#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(root == NULL){
        //Allocate Memory for Node
        TreeNode *newNode = calloc(1, sizeof(TreeNode));
        if(newNode == NULL){
            return NULL; //Memory allocation failed
        }

        //Allocate Memory for data
        newNode->data = malloc(dataSize);
        if(newNode->data == NULL){
            free(newNode); //Free unused Memory
            return NULL;; //Memory allocation failed
        }
        memcpy(newNode->data, data, dataSize); //Copy Data

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

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

        return newNode;

    }
    int cmp = compareFct(root->data, data);
    
    if(cmp == 0){
        //Duplicate
        if(isDuplicate != NULL){
            //Ignore duplicate
            *isDuplicate = 1;
            return root;
        } else{
            //Accept duplicate
            root->right = addToTree(root->right, data, dataSize, compareFct, NULL);
        }
    }
    else if (cmp > 0)
    {
        //Data is smaller -> left
        root->left = addToTree(root->left, data, dataSize, compareFct, isDuplicate);
    }else{
        //Data is bigger -> right
        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;
    static TreeNode *current = NULL;

    if(root != NULL){
        clearStack(stack);
        stack = NULL;
        current = root;
    }

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

    if(stack == NULL){
        return 0;
    }
    TreeNode *node = (TreeNode *)top(stack);
    stack = pop(stack);

    current = node->right;

    return node->data;
    
} 

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