#include "hashtable.h" 

#define DEBUG 1

Hashtable::Hashtable()
{
	for(int i = 0; i < TABLE_SIZE; i++)
		table[i] = 0;
}

//Hash Function: sum of the ASCII codes of the characters % TABLE_SIZE 
int Hashtable::hash (char *l)
{
	int sum = 0;
	
	int len = strlen(l);
	
	for(int i = 0; i < len; i++)
		sum += l[i];
		
	return sum % TABLE_SIZE;

}

//produces new index in the array
int Hashtable::rehash(int i)
{
	i = (i+1)%TABLE_SIZE;
	return i;
}

bool Hashtable::insert (Type* new_item)
{
	int index, new_index, counter = -1;

	index = hash(new_item->get_key()); 

    if(DEBUG) 
		cout << endl << "The index given by a hashfunction is " << index << endl;
	
	bool result = false;

	
	//if the spot is empty, or the record has been deleted, or the keys are the same
	if(table[index] == 0 || (strcmp(table[index]->get_key(), "*") == 0) || strcmp (new_item->get_key(), table[index]->get_key()) == 0) { 
		table[index] = new_item;
		result = true;
		
		if(DEBUG)
			cout << endl << "The index of the available spot is " << index << endl;
		
		return result;
	}
	
	new_index = rehash(index);

	while(new_index != index){
		if(table[new_index] == 0 || (strcmp(table[new_index]->get_key(), "*")==0)){
			table[new_index] = new_item;
			result = true;

			if(DEBUG)
				cout << endl << "The index of the available spot is " << new_index << endl;

			return result;
		}
		else if(strcmp(table[new_index]->get_key(), new_item->get_key()) == 0){//if the keys are the same, update the record
			table[new_index] = new_item;
			result = true;

			if(DEBUG)
				cout << endl << "The index of the available spot is " << new_index << endl;

			return result;
		}

		new_index = rehash(new_index);
	}

	return result;
}

Type * Hashtable::get_data(int ind)
{
	return table[ind];
}

void Hashtable::view()
{
	for(int i = 0; i < TABLE_SIZE; i++) {
		if(table[i] == 0 || (strcmp(table[i]->get_key(), "*") == 0)) //if the spot has never been used or a record has been deleted
			continue;
	cout << "\nIndex " << i << ": " << *table[i];
	}

}

Type * Hashtable::find (char* key)
{
	int index, new_index;
	Type *item;

	new_index = index = hash(key);

	item = table[index];	
	
	if(item != 0) {
		if(strcmp(item->get_key(), key) == 0)
			return item;
	}

	new_index = rehash(index);

	while(new_index != index){
		if(table[new_index] != 0){
			if(strcmp(table[new_index]->get_key(), key) == 0)
				return table[new_index];
		}
		new_index = rehash(new_index);
	}	
	
	return 0;
}


bool Hashtable::remove(char *key)
{
	int index, new_index;
	Type *item;
	bool result = false;

	new_index = index = hash(key);

	item = table[index];
	
	if(item != 0){
		if(strcmp(item->get_key(), key) == 0) {
			item->set_key("*");
			result = true;
			return result;
		}
	}

	new_index = rehash(index);

	while(new_index != index){
		if(table[new_index] != 0){
			if(strcmp(table[new_index]->get_key(), key) == 0){
				table[new_index]->set_key("*");
				result = true;
				return result;
			}
		}

		new_index = rehash(new_index);
	}

	return result;
}