NH_widget

Widgets for user interactions.

Dieses Skript sollte nicht direkt installiert werden. Es handelt sich hier um eine Bibliothek für andere Skripte, welche über folgenden Befehl in den Metadaten eines Skriptes eingebunden wird // @require https://update.greasyfork.org/scripts/478676/1337642/NH_widget.js

// ==UserScript==
// ==UserLibrary==
// @name        NH_widget
// @description Widgets for user interactions.
// @version     45
// @license     GPL-3.0-or-later; https://www.gnu.org/licenses/gpl-3.0-standalone.html
// @homepageURL https://github.com/nexushoratio/userscripts
// @supportURL  https://github.com/nexushoratio/userscripts/issues
// @match       https://www.example.com/*
// ==/UserLibrary==
// ==/UserScript==

window.NexusHoratio ??= {};

window.NexusHoratio.widget = (function widget() {
  'use strict';

  /** @type {number} - Bumped per release. */
  const version = 45;

  const NH = window.NexusHoratio.base.ensure([
    {name: 'xunit', minVersion: 39},
    {name: 'base', minVersion: 52},
  ]);

  /** Library specific exception. */
  class Exception extends NH.base.Exception {}

  /** Thrown on verification errors. */
  class VerificationError extends Exception {}

  /** Useful for matching in tests. */
  const HEX = '[0-9a-f]';
  const GUID = `${HEX}{8}-(${HEX}{4}-){3}${HEX}{12}`;

  /** @typedef {(string|HTMLElement|Widget)} Content */

  /**
   * Base class for rendering widgets.
   *
   * Subclasses should NOT override methods here, except for constructor().
   * Instead they should register listeners for appropriate events.
   *
   * Generally, methods will fire two event verbs.  The first, in present
   * tense, will instruct what should happen (build, destroy, etc).  The
   * second, in past tense, will describe what should have happened (built,
   * destroyed, etc).  Typically, subclasses will act upon the present tense,
   * and users of the class may act upon the past tense.
   *
   * Methods should generally be able to be chained.
   *
   * If a variable holding a widget is set to a new value, the previous widget
   * should be explicitly destroyed.
   *
   * When a Widget is instantiated, it should only create a container of the
   * requested type (done in this base class).  And install any widget styles
   * it needs in order to function.  The container property can then be placed
   * into the DOM.
   *
   * If a Widget needs specific CSS to function, that CSS should be shared
   * across all instances of the Widget by using the same values in a call to
   * installStyle().  Anything used for presentation should include the
   * Widget's id as part of the style's id.
   *
   * The build() method will fire 'build'/'built' events.  Subclasses then
   * populate the container with HTML as appropriate.  Widgets should
   * generally be designed to not update the internal HTML until build() is
   * explicitly called.
   *
   * The destroy() method will fire 'destroy'/'destroyed' events and also
   * clear the innerHTML of the container.  Subclasses are responsible for any
   * internal cleanup, such as nested Widgets.
   *
   * The verify() method will fire 'verify'/'verified' events.  Subclasses can
   * handle these to validate any internal structures they need for.  For
   * example, Widgets that have ARIA support can ensure appropriate attributes
   * are in place.  If a Widget fails, it should throw a VerificationError
   * with details.
   */
  class Widget {

    /**
     * Each subclass should take a caller provided name.
     * @param {string} name - Name for this instance.
     * @param {string} element - Type of element to use for the container.
     */
    constructor(name, element) {
      if (new.target === Widget) {
        throw new TypeError('Abstract class; do not instantiate directly.');
      }

      this.#name = `${this.constructor.name} ${name}`;
      this.#id = NH.base.uuId(NH.base.safeId(this.name));
      this.#container = document.createElement(element);
      this.#container.id = `${this.id}-container`;
      this.#dispatcher = new NH.base.Dispatcher(...Widget.#knownEvents);
      this.#logger = new NH.base.Logger(`${this.constructor.name}`);
      this.#visible = true;

      this.installStyle('nh-widget',
        [`.${Widget.classHidden} {display: none}`]);
    }

    /** @type {string} - CSS class applied to hide element. */
    static get classHidden() {
      return 'nh-widget-hidden';
    }

    /** @type {Element} */
    get container() {
      return this.#container;
    }

    /** @type {string} */
    get id() {
      return this.#id;
    }

    /** @type {NH.base.Logger} */
    get logger() {
      return this.#logger;
    }

    /** @type {string} */
    get name() {
      return this.#name;
    }

    /** @type {boolean} */
    get visible() {
      return this.#visible;
    }

    /**
     * Materialize the contents into the container.
     *
     * Each time this is called, the Widget should repopulate the contents.
     * @fires 'build' 'built'
     * @returns {Widget} - This instance, for chaining.
     */
    build() {
      this.#dispatcher.fire('build', this);
      this.#dispatcher.fire('built', this);
      this.verify();
      return this;
    }

    /**
     * Tears down internals.  E.g., any Widget that has other Widgets should
     * call their destroy() method as well.
     * @fires 'destroy' 'destroyed'
     * @returns {Widget} - This instance, for chaining.
     */
    destroy() {
      this.#container.innerHTML = '';
      this.#dispatcher.fire('destroy', this);
      this.#dispatcher.fire('destroyed', this);
      return this;
    }

    /**
     * Shows the Widget by removing a CSS class.
     * @fires 'show' 'showed'
     * @returns {Widget} - This instance, for chaining.
     */
    show() {
      this.verify();
      this.#dispatcher.fire('show', this);
      this.container.classList.remove(Widget.classHidden);
      this.#visible = true;
      this.#dispatcher.fire('showed', this);
      return this;
    }

    /**
     * Hides the Widget by adding a CSS class.
     * @fires 'hide' 'hidden'
     * @returns {Widget} - This instance, for chaining.
     */
    hide() {
      this.#dispatcher.fire('hide', this);
      this.container.classList.add(Widget.classHidden);
      this.#visible = false;
      this.#dispatcher.fire('hidden', this);
      return this;
    }

    /**
     * Verifies a Widget's internal state.
     *
     * For example, a Widget may use this to enforce certain ARIA criteria.
     * @fires 'verify' 'verified'
     * @returns {Widget} - This instance, for chaining.
     */
    verify() {
      this.#dispatcher.fire('verify', this);
      this.#dispatcher.fire('verified', this);
      return this;
    }

    /** Clears the container element. */
    clear() {
      this.logger.log('clear is deprecated');
      this.#container.innerHTML = '';
    }

    /**
     * Attach a function to an eventType.
     * @param {string} eventType - Event type to connect with.
     * @param {NH.base.Dispatcher~Handler} func - Single argument function to
     * call.
     * @returns {Widget} - This instance, for chaining.
     */
    on(eventType, func) {
      this.#dispatcher.on(eventType, func);
      return this;
    }

    /**
     * Remove all instances of a function registered to an eventType.
     * @param {string} eventType - Event type to disconnect from.
     * @param {NH.base.Dispatcher~Handler} func - Function to remove.
     * @returns {Widget} - This instance, for chaining.
     */
    off(eventType, func) {
      this.#dispatcher.off(eventType, func);
      return this;
    }

    /**
     * Helper that sets an attribute to value.
     *
     * If value is null, the attribute is removed.
     * @example
     * w.attrText('aria-label', 'Information about the application.')
     * @param {string} attr - Name of the attribute.
     * @param {?string} value - Value to assign.
     * @returns {Widget} - This instance, for chaining.
     */
    attrText(attr, value) {
      if (value === null) {
        this.container.removeAttribute(attr);
      } else {
        this.container.setAttribute(attr, value);
      }
      return this;
    }

