#include <stdlib.h>
#include "method_dispatcher.h"


dispatch_tree_t dispatch_tree_t_new(void)
{
	dispatch_tree_t tree = malloc(sizeof(struct dispatch_tree_s));
	tree->root = NULL;
	return tree;
}

void dispatch_tree_t_del(dispatch_tree_t tree)
{
	dispatch_tree_node_t_del(tree->root);
	free(tree);
}

dispatch_tree_node_t dispatch_tree_node_t_new(uint16_t word
					, bci_core_method_t method)
{
	dispatch_tree_node_t node = malloc(sizeof(struct dispatch_tree_node_s));
	node->higher = NULL;
	node->lower = 0;
	node->method = method;
	node->word = word;
	return node;
}

void dispatch_tree_node_t_del(dispatch_tree_node_t node)
{
	if(node->higher)
	{
		dispatch_tree_node_t_del(node->higher);
	}
	if(node->lower)
	{
		dispatch_tree_node_t_del(node->lower);
	}
	free(node);
}

char dispatch_tree_t_insert(dispatch_tree_t tree
			, uint16_t word
			, bci_core_method_t method)
{
	dispatch_tree_node_t new_node = dispatch_tree_node_t_new(word, method);
	if(!new_node)
	{
		return 1;
	}
	// explicitly handle empty tree
	if(!tree->root)
	{
		tree->root = new_node;
		return 0;
	}

	// non-empty tree
	dispatch_tree_node_t this_node = tree->root;
	dispatch_tree_node_t parent_node = NULL;
	// search for place
	do
	{
		parent_node = this_node;
		if(parent_node->word < word)
		{
			this_node = parent_node->higher;
			continue;
		}
		if(parent_node->word > word)
		{
			this_node = parent_node->lower;
			continue;
		}
		if(parent_node->word == word)
		{
			// we already have that key.
			return 2;
		}

	} 
	while(this_node);
	if(parent_node->word < word)
	{
		parent_node->higher = new_node;
	}
	if(parent_node->word > word)
	{
		parent_node->lower = new_node;
	}

	return 0;

}


bci_core_method_t dispatch_tree_t_dispatch(dispatch_tree_t tree
					, uint16_t word)
{
	dispatch_tree_node_t this_node = tree->root;
	while(this_node)
	{
		if(this_node->word < word)
		{
			this_node = this_node->higher;
			continue;
		}
		if(this_node->word > word)
		{
			this_node = this_node->lower;
			continue;
		}
		if(this_node->word == word)
		{
			return this_node->method;
		}
	}
	return NULL;
}