#*****************************************************************************
#       Copyright (C) 2007 Carlo Hamalainen <carlo.hamalainen@gmail.com>, 
#
#  Distributed under the terms of the GNU General Public License (GPL)
#
#    This code 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.
#
#  The full text of the GPL is available at:
#
#                  http://www.gnu.org/licenses/
#*****************************************************************************

#clang c++ 

cdef extern from "stdlib.h":
     ctypedef unsigned long size_t

cdef extern from "dancing_links.cpp":
    ctypedef struct vector_int "std::vector<int>":
        void (* push_back)(int elem)
        void clear()
        int at(size_t loc)
        int size()

    ctypedef struct vector_vector_int "std::vector<vector<int> >":
        void (* push_back)(vector_int elem) 

    ctypedef struct dancing_links:
        vector_int solution
        void add_rows(vector_vector_int rows)
        int search()

cdef extern from "ccobject.h":
    # Some non-allocating versions
    dancing_links* dancing_links_construct "Construct<dancing_links>"(void *mem)
    void dancing_links_destruct "Destruct<dancing_links>"(dancing_links *mem)

    # some allocating versions for completeness
    dancing_links* dancing_links_new "New<dancing_links>"()
    void dancing_links_delete "Delete<dancing_links>"(dancing_links *mem)

cdef class dancing_linksWrapper:
    cdef dancing_links x

    def __init__(self):
        pass

    # Note that the parameters to __new__ must be identical to __init__
    # This is due to some Cython vagary
    def __new__(self):
        dancing_links_construct(&self.x)

    def __dealloc__(self):
        dancing_links_destruct(&self.x)

    def add_rows(self, rows):
        cdef vector_int v
        cdef vector_vector_int vv

        for row in rows:
            v.clear()

            for x in row:
                v.push_back(x)

            vv.push_back(v)

        self.x.add_rows(vv)

    def get_solution(self):
        s = []
        for i in range(self.x.solution.size()):
            s.append(self.x.solution.at(i))

        return s

    def search(self):
        x = self.x.search()

        return x

def dlx_solver(rows):
    cdef dancing_linksWrapper dlw

    dlw = dancing_linksWrapper()
    dlw.add_rows(rows)

    return dlw