""" One of the widgets that main window composes of.

    See :class:`.MainWindow`
    Similar modules: class:`.AddCluster`, :class:`.RemoveCluster`, :class:`.IdactNotebook`,
    :class:`.AdjustTimeouts`, :class:`.ManageJobs`
"""
import copy
from contextlib import ExitStack

from PyQt5.QtCore import pyqtSignal
from PyQt5.QtWidgets import QWidget, QTreeWidgetItem
from idact import show_cluster
from idact.detail.deployment.cancel_local_on_exit import cancel_local_on_exit
from idact.detail.jupyter_app.sleep_until_allocation_ends import sleep_until_allocation_ends
from gui.functionality.loading_window import LoadingWindow
from gui.functionality.popup_window import WindowType, PopUpWindow
from gui.helpers.custom_exceptions import NoClustersError
from gui.helpers.ui_loader import UiLoader
from gui.helpers.worker import Worker


class RunningNotebooks(QWidget):
    """ Module of GUI that is responsible for showing nodes and local ports for Jupyter Notebook (if exists),
    cancelling jobs, opening notebooks in the browser if they exists or deploying them if not.
    """
    deployment_ended = pyqtSignal()

    def __init__(self, parent):
        super().__init__(parent=parent)
        self.ui = UiLoader.load_ui_from_file('running-notebooks.ui', self)

        self.parent = parent

        self.popup_window = PopUpWindow()
        self.loading_window = LoadingWindow()
        self.deployments = None
        self.cluster_name = None

        self.ui.show_nodes_and_notebooks_button.clicked.connect(self.concurrent_show_nodes_and_notebooks)
        self.ui.refresh_button.clicked.connect(self.concurrent_show_nodes_and_notebooks)
        self.ui.open_notebook_button.clicked.connect(self.open_notebook)
        self.ui.deploy_button.clicked.connect(self.concurrent_deploy_notebook)
        self.ui.cancel_job_button.clicked.connect(self.concurrent_cancel_job)

        self.cluster_names = self.parent.data_provider.get_cluster_names()

        self.parent.data_provider.remove_cluster_signal.connect(self.handle_cluster_list_modification)
        self.parent.data_provider.add_cluster_signal.connect(self.handle_cluster_list_modification)
        self.ui.cluster_names_box.addItems(self.cluster_names)

        self.ui.open_notebook_button.setEnabled(False)
        self.ui.deploy_button.setEnabled(False)
        self.ui.cancel_job_button.setEnabled(False)

        self.ui.nodes_tree.itemSelectionChanged.connect(self.change_buttons_to_disabled_or_not)
        self.deployment_ended.connect(self.handle_deployment_ended)

    def handle_deployment_ended(self):
        self.loading_window.hide()

    def change_buttons_to_disabled_or_not(self):
        """Changes buttons visibility"""
        selected_items = self.ui.nodes_tree.selectedItems()

        if len(selected_items) == 1:
            selected_item = selected_items[0]
            if selected_item.parent() and selected_item.parent().parent():
                self.ui.open_notebook_button.setEnabled(selected_item.text(6) != "")
                self.ui.deploy_button.setEnabled(selected_item.text(6) == "" and selected_item.text(1) != "None")
                self.ui.cancel_job_button.setEnabled(False)
                return

            if selected_item.parent() and selected_item.parent().parent() is None:
                self.ui.open_notebook_button.setEnabled(False)
                self.ui.deploy_button.setEnabled(False)
                self.ui.cancel_job_button.setEnabled(True)
                return

        self.ui.open_notebook_button.setEnabled(False)
        self.ui.deploy_button.setEnabled(False)
        self.ui.cancel_job_button.setEnabled(False)

    def concurrent_show_nodes_and_notebooks(self):
        """ Setups the worker that allows to run the show_nodes_and_notebooks functionality
        in the parallel thread.
        """
        self.ui.show_nodes_and_notebooks_button.setEnabled(False)
        self.ui.refresh_button.setEnabled(False)

        worker = Worker(self.show_nodes_and_notebooks)
        worker.signals.result.connect(self.handle_complete_show_nodes_and_notebooks)
        worker.signals.error.connect(self.handle_error_show_nodes_and_notebooks)
        self.parent.threadpool.start(worker)

