#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. */

// 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).
/*
memcpy
dest	-	pointer to the memory location to copy to
src	-	pointer to the memory location to copy from
count	-	number of bytes to copy
*/
TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFctType compareFct, int *isDuplicate)
{
    if (root == NULL)
    {
        TreeNode *newtreenode = malloc(sizeof(TreeNode));
        if (newtreenode != NULL)
        {

            newtreenode->data = malloc(dataSize);
            if (newtreenode->data == NULL)
            {
                free(newtreenode);
                return NULL;
            }

            memcpy(newtreenode->data, data, dataSize);

            newtreenode->left = NULL;
            newtreenode->right = NULL;

            if (isDuplicate != NULL)
            {
                *isDuplicate = 0;
            }
        }
        return newtreenode;
    }

    int compare_value = compareFct(data, root->data); // wie funktioniert comparefcttype funktion? bzw wo steht diese?

    if (compare_value == 0 && isDuplicate != NULL)
    {
        *isDuplicate = 1;
        return root;
    }

    if (compare_value < 0)
    {
        root->left = addToTree(root->left, data, dataSize, compareFct, isDuplicate);
    }
    else
    {
        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)
{
    static StackNode *stack = NULL;
    TreeNode *currentElement = root;

    if (currentElement != NULL)
    {
        clearStack(stack);
        stack = NULL;

        while (currentElement != NULL)
        {
            stack = push(stack, currentElement);
            currentElement = currentElement->left;
        }
    }

    if (stack == NULL)
    {
        return NULL;
    }

    TreeNode *node = (TreeNode *)top(stack);
    stack = pop(stack);

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

// Releases all memory resources (including data copies).
void clearTree(TreeNode *root)
{
    if (root != NULL)
    {
        clearTree(root->left);
        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 count = 0;
    
    if (root != NULL)
    {
        count = 1;
        count += treeSize(root->right);
        count += treeSize(root->left);
    }
    return count;
}