#include <stdlib.h>
#include <string.h>

#include "util.h"

int properList(object list)
{
	object *current = &list;
	while (TYPE(*current) == consObject)
	{
		current = &CDR(*current);
	}
	return TYPE(*current) == nilObject;
}

int listLength(object list)
{
	object *current = &list;
	int i = 0;
	while (TYPE(*current) != nilObject)
	{
		current = &CDR(*current);
		++i;
	}
	return i;
}

void deleteObject(object input)
{
	if ((TYPE(input) == symbolObject) && SYM(input) != NULL)
	{
		free(SYM(input));
		SYM(input) = NULL;
	}
	else if (TYPE(input) == consObject)
	{
		deleteObject(CAR(input));
		deleteObject(CDR(input));
		free(CONS(input));
		CONS(input) = NULL;
	}

	TYPE(input) = nilObject;
}

object copyObject(object input)
{
	object result;
	TYPE(result) = TYPE(input);
	if (TYPE(input) == errorObject)
	{
		ERR(result) = ERR(input);
	}
	else if (TYPE(input) == numberObject)
	{
		NUM(result) = NUM(input);
	}
	else if (TYPE(input) == symbolObject)
	{
		SYM(result) =
			malloc(sizeof(char) * (strlen(SYM(input)) + 1));
		strcpy(SYM(result), SYM(input));
	}
	else if (TYPE(input) == consObject)
	{
		CONS(result) = malloc(sizeof(cons));
		CAR(result) = copyObject(CAR(input));
		CDR(result) = copyObject(CDR(input));
	}

	return result;
}