import { useEffect, useState } from "react";
import { Link } from "react-router-dom";
import {
  api,
  type CurrentUser,
  type IntegrationSummary,
  type ProxmoxGuest,
  type ProxmoxGuestsResponse,
  type ProxmoxNodeStats,
} from "../api/client";
import { useSortable } from "../hooks/useSortable";
import SortableTh from "../components/SortableTh";
import { usePagination } from "../hooks/usePagination";
import Pagination from "../components/Pagination";
import { downloadCsv } from "../utils/csv";

function proxmoxStatusBadge(status: string) {
  return status === "running" ? (
    <span className="badge bg-green-lt text-green">Running</span>
  ) : (
    <span className="badge bg-secondary-lt text-secondary">Stopped</span>
  );
}

function formatUptime(seconds: number | null): string {
  if (!seconds) return "—";
  const days = Math.floor(seconds / 86400);
  const hours = Math.floor((seconds % 86400) / 3600);
  if (days > 0) return `${days}d ${hours}h`;
  const minutes = Math.floor((seconds % 3600) / 60);
  return `${hours}h ${minutes}m`;
}

function formatBytes(bytes: number | null): string {
  if (bytes === null) return "—";
  const units = ["B", "KB", "MB", "GB", "TB", "PB"];
  let value = bytes;
  let unit = 0;
  while (value >= 1024 && unit < units.length - 1) {
    value /= 1024;
    unit++;
  }
  return `${value.toFixed(1)} ${units[unit]}`;
}

function usageBar(used: number | null, total: number | null) {
  if (!total) return null;
  const pct = Math.min(100, Math.round(((used ?? 0) / total) * 100));
  return (
    <div className="progress progress-sm mt-1">
      <div className={`progress-bar ${pct > 90 ? "bg-red" : pct > 75 ? "bg-yellow" : "bg-green"}`} style={{ width: `${pct}%` }} />
    </div>
  );
}

export default function Proxmox({ 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<ProxmoxGuestsResponse | null>(null);
  const [loading, setLoading] = useState(false);
  const [actingOnGuest, setActingOnGuest] = useState<number | null>(null);

  const [nodeStats, setNodeStats] = useState<ProxmoxNodeStats[] | null>(null);
  const [nodeStatsError, setNodeStatsError] = useState<string | null>(null);
  const [loadingNodeStats, setLoadingNodeStats] = useState(false);

  useEffect(() => {
    api.integrations
      .list()
      .then((res) => {
        const proxmoxIntegrations = res.integrations.filter((i) => i.type === "proxmox");
        setIntegrations(proxmoxIntegrations);
        if (!selectedId && proxmoxIntegrations.length > 0) setSelectedId(proxmoxIntegrations[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 loadGuests(id: number) {
    setLoading(true);
    setError(null);
    api.integrations.proxmox
      .guests(id)
      .then((res) => setData(res))
      .catch((err) => setError(err instanceof Error ? err.message : String(err)))
      .finally(() => setLoading(false));
  }

  function loadNodeStats(id: number) {
    setLoadingNodeStats(true);
    setNodeStatsError(null);
    api.integrations.proxmox
      .nodes(id)
      .then((res) => setNodeStats(res.nodes))
      .catch((err) => setNodeStatsError(err instanceof Error ? err.message : String(err)))
      .finally(() => setLoadingNodeStats(false));
  }

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

  async function guestAction(g: ProxmoxGuest, action: "start" | "stop" | "restart" | "shutdown") {
    if (!selectedId) return;
    if (action === "stop" && !confirm(`Stop ${g.type === "qemu" ? "VM" : "container"} "${g.name}" immediately? Use Shutdown instead for a graceful power-off.`))
      return;
    setActingOnGuest(g.vmid);
    setError(null);
    try {
      await api.integrations.proxmox[action](selectedId, g.node, g.type, g.vmid);
      loadGuests(selectedId);
    } catch (err) {
      setError(err instanceof Error ? err.message : String(err));
    } finally {
      setActingOnGuest(null);
    }
  }

  const { sorted: sortedGuests, sortKey: guestSortKey, sortDir: guestSortDir, requestSort: requestGuestSort } = useSortable(data?.guests);
  const { pageItems: guestPageItems, page: guestPage, setPage: setGuestPage, pageCount: guestPageCount, totalCount: guestTotalCount } =
    usePagination(sortedGuests);

  function exportGuestsCsv() {
    if (!sortedGuests) return;
    downloadCsv(
      "proxmox-guests.csv",
      ["Name", "VMID", "Node", "Type", "Uptime", "Status"],
      sortedGuests.map((g) => [g.name, g.vmid, g.node, g.type === "qemu" ? "VM" : "LXC", formatUptime(g.uptime), g.status]),
    );
  }