    /**
     * Helper that sets an attribute to space separated {Element} ids.
     *
     * This will collect the appropriate id from each value passed then assign
     * that collection to the attribute.  If any value is null, the everything
     * up to that point will be reset.  If the collection ends up being empty
     * (e.g., no values were passed or the last was null), the attribute will
     * be removed.
     * @param {string} attr - Name of the attribute.
     * @param {?Content} values - Value to assign.
     * @returns {Widget} - This instance, for chaining.
     */
    attrElements(attr, ...values) {
      const strs = [];
      for (const value of values) {
        if (value === null) {
          strs.length = 0;
        } else if (typeof value === 'string' || value instanceof String) {
          strs.push(value);
        } else if (value instanceof HTMLElement) {
          if (value.id) {
            strs.push(value.id);
          }
        } else if (value instanceof Widget) {
          if (value.container.id) {
            strs.push(value.container.id);
          }
        }
      }
      if (strs.length) {
        this.container.setAttribute(attr, strs.join(' '));
      } else {
        this.container.removeAttribute(attr);
      }
      return this;
    }

    /**
     * Install a style if not already present.
     *
     * It will NOT overwrite an existing one.
     * @param {string} id - Base to use for the style id.
     * @param {string[]} rules - CSS rules in 'selector { declarations }'.
     * @returns {HTMLStyleElement} - Resulting <style> element.
     */
    installStyle(id, rules) {
      const me = 'installStyle';
      this.logger.entered(me, id, rules);

      const safeId = `${NH.base.safeId(id)}-style`;
      let style = document.querySelector(`#${safeId}`);
      if (!style) {
        style = document.createElement('style');
        style.id = safeId;
        style.textContent = rules.join('\n');
        document.head.append(style);
      }

      this.logger.leaving(me, style);
      return style;
    }

    static #knownEvents = [
      'build',
      'built',
      'verify',
      'verified',
      'destroy',
      'destroyed',
      'show',
      'showed',
      'hide',
      'hidden',
    ];

    #container
    #dispatcher
    #id
    #logger
    #name
    #visible

  }

  /* eslint-disable require-jsdoc */
  class Test extends Widget {

    constructor() {
      super('test', 'section');
    }

  }
  /* eslint-enable */

  /* eslint-disable max-statements */
  /* eslint-disable no-magic-numbers */
  /* eslint-disable no-new */
  /* eslint-disable require-jsdoc */
  class WidgetTestCase extends NH.xunit.TestCase {

    testAbstract() {
      this.assertRaises(TypeError, () => {
        new Widget();
      });
    }

    testProperties() {
      // Assemble
      const w = new Test();

      // Assert
      this.assertTrue(w.container instanceof HTMLElement, 'element');
      this.assertRegExp(
        w.container.id,
        RegExp(`^Test-test-${GUID}-container$`, 'u'),
        'container'
      );

      this.assertRegExp(w.id, RegExp(`^Test-test-${GUID}`, 'u'), 'id');
      this.assertTrue(w.logger instanceof NH.base.Logger, 'logger');
      this.assertEqual(w.name, 'Test test', 'name');
    }

    testSimpleEvents() {
      // Assemble
      const calls = [];
      const cb = (...rest) => {
        calls.push(rest);
      };
      const w = new Test()
        .on('build', cb)
        .on('built', cb)
        .on('verify', cb)
        .on('verified', cb)
        .on('destroy', cb)
        .on('destroyed', cb)
        .on('show', cb)
        .on('showed', cb)
        .on('hide', cb)
        .on('hidden', cb);

      // Act
      w.build()
        .show()
        .hide()
        .destroy();

      // Assert
      this.assertEqual(calls, [
        ['build', w],
        ['built', w],
        // After build()
        ['verify', w],
        ['verified', w],
        // Before show()
        ['verify', w],
        ['verified', w],
        ['show', w],
        ['showed', w],
        ['hide', w],
        ['hidden', w],
        ['destroy', w],
        ['destroyed', w],
      ]);
    }

    testDestroyCleans() {
      // Assemble
      const w = new Test();
      // XXX: Broken HTML on purpose
      w.container.innerHTML = '<p>Paragraph<p>';

      this.assertEqual(w.container.innerHTML,
        '<p>Paragraph</p><p></p>',
        'html got fixed');
      this.assertEqual(w.container.children.length, 2, 'initial count');

      // Act
      w.destroy();

      // Assert
      this.assertEqual(w.container.children.length, 0, 'post destroy count');
    }

    testHideShow() {
      // Assemble
      const w = new Test();

      this.assertTrue(w.visible, 'init vis');
      this.assertFalse(w.container.classList.contains(Widget.classHidden),
        'init class');

      w.hide();

      this.assertFalse(w.visible, 'hide vis');
      this.assertTrue(w.container.classList.contains(Widget.classHidden),
        'hide class');

      w.show();

      this.assertTrue(w.visible, 'show viz');
      this.assertFalse(w.container.classList.contains(Widget.classHidden),
        'show class');
    }

    testVerifyFails() {
      // Assemble
      const calls = [];
      const cb = (...rest) => {
        calls.push(rest);
      };
      const onVerify = () => {
        throw new VerificationError('oopsie');
      };
      const w = new Test()
        .on('build', cb)
        .on('verify', onVerify)
        .on('show', cb);

      // Act/Assert
      this.assertRaises(
        VerificationError,
        () => {
          w.build()
            .show();
        },
        'verify fails on purpose'
      );
      this.assertEqual(calls, [['build', w]], 'we made it past build');
    }

    testOnOff() {
      // Assemble
      const calls = [];
      const cb = (...rest) => {
        calls.push(rest);
      };
      const w = new Test()
        .on('build', cb)
        .on('built', cb)
        .on('destroyed', cb)
        .off('build', cb)
        .on('destroy', cb)
        .off('destroyed', cb);

      // Act
      w.build()
        .hide()
        .show()
        .destroy();

      // Assert
      this.assertEqual(calls, [
        ['built', w],
        ['destroy', w],
      ]);
    }

    testAttrText() {
      // Assemble
      const attr = 'aria-label';
      const w = new Test();

      function f() {
        return w.container.getAttribute(attr);
      }

      this.assertEqual(f(), null, 'init does not exist');

      // First value
      w.attrText(attr, 'App info.');
      this.assertEqual(f(), 'App info.', 'exists');

      // Change
      w.attrText(attr, 'Different value');
      this.assertEqual(f(), 'Different value', 'post change');

      // Empty string
      w.attrText(attr, '');
      this.assertEqual(f(), '', 'empty string');

      // Remove
      w.attrText(attr, null);
      this.assertEqual(f(), null, 'now gone');
    }

    testAttrElements() {
      const attr = 'aria-labelledby';
      const text = 'id1 id2';
      const div = document.createElement('div');
      div.id = 'div-id';
      const w = new Test();
      w.container.id = 'w-id';

      function g() {
        return w.container.getAttribute(attr);
      }

      this.assertEqual(g(), null, 'init does not exist');

      // Single value
      w.attrElements(attr, 'bob');
      this.assertEqual(g(), 'bob', 'single value');

      // Replace with spaces
      w.attrElements(attr, text);
      this.assertEqual(g(), 'id1 id2', 'spaces');

      // Remove
      w.attrElements(attr, null);
      this.assertEqual(g(), null, 'first remove');

      // Multiple values of different types
      w.attrElements(attr, text, div, w);
      this.assertEqual(g(), 'id1 id2 div-id w-id', 'everything');

      // Duplicates
      w.attrElements(attr, text, text);
      this.assertEqual(g(), 'id1 id2 id1 id2', 'duplicates');