    def handle_complete_show_nodes_and_notebooks(self):
        """ Handles the completion of show nodes and notebooks function.
        """
        self.ui.show_nodes_and_notebooks_button.setEnabled(True)
        self.ui.refresh_button.setEnabled(True)

        root = QTreeWidgetItem()

        for nodes_collection in self.deployments.nodes:
            nodes_item = QTreeWidgetItem()
            for node in nodes_collection.nodes:
                node_item = QTreeWidgetItem()
                node_item.setText(1, str(node.host))
                node_item.setText(2, str(node.port))
                node_item.setText(3, str(node.cores))
                node_item.setText(4, str(node.memory))
                node_item.setText(5, str(node.allocated_until))
                local_port = ""
                for jupyter_deployment in self.deployments.jupyter_deployments:
                    if node == jupyter_deployment.deployment.node:
                        local_port = str(jupyter_deployment.local_port)
                        break
                node_item.setText(6, local_port)

                nodes_item.addChild(node_item)
            nodes_item.setText(0, 'Job ID: ' + str(nodes_collection.allocation.job_id))
            root.addChild(nodes_item)
        root.setText(0, self.cluster_name)
        self.ui.nodes_tree.clear()
        self.ui.nodes_tree.addTopLevelItem(root)
        self.ui.nodes_tree.expandAll()

    def handle_error_show_nodes_and_notebooks(self, exception):
        """ Handles the error thrown while showing nodes and notebooks.

            :param exception: Instance of the exception.
        """
        self.ui.show_nodes_and_notebooks_button.setEnabled(True)
        self.ui.refresh_button.setEnabled(True)

        if isinstance(exception, NoClustersError):
            self.popup_window.show_message("There are no added clusters", WindowType.error)
        elif isinstance(exception, KeyError):
            self.popup_window.show_message("The cluster does not exist", WindowType.error)
        else:
            self.popup_window.show_message("An error occurred while listing nodes and notebooks", WindowType.error,
                                           exception)

    def show_nodes_and_notebooks(self):
        """ Main function responsible for showing nodes and notebooks.
        """
        self.cluster_name = str(self.ui.cluster_names_box.currentText())
        if not self.cluster_name:
            raise NoClustersError()
        self.deployments = self.parent.deployments_provider.get_deployments(self.cluster_name, update=True)

    def concurrent_deploy_notebook(self):
        """ Setups the worker that allows to run the deploy_notebook functionality
        in the parallel thread.
        """
        self.loading_window.show_message("Notebook is being deployed")
        self.ui.deploy_button.setEnabled(False)

        worker = Worker(self.deploy_notebook)
        worker.signals.result.connect(self.handle_complete_deploy_notebook)
        worker.signals.error.connect(self.handle_error_deploy_notebook)
        self.parent.threadpool.start(worker)

    def handle_complete_deploy_notebook(self):
        """ Handles the completion of deploy of the notebook.
        """
        self.ui.deploy_button.setEnabled(True)
        self.popup_window.show_message("Notebook has been closed", WindowType.success)

    def handle_error_deploy_notebook(self, exception):
        """ Handles the error thrown while deploying notebook.

            :param exception: Instance of the exception.
        """
        self.loading_window.close()
        self.ui.deploy_button.setEnabled(True)
        self.popup_window.show_message("An error occurred while deploying notebook", WindowType.error, exception)
        self.ui.deploy_button.setEnabled(True)

    def deploy_notebook(self):
        """ Main function responsible for deploying the notebook on the node.
        """
        item = self.ui.nodes_tree.selectedItems()[0]
        node = self.get_node_for_tree_item(item)
        nodes_collection = item.parent()
        nodes_collection_index = nodes_collection.indexOfChild(item)
        nodes = self.deployments.nodes[nodes_collection_index]

        with ExitStack() as stack:
            notebook = node.deploy_notebook()
            stack.enter_context(cancel_local_on_exit(notebook))
            cluster = show_cluster(name=self.cluster_name)
            cluster.push_deployment(notebook)
            self.parent.deployments_provider.add_deployment(self.cluster_name, notebook)
            notebook.open_in_browser()
            self.deployment_ended.emit()
            self.concurrent_show_nodes_and_notebooks()
            sleep_until_allocation_ends(nodes=nodes, echo_messages=False)

    def get_node_for_tree_item(self, item):
        """Returns Node instance for the item.

