/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_u_vars.c                                        :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: rbousset <marvin@42.fr>                    +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2020/02/14 17:19:27 by rbousset          #+#    #+#             */
/*   Updated: 2020/02/14 17:19:29 by rbousset         ###   ########lyon.fr   */
/*                                                                            */
/* ************************************************************************** */

#include <libft.h>
#include <stdlib.h>
#include <stdint.h>

#include "ft_d_define.h"
#include "ft_f_fail.h"
#include "ft_s_destroy.h"
#include "ft_s_lcom.h"
#include "ft_s_struct.h"


static char
	*ft_set_rva(const char varname[],
				t_msh *msh)
{
	char	*rvarname;

	if (!(rvarname = (char*)malloc((ft_strlen(varname) + 1) * sizeof(char))))
	{
		ft_lcom_clear(&msh->curr);
		ft_s_destroy(msh);
		ft_fail_alloc(msh);
	}
	ft_memcpy((char*)rvarname, (const char*)varname + 1,
		ft_strlen(varname + 1));
	*(rvarname + ft_strlen(varname + 1)) = '=';
	*(rvarname + ft_strlen(varname + 1) + 1) = '\0';
	return (rvarname);
}

static char
	*ft_dup_env(char *p_env,
				char *rvarname,
				t_msh *msh)
{
	char	*varval;

	if (!(varval = ft_strdup(p_env)))
	{
		ft_memdel((void*)&rvarname);
		ft_lcom_clear(&msh->curr);
		ft_s_destroy(msh);
		ft_fail_alloc(msh);
	}
	ft_memdel((void*)&rvarname);
	return (varval);
}

static char
	*ft_get_frm_env(char rvarname[],
					t_msh *msh)
{
	char	**p_env;
	char	*pp_env;
	char	*varval;

	p_env = msh->envp;
	while (*p_env)
	{
		if (!ft_strncmp(rvarname, *p_env, ft_strlen(rvarname)))
		{
			pp_env = *p_env;
			while (*pp_env != '\0' && *pp_env != '=')
				pp_env += 1;
			if (*pp_env == '=')
				pp_env += 1;
			varval = ft_dup_env(pp_env, rvarname, msh);
			return (varval);
		}
		p_env += 1;
	}
	return (NULL);
}

static char
	*ft_get_special_var(const char varname[],
						t_msh *msh)
{
	char	*varval;

	if (!ft_strncmp(varname, FT_RET_VAR, 3))
	{
		if (!(varval = ft_uitoa(msh->ret)))
		{
			ft_lcom_clear(&msh->curr);
			ft_s_destroy(msh);
			ft_fail_alloc(msh);
		}
		return (varval);
	}
	else if (!ft_strncmp(varname, FT_ZER_VAR, 3))
	{
		if (!(varval = ft_strdup(msh->shname)))
		{
			ft_lcom_clear(&msh->curr);
			ft_s_destroy(msh);
			ft_fail_alloc(msh);
		}
		return (varval);
	}
	return (NULL);
}

static char
	*ft_get_cstm_vr(const char varname[],
					t_msh *msh)
{
	(void)varname;
	(void)msh;
	return (NULL);
}

/*
** char *
** ft_subst_var_value(const char varname[], const t_msh *msh);
**
** DESCRIPTION
** The ft_subst_var_value() function returns
** a heap-allocated, null-terminated string
** that may later be free'd containing the
** value of the variable varname[] including
** the '$' prefix. NULL is returned if varname[]
** wasn't found.
*/

char
	*ft_subst_var_value(const char varname[],
						t_msh *msh)
{
	/* TODO: check behaviour on empty vars -> "QWE=" */
	/* TODO: add support for global variables -> "$hey $nigga..." */
	char	*varval;
	char	*rvarname;

	varval = NULL;
	if ((varval = ft_get_special_var(varname, msh)) != NULL)
	{
		return (varval);
	}
	else if ((varval = ft_get_cstm_vr(varname, msh)) != NULL)
	{
		return (varval);
	}
	else
	{
		rvarname = ft_set_rva(varname, msh);
		varval = ft_get_frm_env(rvarname, msh);
		return (varval);
	}
	return (NULL);
}