      // Null in the middle
      w.attrElements(attr, w, null, text, null, text);
      this.assertEqual(g(), 'id1 id2', 'mid null');

      // Null at the end
      w.attrElements(attr, text, w, div, null);
      this.assertEqual(g(), null, 'end null');
    }

  }
  /* eslint-enable */

  NH.xunit.testing.testCases.push(WidgetTestCase);

  /**
   * An adapter for raw HTML.
   *
   * Other Widgets may use this to wrap any HTML they may be handed so they do
   * not need to special case their implementation outside of construction.
   */
  class StringAdapter extends Widget {

    /**
     * @param {string} name - Name for this instance.
     * @param {string} content - Item to be adapted.
     */
    constructor(name, content) {
      super(name, 'content');
      this.#content = content;
      this.on('build', this.#onBuild);
    }

    #content

    #onBuild = (...rest) => {
      const me = 'onBuild';
      this.logger.entered(me, rest);

      this.container.innerHTML = this.#content;

      this.logger.leaving(me);
    }

  }

  /* eslint-disable no-new-wrappers */
  /* eslint-disable require-jsdoc */
  class StringAdapterTestCase extends NH.xunit.TestCase {

    testPrimitiveString() {
      // Assemble
      let p = '<p id="bob">This is my paragraph.</p>';
      const content = new StringAdapter(this.id, p);

      // Act
      content.build();

      // Assert
      this.assertTrue(content.container instanceof HTMLUnknownElement,
        'is HTMLUnknownElement');
      this.assertTrue((/my paragraph./u).test(content.container.innerText),
        'expected text');
      this.assertEqual(content.container.firstChild.tagName, 'P', 'is para');
      this.assertEqual(content.container.firstChild.id, 'bob', 'is bob');

      // Tweak
      content.container.firstChild.id = 'joe';
      this.assertNotEqual(content.container.firstChild.id, 'bob', 'not bob');

      // Rebuild
      content.build();
      this.assertEqual(content.container.firstChild.id, 'bob', 'bob again');

      // Tweak - Not a live string
      p = '<p id="changed">New para.</p>';
      this.assertEqual(content.container.firstChild.id, 'bob', 'still bob');
    }

    testStringObject() {
      // Assemble
      const p = new String('<p id="pat">This is my paragraph.</p>');
      const content = new StringAdapter(this.id, p);

      // Act
      content.build();
      // Assert
      this.assertTrue(content.container instanceof HTMLUnknownElement,
        'is HTMLUnknownElement');
      this.assertTrue((/my paragraph./u).test(content.container.innerText),
        'expected text');
      this.assertEqual(content.container.firstChild.tagName, 'P', 'is para');
      this.assertEqual(content.container.firstChild.id, 'pat', 'is pat');
    }

  }
  /* eslint-enable */

  NH.xunit.testing.testCases.push(StringAdapterTestCase);

  /**
   * An adapter for HTMLElement.
   *
   * Other Widgets may use this to wrap any HTMLElements they may be handed so
   * they do not need to special case their implementation outside of
   * construction.
   */
  class ElementAdapter extends Widget {

    /**
     * @param {string} name - Name for this instance.
     * @param {HTMLElement} content - Item to be adapted.
     */
    constructor(name, content) {
      super(name, 'content');
      this.#content = content;
      this.on('build', this.#onBuild);
    }

    #content

    #onBuild = (...rest) => {
      const me = 'onBuild';
      this.logger.entered(me, rest);

      this.container.replaceChildren(this.#content);

      this.logger.leaving(me);
    }

  }
  /* eslint-disable require-jsdoc */
  class ElementAdapterTestCase extends NH.xunit.TestCase {

    testElement() {
      // Assemble
      const div = document.createElement('div');
      div.id = 'pat';
      div.innerText = 'I am a div.';
      const content = new ElementAdapter(this.id, div);

      // Act
      content.build();

      // Assert
      this.assertTrue(content.container instanceof HTMLUnknownElement,
        'is HTMLUnknownElement');
      this.assertTrue((/I am a div./u).test(content.container.innerText),
        'expected text');
      this.assertEqual(content.container.firstChild.tagName, 'DIV', 'is div');
      this.assertEqual(content.container.firstChild.id, 'pat', 'is pat');

      // Tweak
      content.container.firstChild.id = 'joe';
      this.assertNotEqual(content.container.firstChild.id, 'pat', 'not pat');
      this.assertEqual(div.id, 'joe', 'demos is a live element');

      // Rebuild
      content.build();
      this.assertEqual(content.container.firstChild.id, 'joe', 'still joe');

      // Multiple times
      content.build();
      content.build();
      content.build();
      this.assertEqual(content.container.childNodes.length, 1, 'child nodes');
    }

  }
  /* eslint-enable */

  NH.xunit.testing.testCases.push(ElementAdapterTestCase);

  /**
   * Selects the best adapter to wrap the content.
   * @param {string} name - Name for this instance.
   * @param {Content} content - Content to be adapted.
   * @throws {TypeError} - On type not handled.
   * @returns {Widget} - Appropriate adapter for content.
   */
  function contentWrapper(name, content) {
    if (typeof content === 'string' || content instanceof String) {
      return new StringAdapter(name, content);
    } else if (content instanceof HTMLElement) {
      return new ElementAdapter(name, content);
    } else if (content instanceof Widget) {
      return content;
    }
    throw new TypeError(`Unknown type for "${name}": ${content}`);
  }

  /* eslint-disable no-magic-numbers */
  /* eslint-disable no-new-wrappers */
  /* eslint-disable require-jsdoc */
  class ContentWrapperTestCase extends NH.xunit.TestCase {

    testPrimitiveString() {
      const x = contentWrapper(this.id, 'a string');

      this.assertTrue(x instanceof StringAdapter);
    }

    testStringObject() {
      const x = contentWrapper(this.id, new String('a string'));

      this.assertTrue(x instanceof StringAdapter);
    }

    testElement() {
      const element = document.createElement('div');
      const x = contentWrapper(this.id, element);

      this.assertTrue(x instanceof ElementAdapter);
    }

    testWidget() {
      const t = new Test();
      const x = contentWrapper(this.id, t);

      this.assertEqual(x, t);
    }

    testUnknown() {
      this.assertRaises(
        TypeError,
        () => {
          contentWrapper(this.id, null);
        },
        'null'
      );

      this.assertRaises(
        TypeError,
        () => {
          contentWrapper(this.id, 5);
        },
        'int'
      );

      this.assertRaises(
        TypeError,
        () => {
          contentWrapper(this.id, new Error('why not?'));
        },
        'error-type'
      );
    }

  }
  /* eslint-enable */

  NH.xunit.testing.testCases.push(ContentWrapperTestCase);

  /**
   * Implements the Layout pattern.
   */
  class Layout extends Widget {

    /** @param {string} name - Name for this instance. */
    constructor(name) {
      super(name, 'div');
      this.on('build', this.#onBuild)
        .on('destroy', this.#onDestroy);
      for (const panel of Layout.#Panel.known) {
        this.set(panel, '');
      }
    }

    /** @type {Widget} */
    get bottom() {
      return this.#panels.get(Layout.BOTTOM);
    }

    /** @type {Widget} */
    get left() {
      return this.#panels.get(Layout.LEFT);
    }

    /** @type {Widget} */
    get main() {
      return this.#panels.get(Layout.MAIN);
    }

    /** @type {Widget} */
    get right() {
      return this.#panels.get(Layout.RIGHT);
    }

    /** @type {Widget} */
    get top() {
      return this.#panels.get(Layout.TOP);
    }

