/** Accessible HUX-06 mode intent selector. The feature is default-off. */

import { useMemo } from "react";

import {
  buildModeRequest,
  friendlyModesEnabled,
  normalizeAdvancedRoutes,
  normalizeModeCatalog,
  normalizeResolvedRoute,
} from "./model.ts";
import type {
  FriendlyModeIntent,
  FriendlyModeName,
  RawAdvancedRouteChoice,
  RawModeIntent,
  RawResolvedRoute,
} from "./types.ts";

interface FriendlyModeSelectorProps {
  flags?: Iterable<string>;
  modes: readonly RawModeIntent[];
  selectedMode: FriendlyModeName;
  advancedRoutes?: readonly RawAdvancedRouteChoice[];
  resolvedRoute?: RawResolvedRoute;
  disabled?: boolean;
  onChange(intent: FriendlyModeIntent): void;
}

const MODE_HELP: Readonly<Record<FriendlyModeName, string>> = {
  fast: "Quick, direct answers with light reasoning.",
  thoughtful: "More reasoning for careful decisions.",
  research: "Source-backed investigation with citations.",
  create: "Generative work with artifact support.",
  private: "Local-only processing with ephemeral retention.",
};

const PROVIDER_LABELS = {
  codex: "OpenAI",
  claude: "Anthropic",
  local: "Local",
} as const;

/** Render nothing unless HUX-11 and HUX-06 are both explicitly enabled. */
export function FriendlyModeSelector({
  flags,
  modes,
  selectedMode,
  advancedRoutes = [],
  resolvedRoute,
  disabled = false,
  onChange,
}: FriendlyModeSelectorProps) {
  const enabled = friendlyModesEnabled(flags);
  const catalog = useMemo(() => normalizeModeCatalog(modes), [modes]);
  const choices = useMemo(
    () => normalizeAdvancedRoutes(advancedRoutes),
    [advancedRoutes],
  );
  const resolved = useMemo(
    () => normalizeResolvedRoute(resolvedRoute),
    [resolvedRoute],
  );
  if (!enabled) return null;

  if (!catalog) {
    return (
      <p className="hux-modes-error" role="alert">
        Mode choices are unavailable because their safety contract could not be
        verified.
      </p>
    );
  }
  const selected = catalog.find((mode) => mode.mode === selectedMode);
  if (!selected) {
    return (
      <p className="hux-modes-error" role="alert">
        The selected mode could not be verified. No routing change was made.
      </p>
    );
  }
  const compatibleChoices = choices.filter((choice) =>
    selected.mode === "private"
      ? choice.localOnly && choice.provider === "local"
      : !choice.localOnly && selected.constraints.providers.includes(choice.provider),
  );

  return (
    <section className="hux-modes" aria-labelledby="hux-modes-heading">
      <div className="hux-modes-heading">
        <div>
          <h2 id="hux-modes-heading">Response mode</h2>
          <p>Choose the intent; Switchyard selects from the allowed pool.</p>
        </div>
        <span className="hux-modes-active" aria-live="polite">
          {selected.label}
        </span>
      </div>

      <fieldset disabled={disabled} className="hux-mode-grid">
        <legend className="sr-only">Choose a response mode</legend>
        {catalog.map((mode) => (
          <label className="hux-mode-card" key={mode.mode}>
            <input
              type="radio"
              name="hermes-friendly-mode"
              value={mode.mode}
              checked={mode.mode === selected.mode}
              aria-describedby={`hux-mode-help-${mode.mode}`}
              onChange={() => {
                const request = buildModeRequest(mode);
                if (request) onChange(request);
              }}
            />
            <span className="hux-mode-card-copy">
              <strong>{mode.label}</strong>
              <span id={`hux-mode-help-${mode.mode}`}>{MODE_HELP[mode.mode]}</span>
            </span>
          </label>
        ))}
      </fieldset>

      <details className="hux-modes-advanced">
        <summary>Advanced routing details</summary>
        <div className="hux-modes-advanced-panel">
          <dl>
            <div>
              <dt>Allowed pools</dt>
              <dd>
                {selected.constraints.providers
                  .map((provider) => PROVIDER_LABELS[provider])
                  .join(" + ")}
              </dd>
            </div>
            <div>
              <dt>Requested route</dt>
              <dd>{selected.switchyard.route_id}</dd>
            </div>
            {resolved?.target && (
              <div>
                <dt>Resolved route</dt>
                <dd>{resolved.target}</dd>
              </div>
            )}
            {resolved?.provider && (
              <div>
                <dt>Resolved provider</dt>
                <dd>{PROVIDER_LABELS[resolved.provider]}</dd>
              </div>
            )}
            {resolved?.effort && (
              <div>
                <dt>Resolved effort</dt>
                <dd>{resolved.effort}</dd>
              </div>
            )}
          </dl>

          <label className="hux-route-pin">
            <span>Exact route pin</span>
            <select
              disabled={disabled}
              defaultValue=""
              onChange={(event) => {
                const request = event.currentTarget.value
                  ? buildModeRequest(selected, event.currentTarget.value, choices)
                  : buildModeRequest(selected);
                if (request) onChange(request);
              }}
            >
              <option value="">Automatic — use all allowed pools</option>
              {compatibleChoices.map((choice) => (
                <option key={choice.routeId} value={choice.routeId}>
                  {choice.label} — {PROVIDER_LABELS[choice.provider]}
                </option>
              ))}
            </select>
          </label>
          <p className="hux-route-pin-help">
            Pinning bypasses automatic selection for this choice. Automatic
            modes otherwise keep both OpenAI and Anthropic eligible.
          </p>
        </div>
      </details>
    </section>
  );
}