import os
import importlib
import logging

import core.input
import core.widget
import core.decorators

try:
    error = ModuleNotFoundError('')
except Exception as e:
    ModuleNotFoundError = Exception

log = logging.getLogger(__name__)

def load(module_name, config=core.config.Config([]), theme=None):
    error = None
    module_short, alias = (module_name.split(':') + [module_name])[0:2]
    config.set('__alias__', alias)
    for namespace in [ 'core', 'contrib' ]:
        try:
            mod = importlib.import_module('modules.{}.{}'.format(namespace, module_short))
            log.debug('importing {} from {}.{}'.format(module_short, namespace, module_short))
            return getattr(mod, 'Module')(config, theme)
        except ImportError as e:
                error = e
    log.fatal('failed to import {}: {}'.format(module_name, error))
    return Error(config=config, module=module_name, error=error)

class Module(core.input.Object):
    def __init__(self, config=core.config.Config([]), theme=None, widgets=[]):
        super().__init__()
        self.__config = config
        self.__widgets = widgets if isinstance(widgets, list) else [ widgets ]

        self.module_name = self.__module__.split('.')[-1]
        self.name = self.module_name
        self.alias = self.__config.get('__alias__', None)
        self.id = self.alias if self.alias else self.name
        self.next_update = None

        self.theme = theme

        for widget in self.__widgets:
            widget.module = self

    def hidden(self):
        return False

    def parameter(self, key, default=None):
        value = default

        for prefix in [ self.name, self.module_name, self.alias ]:
            value = self.__config.get('{}.{}'.format(prefix, key), value)
        # TODO retrieve from config file
        return value

    def set(self, key, value):
        self.__config.set('{}.{}'.format(self.name, key), value)

    def update(self):
        pass

    def update_wrapper(self):
        try:
            self.update()
        except Exception as e:
            self.set('interval', 1)
            module = Error(config=self.__config, module='error', error=str(e))
            self.__widgets = [module.widget()]
            self.update = module.update

    def widgets(self, widgets=None):
        if widgets:
            self.__widgets = widgets
        return self.__widgets

    def add_widget(self, full_text='', name=None):
        widget = core.widget.Widget(full_text=full_text, name=name, module=self)
        self.widgets().append(widget)
        return widget

    def widget(self, name=None):
        if not name: return self.widgets()[0]

        for w in self.widgets():
            if w.name == name: return w
        return None

    def state(self, widget):
        return []

    def threshold_state(self, value, warn, crit):
        if value > float(self.parameter('critical', crit)):
            return 'critical'
        if value > float(self.parameter('warning', warn)):
            return 'warning'
        return None

class Error(Module):
    def __init__(self, module, error, config=core.config.Config([]), theme=None):
        super().__init__(config, theme, core.widget.Widget(self.full_text))
        self.__module = module
        self.__error = error

    def full_text(self, widget):
        return '{}: {}'.format(self.__module, self.__error)

    def state(self, widget):
        return ['critical']

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