/*
 * This file is a part of CMSLU -- Content Management System like Unix
 * and is not publicly distributed
 * 
 * Copyright (c) 2008-2009, Tomasz Sowa
 * All rights reserved.
 * 
 */
 
#include <cstdlib>
#include <limits.h>
#include "log.h"
#include "rebus.h"
#include "misc.h"



bool Rebus::InitPair(int a, int b, Item & item)
{
char buffer[100];
bool add = false;

	if( a+b <= 15 )
	{
		sprintf(buffer, "%d+%d", a, b);
		item.question = buffer;
		item.answer = a+b;
		add = true;
	}

	if( a-b >= 0 )
	{
		sprintf(buffer, "%d-%d", a, b);
		item.question = buffer;
		item.answer = a-b;
		add = true;
	}

return add;
}



void Rebus::Init()
{
int a, b;
Item item;

	item.key = 0;

	for(a=1 ; a<10 ; ++a)
	{
		for(b=1 ; b<10 ; ++b)
		{
			if( InitPair(a, b, item) )
			{
				table.push_back(item);
				item.key += 1;
			}
		}
	}
}


Rebus::Item * Rebus::Rand()
{
size_t len = table.size();

	if( len == 0 )
		// empty table, call Init() first
		return 0;

	size_t i = size_t( ((double)rand()*(double)len) / (double(RAND_MAX)+1.0) );

	if( i >= table.size() )
	{
		log << log1 << "Rebus: Rand() index too big" << logend;
		// oops, it should not be greater then table.size()
		return &table[0];
	}

return &table[0] + i;
}



bool Rebus::IsAnswerOk(Rebus::Item * item, const std::string & answer)
{
	if( item == 0 )
		return false;

	char * end;
	const char * a = answer.c_str();
	a = SkipWhite(a);

	int value = (int)strtol(a, &end, 10);

	if( a == end )
		// nothing has been read
		return false;

	log << log2 << "Rebus: your answer is: " << value << logend;
	end = (char*)SkipWhite(end);

	if( *end != 0 )
	{
		// something is at the end
		return false;
	}

	bool result = (item->answer == value);

	if( result )
		log << log3 << "Rebus: the answer is correct" << logend;

return result;
}