// Undercooked — the help overlay (phase 07, task 05; the task's
// `app/static/ui/help.js`, served from `js/ui/` like the HUD).
//
// The `?`-key in-game help: a body-level, fixed, dismissible panel
// listing the key map. Created once at boot, persists across screens
// (it is not a screen — the state machine never knows it), hidden by
// default. `?` toggles it; `Escape` closes it (the keyboard module's
// `Esc` branch defers to it while it is open); a click on the panel's
// backdrop or its Close button dismisses it. No external docs needed
// mid-game.
//
// The rows are `getKeyMap()`'s — `input/keyboard.js` re-exports it
// (the canonical source) and the README's controls section renders the
// same rows (a test keeps them identical: the browser-rendered map
// against the README's block).

import { el } from "../screens/dom.js";

/**
 * The key map the help panel (and the README's controls section — a
 * test keeps them identical) renders: `{ keys, action }` rows in
 * display order. `keys` are joined with " / " when rendered.
 */
export function getKeyMap() {
  return [
    { keys: ["W", "A", "S", "D"], action: "move (or the arrow keys)" },
    { keys: ["Space", "Enter"], action: "action (pick, work, set down, serve)" },
    { keys: ["1", "2", "3", "4"], action: "emote (wave, cheer, thumbs up, thumbs down)" },
    { keys: ["?"], action: "help overlay" },
    { keys: ["Esc"], action: "close help / leave the room" },
  ];
}

/**
 * The help overlay itself.
 *
 * `onToggle` — optional `(visible) => void` (the census seam; the
 * keyboard module's `?`/`Esc` branches need no hook — they call
 * `toggle()` / `hide()` directly).
 *
 * Returns `{ show, hide, toggle, visible }`.
 */
export function createHelpOverlay({ onToggle = null } = {}) {
  let panel = null;
  let visible = false;

  function build() {
    if (panel !== null) return panel;
    const title = el(
      "div",
      { class: "help-title" },
      el("span", { class: "help-heading", text: "Controls" }),
      el("button", {
        class: "btn help-close",
        type: "button",
        "aria-label": "Close help",
        text: "Close",
        onClick: () => hide(),
      })
    );
    const rows = getKeyMap().map((row) =>
      el(
        "div",
        { class: "help-row" },
        el("kbd", { class: "help-keys", text: row.keys.join(" / ") }),
        el("span", { class: "help-action", text: row.action })
      )
    );
    panel = el(
      "div",
      {
        id: "help-overlay",
        class: "help-overlay",
        role: "dialog",
        "aria-label": "Help",
        "aria-hidden": "true",
      },
      el(
        "div",
        { class: "panel help-panel", onClick: (e) => e.stopPropagation() },
        title,
        el("div", { class: "help-rows" }, ...rows),
        el("p", {
          class: "help-foot",
          text: "Press ? or Esc to close. On the play screen, Esc leaves the room.",
        })
      )
    );
    panel.addEventListener("click", () => hide());
    return panel;
  }

  function show() {
    const node = build();
    if (visible) return;
    node.setAttribute("aria-hidden", "false");
    document.body.append(node);
    visible = true;
    if (onToggle !== null) onToggle(true);
  }

  function hide() {
    if (!visible) return;
    visible = false;
    if (panel !== null) {
      panel.setAttribute("aria-hidden", "true");
      panel.remove();
    }
    if (onToggle !== null) onToggle(false);
  }

  function toggle() {
    if (visible) hide();
    else show();
  }

  return { show, hide, toggle, visible: () => visible };
}