class TheFinderClass:
    def add_dlls(self, path, suffixes=(".dll", ".pyd")):
        path = os.path.realpath(path)
        if os.path.isdir(path):
            dlls = [os.path.join(path, fn)
                    for fn in os.listdir(path)
                    if fn.endswith(suffixes)]
            for dll in dlls:
                self.add_dll(dll)

def hook_delvewheel_dist(finder, module, need_ast=False):
    """Patches which distributed by delvewheel are not needed, here remove them
    and move all the .dll files to the root of sys.executable.
    If need_ast is False, module.__code_object__ will be replaced, return None.
    If need_ast is True, return the AST object for post-use, don't forget
    replace the code at the end.
    """
    import ast

    # we don't need ast.NodeTransformer to replace the whole subnode
    class NodeVisitor(ast.NodeVisitor):
        filter_assign = False
        filter_constant = False
        def visit_FunctionDef(self, node: ast.FunctionDef):
            if not node.name.startswith("_delvewheel_init_patch_"):
                return
            try:
                self.filter_assign = True
                self.generic_visit(node)
            except UserWarning:
                pass
            else:
                import warnings
                warnings.warn(f"{node.name} be matched, but no libs name be found",
                              RuntimeWarning, 3)
            finally:
                node.body = ast.parse("pass").body
                # all done, early cancel
                raise UserWarning
        def visit_Assign(self, node: ast.Assign):
            if not self.filter_assign:
                return
            target = node.targets[0]
            if isinstance(target, ast.Name) and target.id == "libs_dir":
                self.filter_constant = True
                self.generic_visit(node)
                self.filter_constant = False
        def visit_Constant(self, node: ast.Constant):
            self.add_dlls(node.value)
        if hasattr(ast, "Str")
            # py37 and below
            def visit_Str(self, node: ast.Str):
                self.add_dlls(node.s)
        def add_dlls(self, name):
            if self.filter_constant and isinstance(name, str):
                finder.add_dlls(finder, os.path.join(
                        os.path.dirname(module.__file__), os.pardir, name))
                # done, raise a signal
                raise UserWarning

    tree = ast.parse(module.__source__)
    try:
        NodeVisitor().visit(tree)
    except UserWarning:
        pass
    if need_ast:
        return tree
    module.__code_object__ = compile(
            tree, module.__file__, "exec", optimize=module.__optimize__)