#include "binary_search_tree.h"
#include <stdlib.h>
#ifndef BINARY_SEARCH_TREE_H
#define BINARY_SEARCH_TREE_H
#include <stddef.h>

typedef struct node node_t;

struct node {
   node_t *right;
   node_t *left;
   int data;
};

node_t *build_tree(int *tree_data, size_t tree_data_len);
void free_tree(node_t *tree);
int *sorted_data(node_t *tree);

#endif

static node_t *create_node(int data) {
    node_t *new_node = malloc(sizeof(node_t));
    if (new_node != NULL) {
        new_node->data = data;
        new_node->left = NULL;
        new_node->right = NULL;
    }
    return new_node;
}

static node_t *insert_node(node_t *root, int data) {
    if (root == NULL) {
        return create_node(data);
    }
    if (data <= root->data) {
        root->left = insert_node(root->left, data);
    } else {
        root->right = insert_node(root->right, data);
    }
    return root;
}

node_t *build_tree(int *tree_data, size_t tree_data_len) {
    node_t *root = NULL;
    for (size_t i = 0; i < tree_data_len; i++) {
        root = insert_node(root, tree_data[i]);
    }
    return root;
}

void free_tree(node_t *tree) {
    if (tree != NULL) {
        free_tree(tree->left);
        free_tree(tree->right);
        free(tree);
    }
}

static void inorder_traversal(node_t *root, int *sorted_array, size_t *index) {
    if (root != NULL) {
        inorder_traversal(root->left, sorted_array, index);
        sorted_array[(*index)++] = root->data;
        inorder_traversal(root->right, sorted_array, index);
    }
}

static size_t count_nodes_helper(node_t *root);

size_t count_nodes(node_t *tree) {
    return count_nodes_helper(tree);
}

static size_t count_nodes_helper(node_t *root) {
    if (root == NULL) {
        return 0;
    }
    return 1 + count_nodes_helper(root->left) + count_nodes_helper(root->right);
}

int *sorted_data(node_t *tree) {
    size_t index = 0;
    size_t num_nodes = count_nodes(tree);
    int *sorted_array = malloc(sizeof(int) * num_nodes);
    if (sorted_array == NULL) {
        return NULL;
    }
    inorder_traversal(tree, sorted_array, &index);
    return sorted_array;
}