Utilities

/**
 * Combine CSS class names, filtering out falsy values
 * @param classes - Array of class names, objects, or falsy values
 * @returns Single combined class string
 */
function classes(
  ...classes: (string | false | undefined | null | { [className: string]: any })[]
): string;

/**
 * Combine CSS class names removing duplicates
 * @param classes - Array of class names, objects, or falsy values  
 * @returns Single combined class string without duplicates
 */
function classesDedupe(
  ...classes: (string | false | undefined | null | { [className: string]: any })[]
): string;

import { classes, classesDedupe } from '@jupyterlab/ui-components';

// Basic class combination
const buttonClass = classes(
  'jp-Button',
  isActive && 'jp-mod-active',
  isDisabled && 'jp-mod-disabled',
  customClass
);

// Conditional classes with objects
const widgetClass = classes(
  'jp-Widget',
  {
    'jp-mod-hidden': !visible,
    'jp-mod-focused': hasFocus,
    'jp-mod-current': isCurrent
  },
  additionalClasses
);

// Remove duplicates when combining from multiple sources
const combinedClass = classesDedupe(
  baseClasses,
  themeClasses,
  stateClasses,
  userClasses
);

// Use in React components
function MyButton({ active, disabled, className }: ButtonProps) {
  return (
    <button 
      className={classes(
        'my-button',
        active && 'active',
        disabled && 'disabled',
        className
      )}
    >
      Click me
    </button>
  );
}

// Complex conditional styling
const iconClass = classes(
  'icon',
  size === 'small' && 'icon-small',
  size === 'large' && 'icon-large',
  {
    'icon-spin': spinning,
    'icon-disabled': !enabled,
    'icon-primary': variant === 'primary',
    'icon-secondary': variant === 'secondary'
  }
);

/**
 * Convert DOM element attributes to React props
 * @param elem - DOM element to extract attributes from
 * @param options - Options for conversion
 * @returns Object with React-compatible props
 */
function getReactAttrs(
  elem: Element, 
  options?: { ignore?: string[] }
): { [key: string]: string | null };

/**
 * Find tree item element in DOM hierarchy
 * @param el - Element to start search from
 * @returns Tree item element or null if not found
 */
function getTreeItemElement(el: HTMLElement): HTMLElement | null;

import { getReactAttrs, getTreeItemElement } from '@jupyterlab/ui-components';

// Convert DOM element to React props
function domElementToReact(element: Element) {
  const props = getReactAttrs(element, {
    ignore: ['style', 'class'] // Ignore these attributes
  });
  
  return (
    <div {...props}>
      Converted from DOM element
    </div>
  );
}

// Handle tree interactions
function handleTreeClick(event: MouseEvent) {
  const target = event.target as HTMLElement;
  const treeItem = getTreeItemElement(target);
  
  if (treeItem) {
    const itemId = treeItem.dataset.itemId;
    console.log('Clicked tree item:', itemId);
    
    // Handle tree item selection
    selectTreeItem(itemId);
  }
}

// Widget that uses DOM utilities
class InteractiveWidget extends Widget {
  onAfterAttach() {
    super.onAfterAttach();
    
    // Set up tree interaction handlers
    this.node.addEventListener('click', (event) => {
      const treeItem = getTreeItemElement(event.target as HTMLElement);
      if (treeItem) {
        this.handleTreeItemClick(treeItem);
      }
    });
  }
  
  private handleTreeItemClick(element: HTMLElement) {
    // Convert DOM attributes to work with
    const attrs = getReactAttrs(element);
    console.log('Tree item attributes:', attrs);
  }
}

// Extract data attributes
function extractDataAttributes(element: Element) {
  const attrs = getReactAttrs(element);
  const dataAttrs: { [key: string]: string } = {};
  
  Object.entries(attrs).forEach(([key, value]) => {
    if (key.startsWith('data-') && value !== null) {
      dataAttrs[key] = value;
    }
  });
  
  return dataAttrs;
}

/**
 * HoverBox positioning utilities
 */
type OutOfViewDisplay = 'hidden-inside' | 'hidden-outside' | 'stick-inside' | 'stick-outside';

namespace HoverBox {
  interface IOptions {
    /** Anchor element or position to attach to */
    anchor: IAnchor;
    /** Host element that contains the positioned element */
    host: HTMLElement;
    /** Maximum height for the positioned element */
    maxHeight: number;
    /** Minimum height for the positioned element */
    minHeight: number;
    /** Element to be positioned */
    node: HTMLElement;
    /** Positioning offsets */
    offset?: {
      horizontal?: number;
      vertical?: { above?: number; below?: number };
    };
    /** Vertical positioning preference */
    privilege?: 'above' | 'below' | 'forceAbove' | 'forceBelow';
    /** Custom style overrides */
    style?: CSSStyleDeclaration;
    /** Behavior when element goes out of view */
    outOfViewDisplay?: {
      top?: OutOfViewDisplay;
      bottom?: OutOfViewDisplay;
      left?: OutOfViewDisplay;
      right?: OutOfViewDisplay;
    };
    /** Fixed size for the element */
    size?: { width: number; height: number; };
  }
  
