from mpi4py import MPI
import mpiunittest as unittest
try:
    import cffi
except ImportError:
    cffi = None

@unittest.skipIf(cffi is None, 'cffi')
class TestCFFI(unittest.TestCase):

    mpitypes = [
        MPI.Datatype,
        MPI.Request,
        MPI.Info,
        MPI.Errhandler,
        MPI.Session,
        MPI.Group,
        MPI.Win,
        MPI.Op,
        MPI.File,
        MPI.Message,
        MPI.Comm,
    ]

    objects = [
        MPI.DATATYPE_NULL,
        MPI.INT,
        MPI.DOUBLE,
        MPI.REQUEST_NULL,
        MPI.INFO_NULL,
        MPI.INFO_ENV,
        MPI.ERRHANDLER_NULL,
        MPI.ERRORS_RETURN,
        MPI.ERRORS_ARE_FATAL,
        MPI.GROUP_NULL,
        MPI.GROUP_EMPTY,
        MPI.WIN_NULL,
        MPI.OP_NULL,
        MPI.SUM,
        MPI.MIN,
        MPI.MAX,
        MPI.FILE_NULL,
        MPI.MESSAGE_NULL,
        MPI.MESSAGE_NO_PROC,
        MPI.COMM_NULL,
        MPI.COMM_SELF,
        MPI.COMM_WORLD,
    ]

    def testHandleAddress(self):
        ffi = cffi.FFI()
        typemap = {
            ffi.sizeof('int'): 'int',
            ffi.sizeof('void*'): 'void*',
        }
        typename = lambda t: t.__name__.rsplit('.', 1)[-1]
        for tp in self.mpitypes:
            handle_t = typemap[MPI._sizeof(tp)]
            mpi_t = 'MPI_' + typename(tp)
            ffi.cdef(f"typedef {handle_t} {mpi_t};")
        for obj in self.objects:
            if isinstance(obj, MPI.Comm):
                mpi_t = 'MPI_Comm'
            else:
                mpi_t = 'MPI_' + typename(type(obj))
            oldobj = obj
            newobj = type(obj)()
            handle_old = ffi.cast(mpi_t+'*', MPI._addressof(oldobj))
            handle_new = ffi.cast(mpi_t+'*', MPI._addressof(newobj))
            handle_new[0] = handle_old[0]
            self.assertEqual(oldobj, newobj)

    def testHandleValue(self):
        ffi = cffi.FFI()
        typemap = {ffi.sizeof('uint32_t'): 'uint32_t',
                   ffi.sizeof('uint64_t'): 'uint64_t',}
        for obj in self.objects:
            uintptr_t = typemap[MPI._sizeof(obj)]
            handle = ffi.cast(uintptr_t+'*', MPI._addressof(obj))[0]
            self.assertEqual(handle, MPI._handleof(obj))


if __name__ == '__main__':
    unittest.main()