        :param item: Item in the QTreeWidget
        """
        node_collection = item.parent()
        node_index = node_collection.indexOfChild(item)

        root = node_collection.parent()
        nodes_index = root.indexOfChild(node_collection)

        return self.deployments.nodes[nodes_index].nodes[node_index]

    def concurrent_cancel_job(self):
        """ Setups the worker that allows to run the cancel_job functionality
        in the parallel thread.
        """
        self.ui.cancel_job_button.setEnabled(False)

        worker = Worker(self.cancel_job)
        worker.signals.result.connect(self.handle_complete_cancel_job)
        worker.signals.error.connect(self.handle_error_cancel_job)
        self.parent.threadpool.start(worker)

    def handle_complete_cancel_job(self):
        """ Handles the completion of cancel job function.
        """
        self.ui.cancel_job_button.setEnabled(True)
        self.popup_window.show_message("Cancel command has been successfully executed", WindowType.success)

    def handle_error_cancel_job(self, exception):
        """ Handles the error thrown while cancelling the job.

            :param exception: Instance of the exception.
        """
        self.ui.cancel_job_button.setEnabled(True)

        if isinstance(exception, KeyError):
            self.popup_window.show_message("The cluster does not exist", WindowType.error)
        else:
            self.popup_window.show_message("An error occurred while cancelling job", WindowType.error, exception)

    def cancel_job(self):
        """ Main function responsible for cancelling the job.
        """
        item = self.ui.nodes_tree.selectedItems()[0]
        nodes = self.get_nodes_collection_for_tree_item(item)
        nodes_copy = copy.deepcopy(nodes)
        nodes_copy.cancel()
        self.concurrent_show_nodes_and_notebooks()

    def get_nodes_collection_for_tree_item(self, item):
        """Returns Nodes instance for the item.

        :param item: Item in the QTreeWidget
        """
        root = item.parent()
        nodes_index = root.indexOfChild(item)

        return self.deployments.nodes[nodes_index]

    def concurrent_open_notebook(self):
        """ Setups the worker that allows to run the open_notebook functionality
        in the parallel thread.
        """
        self.ui.open_notebook_button.setEnabled(False)

        worker = Worker(self.open_notebook)
        worker.signals.result.connect(self.handle_complete_open_notebook)
        worker.signals.error.connect(self.handle_error_open_notebook)
        self.parent.threadpool.start(worker)

    def handle_complete_open_notebook(self):
        """ Handles the completion of open notebook function.
        """
        self.ui.open_notebook_button.setEnabled(True)

    def handle_error_open_notebook(self, exception):
        """ Handles the error thrown while opening the notebook.

            :param exception: Instance of the exception.
        """
        self.ui.open_notebook_button.setEnabled(True)
        self.popup_window.show_message("An error occurred while opening notebook", WindowType.error, exception)

    def open_notebook(self):
        """ Main function responsible for opening the notebook in the browser.
        """
        for item in self.ui.nodes_tree.selectedItems():
            node_collection = item.parent()
            node_index = node_collection.indexOfChild(item)
            root = node_collection.parent()
            nodes_index = root.indexOfChild(node_collection)

            node = self.deployments.nodes[nodes_index].nodes[node_index]
            for jupyter_deployment in self.deployments.jupyter_deployments:
                if node == jupyter_deployment.deployment.node:
                    jupyter_deployment.open_in_browser()
                    return

    def handle_cluster_list_modification(self):
        """ Handles the modification of the clusters list.
        """
        self.cluster_names = self.parent.data_provider.get_cluster_names()
        self.ui.cluster_names_box.clear()
        self.ui.cluster_names_box.addItems(self.cluster_names)

""" One of the widgets that main window composes of.

    See :class:`.MainWindow`
    Similar modules: class:`.AddCluster`, :class:`.RemoveCluster`, :class:`.IdactNotebook`,
    :class:`.AdjustTimeouts`, :class:`.ManageJobs`
"""
import copy
from contextlib import ExitStack

from PyQt5.QtCore import pyqtSignal
from PyQt5.QtWidgets import QWidget, QTreeWidgetItem
from idact import show_cluster
from idact.detail.deployment.cancel_local_on_exit import cancel_local_on_exit
from idact.detail.jupyter_app.sleep_until_allocation_ends import sleep_until_allocation_ends
from gui.functionality.loading_window import LoadingWindow
from gui.functionality.popup_window import WindowType, PopUpWindow
from gui.helpers.custom_exceptions import NoClustersError
from gui.helpers.ui_loader import UiLoader
from gui.helpers.worker import Worker


