Specialized Utilities

/**
 * Returns a function that will execute all functions passed when called. It is generally used
 * to register multiple lexical listeners and then tear them down with a single function call, such
 * as React's useEffect hook.
 * 
 * The order of cleanup is the reverse of the argument order. Generally it is
 * expected that the first "acquire" will be "released" last (LIFO order),
 * because a later step may have some dependency on an earlier one.
 * 
 * @param func - An array of cleanup functions meant to be executed by the returned function.
 * @returns the function which executes all the passed cleanup functions.
 */
function mergeRegister(...func: Array<() => void>): () => void;

import { mergeRegister } from "@lexical/utils";

// Basic usage with React useEffect
useEffect(() => {
  return mergeRegister(
    editor.registerCommand(SOME_COMMAND, commandHandler),
    editor.registerUpdateListener(updateHandler),
    editor.registerTextContentListener(textHandler)
  );
}, [editor]);

// Manual cleanup management
const cleanupFunctions: Array<() => void> = [];

// Register various listeners
cleanupFunctions.push(editor.registerCommand('INSERT_TEXT', handleInsertText));
cleanupFunctions.push(editor.registerCommand('DELETE_TEXT', handleDeleteText));
cleanupFunctions.push(editor.registerNodeTransform(TextNode, handleTextTransform));

// Create single cleanup function
const cleanup = mergeRegister(...cleanupFunctions);

// Later, clean up everything at once
cleanup();

// Advanced pattern with conditional registration
function setupEditor(editor: LexicalEditor, features: EditorFeatures) {
  const registrations: Array<() => void> = [];
  
  // Always register core handlers
  registrations.push(
    editor.registerUpdateListener(handleUpdate),
    editor.registerCommand('FOCUS', handleFocus)
  );
  
  // Conditionally register feature handlers
  if (features.autoSave) {
    registrations.push(
      editor.registerTextContentListener(handleAutoSave)
    );
  }
  
  if (features.collaboration) {
    registrations.push(
      editor.registerCommand('COLLAB_UPDATE', handleCollabUpdate),
      editor.registerMutationListener(ElementNode, handleMutation)
    );
  }
  
  if (features.spellCheck) {
    registrations.push(
      setupSpellChecker(editor)
    );
  }
  
  return mergeRegister(...registrations);
}

// Plugin pattern
class CustomPlugin {
  private cleanupFn: (() => void) | null = null;
  
  initialize(editor: LexicalEditor) {
    this.cleanupFn = mergeRegister(
      this.registerCommands(editor),
      this.registerTransforms(editor),
      this.registerListeners(editor)
    );
  }
  
  destroy() {
    if (this.cleanupFn) {
      this.cleanupFn();
      this.cleanupFn = null;
    }
  }
  
  private registerCommands(editor: LexicalEditor) {
    return mergeRegister(
      editor.registerCommand('CUSTOM_COMMAND_1', this.handleCommand1),
      editor.registerCommand('CUSTOM_COMMAND_2', this.handleCommand2)
    );
  }
  
  private registerTransforms(editor: LexicalEditor) {
    return mergeRegister(
      editor.registerNodeTransform(CustomNode, this.transformNode),
      editor.registerNodeTransform(TextNode, this.transformText)
    );
  }
  
  private registerListeners(editor: LexicalEditor) {
    return editor.registerUpdateListener(this.handleUpdate);
  }
}

/**
 * Place one or multiple newly created Nodes at the current selection. Multiple
 * nodes will only be created when the selection spans multiple lines (aka
 * client rects).
 *
 * This function can come useful when you want to show the selection but the
 * editor has been focused away.
 */
function markSelection(
  editor: LexicalEditor,
  onReposition?: (node: Array<HTMLElement>) => void
): () => void;

import { markSelection } from "@lexical/utils";

// Basic selection marking
const removeSelectionMark = markSelection(editor);

// Custom repositioning handler
const removeSelectionMark = markSelection(editor, (domNodes) => {
  domNodes.forEach(node => {
    // Custom styling for selection markers
    node.style.backgroundColor = 'rgba(0, 123, 255, 0.3)';
    node.style.border = '2px solid #007bff';
    node.style.borderRadius = '3px';
  });
});

