Collaboration

/**
 * Create a collaboration plugin
 */
function collab(config?: CollabConfig): Plugin;

/**
 * Collaboration plugin configuration
 */
interface CollabConfig {
  /**
   * The starting version number (default: 0)
   */
  version?: number;
  
  /**
   * Client ID for this editor instance  
   */
  clientID?: string | number;
}

/**
 * Get the current collaboration version
 */
function getVersion(state: EditorState): number;

/**
 * Get steps that can be sent to other clients
 */
function sendableSteps(state: EditorState): {
  version: number;
  steps: Step[];
  clientID: string | number;
} | null;

/**
 * Apply steps received from other clients
 */
function receiveTransaction(
  state: EditorState,
  steps: Step[],
  clientIDs: (string | number)[]
): EditorState;

import { collab, getVersion, sendableSteps, receiveTransaction } from "@tiptap/pm/collab";
import { Step } from "@tiptap/pm/transform";

// Basic collaboration setup
const collaborationPlugin = collab({
  version: 0,
  clientID: "user-123"
});

const state = EditorState.create({
  schema: mySchema,
  plugins: [collaborationPlugin]
});

// Collaboration manager
class CollaborationManager {
  private view: EditorView;
  private websocket: WebSocket;
  private sendBuffer: Step[] = [];
  private isConnected = false;
  
  constructor(view: EditorView, websocketUrl: string) {
    this.view = view;
    this.setupWebSocket(websocketUrl);
    this.setupSendHandler();
  }
  
  private setupWebSocket(url: string) {
    this.websocket = new WebSocket(url);
    
    this.websocket.onopen = () => {
      this.isConnected = true;
      this.sendInitialState();
      this.flushSendBuffer();
    };
    
    this.websocket.onmessage = (event) => {
      const message = JSON.parse(event.data);
      this.handleIncomingMessage(message);
    };
    
    this.websocket.onclose = () => {
      this.isConnected = false;
      // Attempt reconnection
      setTimeout(() => this.setupWebSocket(url), 1000);
    };
  }
  
  private setupSendHandler() {
    const originalDispatch = this.view.dispatch;
    
    this.view.dispatch = (tr: Transaction) => {
      const newState = this.view.state.apply(tr);
      this.view.updateState(newState);
      
      // Send changes to other clients
      this.sendLocalChanges();
    };
  }
  
  private sendInitialState() {
    const version = getVersion(this.view.state);
    this.websocket.send(JSON.stringify({
      type: "initialize",
      version,
      clientID: this.getClientID()
    }));
  }
  
  private sendLocalChanges() {
    const sendable = sendableSteps(this.view.state);
    if (sendable) {
      if (this.isConnected) {
        this.websocket.send(JSON.stringify({
          type: "steps",
          ...sendable
        }));
      } else {
        // Buffer steps for later sending
        this.sendBuffer.push(...sendable.steps);
      }
    }
  }
  
  private handleIncomingMessage(message: any) {
    switch (message.type) {
      case "steps":
        this.applyRemoteSteps(message.steps, message.clientIDs, message.version);
        break;
        
      case "version":
        this.handleVersionSync(message.version);
        break;
        
      case "client-joined":
        this.handleClientJoined(message.clientID);
        break;
        
      case "client-left":
        this.handleClientLeft(message.clientID);
        break;
    }
  }
  
  private applyRemoteSteps(steps: any[], clientIDs: string[], version: number) {
    try {
      // Convert serialized steps back to Step instances
      const stepObjects = steps.map(stepData => Step.fromJSON(this.view.state.schema, stepData));
      
      // Apply remote changes
      const newState = receiveTransaction(this.view.state, stepObjects, clientIDs);
      this.view.updateState(newState);
      
    } catch (error) {
      console.error("Failed to apply remote steps:", error);
      this.requestFullSync();
    }
  }
  
  private handleVersionSync(serverVersion: number) {
    const localVersion = getVersion(this.view.state);
    if (localVersion !== serverVersion) {
      // Version mismatch - request full document sync
      this.requestFullSync();
    }
  }
  
  private requestFullSync() {
    this.websocket.send(JSON.stringify({
      type: "request-sync",
      clientID: this.getClientID()
    }));
  }
  
  private flushSendBuffer() {
    if (this.sendBuffer.length > 0 && this.isConnected) {
      this.websocket.send(JSON.stringify({
        type: "buffered-steps",
        steps: this.sendBuffer.map(step => step.toJSON()),
        clientID: this.getClientID()
      }));
      this.sendBuffer = [];
    }
  }
  
  private getClientID(): string {
    return this.view.state.plugins
      .find(p => p.spec.key === collab().spec.key)
      ?.getState(this.view.state)?.clientID || "unknown";
  }
  
  private handleClientJoined(clientID: string) {
    console.log(`Client ${clientID} joined the collaboration`);
    // Update UI to show new collaborator
  }
  
  private handleClientLeft(clientID: string) {
    console.log(`Client ${clientID} left the collaboration`);
    // Update UI to remove collaborator
  }
  
  public disconnect() {
    this.isConnected = false;
    this.websocket.close();
  }
}

