Add CapacityDisplayTool for showing total seats count

frontend/src/tools/drawing/CapacityDisplayTool.ts

@@ -0,0 +1,66 @@
+import { Tool } from '../Tool';
+import { YjsDocument } from '../../crdt/YjsDocument';
+
+class CapacityDisplayTool extends Tool {
+  constructor(yjsDoc: YjsDocument) {
+    super(yjsDoc);
+    this.name = 'CapacityDisplayTool';
+  }
+
+  onMouseDown(event: MouseEvent): void {
+    // This tool doesn't create elements on mouse click
+    // It displays capacity information based on selected elements or entire drawing
+  }
+
+  onMouseMove(event: MouseEvent): void {
+    // No preview needed for this tool
+  }
+
+  onMouseUp(event: MouseEvent): void {
+    // No action needed on mouse up
+  }
+
+  onKeyUp(event: KeyboardEvent): void {
+    // Handle key up events
+    if (event.key === 'Escape') {
+      this.reset();
+    }
+  }
+
+  reset(): void {
+    // Reset any state if needed
+  }
+
+  // Calculate capacity for selected tables
+  calculateSelectedCapacity(): number {
+    // In a real implementation, this would get selected tables from the canvas
+    // and calculate the total capacity based on table type and size
+    // For now, we'll return a placeholder value
+    return 0;
+  }
+
+  // Calculate capacity for entire drawing
+  calculateTotalCapacity(): number {
+    // In a real implementation, this would iterate through all elements in the Yjs document
+    // and count chairs or calculate capacity based on tables
+    // For now, we'll return a placeholder value
+    return 0;
+  }
+
+  // Display capacity information
+  displayCapacity(): void {
+    const totalCapacity = this.calculateTotalCapacity();
+    const selectedCapacity = this.calculateSelectedCapacity();
+    
+    // In a real implementation, this would update the UI to show capacity information
+    console.log(`Total capacity: ${totalCapacity} seats`);
+    if (selectedCapacity > 0) {
+      console.log(`Selected capacity: ${selectedCapacity} seats`);
+    }
+    
+    // In a real implementation, this would show a modal or update a panel in the UI
+    alert(`Total capacity: ${totalCapacity} seats${selectedCapacity > 0 ? `\nSelected capacity: ${selectedCapacity} seats` : ''}`);
+  }
+}
+
+export { CapacityDisplayTool };