// Focus management with selection marking
class FocusManager {
  private editor: LexicalEditor;
  private removeSelectionMark: (() => void) | null = null;
  
  constructor(editor: LexicalEditor) {
    this.editor = editor;
    this.setupFocusHandling();
  }
  
  private setupFocusHandling() {
    const rootElement = this.editor.getRootElement();
    if (!rootElement) return;
    
    rootElement.addEventListener('blur', () => {
      // Mark selection when editor loses focus
      this.removeSelectionMark = markSelection(this.editor, (nodes) => {
        nodes.forEach(node => {
          node.style.backgroundColor = 'rgba(255, 235, 59, 0.3)';
          node.classList.add('selection-marker');
        });
      });
    });
    
    rootElement.addEventListener('focus', () => {
      // Remove selection marks when editor regains focus
      if (this.removeSelectionMark) {
        this.removeSelectionMark();
        this.removeSelectionMark = null;
      }
    });
  }
  
  destroy() {
    if (this.removeSelectionMark) {
      this.removeSelectionMark();
    }
  }
}

// Integration with modal dialogs
function showModalWithSelectionPreserved(editor: LexicalEditor) {
  // Mark selection before showing modal
  const removeSelectionMark = markSelection(editor);
  
  const modal = document.createElement('div');
  modal.className = 'modal';
  
  // Modal close handler
  const closeModal = () => {
    removeSelectionMark(); // Clean up selection markers
    modal.remove();
  };
  
  modal.addEventListener('click', (e) => {
    if (e.target === modal) {
      closeModal();
    }
  });
  
  document.body.appendChild(modal);
}

/**
 * Place one or multiple newly created Nodes at the passed Range's position.
 * Multiple nodes will only be created when the Range spans multiple lines (aka
 * client rects).
 *
 * This function can come particularly useful to highlight particular parts of
 * the text without interfering with the EditorState, that will often replicate
 * the state across collab and clipboard.
 *
 * This function accounts for DOM updates which can modify the passed Range.
 * Hence, the function return to remove the listener.
 */
function positionNodeOnRange(
  editor: LexicalEditor,
  range: Range,
  onReposition: (node: Array<HTMLElement>) => void
): () => void;

import { positionNodeOnRange } from "@lexical/utils";

// Basic text highlighting
function highlightRange(editor: LexicalEditor, range: Range) {
  const removeHighlight = positionNodeOnRange(editor, range, (nodes) => {
    nodes.forEach(node => {
      node.style.backgroundColor = 'yellow';
      node.style.opacity = '0.5';
      node.classList.add('highlight');
    });
  });
  
  // Return cleanup function
  return removeHighlight;
}

// Comment annotation system
class CommentSystem {
  private activeComments = new Map<string, () => void>();
  
  addComment(editor: LexicalEditor, range: Range, commentId: string, text: string) {
    const removePositioning = positionNodeOnRange(editor, range, (nodes) => {
      nodes.forEach(node => {
        node.style.backgroundColor = 'rgba(255, 193, 7, 0.3)';
        node.style.borderBottom = '2px solid #ffc107';
        node.style.cursor = 'pointer';
        node.title = text;
        node.dataset.commentId = commentId;
        
        // Click handler to show comment
        node.addEventListener('click', () => this.showComment(commentId));
      });
    });
    
    this.activeComments.set(commentId, removePositioning);
  }
  
  removeComment(commentId: string) {
    const removePositioning = this.activeComments.get(commentId);
    if (removePositioning) {
      removePositioning();
      this.activeComments.delete(commentId);
    }
  }
  
  clearAllComments() {
    this.activeComments.forEach(removePositioning => removePositioning());
    this.activeComments.clear();
  }
  
  private showComment(commentId: string) {
    // Show comment UI
    console.log(`Show comment ${commentId}`);
  }
}

// Search result highlighting
class SearchHighlighter {
  private highlights: Array<() => void> = [];
  
  highlightSearchResults(editor: LexicalEditor, searchTerm: string) {
    this.clearHighlights();
    
    const rootElement = editor.getRootElement();
    if (!rootElement) return;
    
    const walker = document.createTreeWalker(
      rootElement,
      NodeFilter.SHOW_TEXT
    );
    
    const ranges: Range[] = [];
    let textNode: Text | null;
    
    // Find all text nodes containing search term
    while (textNode = walker.nextNode() as Text) {
      const text = textNode.textContent || '';
      const index = text.toLowerCase().indexOf(searchTerm.toLowerCase());
      
      if (index !== -1) {
        const range = document.createRange();
        range.setStart(textNode, index);
        range.setEnd(textNode, index + searchTerm.length);
        ranges.push(range);
      }
    }
    
