
                                Remove
                              </button>
                            </div>
                          </td>
                        )}
                      </tr>
                    ))}
                    {sorted?.length === 0 && (
                      <tr>
                        <td colSpan={canEdit ? 7 : 6} className="text-secondary text-center">
                          No devices in this tailnet.
                        </td>
                      </tr>
                    )}
                  </tbody>
                </table>
              </div>
            </div>
          )}
        </>
      )}
    </>
  );
}