private static void RestoreRightTree(Model.TreeNode current, TreeNodeContext db)
{
if (current == null)
{
return;
}
var childsOfCurrentNode = db.TreeNodes.Where(n => n.ParentID == current.NodeID);
current.right = childsOfCurrentNode.SingleOrDefault(n => n.value >= current.value);
if (childsOfCurrentNode.SingleOrDefault(n => n.value < current.value) != null)
{
current.left = childsOfCurrentNode.SingleOrDefault(n => n.value < current.value);
RestoreLeftTree(current.left, db);
}
RestoreLeftTree(current.right, db);
}
public static BinaryTree RestoreTree()
{
BinaryTree tree = new BinaryTree();
using (TreeNodeContext db = new TreeNodeContext())
{
if (!db.Database.Exists())
{
db.Database.Create();
return tree;
}
var nodes = db.TreeNodes;
tree.root = nodes.SingleOrDefault(node => node.ParentID == null);
RestoreLeftTree(tree.root, db);
}
return tree;
}
private void RemoveFromDB(TreeNode node, bool needRightChild, TreeNode mostLeft = null)
{
using (TreeNodeContext db = new TreeNodeContext())
{
UpdateIDs(db, needRightChild, node, mostLeft);
var nodeToRemove = db.TreeNodes.SingleOrDefault(n => n.NodeID == node.NodeID);
if (nodeToRemove != null)
{
db.TreeNodes.Remove(nodeToRemove);
}
db.SaveChanges();
}
}
private void UpdateIDs(TreeNodeContext db, bool needRightChild, TreeNode nodeToRemove, TreeNode mostLeft)
{
var firstChildOfRemovingNode = needRightChild ? db.TreeNodes.SingleOrDefault(node => node.ParentID == nodeToRemove.NodeID && node.value >= nodeToRemove.value)
: db.TreeNodes.SingleOrDefault(node => node.ParentID == nodeToRemove.NodeID && node.value < nodeToRemove.value);
var leftChild = needRightChild ? db.TreeNodes.SingleOrDefault(node => node.ParentID == nodeToRemove.NodeID && node.value < nodeToRemove.value) : null;
if (firstChildOfRemovingNode != null)
{
if(mostLeft != null)
{
var mostLeftInDB = db.TreeNodes.SingleOrDefault(node => node.NodeID == mostLeft.NodeID);
mostLeftInDB.ParentID = nodeToRemove.ParentID;
if (leftChild != null)
{
leftChild.ParentID = mostLeft.NodeID;
}
if(mostLeftInDB.NodeID == firstChildOfRemovingNode.NodeID)
{
db.SaveChanges();
return;
}
firstChildOfRemovingNode.ParentID = mostLeftInDB.NodeID;
db.SaveChanges();
return;
}
firstChildOfRemovingNode.ParentID = nodeToRemove.ParentID;
db.SaveChanges();
}
}
private int AddInDB(TreeNode node)
{
using (TreeNodeContext db = new TreeNodeContext())
{
db.TreeNodes.Add(node);
db.SaveChanges();
return node.NodeID;
}
}
