from PyQt5.QtCore import QObject, pyqtProperty, pyqtSignal
from UM.Application import Application
from UM.Settings.SettingInstance import SettingInstance
from UM.Logger import Logger

import UM.Settings.Models

from cura.SettingOverrideDecorator import SettingOverrideDecorator

##  The per object setting visibility handler ensures that only setting defintions that have a matching instance Container
#   are returned as visible. 
class PerObjectSettingVisibilityHandler(UM.Settings.Models.SettingVisibilityHandler):
    def __init__(self, parent = None, *args, **kwargs):
        super().__init__(parent = parent, *args, **kwargs)

        self._selected_object_id = None
        self._node = None
        self._stack = None

    def setSelectedObjectId(self, id):
        if id != self._selected_object_id:
            self._selected_object_id = id

            self._node = Application.getInstance().getController().getScene().findObject(self._selected_object_id)
            if self._node:
                self._stack = self._node.callDecoration("getStack")

            self.visibilityChanged.emit()

    @pyqtProperty("quint64", fset = setSelectedObjectId)
    def selectedObjectId(self):
        return self._selected_object_id

    def setVisible(self, visible):
        if not self._node:
            return

        if not self._stack:
            self._node.addDecorator(SettingOverrideDecorator())
            self._stack = self._node.callDecoration("getStack")

        settings = self._stack.getTop()
        all_instances = settings.findInstances()
        visibility_changed = False  # Flag to check if at the end the signal needs to be emitted

        # Remove all instances that are not in visibility list
        for instance in all_instances:
            if instance.definition.key not in visible:
                settings.removeInstance(instance.definition.key)
                visibility_changed = True

        # Add all instances that are not added, but are in visibility list
        for item in visible:
            if not settings.getInstance(item):
                definition = self._stack.getSettingDefinition(item)
                if definition:
                    settings.addInstance(SettingInstance(definition, settings))
                    visibility_changed = True
                else:
                    Logger.log("w", "Unable to add instance (%s) to perobject visibility because we couldn't find the matching definition", item)

        if visibility_changed:
            self.visibilityChanged.emit()

    def getVisible(self):
        visible_settings = set()
        if not self._node:
            return visible_settings

        if not self._stack:
            return visible_settings

        settings = self._stack.getTop()
        if not settings:
            return visible_settings

        visible_settings = set(map(lambda i: i.definition.key, settings.findInstances()))
        return visible_settings