    /**
     * Sets a panel for this instance.
     *
     * @param {Layout.#Panel} panel - Panel to set.
     * @param {Content} content - Content to use.
     * @returns {Widget} - This instance, for chaining.
     */
    set(panel, content) {
      if (!(panel instanceof Layout.#Panel)) {
        throw new TypeError('"panel" argument is not a Layout.#Panel');
      }

      this.#panels.get(panel)
        ?.destroy();

      this.#panels.set(panel,
        contentWrapper(`${panel} panel content`, content));

      return this;
    }

    /** Panel enum. */
    static #Panel = class {

      /** @param {string} name - Panel name. */
      constructor(name) {
        this.#name = name;

        Layout.#Panel.known.add(this);
      }

      static known = new Set();

      /** @returns {string} - The name. */
      toString() {
        return this.#name;
      }

      #name

    }

    static {
      Layout.BOTTOM = new Layout.#Panel('bottom');
      Layout.LEFT = new Layout.#Panel('left');
      Layout.MAIN = new Layout.#Panel('main');
      Layout.RIGHT = new Layout.#Panel('right');
      Layout.TOP = new Layout.#Panel('top');
    }

    #panels = new Map();

    #onBuild = (...rest) => {
      const me = 'onBuild';
      this.logger.entered(me, rest);

      for (const panel of this.#panels.values()) {
        panel.build();
      }

      const middle = document.createElement('div');
      middle.append(
        this.left.container, this.main.container, this.right.container
      );
      this.container.replaceChildren(
        this.top.container, middle, this.bottom.container
      );

      this.logger.leaving(me);
    }

    #onDestroy = (...rest) => {
      const me = 'onDestroy';
      this.logger.entered(me, rest);

      for (const panel of this.#panels.values()) {
        panel.destroy();
      }
      this.#panels.clear();

      this.logger.leaving(me);
    }

  }

  /* eslint-disable require-jsdoc */
  /* eslint-disable no-undefined */
  class LayoutTestCase extends NH.xunit.TestCase {

    testIsDiv() {
      // Assemble
      const w = new Layout(this.id);

      // Assert
      this.assertEqual(w.container.tagName, 'DIV', 'correct element');
    }

    testPanelsStartSimple() {
      // Assemble
      const w = new Layout(this.id);

      // Assert
      this.assertTrue(w.main instanceof Widget, 'main');
      this.assertRegExp(w.main.name, / main panel content/u, 'main name');
      this.assertTrue(w.top instanceof Widget, 'top');
      this.assertRegExp(w.top.name, / top panel content/u, 'top name');
      this.assertTrue(w.bottom instanceof Widget, 'bottom');
      this.assertTrue(w.left instanceof Widget, 'left');
      this.assertTrue(w.right instanceof Widget, 'right');
    }

    testSetWorks() {
      // Assemble
      const w = new Layout(this.id);

      // Act
      w.set(Layout.MAIN, 'main')
        .set(Layout.TOP, document.createElement('div'));

      // Assert
      this.assertTrue(w.main instanceof Widget, 'main');
      this.assertEqual(
        w.main.name, 'StringAdapter main panel content', 'main name'
      );
      this.assertTrue(w.top instanceof Widget, 'top');
      this.assertEqual(
        w.top.name, 'ElementAdapter top panel content', 'top name'
      );
    }

    testSetRequiresPanel() {
      // Assemble
      const w = new Layout(this.id);

      // Act/Assert
      this.assertRaises(
        TypeError,
        () => {
          w.set('main', 'main');
        }
      );
    }

    testDefaultBuilds() {
      // Assemble
      const w = new Layout(this.id);

      // Act
      w.build();

      // Assert
      const expected = [
        '<content.*-top-panel-.*></content>',
        '<div>',
        '<content.*-left-panel-.*></content>',
        '<content.*-main-panel-.*></content>',
        '<content.*-right-panel-.*></content>',
        '</div>',
        '<content.*-bottom-panel-.*></content>',
      ].join('');
      this.assertRegExp(w.container.innerHTML, RegExp(expected, 'u'));
    }

    testWithContentBuilds() {
      // Assemble
      const w = new Layout(this.id);
      w.set(Layout.MAIN, 'main')
        .set(Layout.TOP, 'top')
        .set(Layout.BOTTOM, 'bottom')
        .set(Layout.RIGHT, 'right')
        .set(Layout.LEFT, 'left');

      // Act
      w.build();

      // Assert
      this.assertEqual(w.container.innerText, 'topleftmainrightbottom');
    }

    testResetingPanelDestroysPrevious() {
      // Assemble
      const calls = [];
      const cb = (...rest) => {
        calls.push(rest);
      };
      const w = new Layout(this.id);
      const initMain = w.main;
      initMain.on('destroy', cb);
      const newMain = contentWrapper(this.id, 'Replacement main');

      // Act
      w.set(Layout.MAIN, newMain);
      w.build();

      // Assert
      this.assertEqual(calls, [['destroy', initMain]], 'old main destroyed');
      this.assertEqual(
        w.container.innerText, 'Replacement main', 'new content'
      );
    }

    testDestroy() {
      // Assemble
      const calls = [];
      const cb = (evt) => {
        calls.push(evt);
      };
      const w = new Layout(this.id)
        .set(Layout.MAIN, 'main')
        .build();

      w.top.on('destroy', cb);
      w.left.on('destroy', cb);
      w.main.on('destroy', cb);
      w.right.on('destroy', cb);
      w.bottom.on('destroy', cb);

      this.assertEqual(w.container.innerText, 'main', 'sanity check');

      // Act
      w.destroy();

      // Assert
      this.assertEqual(w.container.innerText, '', 'post destroy inner');
      this.assertEqual(w.main, undefined, 'post destroy main');
      this.assertEqual(
        calls,
        ['destroy', 'destroy', 'destroy', 'destroy', 'destroy'],
        'each panel was destroyed'
      );
    }

  }
  /* eslint-enable */

  NH.xunit.testing.testCases.push(LayoutTestCase);

  /**
   * Arbitrary object to be used as data for {@link Grid}.
   * @typedef {object} GridRecord
   */

  /** Column for the {@link Grid} widget. */
  class GridColumn {

    /**
     * @callback ColumnClassesFunc
     * @param {GridRecord} record - Record to style.
     * @param {string} field - Field to style.
     * @returns {string[]} - CSS classes for item.
     */

    /**
     * @callback RenderFunc
     * @param {GridRecord} record - Record to render.
     * @param {string} field - Field to render.
     * @returns {Widget} - Rendered content.
     */

    /** @param {string} field - Which field to render by default. */
    constructor(field) {
      if (!field) {
        throw new Exception('A "field" is required');
      }
      this.#field = field;
      this.#uid = NH.base.uuId(this.constructor.name);
      this.colClassesFunc()
        .renderFunc()
        .setTitle();
    }

    /**
     * The default implementation uses the field.
     *
     * @implements {ColumnClassesFunc}
     * @param {GridRecord} record - Record to style.
     * @param {string} field - Field to style.
     * @returns {string[]} - CSS classes for item.
     */
    static defaultClassesFunc = (record, field) => {
      const result = [field];
      return result;
    }

    /**
     * @implements {RenderFunc}
     * @param {GridRecord} record - Record to render.
     * @param {string} field - Field to render.
     * @returns {Widget} - Rendered content.
     */
    static defaultRenderFunc = (record, field) => {
      const result = contentWrapper(field, record[field]);
      return result;
    }

    /** @type {string} - The name of the property from the record to show. */
    get field() {
      return this.#field;
    }

    /** @type {string} - A human readable value to use in the header. */
    get title() {
      return this.#title;
    }

