class MenuItem(object):
    html_id = None

    def __init__(self, url, title, html_id=None):
        self.url = url
        self.title = title
        self.html_id = html_id

    def is_active(self, request, value):
        return request.get_full_path() == str(self.url)

    def check_active(self, request, value):
        self.active = self.is_active(request, value)

    def get_url(self):
        return self.url

    def get_title(self):
        return self.title


class ObjectMenuItem(MenuItem):
    """Menu item corresponding to an object.

    If no url or title is provided, get_absolute_url and __unicode__ are used.
    You can also provide a reverse lookup dictionary, as in {model: field_name}.
    """
    def __init__(self, obj_lookup, url=None, rev_lookups=None, title=None, html_id=None):
        super(ObjectMenuItem, self).__init__(url=url, title=title, html_id=html_id)
        self.obj_lookup = obj_lookup
        self.rev_lookups = rev_lookups

    @property
    def obj(self):
        from migdal.models import Entry
        try:
            entry = Entry.objects.get(**self.obj_lookup)
        except Entry.DoesNotExist:
            return
        if not entry.published:
            return None
        return entry

    def get_title(self):
        return self.title or unicode(self.obj)

    @property
    def get_url(self):
        return self.url or self.obj.get_absolute_url()

    def is_active(self, request, value):
        if value == self.obj:
            return True
        if self.rev_lookups:
            for model, manager in self.rev_lookups.items():
                if (isinstance(value, model) and 
                        self.obj in getattr(value, manager).all()):
                    return True
        return False


class ModelMenuItem(MenuItem):
    """Menu item corresponding to a model, optionally filtered by some fields."""

    def __init__(self, model, url, field_lookups=None, title=None, html_id=None):
        if title is None:
            title = unicode(model)
        super(ModelMenuItem, self).__init__(title=title, url=url, html_id=html_id)
        self.model = model
        self.field_lookups = field_lookups

    def is_active(self, request, value):
        if value == self.model and not self.field_lookups:
            return True
        if isinstance(value, self.model) and self.field_lookups:
            lookups_ok = True
            for field, lookup in self.field_lookups.items():
                if getattr(value, field) != lookup:
                    lookups_ok = False
            if lookups_ok:
                return True
        return False

    def get_title(self):
        return self.title or unicode(self.model)