Refactor: share nav drag and drop logic

2026-06-24 02:11:02 +01:00
parent 69af324b1b
commit 212dd1c435
6 changed files with 626 additions and 712 deletions
@@ -0,0 +1,278 @@
+export type NavTreeDropIntent = "before" | "after" | "inside";
+
+export type NavTreeDropTarget = {
+	parentId: string | null;
+	index: number;
+	intent: NavTreeDropIntent;
+	targetNodeId?: string;
+};
+
+export type NavTreeDragState = {
+	draggedNodeId: string;
+	dropTarget: NavTreeDropTarget | null;
+};
+
+export type NavTreeLocation<TNode> = {
+	parentId: string | null;
+	index: number;
+	node: TNode;
+};
+
+export type NavTreeAdapter<TNode> = {
+	getNodeId: (node: TNode) => string;
+	isBranchNode: (node: TNode) => boolean;
+	getChildren: (node: TNode) => readonly TNode[];
+	withChildren: (node: TNode, children: readonly TNode[]) => TNode;
+};
+
+const UUID_PATTERN = /^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i;
+
+export const isUuidString = (value: string | null | undefined): boolean => {
+	if (typeof value !== "string") {
+		return false;
+	}
+
+	return UUID_PATTERN.test(value.trim());
+};
+
+export const collectBranchNodeIds = <TNode>(
+	nodes: readonly TNode[],
+	adapter: NavTreeAdapter<TNode>,
+): string[] => {
+	const ids: string[] = [];
+
+	for (const node of nodes) {
+		if (!adapter.isBranchNode(node)) {
+			continue;
+		}
+
+		ids.push(adapter.getNodeId(node));
+		ids.push(...collectBranchNodeIds(adapter.getChildren(node), adapter));
+	}
+
+	return ids;
+};
+
+export const findTreeNodeLocation = <TNode>(
+	nodes: readonly TNode[],
+	nodeId: string,
+	adapter: NavTreeAdapter<TNode>,
+	parentId: string | null = null,
+): NavTreeLocation<TNode> | null => {
+	for (let index = 0; index < nodes.length; index += 1) {
+		const node = nodes[index];
+
+		if (adapter.getNodeId(node) === nodeId) {
+			return { parentId, index, node };
+		}
+
+		if (!adapter.isBranchNode(node)) {
+			continue;
+		}
+
+		const nestedLocation = findTreeNodeLocation(adapter.getChildren(node), nodeId, adapter, adapter.getNodeId(node));
+		if (nestedLocation) {
+			return nestedLocation;
+		}
+	}
+
+	return null;
+};
+
+export const findTreeNodeDepth = <TNode>(
+	nodes: readonly TNode[],
+	nodeId: string,
+	adapter: NavTreeAdapter<TNode>,
+	depth = 0,
+): number | null => {
+	for (const node of nodes) {
+		if (adapter.getNodeId(node) === nodeId) {
+			return depth;
+		}
+
+		if (!adapter.isBranchNode(node)) {
+			continue;
+		}
+
+		const nestedDepth = findTreeNodeDepth(adapter.getChildren(node), nodeId, adapter, depth + 1);
+		if (nestedDepth !== null) {
+			return nestedDepth;
+		}
+	}
+
+	return null;
+};
+
+export const treeContainsNode = <TNode>(
+	nodes: readonly TNode[],
+	nodeId: string,
+	adapter: NavTreeAdapter<TNode>,
+): boolean => {
+	for (const node of nodes) {
+		if (adapter.getNodeId(node) === nodeId) {
+			return true;
+		}
+
+		if (adapter.isBranchNode(node) && treeContainsNode(adapter.getChildren(node), nodeId, adapter)) {
+			return true;
+		}
+	}
+
+	return false;
+};
+
+export const removeTreeNode = <TNode>(
+	nodes: readonly TNode[],
+	nodeId: string,
+	adapter: NavTreeAdapter<TNode>,
+): { nodes: TNode[]; removed: TNode | null } => {
+	const nextNodes: TNode[] = [];
+	let removed: TNode | null = null;
+
+	for (const node of nodes) {
+		if (adapter.getNodeId(node) === nodeId) {
+			removed = node;
+			continue;
+		}
+
+		if (adapter.isBranchNode(node)) {
+			const result = removeTreeNode(adapter.getChildren(node), nodeId, adapter);
+
+			if (result.removed) {
+				removed = result.removed;
+				nextNodes.push(adapter.withChildren(node, result.nodes));
