class PluginLoader:
    def __init__(self, client, plugins):
        self.client = client
        self.plugins = plugins
        self.extensions = {'client': self.client}
        self.announce = {}

        for plugin in self.plugins:
            if hasattr(plugin, 'pl_announce'):
                for ident in plugin.pl_announce:
                    self.announce[ident] = plugin
        while self.plugins:
            plugin = self.plugins.pop()
            plugin(self, self.client.plugin_settings.get(plugin, None))

    def requires(self, ident):
        if ident not in self.extensions:
            if ident in self.announce:
                plugin = self.announce[ident]
                self.plugins.remove(plugin)
                plugin(self, self.client.plugin_settings.get(plugin, None))
            else:
                return None

        return self.extensions[ident]

    def provides(self, plugin, ident):
        self.extensions[ident] = plugin

    def reg_event_handler(self, events, handlers):
        self.client.reg_event_handler(events, handlers)