    // Highlight each range
    ranges.forEach((range, index) => {
      const removeHighlight = positionNodeOnRange(editor, range, (nodes) => {
        nodes.forEach(node => {
          node.style.backgroundColor = '#ffeb3b';
          node.style.color = '#000';
          node.style.fontWeight = 'bold';
          node.classList.add('search-highlight');
          node.dataset.searchIndex = index.toString();
        });
      });
      
      this.highlights.push(removeHighlight);
    });
  }
  
  clearHighlights() {
    this.highlights.forEach(removeHighlight => removeHighlight());
    this.highlights = [];
  }
}

// Spell check underlines
function addSpellCheckUnderline(editor: LexicalEditor, range: Range, suggestions: string[]) {
  return positionNodeOnRange(editor, range, (nodes) => {
    nodes.forEach(node => {
      node.style.borderBottom = '2px wavy red';
      node.style.cursor = 'pointer';
      node.title = `Suggestions: ${suggestions.join(', ')}`;
      
      // Right-click context menu
      node.addEventListener('contextmenu', (e) => {
        e.preventDefault();
        showSpellCheckMenu(e.clientX, e.clientY, suggestions);
      });
    });
  });
}

/**
 * Maintains visible selection display even when editor loses focus
 */
function selectionAlwaysOnDisplay(
  editor: LexicalEditor
): () => void;

import { selectionAlwaysOnDisplay } from "@lexical/utils";

// Basic usage - always show selection
const removeAlwaysDisplay = selectionAlwaysOnDisplay(editor);

// Clean up when component unmounts
useEffect(() => {
  const cleanup = selectionAlwaysOnDisplay(editor);
  return cleanup;
}, [editor]);

// Conditional selection display
class EditorManager {
  private removeSelectionDisplay: (() => void) | null = null;
  
  constructor(private editor: LexicalEditor) {}
  
  enablePersistentSelection() {
    if (!this.removeSelectionDisplay) {
      this.removeSelectionDisplay = selectionAlwaysOnDisplay(this.editor);
    }
  }
  
  disablePersistentSelection() {
    if (this.removeSelectionDisplay) {
      this.removeSelectionDisplay();
      this.removeSelectionDisplay = null;
    }
  }
  
  destroy() {
    this.disablePersistentSelection();
  }
}

// Multi-editor setup with selective persistent selection
function setupMultipleEditors(editors: LexicalEditor[], persistentSelectionIndex: number) {
  const cleanupFunctions: Array<() => void> = [];
  
  editors.forEach((editor, index) => {
    if (index === persistentSelectionIndex) {
      // Only one editor maintains persistent selection
      cleanupFunctions.push(selectionAlwaysOnDisplay(editor));
    }
    
    // Other setup for each editor
    cleanupFunctions.push(
      editor.registerUpdateListener(handleUpdate),
      editor.registerCommand('FOCUS', () => {
        // Switch persistent selection to focused editor
        // Implementation would switch which editor has persistent selection
      })
    );
  });
  
  return mergeRegister(...cleanupFunctions);
}

import { 
  mergeRegister, 
  markSelection, 
  positionNodeOnRange, 
  selectionAlwaysOnDisplay
} from "@lexical/utils";

// Complete rich text editor setup
function setupAdvancedEditor(editor: LexicalEditor) {
  const registrations: Array<() => void> = [];
  
  // Persistent selection display
  registrations.push(selectionAlwaysOnDisplay(editor));
  
  // Selection-based tools
  registrations.push(
    editor.registerCommand('SHOW_TOOLTIP', (payload) => {
      const selection = $getSelection();
      if ($isRangeSelection(selection)) {
        const range = createDOMRange(selection);
        const removeTooltip = positionNodeOnRange(editor, range, (nodes) => {
          const tooltip = document.createElement('div');
          tooltip.textContent = payload.text;
          tooltip.style.backgroundColor = '#333';
          tooltip.style.color = 'white';
          tooltip.style.padding = '8px';
          tooltip.style.borderRadius = '4px';
          tooltip.style.position = 'absolute';
          tooltip.style.zIndex = '1000';
          
          nodes[0]?.appendChild(tooltip);
        });
        
        // Auto-remove after delay
        setTimeout(removeTooltip, 3000);
      }
      return true;
    })
  );
  
  // Other editor features...
  
  return mergeRegister(...registrations);
}