/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   bfs.c                                              :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: tmaze <tmaze@student.42.fr>                +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2019/03/27 14:41:49 by tmaze             #+#    #+#             */
/*   Updated: 2019/03/27 17:06:33 by tmaze            ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "lem_in.h"

static void	bfs_addtoqueue(int *queue, int node, int nb_nodes)
{
	int	i;

	i = 0;
	while (i < nb_nodes && (queue[i] == -1 || queue[i] != node))
		i++;
	if (i < nb_nodes && queue[i] == -1)
		queue[i] = node;
}

static void	bfs_checkadj(t_lmdata *data, int *queue, int *parent, int i)
{
	t_ind	*it;

	it = data->adj[queue[i]];
	while (it != NULL)
	{
		bfs_addtoqueue(queue, it->index, data->nb_nodes);
		parent[it->index] = queue[i];
		it = it->next;
	}
}

static void	bfs_init(int *queue, char *visited, int *parent, t_lmdata *data)
{
	ft_bzero(queue, data->nb_nodes * sizeof(int));
	ft_bzero(visited, data->nb_nodes);
	ft_memset(parent, -1, data->nb_nodes * sizeof(int));
}

t_ind		*bfs(t_lmdata *data, int start_ind, int end_ind)
{
	int		parent[data->nb_nodes];
	char	visited[data->nb_nodes];
	int		queue[data->nb_nodes];
	int		i;
	t_ind	*ret;

	bfs_init(queue, visited, parent, data);
	bfs_addtoqueue(queue, start_ind, data->nb_nodes);
	i = 0;
	while (i < data->nb_nodes && queue[i] != -1 && parent[end_ind] == -1
			&& (visited[queue[i]] = 1))
		bfs_checkadj(data, queue, parent, i++);
	ret = NULL;
	i = end_ind;
	while (i != -1)
	{
		if (lst_indadd(&ret, i) == NULL)
		{
			lst_inddel(&ret);
			return (NULL);
		}
		i = parent[i];
	}
	return (ret);
}