    /** @type {string} */
    get uid() {
      return this.#uid;
    }

    /**
     * Use the registered rendering function to create the widget.
     *
     * @param {GridRecord} record - Record to render.
     * @returns {Widget} - Rendered content.
     */
    render(record) {
      return contentWrapper(
        this.#field, this.#renderFunc(record, this.#field)
      );
    }

    /**
     * Use the registered {ColClassesFunc} to return CSS classes.
     *
     * @param {GridRecord} record - Record to examine.
     * @returns {string[]} - CSS classes for this record.
     */
    classList(record) {
      return this.#colClassesFunc(record, this.#field);
    }

    /**
     * Sets the function used to style a cell.
     *
     * If no value is passed, it will set the default function.
     *
     * @param {ColClassesFunc} func - Styling function.
     * @returns {GridColumn} - This instance, for chaining.
     */
    colClassesFunc(func = GridColumn.defaultClassesFunc) {
      if (!(func instanceof Function)) {
        throw new Exception(
          'Invalid argument: is not a function'
        );
      }
      this.#colClassesFunc = func;
      return this;
    }

    /**
     * Sets the function used to render the column.
     *
     * If no value is passed, it will set the default function.
     *
     * @param {RenderFunc} [func] - Rendering function.
     * @returns {GridColumn} - This instance, for chaining.
     */
    renderFunc(func = GridColumn.defaultRenderFunc) {
      if (!(func instanceof Function)) {
        throw new Exception(
          'Invalid argument: is not a function'
        );
      }
      this.#renderFunc = func;
      return this;
    }

    /**
     * Set the title string.
     *
     * If no value is passed, it will default back to the name of the field.
     *
     * @param {string} [title] - New title for the column.
     * @returns {GridColumn} - This instance, for chaining.
     */
    setTitle(title) {
      this.#title = title ?? NH.base.simpleParseWords(this.#field)
        .join(' ');
      return this;
    }

    #colClassesFunc
    #field
    #renderFunc
    #title
    #uid

  }

  /* eslint-disable no-empty-function */
  /* eslint-disable no-new */
  /* eslint-disable require-jsdoc */
  class GridColumnTestCase extends NH.xunit.TestCase {

    testNoArgment() {
      this.assertRaisesRegExp(
        Exception,
        /A "field" is required/u,
        () => {
          new GridColumn();
        }
      );
    }

    testWithFieldName() {
      // Assemble
      const col = new GridColumn('fieldName');

      // Assert
      this.assertEqual(col.field, 'fieldName');
    }

    testBadRenderFunc() {
      this.assertRaisesRegExp(
        Exception,
        /Invalid argument: is not a function/u,
        () => {
          new GridColumn('testField')
            .renderFunc('string');
        }
      );
    }

    testGoodRenderFunc() {
      this.assertNoRaises(
        () => {
          new GridColumn('fiend')
            .renderFunc(() => {});
        }
      );
    }

    testExplicitTitle() {
      // Assemble
      const col = new GridColumn('fieldName')
        .setTitle('Col Title');

      // Assert
      this.assertEqual(col.title, 'Col Title');
    }

    testDefaultTitle() {
      // Assemble
      const col = new GridColumn('fieldName');

      // Assert
      this.assertEqual(col.title, 'field Name');
    }

    testUid() {
      // Assemble
      const col = new GridColumn(this.id);

      // Assert
      this.assertRegExp(col.uid, /^GridColumn-/u);
    }

    testDefaultRenderer() {
      // Assemble
      const col = new GridColumn('name');
      const record = {name: 'Bob', job: 'Artist'};

      // Act
      const w = col.render(record);

      // Assert
      this.assertTrue(w instanceof Widget, 'correct type');
      this.assertEqual(w.build().container.innerHTML, 'Bob', 'right content');
    }

    testCanSetRenderFunc() {
      // Assemble
      function renderFunc(record, field) {
        return contentWrapper(
          this.id, `${record.name}|${record.job}|${field}`
        );
      }

      const col = new GridColumn('name');
      const record = {name: 'Bob', job: 'Artist'};

      // Act I - Default
      this.assertEqual(
        col.render(record)
          .build().container.innerHTML,
        'Bob',
        'default func'
      );

      // Act II - Custom
      this.assertEqual(
        col.renderFunc(renderFunc)
          .render(record)
          .build().container.innerHTML,
        'Bob|Artist|name',
        'custom func'
      );

      // Act III - Back to default
      this.assertEqual(
        col.renderFunc()
          .render(record)
          .build().container.innerHTML,
        'Bob',
        'back to default'
      );
    }

    testRenderAlwaysReturnsWidget() {
      // Assemble
      function renderFunc(record, field) {
        return `${record.name}|${record.job}|${field}`;
      }

      const col = new GridColumn('name')
        .renderFunc(renderFunc);
      const record = {name: 'Bob', job: 'Artist'};

      // Act
      const w = col.render(record);

      // Assert
      this.assertTrue(w instanceof Widget);
    }

    testDefaultClassesFunc() {
      // Assemble
      const col = new GridColumn('name');
      const record = {name: 'Bob', job: 'Artist'};

      // Act
      const cl = col.classList(record);

      // Assert
      this.assertTrue(cl.includes('name'));
    }

    testCanSetClassesFunc() {
      // Assemble
      function colClassesFunc(record, field) {
        return [`my-${field}`, 'xyzzy'];
      }
      const col = new GridColumn('name');
      const record = {name: 'Bob', job: 'Artist'};

      // Act I - Default
      let cl = col.classList(record);

      // Assert
      this.assertTrue(cl.includes('name'), 'default func has field');
      this.assertFalse(cl.includes('xyzzy'), 'no magic');

      // Act II - Custom
      col.colClassesFunc(colClassesFunc);
      cl = col.classList(record);

      // Assert
      this.assertTrue(cl.includes('my-name'), 'custom has field');
      this.assertTrue(cl.includes('xyzzy'), 'plays adventure');

      // Act III - Back to default
      col.colClassesFunc();
      cl = col.classList(record);

      // Assert
      this.assertTrue(cl.includes('name'), 'back to default');
      this.assertFalse(cl.includes('xyzzy'), 'no more magic');
    }

  }
  /* eslint-enable */

  NH.xunit.testing.testCases.push(GridColumnTestCase);

  /**
   * Implements the Grid pattern.
   *
   * Grid widgets will need `aria-*` attributes, TBD.
   *
   * A Grid consist of defined columns and data.
   *
   * The data is an array of objects that the caller can manipulate as needed,
   * such as adding/removing/updating items, sorting, etc.
   *
   * The columns is an array of {@link GridColumn}s that the caller can
   * manipulate as needed.
   *
   * Row based CSS classes can be controlled by setting a {Grid~ClassFunc}
   * using the rowClassesFunc() method.
   */
  class Grid extends Widget {

    /**
     * @callback RowClassesFunc
     * @param {GridRecord} record - Record to style.
     * @returns {string[]} - CSS classes to add to row.
     */

    /** @param {string} name - Name for this instance. */
    constructor(name) {
      super(name, 'table');
      this.on('build', this.#onBuild)
        .on('destroy', this.#onDestroy)
        .rowClassesFunc();
    }

    /**
     * The default implementation sets no classes.
     *
     * @implements {RowClassesFunc}
     * @returns {string[]} - CSS classes to add to row.
     */
    static defaultClassesFunc = () => {
      const result = [];
      return result;
    }

    /** @type {GridColumns[]} - Column definitions for the Grid. */
    get columns() {
      return this.#columns;
    }

    /** @type {object[]} - Data used by the Grid. */
    get data() {
      return this.#data;
    }

    /**
     * @param {object[]} array - Data used by the Grid.
     * @returns {Grid} - This instance, for chaining.
     */
    set(array) {
      this.#data = array;
      return this;
    }

