import { useCallback, useEffect, useRef, useState } from 'react';
import { useSearchParams } from 'react-router';
import { useClient } from 'hooks/useClient';
import { DEFAULT_SECTION, SECTIONS, isSectionKey, type SectionKey } from './sections';
import { HostsPanel } from './HostsPanel';
import { CertificatesPanel } from './CertificatesPanel';
import { ConnectionPanel } from './ConnectionPanel';
import { ListSection, REDIRECTIONS, STREAMS, DEAD_HOSTS, ACCESS_LISTS } from './ListSection';
import { PlannedSection } from './PlannedSection';
import { useNpmChanged } from './channel';

/**
 * The right column: whichever section the nav has selected.
 *
 * It reads `?section=` from the URL rather than being handed it — the two panels are siblings in a
 * workspace and neither owns the other, and `docs/navigation-audit.md` puts addressable state in the URL
 * for exactly this reason. A bogus or missing value falls back rather than rendering nothing.
 *
 * ── The unconfigured check lives HERE, once ──
 *
 * Every section needs a connection, so every section would otherwise have to handle its absence, and each
 * one would say something slightly different. Asking `/status` once and rendering the connection form
 * instead of any section is the same answer for all seven, and it means "no connection yet" reads as a
 * setup step rather than as six broken lists.
 */

type Status = { configured: boolean };

export const DetailPanel = () => {
  const [params] = useSearchParams();
  const raw = params.get('section');
  const section: SectionKey = isSectionKey(raw) ? raw : DEFAULT_SECTION;

  const client = useClient();
  const clientRef = useRef(client);
  clientRef.current = client;

  const [configured, setConfigured] = useState<boolean | null>(null);
  const [connectionSignal] = useNpmChanged();

  const check = useCallback(async () => {
    try {
      const status = await clientRef.current.get<Status>('/proxy-manager/status');
      setConfigured(status.configured);
    } catch {
      // Cannot tell. Render the section rather than the setup form — a transient failure must not look
      // like "you have not set this up", which is a much more alarming thing to be told.
      setConfigured(true);
    }
  }, []);

  useEffect(() => {
    void check();
  }, [check, connectionSignal]);

  if (configured === null) {
    return <div className="flex size-full items-center justify-center p-6 text-sm text-muted-foreground">Loading…</div>;
  }

  // A planned section says so before anything else — including before the connection check, because "you
  // have not connected NPM" is not why Domains is empty and would be a misleading thing to be told.
  const planned = SECTIONS.find((s) => s.key === section && s.planned);
  if (planned) return <PlannedSection section={planned} />;

  if (!configured || section === 'connection') return <ConnectionPanel />;

  switch (section) {
    case 'proxy-hosts':
      return <HostsPanel />;
    case 'certificates':
      return <CertificatesPanel />;
    case 'redirections':
      return <ListSection {...REDIRECTIONS} />;
    case 'streams':
      return <ListSection {...STREAMS} />;
    case 'dead-hosts':
      return <ListSection {...DEAD_HOSTS} />;
    case 'access-lists':
      return <ListSection {...ACCESS_LISTS} />;
    default:
      // `domains` and `dns-providers` are handled above; this keeps the switch total without a cast.
      return null;
  }
};