// Usage
const collaborationManager = new CollaborationManager(
  view, 
  "wss://your-collab-server.com/ws"
);

interface CollaboratorInfo {
  clientID: string;
  name: string;
  color: string;
  selection?: Selection;
  cursor?: number;
}

class PresenceManager {
  private collaborators = new Map<string, CollaboratorInfo>();
  private decorations = DecorationSet.empty;
  
  constructor(private view: EditorView) {
    this.setupPresencePlugin();
  }
  
  private setupPresencePlugin() {
    const presencePlugin = new Plugin({
      state: {
        init: () => DecorationSet.empty,
        apply: (tr, decorations) => {
          // Update decorations based on collaborator presence
          return this.updatePresenceDecorations(decorations, tr);
        }
      },
      
      props: {
        decorations: (state) => presencePlugin.getState(state)
      }
    });
    
    const newState = this.view.state.reconfigure({
      plugins: this.view.state.plugins.concat(presencePlugin)
    });
    this.view.updateState(newState);
  }
  
  updateCollaborator(collaborator: CollaboratorInfo) {
    this.collaborators.set(collaborator.clientID, collaborator);
    this.updateView();
  }
  
  removeCollaborator(clientID: string) {
    this.collaborators.delete(clientID);
    this.updateView();
  }
  
  private updatePresenceDecorations(decorations: DecorationSet, tr: Transaction): DecorationSet {
    let newDecorations = decorations.map(tr.mapping, tr.doc);
    
    // Clear old presence decorations
    newDecorations = newDecorations.remove(
      newDecorations.find(0, tr.doc.content.size, 
        spec => spec.presence
      )
    );
    
    // Add new presence decorations
    for (const collaborator of this.collaborators.values()) {
      if (collaborator.selection) {
        const decoration = this.createSelectionDecoration(collaborator);
        if (decoration) {
          newDecorations = newDecorations.add(tr.doc, [decoration]);
        }
      }
      
      if (collaborator.cursor !== undefined) {
        const cursorDecoration = this.createCursorDecoration(collaborator);
        if (cursorDecoration) {
          newDecorations = newDecorations.add(tr.doc, [cursorDecoration]);
        }
      }
    }
    
    return newDecorations;
  }
  
  private createSelectionDecoration(collaborator: CollaboratorInfo): Decoration | null {
    if (!collaborator.selection) return null;
    
    const { from, to } = collaborator.selection;
    return Decoration.inline(from, to, {
      class: `collaborator-selection collaborator-${collaborator.clientID}`,
      style: `background-color: ${collaborator.color}33;` // 33 for transparency
    }, { presence: true });
  }
  
  private createCursorDecoration(collaborator: CollaboratorInfo): Decoration | null {
    if (collaborator.cursor === undefined) return null;
    
    const cursorElement = document.createElement("span");
    cursorElement.className = `collaborator-cursor collaborator-${collaborator.clientID}`;
    cursorElement.style.borderColor = collaborator.color;
    cursorElement.setAttribute("data-name", collaborator.name);
    
    return Decoration.widget(collaborator.cursor, cursorElement, { 
      presence: true,
      side: 1 
    });
  }
  
  private updateView() {
    // Force view update to reflect presence changes
    this.view.dispatch(this.view.state.tr);
  }
}

class ConflictResolver {
  static resolveConflicts(
    localSteps: Step[],
    remoteSteps: Step[],
    doc: Node
  ): { 
    transformedLocal: Step[];
    transformedRemote: Step[];
    resolved: boolean;
  } {
    let currentDoc = doc;
    const transformedLocal: Step[] = [];
    const transformedRemote: Step[] = [];
    
    // Use operational transformation to resolve conflicts
    const mapping = new Mapping();
    
    try {
      // Apply remote steps first, transforming local steps
      for (const remoteStep of remoteSteps) {
        const result = remoteStep.apply(currentDoc);
        if (result.failed) {
          throw new Error(`Remote step failed: ${result.failed}`);
        }
        
        currentDoc = result.doc;
        transformedRemote.push(remoteStep);
        
        // Transform remaining local steps
        for (let i = 0; i < localSteps.length; i++) {
          localSteps[i] = localSteps[i].map(mapping);
        }
        
        mapping.appendMapping(remoteStep.getMap());
      }
      
      // Apply transformed local steps
      for (const localStep of localSteps) {
        const result = localStep.apply(currentDoc);
        if (result.failed) {
          throw new Error(`Local step failed: ${result.failed}`);
        }
        
        currentDoc = result.doc;
        transformedLocal.push(localStep);
      }
      
      return {
        transformedLocal,
        transformedRemote,
        resolved: true
      };
      