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

      {integrations?.length === 0 ? (
        <div className="card">
          <div className="card-body text-secondary">
            No Proxmox 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
                VMs and containers.
              </div>
            </div>
          ) : (
            <>
              {nodeStatsError && <div className="alert alert-danger">{nodeStatsError}</div>}
              <div className="row row-cards mb-3">
                {nodeStats?.map((n) => (
                  <div className="col-12" key={n.node}>
                    <div className="card h-100">
                      <div className="card-header">
                        <h3 className="card-title">
                          {n.node}
                          {n.pveVersion && <span className="text-secondary fw-normal ms-2">{n.pveVersion}</span>}
                        </h3>
                        <div className="card-actions">
                          <button
                            className="btn btn-sm btn-outline-secondary"
                            onClick={() => selected && loadNodeStats(selected.id)}
                            disabled={loadingNodeStats}
                          >
                            {loadingNodeStats ? "Refreshing…" : "Refresh"}
                          </button>
                        </div>
                      </div>
                      <div className="card-body">
                        {n.error && <div className="alert alert-danger">{n.error}</div>}
                        <div className="row g-3">
                          <div className="col-md-6">
                            <div className="mb-3">
                              <div className="text-secondary small">Uptime</div>
                              <div>{formatUptime(n.uptime)}</div>
                            </div>
                            <div className="mb-3">
                              <div className="text-secondary small">CPU</div>
                              <div>
                                {n.cpuUsagePercent !== null ? `${n.cpuUsagePercent.toFixed(1)}%` : "—"}
                                {n.cpuCores ? <span className="text-secondary"> ({n.cpuCores} cores)</span> : null}
                              </div>
                              {n.loadAverage && (
                                <div className="text-secondary small">Load: {n.loadAverage.map((l) => l.toFixed(2)).join(", ")}</div>
                              )}
                            </div>
                            <div className={n.swapTotalBytes ? "mb-3" : ""}>
                              <div className="text-secondary small">Memory</div>
                              <div>
                                {formatBytes(n.memUsedBytes)} / {formatBytes(n.memTotalBytes)}
                              </div>
                              {usageBar(n.memUsedBytes, n.memTotalBytes)}
                            </div>
                            {!!n.swapTotalBytes && (
                              <div>
                                <div className="text-secondary small">Swap</div>
                                <div>
                                  {formatBytes(n.swapUsedBytes)} / {formatBytes(n.swapTotalBytes)}
                                </div>
                                {usageBar(n.swapUsedBytes, n.swapTotalBytes)}
                              </div>
                            )}
                          </div>

                          <div className="col-md-6">
                            <div className="text-secondary small mb-1">Storage</div>
                            {n.storages.length > 0 ? (
                              <table className="table table-sm table-vcenter mb-0">
                                <tbody>
                                  {n.storages.map((s) => (
                                    <tr key={s.id}>
                                      <td>
                                        {s.id}
                                        {!s.active && <span className="badge bg-secondary-lt text-secondary ms-1">Inactive</span>}
                                      </td>
                                      <td className="text-secondary">{s.type}</td>
                                      <td>
                                        {formatBytes(s.usedBytes)} / {formatBytes(s.totalBytes)}
                                        {usageBar(s.usedBytes, s.totalBytes)}
                                      </td>
                                    </tr>
                                  ))}
                                </tbody>
                              </table>
                            ) : (
                              !n.error && (
                                <div className="text-secondary small">
                                  No storage visible to this API token. Proxmox filters the storage list
                                  per-token — grant it <code>Datastore.Audit</code> (e.g. on{" "}
                                  <code>/storage</code>) to see disk usage here.
                                </div>
                              )
                            )}
                          </div>
                        </div>
                      </div>
                    </div>
                  </div>
                ))}
                {nodeStats?.length === 0 && (
                  <div className="col-12">
                    <div className="card">
                      <div className="card-body text-secondary">No online Proxmox nodes found.</div>
                    </div>
                  </div>
                )}
              </div>

