// <CreateAgentForm> — minimal agent creation form, POSTs to
// swarm-controller's `POST /api/agents`. That endpoint only queues a
// `CreateIdentity` job and returns its node id — the identity isn't
// guaranteed to exist yet when this gets a response — so this shows
// the queued confirmation and links to the Jobs page to watch it
// settle, rather than duplicating JobqGraph's per-node polling here.
// Scope matches the originating issue exactly: name field only, no
// forge/deploy options (those aren't wired server-side yet either).
//
// Rendered inside a `Dialog` from `AgentsPage`'s own "+ agent" button,
// not a standalone route — the roster it feeds is the natural home for
// the action that populates it, and a distinct top-level nav item next
// to it was one click of indirection for no benefit. Kept as its own
// component (not inlined into AgentsPage) since the two-panel layout
// below is unchanged from its former life as a page: same content, same
// review history, just a different mount point.
//
// `hive` field added because agent creation had no way to record which
// hive an agent runs on. `POST /api/agents` now requires it, so the
// roster fetched off `GET /api/hives` backs a required select here
// rather than a free-text field — a spawn target has to be one of the
// swarm's actual hives, same reasoning `Ident.parse` gets client-side
// pattern validation for `name`.
//
// Its name field, hive select, and submit button all come from the
// shared `ui/` form kit (`TextField`/`SelectField`/`Button`) rather than
// page-scoped input/button chrome — see that kit's own comments for why.
import { useEffect, useState } from 'preact/hooks';
import { Link } from 'wouter-preact';
import { ApiErrorPanel } from '@hive/shared/api-error-panel.js';
import { readApiError, type ProblemDetails } from '@hive/shared/api-error.js';
import { Panel } from '../ui/panel/Panel.js';
import { TextField } from '../ui/text-field/TextField.js';
import { SelectField, type SelectOption } from '../ui/select-field/SelectField.js';
import { Button } from '../ui/button/Button.js';
import './CreateAgentForm.css';

// Mirrors swarm-controller's `HiveEntry` — same shape `HivesPage`
// consumes off `/api/hives/status`, but this page hits the plain
// `/api/hives` roster (no status/freshness needed, just "what hives
// exist to spawn into").
interface HiveEntry {
  name: string;
  domain: string;
}

interface CreateAgentResponse {
  node_id: number;
}

type SubmitState =
  | { status: 'idle' }
  | { status: 'submitting' }
  | { status: 'done'; nodeId: number }
  | { status: 'error'; problem: ProblemDetails };

// Client-side mirror of `hive_types::Ident` (1-63 chars of `[a-z0-9-]`) —
// a `pattern` hint only, not a substitute for the server's own
// validation; a name this rejects would fail server-side anyway, so
// catching it before a round-trip is a pure UX win, not a new gate.
//
// Hyphen escaped (`\-`) rather than left trailing in the class: modern
// browsers validate the `pattern` attribute's regex in Unicode-set (`v`)
// mode, which is far stricter about hyphen placement than classic mode —
// `[a-z0-9-]` throws "Invalid character class" under `v` mode even though
// it's valid classic-mode regex (a trailing `-` is unambiguous there).
// Reproduced directly: `new RegExp('[a-z0-9-]', 'v')` throws,
// `new RegExp('[a-z0-9\\-]', 'v')` doesn't — confirmed via mara's console
// exception report on this page.
const NAME_PATTERN = '[a-z0-9\\-]{1,63}';

export function CreateAgentForm() {
  const [name, setName] = useState('');
  const [hive, setHive] = useState('');
  // `null` = still loading, `[]` = loaded but empty (a real, if unusual,
  // swarm state) — distinct from "not fetched yet" so the placeholder
  // option's label can tell the two apart.
  const [hives, setHives] = useState<HiveEntry[] | null>(null);
  const [hivesError, setHivesError] = useState<ProblemDetails | null>(null);
  const [result, setResult] = useState<SubmitState>({ status: 'idle' });

