/**
 * llist.c - a basic linked list implementation.
 * 
 * Used for the hashtable.
 * 
 */

#include <stdlib.h>
#include <stdio.h>

#include "llist.h"

/**
 * Node in the linked list
 */
typedef struct LLNodeT
{
	void* data;
	struct LLNodeT* next;
}
LLNode;

/**
 * Create a new linked list
 */
LL* ll_create(void)
{
	LL* ll = malloc(sizeof(LL));
	ll->entries = 0;
	return ll;
}

/**
 * Add item to beginning of a linked list
 */
int ll_push(LL* ll, void* data)
{
	LLNode* n = malloc(sizeof(*n));

	n->data = data;

	// Reassign the head
	n->next = ll->head;
	ll->head = n;

	ll->entries++;

	return 0;
}

/**
 * Add item to end of a linked list
 */
int ll_append(LL* ll, void* data)
{
	LLNode* tail = ll->head;

	// Just push if there are no nodes yet
	if (tail == NULL)
	{
		return ll_push(ll, data);
	}

	// Travserse list to find tail
	while (tail->next != NULL)
	{
		tail = tail->next;
	}

	// Create new node and assign it as tail
	LLNode* n = malloc(sizeof(LLNode));
	n->data = data;
	tail->next = n;

	ll->entries++;

	return 0;
}

/**
 * Get an item from the list via cb function
 */
void* ll_search(LL* ll, LLCb cb, void* arg)
{
	LLNode* n = ll->head;

	// Keep going until tail is reached
	while (n != NULL)
	{
		if (cb(n->data, arg) == 0)
		{
			break;
		}

		n = n->next;
	}

	if (n == NULL)
	{
		return NULL;
	}

	return n->data;
}

/**
 * Find and delete an entry from a linked list 
 */
void* ll_delete(LL* ll, LLCb cb, void* arg)
{
	LLNode* n = ll->head, *prev = NULL;

	while (n != NULL)
	{
		if (cb(n->data, arg) == 0)
		{
			void* data = n->data;

			// We are at the head
			if (prev == NULL)
			{
				ll->head = n->next;
				free(n);
			}
			else
			{
				prev->next = n->next;
				free(n);
			}

			return data;
		}

		prev = n;
		n = n->next;
	}

	return NULL;
}

/**
 * Apply a function to every node in a linked list
 */
int ll_loop(LL* ll, LLCb cb, void* arg)
{
	LLNode* n = ll->head, *next;

	while (n != NULL)
	{
		next = n->next;
		cb(n->data, arg);
		n = next;
	}

	return 0;
}

/**
 * Free a linked list
 */
void ll_free(LL* ll)
{
	LLNode* n = ll->head, *next;

	while (n != NULL)
	{
		next = n->next;
		free(n);
		n = next;
	}

	free(ll);
}