    /**
     * Sets the function used to style a row.
     *
     * If no value is passed, it will set the default function.
     *
     * @param {RowClassesFunc} func - Styling function.
     * @returns {Grid} - This instance, for chaining.
     */
    rowClassesFunc(func = Grid.defaultClassesFunc) {
      if (!(func instanceof Function)) {
        throw new Exception(
          'Invalid argument: is not a function'
        );
      }
      this.#rowClassesFunc = func;
      return this;
    }

    #built = [];
    #columns = [];
    #data = [];
    #rowClassesFunc;
    #tbody
    #thead

    #resetBuilt = () => {
      for (const row of this.#built) {
        for (const cell of row.cells) {
          cell.widget.destroy();
        }
      }

      this.#built.length = 0;
    }

    #resetContainer = () => {
      this.container.innerHTML = '';
      this.#thead = document.createElement('thead');
      this.#tbody = document.createElement('tbody');
      this.container.append(this.#thead, this.#tbody);
    }

    #populateBuilt = () => {
      for (const row of this.#data) {
        const built = {
          classes: this.#rowClassesFunc(row),
          cells: [],
        };
        for (const col of this.#columns) {
          built.cells.push(
            {
              widget: col.render(row),
              classes: col.classList(row),
            }
          );
        }
        this.#built.push(built);
      }
    }

    #buildHeader = () => {
      const tr = document.createElement('tr');
      for (const col of this.#columns) {
        const th = document.createElement('th');
        th.append(col.title);
        tr.append(th);
      }
      this.#thead.append(tr);
    }

    #buildRows = () => {
      for (const row of this.#built) {
        const tr = document.createElement('tr');
        tr.classList.add(...row.classes);
        for (const cell of row.cells) {
          const td = document.createElement('td');
          td.append(cell.widget.build().container);
          td.classList.add(...cell.classes);
          tr.append(td);
        }
        this.#tbody.append(tr);
      }
    }

    #onBuild = (...rest) => {
      const me = 'onBuild';
      this.logger.entered(me, rest);

      this.#resetBuilt();
      this.#resetContainer();
      this.#populateBuilt();
      this.#buildHeader();
      this.#buildRows();

      this.logger.leaving(me);
    }

    #onDestroy = (...rest) => {
      const me = 'onDestroy';
      this.logger.entered(me, rest);

      this.#resetBuilt();

      this.logger.leaving(me);
    }

  }

  /* eslint-disable max-lines-per-function */
  /* eslint-disable require-jsdoc */
  class GridTestCase extends NH.xunit.TestCase {

    testDefaults() {
      // Assemble
      const w = new Grid(this.id);

      // Assert
      this.assertEqual(w.container.tagName, 'TABLE', 'correct element');
      this.assertEqual(w.columns, [], 'default columns');
      this.assertEqual(w.data, [], 'default data');
    }

    testColumnsAreLive() {
      // Assemble
      const w = new Grid(this.id);
      const col = new GridColumn('fieldName');

      // Act
      w.columns.push(col, 1);

      // Assert
      this.assertEqual(w.columns, [col, 1], 'note lack of sanity checking');
    }

    testSetUpdatesData() {
      // Assemble
      const w = new Grid(this.id);

      // Act
      w.set([{id: 1, name: 'Sally'}]);

      // Assert
      this.assertEqual(w.data, [{id: 1, name: 'Sally'}]);
    }

    testBadRowClasses() {
      this.assertRaisesRegExp(
        Exception,
        /Invalid argument: is not a function/u,
        () => {
          new Grid(this.id)
            .rowClassesFunc('string');
        }
      );
    }

    testDataIsLive() {
      // Assemble
      const w = new Grid(this.id);
      const data = [{id: 1, name: 'Sally'}];
      w.set(data);

      // Act I - More
      data.push({id: 2, name: 'Jane'}, {id: 3, name: 'Puff'});

      // Assert
      this.assertEqual(
        w.data,
        [
          {id: 1, name: 'Sally'},
          {id: 2, name: 'Jane'},
          {id: 3, name: 'Puff'},
        ],
        'new data was added'
      );

      // Act II - Sort
      data.sort((a, b) => a.name.localeCompare(b.name));

      // Assert
      this.assertEqual(
        w.data,
        [
          {name: 'Jane', id: 2},
          {name: 'Puff', id: 3},
          {name: 'Sally', id: 1},
        ],
        'data was sorted'
      );
    }

    testEmptyBuild() {
      // Assemble
      const w = new Grid(this.id);

      // Act
      w.build();

      // Assert
      const expected = [
        `<table id="Grid-[^-]*-${GUID}[^"]*">`,
        '<thead><tr></tr></thead>',
        '<tbody></tbody>',
        '</table>',
      ].join('');
      this.assertRegExp(w.container.outerHTML, RegExp(expected, 'u'));
    }

    testBuildWithData() {
      // Assemble
      function renderInt(record, field) {
        const span = document.createElement('span');
        span.append(record[field]);
        return span;
      }
      function renderType(record) {
        return `${record.stage}, ${record.species}`;
      }

      const w = new Grid(this.id);
      const data = [
        {id: 1, name: 'Sally', species: 'human', stage: 'juvenile'},
        {name: 'Jane', id: 2, species: 'human', stage: 'juvenile'},
        {name: 'Puff', id: 3, species: 'feline', stage: 'juvenile'},
      ];
      w.set(data);
      w.columns.push(
        new GridColumn('id')
          .renderFunc(renderInt),
        new GridColumn('name'),
        new GridColumn('typ')
          .setTitle('Type')
          .renderFunc(renderType),
      );

      // Act I - First build
      w.build();

      // Assert
      const expected = [
        '<table id="Grid-[^"]*">',
        '<thead>',
        '<tr><th>id</th><th>name</th><th>Type</th></tr>',
        '</thead>',
        '<tbody>',
        '<tr class="">',

        `<td class="id"><content id="ElementAdapter-id-${GUID}-container">`,
        '<span>1</span>',
        '</content></td>',

        '<td class="name"><content id="StringAdapter-name-.*-container">',
        'Sally',
        '</content></td>',

        `<td class="typ"><content id="StringAdapter-typ-${GUID}-container">`,
        'juvenile, human',
        '</content></td>',

        '</tr>',
        '<tr class="">',

        `<td class="id"><content id="ElementAdapter-id-${GUID}-container">`,
        '<span>2</span>',
        '</content></td>',

        '<td class="name"><content id="StringAdapter-name-.*-container">',
        'Jane',
        '</content></td>',

        `<td class="typ"><content id="StringAdapter-typ-${GUID}-container">`,
        'juvenile, human',
        '</content></td>',

        '</tr>',
        '<tr class="">',

        `<td class="id"><content id="ElementAdapter-id-${GUID}-container">`,
        '<span>3</span>',
        '</content></td>',

        '<td class="name"><content id="StringAdapter-name-.*-container">',
        'Puff',
        '</content></td>',

        `<td class="typ"><content id="StringAdapter-typ-${GUID}-container">`,
        'juvenile, feline',
        '</content></td>',

        '</tr>',
        '</tbody>',
        '</table>',
      ].join('');
      this.assertRegExp(
        w.container.outerHTML,
        RegExp(expected, 'u'),
        'first build'
      );