class RunningNotebooks(QWidget):
    """ Module of GUI that is responsible for showing nodes and local ports for Jupyter Notebook (if exists),
    cancelling jobs, opening notebooks in the browser if they exists or deploying them if not.
    """
    deployment_ended = pyqtSignal()

    def __init__(self, parent):
        super().__init__(parent=parent)
        self.ui = UiLoader.load_ui_from_file('running-notebooks.ui', self)

        self.parent = parent

        self.popup_window = PopUpWindow()
        self.loading_window = LoadingWindow()
        self.deployments = None
        self.cluster_name = None

        self.ui.show_nodes_and_notebooks_button.clicked.connect(self.concurrent_show_nodes_and_notebooks)
        self.ui.refresh_button.clicked.connect(self.concurrent_show_nodes_and_notebooks)
        self.ui.open_notebook_button.clicked.connect(self.open_notebook)
        self.ui.deploy_button.clicked.connect(self.concurrent_deploy_notebook)
        self.ui.cancel_job_button.clicked.connect(self.concurrent_cancel_job)

        self.cluster_names = self.parent.data_provider.get_cluster_names()

        self.parent.data_provider.remove_cluster_signal.connect(self.handle_cluster_list_modification)
        self.parent.data_provider.add_cluster_signal.connect(self.handle_cluster_list_modification)
        self.ui.cluster_names_box.addItems(self.cluster_names)

        self.ui.open_notebook_button.setEnabled(False)
        self.ui.deploy_button.setEnabled(False)
        self.ui.cancel_job_button.setEnabled(False)

        self.ui.nodes_tree.itemSelectionChanged.connect(self.change_buttons_to_disabled_or_not)
        self.deployment_ended.connect(self.handle_deployment_ended)

    def handle_deployment_ended(self):
        self.loading_window.hide()

    def change_buttons_to_disabled_or_not(self):
        """Changes buttons visibility"""
        selected_items = self.ui.nodes_tree.selectedItems()

        if len(selected_items) == 1:
            selected_item = selected_items[0]
            if selected_item.parent() and selected_item.parent().parent():
                self.ui.open_notebook_button.setEnabled(selected_item.text(6) != "")
                self.ui.deploy_button.setEnabled(selected_item.text(6) == "" and selected_item.text(1) != "None")
                self.ui.cancel_job_button.setEnabled(False)
                return

            if selected_item.parent() and selected_item.parent().parent() is None:
                self.ui.open_notebook_button.setEnabled(False)
                self.ui.deploy_button.setEnabled(False)
                self.ui.cancel_job_button.setEnabled(True)
                return

        self.ui.open_notebook_button.setEnabled(False)
        self.ui.deploy_button.setEnabled(False)
        self.ui.cancel_job_button.setEnabled(False)

    def concurrent_show_nodes_and_notebooks(self):
        """ Setups the worker that allows to run the show_nodes_and_notebooks functionality
        in the parallel thread.
        """
        self.ui.show_nodes_and_notebooks_button.setEnabled(False)
        self.ui.refresh_button.setEnabled(False)

        worker = Worker(self.show_nodes_and_notebooks)
        worker.signals.result.connect(self.handle_complete_show_nodes_and_notebooks)
        worker.signals.error.connect(self.handle_error_show_nodes_and_notebooks)
        self.parent.threadpool.start(worker)

    def handle_complete_show_nodes_and_notebooks(self):
        """ Handles the completion of show nodes and notebooks function.
        """
        self.ui.show_nodes_and_notebooks_button.setEnabled(True)
        self.ui.refresh_button.setEnabled(True)

        root = QTreeWidgetItem()

        for nodes_collection in self.deployments.nodes:
            nodes_item = QTreeWidgetItem()
            for node in nodes_collection.nodes:
                node_item = QTreeWidgetItem()
                node_item.setText(1, str(node.host))
                node_item.setText(2, str(node.port))
                node_item.setText(3, str(node.cores))
                node_item.setText(4, str(node.memory))
                node_item.setText(5, str(node.allocated_until))
                local_port = ""
                for jupyter_deployment in self.deployments.jupyter_deployments:
                    if node == jupyter_deployment.deployment.node:
                        local_port = str(jupyter_deployment.local_port)
                        break
                node_item.setText(6, local_port)

                nodes_item.addChild(node_item)
            nodes_item.setText(0, 'Job ID: ' + str(nodes_collection.allocation.job_id))
            root.addChild(nodes_item)
        root.setText(0, self.cluster_name)
        self.ui.nodes_tree.clear()
        self.ui.nodes_tree.addTopLevelItem(root)
        self.ui.nodes_tree.expandAll()

    def handle_error_show_nodes_and_notebooks(self, exception):
        """ Handles the error thrown while showing nodes and notebooks.

