#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).
TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFctType compareFct, int *isDuplicate)
{
    if (!data){
        return NULL;
    }

    if (!root){                                                     //Neuen Node
        TreeNode *new = malloc(sizeof(TreeNode));
        if (!new){
            return NULL;
        }
        new->data = malloc(dataSize);
        if (!new->data){
            free(new);
            return NULL;
        }

        memcpy(new->data, data, dataSize);                          //data übertragen
        new->left = new->right = NULL;

        if (isDuplicate){
            *isDuplicate = 0;
        }
        return new;
    }

    int cmp = compareFct(data, root->data);

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

    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;
    static int initialized = 0;

    if (root != NULL) {                                         // Initialisierung: Stack leeren und mit root + linke elemente befüllen
        while (stack != NULL) {
            stack = pop(stack);
        }
        while (root != NULL) {
            stack = push(stack, root);
            root = root->left;
        }
        initialized = 1;
    } else if (!initialized) {                                  // Noch nicht initialisiert und kein root übergeben
        return NULL;
    }

    if (stack == NULL) {                                        //Ende
        initialized = 0;
        return NULL;
    }

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

    if (topNode->right != NULL) {
        TreeNode *r = topNode->right;
        while (r != NULL) {
            stack = push(stack, r);
            r = r->left;
        }
    }

    return topNode->data;
}

// Releases all memory resources (including data copies).
void clearTree(TreeNode *root)
{

}

// Returns the number of entries in the tree given by root.
unsigned int treeSize(const TreeNode *root)
{

}