/*  Copyright 2013 IST Austria
    Contributed by: Ulrich Bauer, Michael Kerber, Jan Reininghaus

    This file is part of PHAT.

    PHAT is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    PHAT 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 Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with PHAT.  If not, see <http://www.gnu.org/licenses/>. */

#pragma once

#include <phat/helpers/misc.h>
#include <phat/representations/vector_vector.h>

namespace phat {

    // Note: We could even make the rep generic in the underlying Const representation
    //       But I cannot imagine that anything else than vector<vector<index>> would
    //       make sense
    template< typename PivotColumn >
    class abstract_pivot_column : public vector_vector {
        
    protected:
        typedef vector_vector Base;
        typedef PivotColumn pivot_col;

        // For parallization purposes, it could be more than one full column
        mutable thread_local_storage< pivot_col > pivot_cols;
        mutable thread_local_storage< index > idx_of_pivot_cols;

        pivot_col& get_pivot_col() const {
            return pivot_cols();
        }

        bool is_pivot_col( index idx ) const {
            return idx_of_pivot_cols() == idx;
        }
      
        void release_pivot_col() {
            index idx = idx_of_pivot_cols();
            if( idx != -1 ) {
                this->matrix[ idx ].clear();
                pivot_cols().get_col_and_clear( this->matrix[ idx ] );
            }
            idx_of_pivot_cols() = -1;
        }
        
        void make_pivot_col( index idx ) {
            release_pivot_col();
            idx_of_pivot_cols() = idx;
            get_pivot_col().add_col( matrix[ idx ] );
        }

    public:  

        void _set_num_cols( index nr_of_cols ) {
            #pragma omp parallel for
            for( int tid = 0; tid < omp_get_num_threads(); tid++ ) {
                pivot_cols[ tid ].init( nr_of_cols );
                idx_of_pivot_cols[ tid ] = -1;
            }
            Base::_set_num_cols( nr_of_cols );
        }

        void _add_to( index source, index target ) {
            if( !is_pivot_col( target ) )
                make_pivot_col( target );
            get_pivot_col().add_col( matrix[source] );
        }

        void _sync() { 
            #pragma omp parallel for
            for( int tid = 0; tid < omp_get_num_threads(); tid++ )
                release_pivot_col();
        } 

        void _get_col( index idx, column& col  ) const { is_pivot_col( idx ) ? get_pivot_col().get_col( col ) : Base::_get_col( idx, col ); }
        
        bool _is_empty( index idx ) const { return is_pivot_col( idx ) ? get_pivot_col().is_empty() : Base::_is_empty( idx ); }

        index _get_max_index( index idx ) const { return is_pivot_col( idx ) ? get_pivot_col().get_max_index() : Base::_get_max_index( idx ); }

        void _clear( index idx ) { is_pivot_col( idx ) ? get_pivot_col().clear() : Base::_clear( idx ); }

        void _set_col( index idx, const column& col  ) { is_pivot_col( idx ) ? get_pivot_col().set_col( col ) : Base::_set_col( idx, col ); }

        void _remove_max( index idx ) {	is_pivot_col( idx ) ? get_pivot_col().remove_max() : Base::_remove_max( idx ); }
    };
}