/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   read_all_text.c                                    :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: mcolonna <mcolonna@student.42.fr>          +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2024/10/02 16:18:35 by mcolonna          #+#    #+#             */
/*   Updated: 2024/10/15 16:28:22 by mcolonna         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "read_all_text.h"
#include "map.h"
#include "libft.h"
#include <stdlib.h>
#include <stdbool.h>
#include <unistd.h>

/// @brief Concatenate *dest and src and put the result in *dest.
///
/// *dest is alloc'd to contain the result value.
///
/// the old *dest is freed only if the function succeds.
///
/// src doesn't have to be nul-terminated, instead n is the size of src.
///
/// @return true if success, false if error.
static bool	strconcat(char **dest, char *src, int n)
{
	const int	len_dest = ft_strlen(*dest);
	char		*old_dest;
	int			i;

	old_dest = *dest;
	*dest = malloc((len_dest + n + 1) * sizeof(char));
	if (!*dest)
		return (false);
	i = -1;
	while (old_dest[++i])
		(*dest)[i] = old_dest[i];
	while (i < len_dest + n)
	{
		(*dest)[i] = src[i - len_dest];
		i++;
	}
	(*dest)[i] = '\0';
	free(old_dest);
	return (true);
}

/// @brief If the string isn't empty and isn't ended by a '\\n', add one and
///        return the result.
///
/// str is either returned directly, or another freeable pointer is returned
/// and str is freed.
///
/// @return Return the result or NULL if error.
static char	*add_endline_if_necessary(char *str)
{
	char	*endline;

	if (str[0] == '\0' || str[ft_strlen(str) - 1] == '\n')
		return (str);
	endline = malloc(1 * sizeof(char));
	if (!endline)
		return (free(str), NULL);
	endline[0] = '\n';
	if (!strconcat(&str, endline, 1))
		return (free(str), NULL);
	return (str);
}

char	*read_all_text(int fd)
{
	char	buf[BUFFER_SIZE];
	int		n;
	char	*r;

	r = malloc(sizeof(char));
	if (!r)
		return (NULL);
	r[0] = '\0';
	n = 1;
	while (n)
	{
		n = read(fd, buf, BUFFER_SIZE);
		if (n < 0 || (n && !strconcat(&r, buf, n)))
		{
			free(r);
			return (NULL);
		}
	}
	return (add_endline_if_necessary(r));
}