class TreeNode:
    def __init__(self, key, val, left = None, right = None, parent = None):
        self.key = key
        self.payload = val
        self.leftChild = left
        self.rightChild = right
        self.parent = parent
        self.successor = None

    def hasLeftChild(self):
        return self.leftChild

    def hasRightChild(self):
        return self.rightChild

    def isLeftChild(self):
        return self.parent and self.parent.leftChild == self

    def isRightChild(self):
        return self.parent and self.parent.rightChild == self

    def isRoot(self):
        return not self.parent

    def isLeaf(self):
        return not (self.rightChild or self.leftChild)

    def hasAnyChildren(self):
        return self.rightChild or self.leftChild

    def hasBothChildren(self):
        return self.rightChild and self.leftChild

    def spliceOut(self):
        if self.isLeaf():
            if self.isLeftChild():
                self.parent.leftChild = None
            else:
                self.parent.rightChild = None
        elif self.hasAnyChildren():
            if self.hasLeftChild():
                if self.isLeftChild():
                    self.parent.leftChild = self.leftChild
                else:
                    self.parent.rightChild = self.leftChild
                self.leftChild.parent = self.parent
            else:
                if self.isLeftChild():
                    self.parent.leftChild = self.rightChild
                else:
                    self.parent.rightChild = self.rightChild
                self.rightChild.parent = self.parent

    def findSuccessor(self):
        succ = None
        if self.hasRightChild():
            succ = self.rightChild.findMin()
        else:
            if self.parent:
                if self.isLeftChild():
                    succ = self.parent
                else:
                    self.parent.rightChild = None
                    succ = self.parent.findSuccessor()
                    self.parent.rightChild = self
        return succ

    def findPredeccessor(self):
        pred = None

        if self.hasLeftChild():
            pred = self.leftChild.findMax()
        else:
            if self.parent:
                if self.isRightChild():
                    pred = self.parent
                else:
                    self.parent.leftChild = None
                    pred = self.parent.findPredeccessor()
                    self.parent.leftChild = self
        return pred


    def findMin(self):
        current = self
        while current.hasLeftChild():
            current = current.leftChild
        return current

    def findMax(self):
        current = self
        while current.hasRightChild():
            current = current.rightChild
        return current

    def replaceNodeData(self, key, value, lc, rc):
        self.key = key
        self.payload = value
        self.leftChild = lc
        self.rightChild = rc
        if self.hasLeftChild():
            self.leftChild.parent = self
        if self.hasRightChild():
            self.rightChild.parent = self


class BinarySearchTree:

    def __init__(self):
        self.root = None
        self.size = 0

    def length(self):
        return self.size

    def __len__(self):
        return self.size

    def put(self, key, val):
        if self.root:
            self._put(key, val, self.root)
        else:
            self.root = TreeNode(key, val)
        self.size = self.size + 1

    def _put(self, key, val, currentNode):
        if key < currentNode.key:
            if currentNode.hasLeftChild():
                self._put(key, val, currentNode.leftChild)
            else:
                currentNode.leftChild = TreeNode(key, val, parent=currentNode)
                currentNode.leftChild.successor = currentNode.leftChild.findSuccessor()
                predeccessor = currentNode.leftChild.findPredeccessor()
                if predeccessor is not None:
                    predeccessor.successor = currentNode.leftChild

        else:
            if currentNode.hasRightChild():
                self._put(key, val, currentNode.rightChild)
            else:
                currentNode.rightChild = TreeNode(key, val, parent=currentNode)
                currentNode.rightChild.successor = currentNode.rightChild.findSuccessor()
                predeccessor = currentNode.rightChild.findPredeccessor()
                if predeccessor is not None:
                    predeccessor.successor = currentNode.rightChild


    def __setitem__(self, k, v):
        self.put(k, v)

    def get(self, key):
        if self.root:
            res = self._get(key, self.root)
            if res:
                return res.payload
            else:
                return None
        else:
            return None

    def _get(self, key, currentNode):
        if not currentNode:
            return None
        elif currentNode.key == key:
            return currentNode
        elif key < currentNode.key:
            return self._get(key, currentNode.leftChild)
        else:
            return self._get(key, currentNode.rightChild)

    def __getitem__(self, key):
        return self.get(key)

    def __contains__(self, key):
        if self._get(key, self.root):
            return True
        else:
            return False

    def delete(self, key):
        if self.size > 1:
            nodeToRemove = self._get(key, self.root)
            if nodeToRemove:
                self.remove(nodeToRemove)
                self.size = self.size - 1
            else:
                raise KeyError('Error, key not in tree')
        elif self.size == 1 and self.root.key == key:
            self.root = None
            self.size = self.size - 1
        else:
            raise KeyError('Error, key not in tree')

    def __delitem__(self, key):
        self.delete(key)

    def remove(self, currentNode):

        predeccessor = currentNode.findPredeccessor()
        predeccessor.successor = currentNode.successor

        if currentNode.isLeaf():  # leaf
            if currentNode == currentNode.parent.leftChild:
                currentNode.parent.leftChild = None
            else:
                currentNode.parent.rightChild = None
        elif currentNode.hasBothChildren():  # interior
            succ = currentNode.findSuccessor()
            succ.spliceOut()
            currentNode.key = succ.key
            currentNode.payload = succ.payload

        else:  # this node has one child
            if currentNode.hasLeftChild():
                if currentNode.isLeftChild():
                    currentNode.leftChild.parent = currentNode.parent
                    currentNode.parent.leftChild = currentNode.leftChild
                elif currentNode.isRightChild():
                    currentNode.leftChild.parent = currentNode.parent
                    currentNode.parent.rightChild = currentNode.leftChild
                else:
                    currentNode.replaceNodeData(currentNode.leftChild.key,
                                                currentNode.leftChild.payload,
                                                currentNode.leftChild.leftChild,
                                                currentNode.leftChild.rightChild)
            else:
                if currentNode.isLeftChild():
                    currentNode.rightChild.parent = currentNode.parent
                    currentNode.parent.leftChild = currentNode.rightChild
                elif currentNode.isRightChild():
                    currentNode.rightChild.parent = currentNode.parent
                    currentNode.parent.rightChild = currentNode.rightChild
                else:
                    currentNode.replaceNodeData(currentNode.rightChild.key,
                                                currentNode.rightChild.payload,
                                                currentNode.rightChild.leftChild,
                                                currentNode.rightChild.rightChild)

    def inorder_successors(self):
        min = self.root.findMin()
        max = self.root.findMax()
        current = min
        inorder = []

        while current.key is not max.key:
            inorder.append(current.key)
            current = current.findSuccessor()

        inorder.append(current.key)
        return inorder

    def inorder_predeccessors(self):
        min = self.root.findMin()
        max = self.root.findMax()
        current = max
        inorder = []

        while current.key is not min.key:
            inorder.append(current.key)
            current = current.findPredeccessor()

        inorder.append(current.key)
        return inorder

    def inorder_traversal(self):
        currentnode = self.root.findMin()
        outputlist = []

        while currentnode is not None:
            outputlist.append(currentnode.key)
            currentnode = currentnode.successor

        return outputlist



mytree = BinarySearchTree()
mytree[3] = "red"
mytree[4] = "blue"
mytree[6] = "yellow"
mytree[2] = "at"



mytree[7] = "purple"

print(mytree.inorder_traversal())

mytree.delete(4)

print(mytree.inorder_traversal())

mytree[4] = "pink"

print(mytree.inorder_traversal())

mytree[8] = "ta"

print(mytree.inorder_traversal())