+				continue;
+			}
+		}
+
+		nextNodes.push(node);
+	}
+
+	return { nodes: nextNodes, removed };
+};
+
+export const insertTreeNode = <TNode>(
+	nodes: readonly TNode[],
+	parentId: string | null,
+	index: number,
+	nodeToInsert: TNode,
+	adapter: NavTreeAdapter<TNode>,
+): TNode[] => {
+	if (parentId === null) {
+		const nextNodes = [...nodes];
+		nextNodes.splice(Math.max(0, Math.min(index, nextNodes.length)), 0, nodeToInsert);
+		return nextNodes;
+	}
+
+	return nodes.map((node) => {
+		if (!adapter.isBranchNode(node)) {
+			return node;
+		}
+
+		if (adapter.getNodeId(node) === parentId) {
+			const nextChildren = [...adapter.getChildren(node)];
+			nextChildren.splice(Math.max(0, Math.min(index, nextChildren.length)), 0, nodeToInsert);
+			return adapter.withChildren(node, nextChildren);
+		}
+
+		return adapter.withChildren(node, insertTreeNode(adapter.getChildren(node), parentId, index, nodeToInsert, adapter));
+	});
+};
+
+export const moveTreeNode = <TNode>(
+	nodes: readonly TNode[],
+	draggedNodeId: string,
+	dropTarget: NavTreeDropTarget,
+	adapter: NavTreeAdapter<TNode>,
+): TNode[] => {
+	const location = findTreeNodeLocation(nodes, draggedNodeId, adapter);
+
+	if (!location) {
+		return [...nodes];
+	}
+
+	if (
+		adapter.isBranchNode(location.node) &&
+		dropTarget.parentId !== null &&
+		(treeContainsNode(adapter.getChildren(location.node), dropTarget.parentId, adapter) ||
+			dropTarget.parentId === adapter.getNodeId(location.node))
+	) {
+		return [...nodes];
+	}
+
+	let normalizedIndex = dropTarget.index;
+	if (dropTarget.parentId === location.parentId && dropTarget.index > location.index) {
+		normalizedIndex -= 1;
+	}
+
+	if (dropTarget.parentId === location.parentId && normalizedIndex === location.index) {
+		return [...nodes];
+	}
+
+	const removalResult = removeTreeNode(nodes, draggedNodeId, adapter);
+	if (!removalResult.removed) {
+		return [...nodes];
+	}
+
+	return insertTreeNode(removalResult.nodes, dropTarget.parentId, normalizedIndex, removalResult.removed, adapter);
+};
+
+export const getPointerRelativeY = (event: PointerEvent): number | null => {
+	const currentTarget = event.currentTarget;
+	if (!(currentTarget instanceof HTMLElement)) {
+		return null;
+	}
+
+	const bounds = currentTarget.getBoundingClientRect();
+	return bounds.height <= 0 ? 0.5 : (event.clientY - bounds.top) / bounds.height;
+};
+
+export const resolveTreeDropTarget = <TNode>(params: {
+	parentId: string | null;
+	index: number;
+	node: TNode;
+	relativeY: number;
+	adapter: NavTreeAdapter<TNode>;
+	beforeThreshold?: number;
+	beforeThresholdFirstSibling?: number;
+	afterThreshold?: number;
+}): NavTreeDropTarget => {
+	const {
+		parentId,
+		index,
+		node,
+		relativeY,
+		adapter,
+		beforeThreshold = 0.28,
+		beforeThresholdFirstSibling = 0.42,
+		afterThreshold = 0.72,
+	} = params;
+
+	const targetNodeId = adapter.getNodeId(node);
+
+	if (adapter.isBranchNode(node)) {
+		const nextBeforeThreshold = index === 0 ? beforeThresholdFirstSibling : beforeThreshold;
+
+		if (relativeY < nextBeforeThreshold) {
+			return { parentId, index, intent: "before", targetNodeId };
+		}
+
+		if (relativeY > afterThreshold) {
+			return { parentId, index: index + 1, intent: "after", targetNodeId };
+		}
+
+		return {
+			parentId: targetNodeId,
+			index: adapter.getChildren(node).length,
+			intent: "inside",
+			targetNodeId,
+		};
+	}
+
+	return {
+		parentId,
+		index: relativeY < 0.5 ? index : index + 1,
+		intent: relativeY < 0.5 ? "before" : "after",
+		targetNodeId,
+	};
+};