import type { NodeTree, Node, NodeId } from '@craftjs/core';
import { getRandomId } from '@craftjs/utils';

/**
 * Returns a deep-cloned NodeTree where every node id in the tree
 * (rootNodeId, the `nodes` map keys, each `node.id`, each internal
 * `node.data.parent`, every `node.data.nodes` entry, and every
 * `node.data.linkedNodes` value) has been remapped to a fresh,
 * collision-free id generated by Craft.js's own id generator.
 *
 * The subtree root's `data.parent` is deliberately left untouched --
 * `actions.addNodeTree(tree, parentId)` sets that itself when the tree is
 * attached to its new parent.
 *
 * The input tree is not mutated.
 */
export function regenerateTreeIds(tree: NodeTree): NodeTree {
  const oldIds = Object.keys(tree.nodes);

  // Build old -> new id map first so all cross-references can be rewritten
  // consistently regardless of iteration order.
  const idMap = new Map<NodeId, NodeId>();
  for (const oldId of oldIds) {
    idMap.set(oldId, getRandomId());
  }

  const remapId = (id: NodeId): NodeId => idMap.get(id) ?? id;

  const newNodes: Record<NodeId, Node> = {};
  for (const oldId of oldIds) {
    const oldNode = tree.nodes[oldId];
    const newId = idMap.get(oldId)!;

    const newParent =
      oldId === tree.rootNodeId
        ? oldNode.data.parent // subtree root's parent is set by the caller
        : oldNode.data.parent !== null && oldNode.data.parent !== undefined
          ? remapId(oldNode.data.parent)
          : oldNode.data.parent;

    const newLinkedNodes: Record<string, NodeId> = {};
    for (const [slot, linkedId] of Object.entries(oldNode.data.linkedNodes || {})) {
      newLinkedNodes[slot] = remapId(linkedId);
    }

    // Deep-clone data so mutable sub-objects (props, custom, etc.) are never
    // shared by reference between the original node and its regenerated
    // copy. Craft.js's setProp mutates data.props in place, so a shallow
    // copy here would let edits to the duplicate silently corrupt the
    // original.
    const clonedData = structuredClone(oldNode.data);

    const newNode: Node = {
      ...oldNode,
      id: newId,
      data: {
        ...clonedData,
        parent: newParent,
        nodes: (oldNode.data.nodes || []).map(remapId),
        linkedNodes: newLinkedNodes,
      },
    };

    newNodes[newId] = newNode;
  }

  return {
    rootNodeId: remapId(tree.rootNodeId),
    nodes: newNodes,
  };
}