      // Act II - Rebuild is sensible
      w.build();
      this.assertRegExp(
        w.container.outerHTML,
        RegExp(expected, 'u'),
        'second build'
      );
    }

    testBuildWithClasses() {
      // Assemble
      function renderInt(record, field) {
        const span = document.createElement('span');
        span.append(record[field]);
        return span;
      }
      function renderType(record) {
        return `${record.stage}, ${record.species}`;
      }
      function rowClassesFunc(record) {
        return [record.species, record.stage];
      }

      const data = [
        {id: 1, name: 'Sally', species: 'human', stage: 'juvenile'},
        {name: 'Puff', id: 3, species: 'feline', stage: 'juvenile'},
        {name: 'Bob', id: 4, species: 'alien', stage: 'adolescent'},
      ];
      const w = new Grid(this.id)
        .set(data)
        .rowClassesFunc(rowClassesFunc);
      w.columns.push(
        new GridColumn('id')
          .renderFunc(renderInt),
        new GridColumn('name'),
        new GridColumn('tpe')
          .setTitle('Type')
          .renderFunc(renderType),
      );

      // Act
      w.build();

      // Assert
      const expected = [
        '<table id="Grid-[^"]*">',
        '<thead>',
        '<tr><th>id</th><th>name</th><th>Type</th></tr>',
        '</thead>',
        '<tbody>',
        '<tr class="human juvenile">',

        `<td class="id"><content id="ElementAdapter-id-${GUID}-container">`,
        '<span>1</span>',
        '</content></td>',

        '<td class="name"><content id="StringAdapter-name-.*-container">',
        'Sally',
        '</content></td>',

        `<td class="tpe"><content id="StringAdapter-tpe-${GUID}-container">`,
        'juvenile, human',
        '</content></td>',

        '</tr>',
        '<tr class="feline juvenile">',

        `<td class="id"><content id="ElementAdapter-id-${GUID}-container">`,
        '<span>3</span>',
        '</content></td>',

        '<td class="name"><content id="StringAdapter-name-.*-container">',
        'Puff',
        '</content></td>',

        `<td class="tpe"><content id="StringAdapter-tpe-${GUID}-container">`,
        'juvenile, feline',
        '</content></td>',

        '</tr>',
        '<tr class="alien adolescent">',

        `<td class="id"><content id="ElementAdapter-id-${GUID}-container">`,
        '<span>4</span>',
        '</content></td>',

        '<td class="name"><content id="StringAdapter-name-.*-container">',
        'Bob',
        '</content></td>',

        `<td class="tpe"><content id="StringAdapter-tpe-${GUID}-container">`,
        'adolescent, alien',
        '</content></td>',

        '</tr>',
        '</tbody>',
        '</table>',
      ].join('');
      this.assertRegExp(
        w.container.outerHTML,
        RegExp(expected, 'u'),
      );
    }

    testRebuildDestroys() {
      // Assemble
      const calls = [];
      const cb = (...rest) => {
        calls.push(rest);
      };
      const item = contentWrapper(this.id, 'My data.')
        .on('destroy', cb);
      const w = new Grid(this.id);
      w.data.push({item: item});
      w.columns.push(new GridColumn('item'));

      // Act
      w.build()
        .build();

      // Assert
      this.assertEqual(calls, [['destroy', item]]);
    }

    testDestroy() {
      // Assemble
      const calls = [];
      const cb = (...rest) => {
        calls.push(rest);
      };
      const item = contentWrapper(this.id, 'My data.')
        .on('destroy', cb);
      const w = new Grid(this.id);
      w.data.push({item: item});
      w.columns.push(new GridColumn('item'));

      // Act
      w.build()
        .destroy();

      // Assert
      this.assertEqual(calls, [['destroy', item]]);
    }

  }
  /* eslint-enable */

  NH.xunit.testing.testCases.push(GridTestCase);

  /** Tab for the {@link Tabs} widget. */
  class TabEntry {

    /**
     * @callback LabelClassesFunc
     * @param {string} label - Label to style.
     * @returns {string[]} - CSS classes for item.
     */

    /** @param {string} label - The label for this entry. */
    constructor(label) {
      if (!label) {
        throw new Exception('A "label" is required');
      }
      this.#label = label;
      this.#uid = NH.base.uuId(this.constructor.name);
      this.labelClassesFunc()
        .set();
    }

    /**
     * The default implementation uses the label.
     *
     * @implements {LabelClassesFunc}
     * @param {string} label - Label to style.
     * @returns {string[]} - CSS classes for item.
     */
    static defaultClassesFunc(label) {
      const result = [NH.base.safeId(label)];
      return result;
    }

    /** @type {string} */
    get label() {
      return this.#label;
    }

    /** @type {Widget} */
    get panel() {
      return this.#panel;
    }

    /** @type {string} */
    get uid() {
      return this.#uid;
    }

    /**
     * Use the registered {LabelClassesFunc} to return CSS classes.
     *
     * @returns {string[]} - CSS classes for this record.
     */
    classList() {
      return this.#labelClassesFunc(this.#label);
    }

    /**
     * Sets the function used to style the label.
     *
     * If no value is passed, it will set the default function.
     *
     * @param {LabelClassesFunc} func - Styling function.
     * @returns {TabEntry} - This instance, for chaining.
     */
    labelClassesFunc(func = TabEntry.defaultClassesFunc) {
      if (!(func instanceof Function)) {
        throw new Exception(
          'Invalid argument: is not a function'
        );
      }
      this.#labelClassesFunc = func;
      return this;
    }

    /**
     * Set the panel content for this entry.
     *
     * If no value is passed, defaults to an empty string.
     * @param {Content} [panel] - Panel content.
     * @returns {TabEntry} - This instance, for chaining.
     */
    set(panel = '') {
      this.#panel = contentWrapper('panel content', panel);
      return this;
    }

    #label
    #labelClassesFunc
    #panel
    #uid

  }

  /* eslint-disable no-new */
  /* eslint-disable require-jsdoc */
  class TabEntryTestCase extends NH.xunit.TestCase {

    testNoArgument() {
      this.assertRaisesRegExp(
        Exception,
        /A "label" is required/u,
        () => {
          new TabEntry();
        }
      );
    }

    testWithLabel() {
      // Assemble
      const entry = new TabEntry(this.id);

      this.assertEqual(entry.label, this.id);
    }

    testUid() {
      // Assemble
      const entry = new TabEntry(this.id);

      // Assert
      this.assertRegExp(entry.uid, RegExp(`^TabEntry-${GUID}`, 'u'));
    }

    testDefaultClassesFunc() {
      // Assemble
      const entry = new TabEntry('Tab Entry');

      // Assert
      this.assertEqual(entry.classList(), ['Tab-Entry']);
    }

    testCanSetClassesFunc() {
      // Assemble
      function labelClassesFunc(label) {
        return [`my-${label}`, 'abc123'];
      }
      const entry = new TabEntry('tab-entry');

      // Act I - Default
      let cl = entry.classList();

      // Assert
      this.assertTrue(cl.includes('tab-entry'), 'default func has label');
      this.assertFalse(cl.includes('abc123'), 'no alnum');

      // Act II - Custom
      entry.labelClassesFunc(labelClassesFunc);
      cl = entry.classList();

      // Assert
      this.assertTrue(cl.includes('my-tab-entry'), 'custom func is custom');
      this.assertTrue(cl.includes('abc123'), 'has alnum');

      // Act III - Back to default
      entry.labelClassesFunc();
      cl = entry.classList();

      // Assert
      this.assertTrue(cl.includes('tab-entry'), 'default func back to label');
      this.assertFalse(cl.includes('abc123'), 'no more alnum');
    }

    testPanel() {
      // Assemble/Act I - Default
      const entry = new TabEntry(this.id);

      // Assert
      this.assertTrue(entry.panel instanceof Widget, 'default widget');
      this.assertEqual(
        entry.panel.name, 'StringAdapter panel content', 'default name'
      );

      // Act II - Custom
      entry.set(contentWrapper('custom content', 'new panel content'));

