F: Implement node dragging behavior

rsconcept/frontend/src/features/oss/pages/oss-page/editor-oss-graph/editor-oss-graph.tsx

@@ -3,11 +3,14 @@
 import { ReactFlowProvider } from 'reactflow';
 
 import { OssFlow } from './oss-flow';
+import { OssFlowState } from './oss-flow-state';
 
 export function EditorOssGraph() {
   return (
     <ReactFlowProvider>
-      <OssFlow />
+      <OssFlowState>
+        <OssFlow />
+      </OssFlowState>
     </ReactFlowProvider>
   );
 }

rsconcept/frontend/src/features/oss/pages/oss-page/editor-oss-graph/graph/block-node.tsx

@@ -11,12 +11,14 @@ import { globalIDs } from '@/utils/constants';
 
 import { type BlockInternalNode } from '../../../../models/oss-layout';
 import { useOssEdit } from '../../oss-edit-context';
+import { useOssFlow } from '../oss-flow-context';
 
 export const BLOCK_NODE_MIN_WIDTH = 160;
 export const BLOCK_NODE_MIN_HEIGHT = 100;
 
 export function BlockNode(node: BlockInternalNode) {
   const { selected, schema } = useOssEdit();
+  const { dropTarget } = useOssFlow();
   const showCoordinates = useOSSGraphStore(state => state.showCoordinates);
   const setHover = useOperationTooltipStore(state => state.setHoverItem);
 
@@ -42,7 +44,8 @@ export function BlockNode(node: BlockInternalNode) {
       <div
         className={clsx(
           'cc-node-block h-full w-full',
-          isParent && 'border-primary',
+          dropTarget && isParent && dropTarget !== node.data.block.id && 'border-destructive',
+          ((isParent && !dropTarget) || dropTarget === node.data.block.id) && 'border-primary',
           isChild && 'border-accent-orange50'
         )}
       >

rsconcept/frontend/src/features/oss/pages/oss-page/editor-oss-graph/oss-flow-context.tsx

@@ -0,0 +1,19 @@
+'use client';
+
+import { createContext, use } from 'react';
+
+interface IOssFlowContext {
+  dropTarget: number | null;
+  setDropTarget: React.Dispatch<React.SetStateAction<number | null>>;
+  containMovement: boolean;
+  setContainMovement: React.Dispatch<React.SetStateAction<boolean>>;
+}
+
+export const OssFlowContext = createContext<IOssFlowContext | null>(null);
+export const useOssFlow = () => {
+  const context = use(OssFlowContext);
+  if (context === null) {
+    throw new Error('useOssFlow has to be used within <OssFlowState>');
+  }
+  return context;
+};

rsconcept/frontend/src/features/oss/pages/oss-page/editor-oss-graph/oss-flow-state.tsx

@@ -0,0 +1,24 @@
+'use client';
+
+import { useState } from 'react';
+
+import { OssFlowContext } from './oss-flow-context';
+
+export const OssFlowState = ({ children }: React.PropsWithChildren) => {
+  const [dropTarget, setDropTarget] = useState<number | null>(null);
+  const [containMovement, setContainMovement] = useState(false);
+
+  return (
+    <OssFlowContext
+      value={{
+        dropTarget,
+        setDropTarget,
+
+        containMovement,
+        setContainMovement
+      }}
+    >
+      {children}
+    </OssFlowContext>
+  );
+};

rsconcept/frontend/src/features/oss/pages/oss-page/editor-oss-graph/oss-flow.tsx

@@ -11,6 +11,7 @@ import {
   useReactFlow,
   useStoreApi
 } from 'reactflow';
+import clsx from 'clsx';
 
 import { useDeleteBlock } from '@/features/oss/backend/use-delete-block';
 import { type IOperationSchema } from '@/features/oss/models/oss';
@@ -30,6 +31,7 @@ import { useOssEdit } from '../oss-edit-context';
 
 import { ContextMenu, type ContextMenuData } from './context-menu/context-menu';
 import { OssNodeTypes } from './graph/oss-node-types';
+import { useOssFlow } from './oss-flow-context';
 import { ToolbarOssGraph } from './toolbar-oss-graph';
 import { useGetLayout } from './use-get-layout';
 
@@ -51,7 +53,8 @@ export function OssFlow() {
     isMutable,
     canDeleteOperation: canDelete
   } = useOssEdit();
-  const { fitView, screenToFlowPosition } = useReactFlow();
+  const { fitView, screenToFlowPosition, getIntersectingNodes } = useReactFlow();
+  const { setDropTarget, setContainMovement, containMovement } = useOssFlow();
   const store = useStoreApi();
   const { resetSelectedElements, addSelectedNodes } = store.getState();
 