  // Loaded once, not re-fetched on submit: the roster changes rarely
  // enough (a nix-level swarm config change) that staleness within one
  // page visit isn't worth a second round-trip per keystroke/submit.
  useEffect(() => {
    (async () => {
      const r = await fetch('/api/hives');
      if (!r.ok) {
        setHivesError(await readApiError(r));
        return;
      }
      const data = (await r.json()) as HiveEntry[];
      setHives(data);
      // Single-hive swarms are the common case — default it rather than
      // making the operator pick the only option. Multi-hive swarms get
      // no default (the placeholder stays selected), so `required` on
      // the select below forces an explicit choice per mara's scope.
      if (data.length === 1) setHive(data[0].name);
    })().catch((e: unknown) => setHivesError({ detail: String(e) }));
  }, []);

  const hiveOptions: SelectOption[] = (hives ?? []).map((h) => ({ value: h.name, label: h.name }));
  const hivesReady = hives !== null && hives.length > 0;

  async function submit(e: Event) {
    e.preventDefault();
    setResult({ status: 'submitting' });
    try {
      const r = await fetch('/api/agents', {
        method: 'POST',
        headers: { 'content-type': 'application/json' },
        body: JSON.stringify({ name, hive }),
      });
      if (!r.ok) {
        setResult({ status: 'error', problem: await readApiError(r) });
        return;
      }
      const data = (await r.json()) as CreateAgentResponse;
      setResult({ status: 'done', nodeId: data.node_id });
      setName('');
    } catch (err) {
      setResult({ status: 'error', problem: { detail: String(err) } });
    }
  }

  return (
    <div class="create-agent-layout">
      <div class="create-agent-form-col">
        <Panel title="create agent" icon="🤖">
          <p class="create-agent-intro">
            Create a new agent's swarm-level identity. This only queues the job — check{' '}
            <Link href="/jobs">jobs</Link> to watch it settle.
          </p>
          {hivesError && (
            <ApiErrorPanel context="failed to load the hive list" problem={hivesError} />
          )}
          <form class="create-agent-form" onSubmit={submit}>
            <TextField
              id="agent-name"
              label="agent name"
              value={name}
              pattern={NAME_PATTERN}
              title="1-63 chars: lowercase letters, digits, hyphens"
              required
              onInput={setName}
            />
            <SelectField
              id="agent-hive"
              label="hive"
              value={hive}
              onChange={setHive}
              options={hiveOptions}
              required
              disabled={!hivesReady}
              placeholder={
                !hives ? 'loading…' : hives.length === 0 ? 'no hives configured' : 'select a hive'
              }
            />
            <Button
              variant="primary"
              type="submit"
              disabled={result.status === 'submitting' || !hivesReady}
            >
              {result.status === 'submitting' ? 'creating…' : 'create'}
            </Button>
          </form>
          {result.status === 'done' && (
            <p class="create-agent-result create-agent-result-ok">
              queued as job node #{result.nodeId} — <Link href="/jobs">watch it in jobs</Link>
            </p>
          )}
          {result.status === 'error' && (
            <ApiErrorPanel context="failed to queue" problem={result.problem} />
          )}
        </Panel>
      </div>
      <div class="create-agent-info-col">
        {/* Describes the intended end state (a running agent), not today's
            literal behaviour (deploying the container onto the hive isn't
            wired up server-side yet — see this file's top comment) —
            mara's explicit call on this copy: read as finished, not as a
            running commentary on partial implementation. The 🪪 glyph that
            used to sit here as body copy now lives on `Panel`'s own `icon`
            prop instead — it's what prompted that prop to exist at all
            (see Panel.tsx's doc comment) */}
        <Panel title="what this creates" icon="🪪">
          <p>
            Submitting this queues everything a new agent needs: a swarm-level identity, a config
            repo on the forge with the operator added as a collaborator, and a container running
            the agent on the hive you pick above. Watch it all settle on{' '}
            <Link href="/jobs">jobs</Link>.
          </p>
        </Panel>
      </div>
    </div>
  );
}