            :param exception: Instance of the exception.
        """
        self.ui.show_nodes_and_notebooks_button.setEnabled(True)
        self.ui.refresh_button.setEnabled(True)

        if isinstance(exception, NoClustersError):
            self.popup_window.show_message("There are no added clusters", WindowType.error)
        elif isinstance(exception, KeyError):
            self.popup_window.show_message("The cluster does not exist", WindowType.error)
        else:
            self.popup_window.show_message("An error occurred while listing nodes and notebooks", WindowType.error,
                                           exception)

    def show_nodes_and_notebooks(self):
        """ Main function responsible for showing nodes and notebooks.
        """
        self.cluster_name = str(self.ui.cluster_names_box.currentText())
        if not self.cluster_name:
            raise NoClustersError()
        self.deployments = self.parent.deployments_provider.get_deployments(self.cluster_name, update=True)

    def concurrent_deploy_notebook(self):
        """ Setups the worker that allows to run the deploy_notebook functionality
        in the parallel thread.
        """
        self.loading_window.show_message("Notebook is being deployed")
        self.ui.deploy_button.setEnabled(False)

        worker = Worker(self.deploy_notebook)
        worker.signals.result.connect(self.handle_complete_deploy_notebook)
        worker.signals.error.connect(self.handle_error_deploy_notebook)
        self.parent.threadpool.start(worker)

    def handle_complete_deploy_notebook(self):
        """ Handles the completion of deploy of the notebook.
        """
        self.ui.deploy_button.setEnabled(True)
        self.popup_window.show_message("Notebook has been closed", WindowType.success)

    def handle_error_deploy_notebook(self, exception):
        """ Handles the error thrown while deploying notebook.

            :param exception: Instance of the exception.
        """
        self.loading_window.close()
        self.ui.deploy_button.setEnabled(True)
        self.popup_window.show_message("An error occurred while deploying notebook", WindowType.error, exception)
        self.ui.deploy_button.setEnabled(True)

    def deploy_notebook(self):
        """ Main function responsible for deploying the notebook on the node.
        """
        item = self.ui.nodes_tree.selectedItems()[0]
        node = self.get_node_for_tree_item(item)
        nodes_collection = item.parent()
        nodes_collection_index = nodes_collection.indexOfChild(item)
        nodes = self.deployments.nodes[nodes_collection_index]

        with ExitStack() as stack:
            notebook = node.deploy_notebook()
            stack.enter_context(cancel_local_on_exit(notebook))
            cluster = show_cluster(name=self.cluster_name)
            cluster.push_deployment(notebook)
            self.parent.deployments_provider.add_deployment(self.cluster_name, notebook)
            notebook.open_in_browser()
            self.deployment_ended.emit()
            self.concurrent_show_nodes_and_notebooks()
            sleep_until_allocation_ends(nodes=nodes, echo_messages=False)

    def get_node_for_tree_item(self, item):
        """Returns Node instance for the item.

        :param item: Item in the QTreeWidget
        """
        node_collection = item.parent()
        node_index = node_collection.indexOfChild(item)

        root = node_collection.parent()
        nodes_index = root.indexOfChild(node_collection)

        return self.deployments.nodes[nodes_index].nodes[node_index]

    def concurrent_cancel_job(self):
        """ Setups the worker that allows to run the cancel_job functionality
        in the parallel thread.
        """
        self.ui.cancel_job_button.setEnabled(False)

        worker = Worker(self.cancel_job)
        worker.signals.result.connect(self.handle_complete_cancel_job)
        worker.signals.error.connect(self.handle_error_cancel_job)
        self.parent.threadpool.start(worker)

    def handle_complete_cancel_job(self):
        """ Handles the completion of cancel job function.
        """
        self.ui.cancel_job_button.setEnabled(True)
        self.popup_window.show_message("Cancel command has been successfully executed", WindowType.success)

    def handle_error_cancel_job(self, exception):
        """ Handles the error thrown while cancelling the job.

