import os
import sys
import importlib
import inspect
import logging

def load_module(module_path, filename):
    """ returns the module if filename is a module else None """
    if filename.endswith('.py'):
        module = filename[:-3]
    elif os.path.exists(os.path.join(module_path, filename, '__init__.py')):
        module = filename
    else:
        return None
    try:
        return importlib.import_module(module)
    except:
        logging.exception('Loading %s failed.' % module)
        return None

class PluginManager(object):
    def __init__(self):
        self.modules = {}
        self.classes = {}

    def add_path(self, module_path):
        sys.path.append(module_path)
        for filename in os.listdir(module_path):
            module = load_module(module_path, filename)
            if module:
                self.modules[module.__name__] = module
                self._extract_classes(module)
        sys.path.remove(module_path)

    def _extract_classes(self, module):
        for name in dir(module):
            obj = getattr(module, name)
            if inspect.isclass(obj):
                if hasattr(obj, '_VERSION'):
                    version = getattr(obj, '_VERSION')
                    logging.info("Found %s.%s %s" % (module.__name__, name, version))
                    self.classes[name] = obj

logging.getLogger().level = logging.INFO
plugins = PluginManager()
plugins.add_path('/home/test/multitool')