#include <string.h>
#include "stack.h"
#include "bintree.h"

//TODO: binären Suchbaum implementieren
/*  * `addToTree`: fügt ein neues Element in den Baum ein (rekursiv),
    * `clearTree`: gibt den gesamten Baum frei (rekursiv),
    * `treeSize`: zählt die Knoten im Baum (rekursiv),
    * `nextTreeData`: Traversierung mit Hilfe des zuvor implementierten Stacks. */

static StackNode *stack = NULL;

	TreeNode* createNode(const void *data, size_t dataSize) {
		TreeNode* newNode = (TreeNode*)malloc(sizeof(TreeNode));
		if (newNode == NULL) {
			// Fehlerbehandlung: Speicher konnte nicht alloziiert werden
			return NULL;
		}

		// Speicher für die Daten allozieren und kopieren
		newNode->data = malloc(dataSize);
		if (newNode->data == NULL) {
			free(newNode); // newNode freigeben, wenn Datenallokation fehlschlägt
			return NULL;
		}
		memcpy(newNode->data, data, dataSize);

		newNode->left = NULL;
		newNode->right = NULL;
		return newNode;
	}


// Adds a copy of data's pointer destination to the tree using compareFct for ordering. Accepts duplicates
// if isDuplicate is NULL, otherwise ignores duplicates and sets isDuplicate to 1 (or to 0 if a new entry is added).
TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFctType compareFct, int *isDuplicate)
{


	if (root == NULL)
	{
		TreeNode *newNode = createNode(data,dataSize);
		if (isDuplicate != NULL)
			*isDuplicate = 0;

		return newNode;
	}
	if (compareFct(root->data, data)==0)
	{
		if (isDuplicate != NULL) {
			*isDuplicate=1;
			return root;
		}
		TreeNode *newNode = createNode(data,dataSize);
		return newNode;
	}
	else if (compareFct(root->data, data)>0)
	{
		root->left = addToTree(root->left, data, dataSize, compareFct, isDuplicate);
	}
	else if (compareFct(root->data, data)<0)
	{
		root->right= addToTree(root->right, data, dataSize, compareFct, isDuplicate);
	}
	return root;
}

// Iterates over the tree given by root. Follows the usage of strtok. If tree is NULL, the next entry of the last tree given is returned in ordering direction.
// Use your implementation of a stack to organize the iterator. Push the root node and all left nodes first. On returning the next element,
// push the top node and push all its left nodes.
void *nextTreeData(TreeNode *root)
{
	if (root != NULL) {
		clearStack(stack);
		stack = NULL;
		TreeNode *current = root;
		while (current != NULL) {
			stack = push(stack,current);
			current = current->left;
		}
	}
		if (stack == NULL) {
			return NULL;
		}
		TreeNode *node = (TreeNode*) top(stack);
		stack = pop(stack);

		TreeNode *right = node->right;
		while (right != NULL) {
			stack = push(stack,right);
			right = right->left;
		}
		return node->data;
}

// Releases all memory resources (including data copies).
void clearTree(TreeNode *root)
{
	if (root != NULL) {
		if (root->left != NULL) {
			clearTree(root->left);
		}
		if (root->right != NULL) {
			clearTree(root->right);
		}
		free(root->data);
		free(root);
	}
}

// Returns the number of entries in the tree given by root.
unsigned int treeSize(const TreeNode *root)
{
		unsigned int size = 0;
		if (root == NULL) {
			return 0;
		}

		if (root->left != NULL)
		{
			size += treeSize(root->left);
		}
		if (root->right != NULL)
		{
			size += treeSize(root->right);
		}
		return size+1;

}