            :param exception: Instance of the exception.
        """
        self.ui.cancel_job_button.setEnabled(True)

        if isinstance(exception, KeyError):
            self.popup_window.show_message("The cluster does not exist", WindowType.error)
        else:
            self.popup_window.show_message("An error occurred while cancelling job", WindowType.error, exception)

    def cancel_job(self):
        """ Main function responsible for cancelling the job.
        """
        item = self.ui.nodes_tree.selectedItems()[0]
        nodes = self.get_nodes_collection_for_tree_item(item)
        nodes_copy = copy.deepcopy(nodes)
        nodes_copy.cancel()
        self.concurrent_show_nodes_and_notebooks()

    def get_nodes_collection_for_tree_item(self, item):
        """Returns Nodes instance for the item.

        :param item: Item in the QTreeWidget
        """
        root = item.parent()
        nodes_index = root.indexOfChild(item)

        return self.deployments.nodes[nodes_index]

    def concurrent_open_notebook(self):
        """ Setups the worker that allows to run the open_notebook functionality
        in the parallel thread.
        """
        self.ui.open_notebook_button.setEnabled(False)

        worker = Worker(self.open_notebook)
        worker.signals.result.connect(self.handle_complete_open_notebook)
        worker.signals.error.connect(self.handle_error_open_notebook)
        self.parent.threadpool.start(worker)

    def handle_complete_open_notebook(self):
        """ Handles the completion of open notebook function.
        """
        self.ui.open_notebook_button.setEnabled(True)

    def handle_error_open_notebook(self, exception):
        """ Handles the error thrown while opening the notebook.

            :param exception: Instance of the exception.
        """
        self.ui.open_notebook_button.setEnabled(True)
        self.popup_window.show_message("An error occurred while opening notebook", WindowType.error, exception)

    def open_notebook(self):
        """ Main function responsible for opening the notebook in the browser.
        """
        for item in self.ui.nodes_tree.selectedItems():
            node_collection = item.parent()
            node_index = node_collection.indexOfChild(item)
            root = node_collection.parent()
            nodes_index = root.indexOfChild(node_collection)

            node = self.deployments.nodes[nodes_index].nodes[node_index]
            for jupyter_deployment in self.deployments.jupyter_deployments:
                if node == jupyter_deployment.deployment.node:
                    jupyter_deployment.open_in_browser()
                    return

    def handle_cluster_list_modification(self):
        """ Handles the modification of the clusters list.
        """
        self.cluster_names = self.parent.data_provider.get_cluster_names()
        self.ui.cluster_names_box.clear()
        self.ui.cluster_names_box.addItems(self.cluster_names)

One of the widgets that main window composes of.      See :class:`.MainWindow`     Similar modules: class:`.AddCluster`, :class:`.RemoveCluster`, :class:`.IdactNotebook`,     :class:`.AdjustTimeouts`, :class:`.ManageJobs` Module of GUI that is responsible for showing nodes and local ports for Jupyter Notebook (if exists),     cancelling jobs, opening notebooks in the browser if they exists or deploying them if not. Changes buttons visibility Setups the worker that allows to run the show_nodes_and_notebooks functionality         in the parallel thread. Handles the completion of show nodes and notebooks function. Handles the error thrown while showing nodes and notebooks.              :param exception: Instance of the exception. Main function responsible for showing nodes and notebooks. Setups the worker that allows to run the deploy_notebook functionality         in the parallel thread. Handles the completion of deploy of the notebook. Handles the error thrown while deploying notebook.              :param exception: Instance of the exception. Main function responsible for deploying the notebook on the node. Returns Node instance for the item.          :param item: Item in the QTreeWidget Setups the worker that allows to run the cancel_job functionality         in the parallel thread. Handles the completion of cancel job function. Handles the error thrown while cancelling the job.              :param exception: Instance of the exception. Main function responsible for cancelling the job. Returns Nodes instance for the item.          :param item: Item in the QTreeWidget Setups the worker that allows to run the open_notebook functionality         in the parallel thread. Handles the completion of open notebook function. Handles the error thrown while opening the notebook.              :param exception: Instance of the exception. Main function responsible for opening the notebook in the browser. Handles the modification of the clusters list.