@@ -109,8 +112,6 @@ export function OssFlow() {
               height: block.height
             },
             parentId: block.parent ? `-${block.parent}` : undefined,
-            expandParent: true,
-            extent: 'parent' as const,
             zIndex: Z_BLOCK
           };
         }),
@@ -120,8 +121,6 @@ export function OssFlow() {
         data: { label: operation.alias, operation: operation },
         position: computeRelativePosition(schema, { x: operation.x, y: operation.y }, operation.parent),
         parentId: operation.parent ? `-${operation.parent}` : undefined,
-        expandParent: true,
-        extent: 'parent' as const,
         zIndex: Z_SCHEMA
       }))
     ]);
@@ -266,6 +265,81 @@ export function OssFlow() {
     setMouseCoords(targetPosition);
   }
 
+  function handleDragStart(event: React.MouseEvent, target: Node) {
+    if (event.shiftKey) {
+      setContainMovement(true);
+      setNodes(prev =>
+        prev.map(node =>
+          node.id === target.id || selected.includes(Number(node.id))
+            ? {
+                ...node,
+                extent: 'parent',
+                expandParent: true
+              }
+            : node
+        )
+      );
+    } else {
+      setContainMovement(false);
+    }
+    setIsContextMenuOpen(false);
+  }
+
+  function handleDrag(event: React.MouseEvent) {
+    if (containMovement) {
+      return;
+    }
+    const mousePosition = screenToFlowPosition({ x: event.clientX, y: event.clientY });
+    const blocks = getIntersectingNodes({
+      x: mousePosition.x,
+      y: mousePosition.y,
+      width: 1,
+      height: 1
+    })
+      .map(node => Number(node.id))
+      .filter(id => id < 0)
+      .map(id => schema.blockByID.get(-id))
+      .filter(block => !!block);
+
+    if (blocks.length === 0) {
+      setDropTarget(null);
+      return;
+    } else if (blocks.length === 1) {
+      setDropTarget(blocks[0].id);
+      return;
+    }
+
+    const parents = blocks.map(block => block.parent).filter(id => !!id);
+    const potentialTargets = blocks.map(block => block.id).filter(id => !parents.includes(id));
+    if (potentialTargets.length === 0) {
+      setDropTarget(null);
+      return;
+    } else {
+      setDropTarget(potentialTargets[0]);
+      return;
+    }
+  }
+
+  function handleDragStop(_: React.MouseEvent, target: Node) {
+    if (containMovement) {
+      setNodes(prev =>
+        prev.map(node =>
+          node.id === target.id || selected.includes(Number(node.id))
+            ? {
+                ...node,
+                extent: undefined,
+                expandParent: undefined
+              }
+            : node
+        )
+      );
+    } else {
+      // TODO: process drop event
+    }
+    setContainMovement(false);
+    setDropTarget(null);
+  }
+
   return (
     <div
       tabIndex={-1}
@@ -288,7 +362,10 @@ export function OssFlow() {
 
       <ContextMenu isOpen={isContextMenuOpen} onHide={() => setIsContextMenuOpen(false)} {...menuProps} />
 
-      <div className='cc-fade-in relative w-[100vw] cc-mask-sides' style={{ height: mainHeight, fontFamily: 'Rubik' }}>
+      <div
+        className={clsx('cc-fade-in relative w-[100vw] cc-mask-sides', !containMovement && 'cursor-relocate')}
+        style={{ height: mainHeight, fontFamily: 'Rubik' }}
+      >
         <ReactFlow
           nodes={nodes}
           edges={edges}
@@ -306,7 +383,9 @@ export function OssFlow() {
           onClick={() => setIsContextMenuOpen(false)}
           onNodeDoubleClick={handleNodeDoubleClick}
           onNodeContextMenu={handleContextMenu}
-          onNodeDragStart={() => setIsContextMenuOpen(false)}
+          onNodeDragStart={handleDragStart}
+          onNodeDrag={handleDrag}
+          onNodeDragStop={handleDragStop}
         >
           {showGrid ? <Background gap={GRID_SIZE} /> : null}
         </ReactFlow>

rsconcept/frontend/src/styling/components.css

@@ -304,6 +304,10 @@
     outline-color: var(--color-graph-selected);
     border-color: var(--color-foreground);
   }
+
+  .cursor-relocate .dragging & {
+    cursor: move;
+  }
 }
 
 @utility cc-node-block {
@@ -326,4 +330,8 @@
   &:hover {
     color: var(--color-foreground);
   }
+
+  .cursor-relocate .dragging & {
+    cursor: move;
+  }
 }