              <div className="card">
              <div className="card-header">
                <h3 className="card-title">
                  VMs &amp; Containers
                  {data && (
                    <span className="text-secondary fw-normal ms-2">
                      {data.summary.running}/{data.summary.total} running
                    </span>
                  )}
                </h3>
                <div className="card-actions">
                  <button
                    className="btn btn-sm btn-outline-secondary"
                    onClick={exportGuestsCsv}
                    disabled={!sortedGuests || sortedGuests.length === 0}
                  >
                    Export CSV
                  </button>
                  <button
                    className="btn btn-sm btn-outline-secondary"
                    onClick={() => selected && loadGuests(selected.id)}
                    disabled={loading}
                  >
                    {loading ? "Refreshing…" : "Refresh"}
                  </button>
                </div>
              </div>
              <div className="table-responsive">
                <table className="table table-vcenter card-table">
                  <thead>
                    <tr>
                      <SortableTh<ProxmoxGuest> label="Name" sortKeyName="name" activeKey={guestSortKey} direction={guestSortDir} onSort={requestGuestSort} />
                      <SortableTh<ProxmoxGuest> label="Node" sortKeyName="node" activeKey={guestSortKey} direction={guestSortDir} onSort={requestGuestSort} />
                      <SortableTh<ProxmoxGuest> label="Type" sortKeyName="type" activeKey={guestSortKey} direction={guestSortDir} onSort={requestGuestSort} />
                      <SortableTh<ProxmoxGuest>
                        label="Uptime"
                        sortKeyName="uptime"
                        activeKey={guestSortKey}
                        direction={guestSortDir}
                        onSort={requestGuestSort}
                      />
                      <SortableTh<ProxmoxGuest>
                        label="Status"
                        sortKeyName="status"
                        activeKey={guestSortKey}
                        direction={guestSortDir}
                        onSort={requestGuestSort}
                      />
                      {canEdit && <th className="w-1">Actions</th>}
                    </tr>
                  </thead>
                  <tbody>
                    {guestPageItems?.map((g) => (
                      <tr key={`${g.node}:${g.type}:${g.vmid}`}>
                        <td>
                          {g.name} <span className="text-secondary">#{g.vmid}</span>
                        </td>
                        <td className="text-secondary">{g.node}</td>
                        <td>
                          <span className="badge bg-blue-lt">{g.type === "qemu" ? "VM" : "LXC"}</span>
                        </td>
                        <td className="text-secondary">{formatUptime(g.uptime)}</td>
                        <td>{proxmoxStatusBadge(g.status)}</td>
                        {canEdit && (
                          <td>
                            <div className="btn-list flex-nowrap">
                              {g.status === "running" ? (
                                <>
                                  <button
                                    className="btn btn-sm"
                                    onClick={() => guestAction(g, "restart")}
                                    disabled={actingOnGuest === g.vmid}
                                  >
                                    Restart
                                  </button>
                                  <button
                                    className="btn btn-sm"
                                    onClick={() => guestAction(g, "shutdown")}
                                    disabled={actingOnGuest === g.vmid}
                                  >
                                    Shutdown
                                  </button>
                                  <button
                                    className="btn btn-sm btn-outline-danger"
                                    onClick={() => guestAction(g, "stop")}
                                    disabled={actingOnGuest === g.vmid}
                                  >
                                    Stop
                                  </button>
                                </>
                              ) : (
                                <button
                                  className="btn btn-sm btn-primary"
                                  onClick={() => guestAction(g, "start")}
                                  disabled={actingOnGuest === g.vmid}
                                >
                                  Start
                                </button>
                              )}
                            </div>
                          </td>
                        )}
                      </tr>
                    ))}
                    {sortedGuests?.length === 0 && (
                      <tr>
                        <td colSpan={canEdit ? 6 : 5} className="text-secondary text-center">
                          No VMs or containers found across any node.
                        </td>
                      </tr>
                    )}
                  </tbody>
                </table>
              </div>
              <Pagination page={guestPage} pageCount={guestPageCount} totalCount={guestTotalCount} onPageChange={setGuestPage} />
              </div>
            </>
          )}
        </>
      )}
    </>
  );
}