Unify segmented selectors and fix compact panel spacing

src/ui/segmentedControl.js

@@ -0,0 +1,109 @@
+const STEPS = { ArrowRight: 1, ArrowDown: 1, ArrowLeft: -1, ArrowUp: -1 };
+
+/** Pure value navigation, also usable by a future template-based view. */
+export function nextSegmentValue(values, value, key, { homeEnd = true } = {}) {
+  if (!values.length) return undefined;
+  if (homeEnd && key === 'Home') return values[0];
+  if (homeEnd && key === 'End') return values.at(-1);
+  const step = STEPS[key];
+  if (!step) return undefined;
+  return values[(values.indexOf(value) + step + values.length) % values.length];
+}
+
+/** Paint controlled selection without emitting changes or moving focus. */
+export function syncSegmentedControl(
+  buttons,
+  value,
+  { valueOf, activeClass = 'active', rovingFocus = false } = {},
+) {
+  for (const button of buttons || []) {
+    if (!button) continue;
+    const selected = valueOf(button) === value;
+    if (button.classList.contains(activeClass) !== selected)
+      button.classList.toggle(activeClass, selected);
+    const set = (name, content) => {
+      if (button.getAttribute?.(name) !== content)
+        button.setAttribute(name, content);
+    };
+    set('aria-checked', String(selected));
+    if (rovingFocus) set('tabindex', selected ? '0' : '-1');
+  }
+}
+
+/**
+ * Controlled segmented-selector DOM adapter. Feature owners supply values and
+ * receive changes; rendering a restored value never triggers the callback.
+ * `keyboard` retains each existing group's policy: none, arrows, or radio
+ * (arrows plus Home/End). Pointer and native Enter/Space share the click path.
+ * An injected listener owner keeps the feature's existing teardown boundary.
+ * @param {object} options
+ * @param {Iterable<HTMLButtonElement>} options.buttons
+ * @param {Function} options.valueOf Maps a button to the feature's value.
+ * @param {Function} options.onChange Receives value and originating button.
+ * @param {'none'|'arrows'|'radio'} [options.keyboard]
+ * @param {HTMLElement} [options.keyTarget] Delegated keyboard target, if any.
+ * @param {Function} [options.readValue] Current controlled value for delegation.
+ * @param {Function} [options.listen] Feature-owned event registration.
+ * @returns {{ update: Function, destroy: Function }}
+ */
+export function createSegmentedControl({
+  buttons,
+  valueOf,
+  onChange,
+  keyboard = 'none',
+  keyTarget,
+  readValue,
+  listen,
+}) {
+  const options = [...buttons].filter(Boolean);
+  const removers = [];
+  let destroyed = false;
+  const bind = (target, type, handler) => {
+    const owned = (event) => {
+      if (!destroyed) handler(event);
+    };
+    if (listen) listen(target, type, owned);
+    else {
+      target.addEventListener(type, owned);
+      removers.push(() => target.removeEventListener(type, owned));
+    }
+  };
+  for (const button of options)
+    bind(button, 'click', () => {
+      if (!button.disabled) onChange(valueOf(button), button);
+    });
+  const navigate = (event, from) => {
+    const enabled = options.filter((button) => !button.disabled);
+    const values = enabled.map(valueOf);
+    const next = nextSegmentValue(values, from, event.key, {
+      homeEnd: keyboard === 'radio',
+    });
+    if (next === undefined) return;
+    const button = enabled.find((option) => valueOf(option) === next);
+    event.preventDefault();
+    if (keyTarget) {
+      button.click();
+      button.focus();
+    } else {
+      button.focus();
+      if (next !== from) button.click();
+    }
+  };
+  if (keyboard !== 'none') {
+    if (keyTarget)
+      bind(keyTarget, 'keydown', (event) => navigate(event, readValue()));
+    else
+      for (const button of options)
+        bind(button, 'keydown', (event) => navigate(event, valueOf(button)));
+  }
+  return {
+    update(value, presentation) {
+      if (!destroyed)
+        syncSegmentedControl(options, value, { valueOf, ...presentation });
+    },
+    destroy() {
+      destroyed = true;
+      for (const remove of removers.splice(0)) remove();
+    },
+  };
+}