All files / webview-app/src/hooks useCanvasDragDrop.ts

100% Statements 66/66
100% Branches 30/30
100% Functions 12/12
100% Lines 66/66

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218                      4x                                           7x       2x                                             4x                       5x 5x   5x 4x 1x     3x 3x 2x 2x       5x                         21x 21x   21x 13x 13x 1x     12x 3x 3x     12x 2x 2x 1x 1x       12x 1x 1x     12x 12x 12x   12x 12x 12x 12x       21x   2x 2x   2x 1x           21x   7x   7x 7x     7x     7x 7x 2x     5x 5x 5x   5x 5x 5x 5x 5x   5x                     5x 2x 2x           5x 5x                             21x            
import { useCallback, useEffect, useRef, useState } from "react";
 
import { getDefaultProps, getDefaultSize } from "@/lib/componentDefaults";
import { snapToGrid } from "@/lib/geometry";
import type { CanvasComponent, ComponentType } from "@/types/canvas";
 
interface Point {
  x: number;
  y: number;
}
 
const PALETTE_TO_COMPONENT_TYPE: Record<string, ComponentType> = {
  JPanel: "Panel",
  JButton: "Button",
  JLabel: "Label",
  JPasswordField: "PasswordField",
  JTextField: "TextField",
  JTextArea: "TextArea",
  JCheckBox: "CheckBox",
  JRadioButton: "RadioButton",
  JComboBox: "ComboBox",
  JList: "List",
  JProgressBar: "ProgressBar",
  JSlider: "Slider",
  JSpinner: "Spinner",
  JSeparator: "Separator",
  JMenuBar: "MenuBar",
  JMenu: "Menu",
  JMenuItem: "MenuItem",
  JToolBar: "ToolBar",
};
 
function toComponentType(rawType: string): ComponentType | null {
  return PALETTE_TO_COMPONENT_TYPE[rawType] ?? null;
}
 
function createComponentId(): string {
  return (
    globalThis.crypto?.randomUUID?.() ?? `${Date.now()}-${Math.random().toString(16).slice(2)}`
  );
}
 
export interface UseCanvasDragDropOptions {
  viewportRef: React.RefObject<HTMLDivElement | null>;
  zoom: number;
  pan: Point;
  components: CanvasComponent[];
  onAddComponent: (component: CanvasComponent) => void;
  onSelectComponent: (id: string) => void;
  resolveComponentType?: (paletteType: string) => ComponentType | null;
  createId?: () => string;
}
 
export interface UseCanvasDragDropResult {
  handleDragOver: (event: React.DragEvent<HTMLDivElement>) => void;
  handleDrop: (event: React.DragEvent<HTMLDivElement>) => void;
  isDragging: boolean;
}
 
function isPointInsideComponent(component: CanvasComponent, point: Point): boolean {
  return (
    point.x >= component.x &&
    point.x <= component.x + component.width &&
    point.y >= component.y &&
    point.y <= component.y + component.height
  );
}
 
function resolvePanelDropTarget(
  components: CanvasComponent[],
  point: Point,
): CanvasComponent | null {
  let targetPanel: CanvasComponent | null = null;
  let targetArea = Number.POSITIVE_INFINITY;
 
  for (const component of components) {
    if (component.type !== "Panel" || !isPointInsideComponent(component, point)) {
      continue;
    }
 
    const area = component.width * component.height;
    if (area <= targetArea) {
      targetPanel = component;
      targetArea = area;
    }
  }
 
  return targetPanel;
}
 
export function useCanvasDragDrop({
  viewportRef,
  zoom,
  pan,
  components,
  onAddComponent,
  onSelectComponent,
  resolveComponentType = toComponentType,
  createId = createComponentId,
}: UseCanvasDragDropOptions): UseCanvasDragDropResult {
  const [isDragging, setIsDragging] = useState(false);
  const dragDepthRef = useRef(0);
 
  useEffect(() => {
    const viewportElement = viewportRef.current;
    if (!viewportElement) {
      return;
    }
 
    const handleNativeDragEnter = () => {
      dragDepthRef.current += 1;
      setIsDragging(true);
    };
 
    const handleNativeDragLeave = () => {
      dragDepthRef.current -= 1;
      if (dragDepthRef.current <= 0) {
        dragDepthRef.current = 0;
        setIsDragging(false);
      }
    };
 
    const handleNativeDrop = () => {
      dragDepthRef.current = 0;
      setIsDragging(false);
    };
 
    viewportElement.addEventListener("dragenter", handleNativeDragEnter);
    viewportElement.addEventListener("dragleave", handleNativeDragLeave);
    viewportElement.addEventListener("drop", handleNativeDrop);
 
    return () => {
      viewportElement.removeEventListener("dragenter", handleNativeDragEnter);
      viewportElement.removeEventListener("dragleave", handleNativeDragLeave);
      viewportElement.removeEventListener("drop", handleNativeDrop);
    };
  }, [viewportRef]);
 
  const handleDragOver = useCallback(
    (event: React.DragEvent<HTMLDivElement>) => {
      event.preventDefault();
      event.dataTransfer.dropEffect = "copy";
 
      if (!isDragging) {
        setIsDragging(true);
      }
    },
    [isDragging],
  );
 
  const handleDrop = useCallback(
    (event: React.DragEvent<HTMLDivElement>) => {
      event.preventDefault();
 
      dragDepthRef.current = 0;
      setIsDragging(false);
 
      const paletteType =
        event.dataTransfer.getData("application/x-swing-component") ||
        event.dataTransfer.getData("text/plain");
 
      const componentType = resolveComponentType(paletteType);
      if (!componentType || !viewportRef.current) {
        return;
      }
 
      const viewportRect = viewportRef.current.getBoundingClientRect();
      const pointerX = (event.clientX - viewportRect.left - pan.x) / zoom;
      const pointerY = (event.clientY - viewportRect.top - pan.y) / zoom;
 
      const size = getDefaultSize(componentType);
      const defaultProps = getDefaultProps(componentType);
      const dropX = Math.round(snapToGrid(pointerX - size.width / 2));
      const dropY = Math.round(snapToGrid(pointerY - size.height / 2));
      const targetPanel = resolvePanelDropTarget(components, { x: pointerX, y: pointerY });
 
      const component: CanvasComponent = {
        id: createId(),
        type: componentType,
        variableName: `${componentType.charAt(0).toLowerCase()}${componentType.slice(1)}${components.length + 1}`,
        x: dropX,
        y: dropY,
        width: size.width,
        height: size.height,
        ...defaultProps,
      };
 
      if (targetPanel) {
        component.parentId = targetPanel.id;
        component.parentOffset = {
          x: Math.round(snapToGrid(dropX - targetPanel.x)),
          y: Math.round(snapToGrid(dropY - targetPanel.y)),
        };
      }
 
      onAddComponent(component);
      onSelectComponent(component.id);
    },
    [
      components,
      createId,
      onAddComponent,
      onSelectComponent,
      pan.x,
      pan.y,
      resolveComponentType,
      viewportRef,
      zoom,
    ],
  );
 
  return {
    handleDragOver,
    handleDrop,
    isDragging,
  };
}