  /** Anchor position interface */
  interface IAnchor extends Pick<DOMRect, 'left' | 'right' | 'top' | 'bottom'> {}
  
  /**
   * Set geometry for positioned element
   * @param options - Positioning configuration
   */
  function setGeometry(options: IOptions): void;
}

import { HoverBox } from '@jupyterlab/ui-components';

// Create tooltip positioning
function createTooltip(anchorElement: HTMLElement, content: string) {
  const tooltip = document.createElement('div');
  tooltip.className = 'tooltip';
  tooltip.textContent = content;
  tooltip.style.position = 'absolute';
  tooltip.style.zIndex = '1000';
  
  document.body.appendChild(tooltip);
  
  // Position tooltip relative to anchor
  const anchorRect = anchorElement.getBoundingClientRect();
  
  HoverBox.setGeometry({
    anchor: {
      left: anchorRect.left,
      right: anchorRect.right,
      top: anchorRect.top,
      bottom: anchorRect.bottom
    },
    host: document.body,
    node: tooltip,
    maxHeight: 200,
    minHeight: 20,
    privilege: 'above',
    offset: {
      vertical: { above: 5, below: 5 },
      horizontal: 0
    }
  });
  
  return tooltip;
}

// Advanced positioning for dropdown
class DropdownWidget extends Widget {
  private _dropdown: HTMLElement;
  
  constructor() {
    super();
    this._dropdown = this.createDropdown();
  }
  
  showDropdown() {
    const buttonRect = this.node.getBoundingClientRect();
    
    HoverBox.setGeometry({
      anchor: {
        left: buttonRect.left,
        right: buttonRect.right,
        top: buttonRect.top,
        bottom: buttonRect.bottom
      },
      host: document.body,
      node: this._dropdown,
      maxHeight: 300,
      minHeight: 50,
      privilege: 'below',
      offset: {
        vertical: { below: 2 }
      },
      outOfViewDisplay: {
        bottom: 'stick',
        top: 'stick'
      }
    });
    
    this._dropdown.style.display = 'block';
  }
  
  hideDropdown() {
    this._dropdown.style.display = 'none';
  }
  
  private createDropdown(): HTMLElement {
    const dropdown = document.createElement('div');
    dropdown.className = 'dropdown-menu';
    dropdown.style.position = 'absolute';
    dropdown.style.display = 'none';
    dropdown.style.zIndex = '1000';
    
    document.body.appendChild(dropdown);
    return dropdown;
  }
}

// Context menu positioning
function showContextMenu(event: MouseEvent, items: MenuItem[]) {
  const menu = document.createElement('div');
  menu.className = 'context-menu';
  
  items.forEach(item => {
    const menuItem = document.createElement('div');
    menuItem.className = 'context-menu-item';
    menuItem.textContent = item.label;
    menuItem.onclick = item.action;
    menu.appendChild(menuItem);
  });
  
  document.body.appendChild(menu);
  
  // Position at mouse location
  HoverBox.setGeometry({
    anchor: {
      left: event.clientX,
      right: event.clientX,
      top: event.clientY,
      bottom: event.clientY
    },
    host: document.body,
    node: menu,
    maxHeight: 400,
    minHeight: 30,
    privilege: 'below',
    outOfViewDisplay: {
      right: 'stick',
      bottom: 'stick'
    }
  });
}

/**
 * Interface for element reference properties
 */
interface IElementRefProps<E extends HTMLElement> {
  /** Callback function to receive element reference */
  elementRef?: (ref: E | null) => void;
}

/**
 * Default style class constant
 */
const DEFAULT_STYLE_CLASS = 'jp-DefaultStyle';

import { IElementRefProps, DEFAULT_STYLE_CLASS } from '@jupyterlab/ui-components';

// Component with element reference
interface CustomInputProps extends IElementRefProps<HTMLInputElement> {
  placeholder?: string;
  value?: string;
  onChange?: (value: string) => void;
}

function CustomInput({ elementRef, placeholder, value, onChange }: CustomInputProps) {
  const handleRef = (element: HTMLInputElement | null) => {
    if (element) {
      element.classList.add(DEFAULT_STYLE_CLASS);
    }
    elementRef?.(element);
  };
  
  return (
    <input
      ref={handleRef}
      placeholder={placeholder}
      value={value}
      onChange={(e) => onChange?.(e.target.value)}
      className="custom-input"
    />
  );
}

// Use with element reference
function ParentComponent() {
  const [inputElement, setInputElement] = useState<HTMLInputElement | null>(null);
  
  const focusInput = () => {
    inputElement?.focus();
  };
  
  return (
    <div>
      <CustomInput
        elementRef={setInputElement}
        placeholder="Enter text..."
      />
      <button onClick={focusInput}>Focus Input</button>
    </div>
  );
}