      // Assert
      this.assertEqual(
        entry.panel.name, 'StringAdapter custom content', 'custom content'
      );

      // Act III - Back to default
      entry.set();

      // Assert
      this.assertEqual(
        entry.panel.name, 'StringAdapter panel content', 'default again'
      );
    }

  }
  /* eslint-enable */

  NH.xunit.testing.testCases.push(TabEntryTestCase);

  /**
   * Implements the Tabs pattern.
   *
   * Tabs widgets will need `aria-*` attributes, TBD.
   */
  class Tabs extends Widget {

    /** @param {string} name - Name for this instance. */
    constructor(name) {
      super(name, 'tabs');
      this.on('build', this.#onBuild)
        .on('destroy', this.#onDestroy);
    }

    #tablist

    #resetContainer = () => {
      this.container.innerHTML = '';
      this.#tablist = document.createElement('tablist');
      this.#tablist.role = 'tablist';
      this.container.append(this.#tablist);
    }

    #onBuild = (...rest) => {
      const me = 'onBuild';
      this.logger.entered(me, rest);

      this.#resetContainer();

      this.logger.leaving(me);
    }

    #onDestroy = (...rest) => {
      const me = 'onDestroy';
      this.logger.entered(me, rest);

      this.logger.leaving(me);
    }

  }

  /* eslint-disable require-jsdoc */
  class TabsTestCase extends NH.xunit.TestCase {

    testDefaults() {
      // Assemble
      const w = new Tabs(this.id);

      // Assert
      this.assertEqual(w.container.tagName, 'TABS', 'correct element');
    }

    testEmptyBuild() {
      // Assemble
      const w = new Tabs(this.id);

      // Act
      w.build();

      // Assert
      const expected = [
        `^<tabs id="Tabs-[^-]*-${GUID}[^"]*">`,
        '<tablist role="tablist">',
        '</tablist>',
        '</tabs>$',
      ].join('');
      this.assertRegExp(w.container.outerHTML, RegExp(expected, 'u'));
    }

  }
  /* eslint-enable */

  NH.xunit.testing.testCases.push(TabsTestCase);

  /**
   * Implements the Modal pattern.
   *
   * Modal widgets should have exactly one of the `aria-labelledby` or
   * `aria-label` attributes.
   *
   * Modal widgets can use `aria-describedby` to reference an element that
   * describes the purpose if not clear from the initial content.
   */
  class Modal extends Widget {

    /** @param {string} name - Name for this instance. */
    constructor(name) {
      super(name, 'dialog');
      this.on('build', this.#onBuild)
        .on('destroy', this.#onDestroy)
        .on('verify', this.#onVerify)
        .on('show', this.#onShow)
        .on('hide', this.#onHide)
        .set('')
        .hide();
    }

    /** @type {Widget} */
    get content() {
      return this.#content;
    }

    /**
     * Sets the content of this instance.
     * @param {Content} content - Content to use.
     * @returns {Widget} - This instance, for chaining.
     */
    set(content) {
      this.#content?.destroy();
      this.#content = contentWrapper('modal content', content);
      return this;
    }

    #content

    #onBuild = (...rest) => {
      const me = 'onBuild';
      this.logger.entered(me, rest);

      this.#content.build();
      this.container.replaceChildren(this.#content.container);

      this.logger.leaving(me);
    }

    #onDestroy = (...rest) => {
      const me = 'onDestroy';
      this.logger.entered(me, rest);

      this.#content.destroy();
      this.#content = null;

      this.logger.leaving(me);
    }

    #onVerify = (...rest) => {
      const me = 'onVerify';
      this.logger.entered(me, rest);

      const labelledBy = this.container.getAttribute('aria-labelledby');
      const label = this.container.getAttribute('aria-label');

      if (!labelledBy && !label) {
        throw new VerificationError(
          `Modal "${this.name}" should have one of "aria-labelledby" ` +
            'or "aria-label" attributes'
        );
      }

      if (labelledBy && label) {
        throw new VerificationError(
          `Modal "${this.name}" should not have both ` +
            `"aria-labelledby=${labelledBy}" and "aria-label=${label}"`
        );
      }

      this.logger.leaving(me);
    }

    #onShow = (...rest) => {
      const me = 'onShow';
      this.logger.entered(me, rest);

      this.container.showModal();
      this.#content.show();

      this.logger.leaving(me);
    }

    #onHide = (...rest) => {
      const me = 'onHide';
      this.logger.entered(me, rest);

      this.#content.hide();
      this.container.close();

      this.logger.leaving(me);
    }

  }

  /* eslint-disable require-jsdoc */
  class ModalTestCase extends NH.xunit.TestCase {

    testDefaults() {
      // Assemble
      const w = new Modal(this.id);

      // Assert
      this.assertEqual(w.container.tagName, 'DIALOG', 'correct element');
      this.assertFalse(w.visible, 'visibility');
      this.assertTrue(w.content instanceof Widget, 'is widget');
      this.assertRegExp(w.content.name, / modal content/u, 'content name');
    }

    testSetDestroysPrevious() {
      // Assemble
      const calls = [];
      const cb = (...rest) => {
        calls.push(rest);
      };
      const w = new Modal(this.id);
      const content = w.content.on('destroy', cb);

      // Act
      w.set('new stuff');

      // Assert
      this.assertEqual(calls, [['destroy', content]]);
    }

    testCallsNestedWidget() {
      // Assemble
      const calls = [];
      const cb = (...rest) => {
        calls.push(rest);
      };
      const w = new Modal(this.id)
        .attrText('aria-label', 'test widget');
      const nest = contentWrapper(this.id, 'test content');

      nest.on('build', cb)
        .on('destroy', cb)
        .on('show', cb)
        .on('hide', cb);

      // Act
      w.set(nest)
        .build()
        .hide()
        .destroy();

      // Assert
      this.assertEqual(calls, [
        ['build', nest],
        ['hide', nest],
        ['destroy', nest],
      ]);
    }

    testVerify() {
      // Assemble
      const w = new Modal(this.id);

      // Assert
      this.assertRaisesRegExp(
        VerificationError,
        /should have one of/u,
        () => {
          w.build();
        },
        'no aria attributes'
      );

      // Add labelledby
      w.attrText('aria-labelledby', 'some-element');
      this.assertNoRaises(() => {
        w.build();
      }, 'post add aria-labelledby');

      // Add label
      w.attrText('aria-label', 'test modal');
      this.assertRaisesRegExp(
        VerificationError,
        /should not have both "[^"]*" and "[^"]*"/u,
        () => {
          w.build();
        },
        'both aria attributes'
      );

      // Remove labelledby
      w.attrText('aria-labelledby', null);
      this.assertNoRaises(() => {
        w.build();
      }, 'post remove aria-labelledby');
    }

  }
  /* eslint-enable */

  NH.xunit.testing.testCases.push(ModalTestCase);

  /**
   * A widget that can be opened and closed on demand, designed for fairly
   * persistent information.
   *
   * The element will get `open` and `close` events.
   */
  class Info extends Widget {

    /** @param {string} name - Name for this instance. */
    constructor(name) {
      super(name, 'dialog');
      this.logger.log(`${this.name} constructed`);
    }

    /** Open the widget. */
    open() {
      this.container.showModal();
      this.container.dispatchEvent(new Event('open'));
    }

    /** Close the widget. */
    close() {
      // HTMLDialogElement sends a close event natively.
      this.container.close();
    }

  }

  return {
    version: version,
    Widget: Widget,
    Layout: Layout,
    GridColumn: GridColumn,
    Grid: Grid,
    Modal: Modal,
    Info: Info,
  };

}());