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

// --------------------------
// Hilfsfunktion für Vergleich von unsigned int
// --------------------------
static int compareUint(const void *a, const void *b)
{
    unsigned int x = *(unsigned int *)a;
    unsigned int y = *(unsigned int *)b;
    if (x < y) return -1;
    if (x > y) return 1;
    return 0;
}

// --------------------------
// addToTree
// --------------------------
TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFctType compareFct, int *isDuplicate)
{
    if (!compareFct)
        compareFct = compareUint;

    if (!root)
    {
        TreeNode *node = malloc(sizeof(TreeNode));
        if (!node) return NULL;
        node->data = malloc(dataSize);
        if (!node->data)
        {
            free(node);
            return NULL;
        }
        memcpy(node->data, data, dataSize);
        node->left = node->right = NULL;
        if (isDuplicate) *isDuplicate = 0;
        return node;
    }

    int cmp = compareFct(data, root->data);
    if (cmp == 0)
    {
        if (isDuplicate) *isDuplicate = 1;
        return root;
    }
    else if (cmp < 0)
        root->left = addToTree(root->left, data, dataSize, compareFct, isDuplicate);
    else
        root->right = addToTree(root->right, data, dataSize, compareFct, isDuplicate);

    return root;
}

// --------------------------
// clearTree
// --------------------------
void clearTree(TreeNode *root)
{
    if (!root) return;
    clearTree(root->left);
    clearTree(root->right);
    free(root->data);
    free(root);
}

// --------------------------
// treeSize
// --------------------------
unsigned int treeSize(const TreeNode *root)
{
    if (!root) return 0;
    return 1 + treeSize(root->left) + treeSize(root->right);
}

// --------------------------
// nextTreeData (In-Order Traversal mit Stack) – minimal
// --------------------------
#include "stack.h"
void *nextTreeData(TreeNode *root)
{
    static StackNode *stack = NULL;
    static TreeNode *current = NULL;

    if (root) current = root;

    while (current)
    {
        stack = push(stack, current);
        current = current->left;
    }

    if (!stack) return NULL;

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

    current = node->right;
    return node->data;
}