/*    This file is part of the Gudhi Library. The Gudhi library
 *    (Geometric Understanding in Higher Dimensions) is a generic C++
 *    library for computational topology.
 *
 *    Author(s):       Pawel Dlotko
 *
 *    Copyright (C) 2015  INRIA Sophia-Saclay (France)
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation, either version 3 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#pragma once

#include <iostream>
#include <vector>

using namespace std;

namespace Gudhi
{

namespace Cubical_complex
{

/**
* This is an implementation of a counter being a vector of integers. 
* The constructor of the class takes as an input two vectors W and V. 
* It assumes that W < V coordinatewise.
* If the initial counter W is not specified, it is assumed to be vector of zeros. 
* The class allows to iterate between W and V by using increment() function.
* The increment() function returns a bool value. 
* The current counter reach the end counter V if the value returned by the increment function is FALSE.
* This class is needed for the implementation of a bitmapCubicalComplex.
**/

class counter
{
public:
    /**
    * Constructor of a counter class. It takes only the parameter which is the end value of the counter. 
    * The default beginning value is a vector of the same length as the endd, filled-in with zeros.
    **/
    counter(std::vector<unsigned> const& endd): begin(endd.size(),0), end(endd), current(endd.size(),0){}
	//counter(std::vector< int >& endd)
	//{
	//    for ( size_t i = 0 ; i != endd.size() ; ++i )
    //    {
    //        this->current.push_back(0);
    //        this->begin.push_back(0);
    //        this->end.push_back( endd[i] );
    //    }
	//}


    /**
    * Constructor of a counter class. It takes as the input beginn and end vector. 
    * It assumes that begin vector is lexicographically below the end vector.
    **/
	counter(std::vector< unsigned >& beginn , std::vector< unsigned >& endd)
	{
	    if ( beginn.size() != endd.size() )
		throw "In constructor of a counter, begin and end vectors do not have the same size. Program terminate";
	    for ( size_t i = 0 ; i != endd.size() ; ++i )
        {
            this->current.push_back(0);
            this->begin.push_back(0);
            this->end.push_back( endd[i] );
        }
	}

    /**
    * Function to increment the counter. If the value returned by the function is true, 
    * then the incrementation process was successful.
    * If the value of the function is false, that means, that the counter have reached its end-value.
    **/
	bool increment()
	{
	    size_t i = 0;
	    while( (i != this->end.size()) && (this->current[i] == this->end[i]) )
        {
            ++i;
        }

        if ( i == this->end.size() )return false;
        ++this->current[i];
        for ( size_t j = 0 ; j != i ; ++j )
        {
            this->current[j] = this->begin[j];
        }
        return true;
	}

    /**
    * Function to check if we are at the end of counter.
    **/
	bool isFinal()
	{
	    for ( size_t i = 0 ; i != this->current.size() ; ++i )
        {
            if ( this->current[i] == this->end[i] )return true;
        }
        return false;
	}

    /**
    * Function required in the implementation of bitmapCubicalComplexWPeriodicBoundaryCondition. 
    * Its aim is to find an counter corresponding to the element the following
    * boundary element is identified with when periodic boundary conditions are imposed.
    **/
    std::vector< unsigned > find_opposite( std::vector< bool >& directionsForPeriodicBCond )
    {
        std::vector< unsigned > result;
        for ( size_t i = 0 ; i != this->current.size() ; ++i )
        {
            if ( (this->current[i] == this->end[i]) && (directionsForPeriodicBCond[i] == true) )
            {
                result.push_back( this->begin[i] );
            }
            else
            {
                result.push_back( this->current[i] );
            }
        }
        return result;
    }

    /**
    * Function checking at which positions the current value of a counter is the final value of the counter.
    **/
    std::vector< bool > directions_of_finals()
    {
        std::vector< bool > result;
        for ( size_t i = 0 ; i != this->current.size() ; ++i )
        {
            if ( this->current[i] == this->end[i] )
            {
                result.push_back( true );
            }
            else
            {
                result.push_back( false );
            }
        }
        return result;
    }

    /**
    * Function to write counter to the stream.
    **/
    friend std::ostream& operator<<(std::ostream& out , const counter& c )
    {
        //cerr << "c.current.size() : " << c.current.size() << endl;
        for ( size_t i = 0 ; i != c.current.size() ; ++i )
        {
            out << c.current[i] << " ";
        }
        return out;
    }
private:
	std::vector< unsigned > begin;
	std::vector< unsigned > end;
	std::vector< unsigned > current;
};

}
}