// Widget that uses element references
class FormWidget extends ReactWidget {
  private _formElement: HTMLFormElement | null = null;
  
  protected render() {
    return (
      <form
        ref={(el) => this._formElement = el}
        className={DEFAULT_STYLE_CLASS}
      >
        <CustomInput
          elementRef={(el) => console.log('Input element:', el)}
          placeholder="Widget input"
        />
      </form>
    );
  }
  
  submitForm() {
    if (this._formElement) {
      this._formElement.requestSubmit();
    }
  }
}

// Generic element ref hook pattern
function useElementRef<T extends HTMLElement>() {
  const [element, setElement] = useState<T | null>(null);
  
  const ref = useCallback((el: T | null) => {
    if (el) {
      el.classList.add(DEFAULT_STYLE_CLASS);
    }
    setElement(el);
  }, []);
  
  return [element, ref] as const;
}

/**
 * Namespace for DOM node styling utilities
 */
namespace Styling {
  /**
   * Style a node and its child elements with default tag names
   * @param node - Base DOM element to style 
   * @param className - Optional CSS class to add to styled nodes
   */
  function styleNode(node: HTMLElement, className?: string): void;
  
  /**
   * Style a node and elements with a specific tag name
   * @param node - Base DOM element to style
   * @param tagName - HTML tag name to target for styling
   * @param className - Optional CSS class to add to styled nodes  
   */
  function styleNodeByTag(node: HTMLElement, tagName: string, className?: string): void;
  
  /**
   * Wrap select elements with custom styling container
   * @param select - Select element to wrap
   * @param multiple - Whether select allows multiple selections
   */
  function wrapSelect(select: HTMLSelectElement, multiple?: boolean): void;
}

import { Styling } from '@jupyterlab/ui-components';

// Style all form elements in a container
function styleFormContainer(container: HTMLElement) {
  // Apply default styling to common form elements
  Styling.styleNode(container, 'custom-form-style');
  
  // This will add 'jp-mod-styled' class to all:
  // - select elements
  // - textarea elements  
  // - input elements
  // - button elements
}

// Style specific element types
function styleSpecificElements(container: HTMLElement) {
  // Style only input elements
  Styling.styleNodeByTag(container, 'input', 'styled-input');
  
  // Style only buttons
  Styling.styleNodeByTag(container, 'button', 'styled-button');
  
  // Style textareas with special class
  Styling.styleNodeByTag(container, 'textarea', 'styled-textarea');
}

// Widget that applies styling on render
class StyledFormWidget extends Widget {
  onAfterAttach() {
    super.onAfterAttach();
    
    // Apply JupyterLab styling to all form elements
    Styling.styleNode(this.node);
  }
  
  addFormField(fieldType: string, className?: string) {
    const field = document.createElement(fieldType);
    this.node.appendChild(field);
    
    // Style the new field specifically
    Styling.styleNodeByTag(this.node, fieldType, className);
  }
}

// Custom select wrapper usage
function createStyledSelect(options: string[], multiple = false) {
  const select = document.createElement('select');
  select.multiple = multiple;
  
  options.forEach(option => {
    const optionElement = document.createElement('option');
    optionElement.value = option;
    optionElement.textContent = option;
    select.appendChild(optionElement);
  });
  
  // Wrap with custom styling - handled automatically by styleNode
  const container = document.createElement('div');
  container.appendChild(select);
  Styling.styleNode(container);
  
  return container;
}

// Apply styling to dynamically created content
function createStyledDialog(content: HTMLElement) {
  const dialog = document.createElement('div');
  dialog.className = 'dialog-container';
  dialog.appendChild(content);
  
  // Ensure all form controls are properly styled
  Styling.styleNode(dialog, 'dialog-form');
  
  return dialog;
}

// Utility for styling imported HTML content
function styleImportedContent(htmlContent: string) {
  const container = document.createElement('div');
  container.innerHTML = htmlContent;
  
  // Style all form elements in the imported content
  Styling.styleNode(container);
  
  return container;
}

// SVG type definitions (from svg.d.ts)
declare module '*.svg' {
  const value: string;
  export default value;
}

// React render element type
type ReactRenderElement = React.ReactElement<any> | null;

// Common interfaces and types used across utilities
interface IChangedArgs<T, U, K extends string> {
  name: K;
  oldValue: T;
  newValue: U;
}

// Import SVG files as strings
import iconSvg from './my-icon.svg';

// Create LabIcon from imported SVG
const myIcon = new LabIcon({
  name: 'my-app:my-icon',
  svgstr: iconSvg
});

// Use changed args in signals
class CounterModel extends VDomModel {
  private _count = 0;
  
  get count(): number {
    return this._count;
  }
  
  set count(value: number) {
    const oldValue = this._count;
    this._count = value;
    
    // Emit change signal with typed args
    this.stateChanged.emit({
      name: 'count',
      oldValue,
      newValue: value
    } as IChangedArgs<number, number, 'count'>);
  }
}

// Utility functions that work with React elements
function isValidRenderElement(element: any): element is ReactRenderElement {
  return element === null || React.isValidElement(element);
}

function renderIfValid(element: ReactRenderElement) {
  if (isValidRenderElement(element)) {
    return ReactDOM.render(element, container);
  }
  return null;
}