    } catch (error) {
      console.error("Conflict resolution failed:", error);
      return {
        transformedLocal: [],
        transformedRemote,
        resolved: false
      };
    }
  }
  
  static handleFailedResolution(
    view: EditorView,
    localSteps: Step[],
    remoteSteps: Step[]
  ) {
    // Show conflict resolution UI
    const conflictDialog = this.createConflictDialog(localSteps, remoteSteps);
    document.body.appendChild(conflictDialog);
  }
  
  private static createConflictDialog(localSteps: Step[], remoteSteps: Step[]): HTMLElement {
    const dialog = document.createElement("div");
    dialog.className = "conflict-resolution-dialog";
    
    dialog.innerHTML = `
      <h3>Editing Conflict Detected</h3>
      <p>Your changes conflict with recent changes from another user.</p>
      <div class="conflict-options">
        <button id="accept-remote">Accept Their Changes</button>
        <button id="keep-local">Keep My Changes</button>
        <button id="merge-manual">Resolve Manually</button>
      </div>
    `;
    
    // Add event handlers for resolution options
    dialog.querySelector("#accept-remote")?.addEventListener("click", () => {
      // Accept remote changes, discard local
      dialog.remove();
    });
    
    dialog.querySelector("#keep-local")?.addEventListener("click", () => {
      // Keep local changes, may cause issues
      dialog.remove();
    });
    
    dialog.querySelector("#merge-manual")?.addEventListener("click", () => {
      // Open manual merge interface
      dialog.remove();
      this.openManualMergeInterface(localSteps, remoteSteps);
    });
    
    return dialog;
  }
  
  private static openManualMergeInterface(localSteps: Step[], remoteSteps: Step[]) {
    // Implementation for manual conflict resolution UI
    console.log("Opening manual merge interface...");
  }
}

// Server-side collaboration handler (Node.js/WebSocket example)
class CollaborationServer {
  private documents = new Map<string, DocumentSession>();
  
  handleConnection(websocket: WebSocket, documentId: string, clientId: string) {
    let session = this.documents.get(documentId);
    if (!session) {
      session = new DocumentSession(documentId);
      this.documents.set(documentId, session);
    }
    
    session.addClient(websocket, clientId);
    
    websocket.on("message", (data) => {
      const message = JSON.parse(data.toString());
      this.handleMessage(session!, websocket, message);
    });
    
    websocket.on("close", () => {
      session?.removeClient(clientId);
      if (session?.isEmpty()) {
        this.documents.delete(documentId);
      }
    });
  }
  
  private handleMessage(session: DocumentSession, websocket: WebSocket, message: any) {
    switch (message.type) {
      case "steps":
        session.applySteps(websocket, message.steps, message.version, message.clientID);
        break;
        
      case "initialize":
        session.sendInitialState(websocket, message.clientID);
        break;
        
      case "request-sync":
        session.sendFullDocument(websocket);
        break;
    }
  }
}

class DocumentSession {
  private clients = new Map<string, WebSocket>();
  private version = 0;
  private steps: any[] = [];
  
  constructor(private documentId: string) {}
  
  addClient(websocket: WebSocket, clientId: string) {
    this.clients.set(clientId, websocket);
    
    // Notify other clients
    this.broadcast({
      type: "client-joined",
      clientID: clientId
    }, clientId);
  }
  
  removeClient(clientId: string) {
    this.clients.delete(clientId);
    
    // Notify remaining clients
    this.broadcast({
      type: "client-left", 
      clientID: clientId
    }, clientId);
  }
  
  applySteps(sender: WebSocket, steps: any[], expectedVersion: number, clientId: string) {
    if (expectedVersion !== this.version) {
      // Version mismatch - send current version
      sender.send(JSON.stringify({
        type: "version",
        version: this.version
      }));
      return;
    }
    
    // Apply steps and increment version
    this.steps.push(...steps);
    this.version += steps.length;
    
    // Broadcast to other clients
    this.broadcast({
      type: "steps",
      steps,
      version: expectedVersion,
      clientIDs: [clientId]
    }, clientId);
  }
  
  private broadcast(message: any, excludeClient?: string) {
    for (const [clientId, websocket] of this.clients) {
      if (clientId !== excludeClient) {
        websocket.send(JSON.stringify(message));
      }
    }
  }
  
  isEmpty(): boolean {
    return this.clients.size === 0;
  }
  
  sendInitialState(websocket: WebSocket, clientId: string) {
    websocket.send(JSON.stringify({
      type: "initialize-response",
      version: this.version,
      steps: this.steps
    }));
  }
  
  sendFullDocument(websocket: WebSocket) {
    websocket.send(JSON.stringify({
      type: "full-sync",
      version: this.version,
      steps: this.steps
    }));
  }
}

/**
 * Collaboration configuration options
 */
interface CollabConfig {
  version?: number;
  clientID?: string | number;
}

/**
 * Sendable steps data structure
 */
interface SendableSteps {
  version: number;
  steps: Step[];
  clientID: string | number;
}

/**
 * Collaboration event types
 */
type CollabEventType = "steps" | "version" | "client-joined" | "client-left" | "initialize";

/**
 * Collaboration message structure
 */
interface CollabMessage {
  type: CollabEventType;
  [key: string]: any;
}