stream_feature_extractor.py

# -*- coding: utf-8 -*-
"""
/***************************************************************************
 StreamFeatureExtractor
                                 A QGIS plugin
 A tool to extract features from a stream network.
                              -------------------
        begin                : 2014-05-07
        copyright            : (C) Kartoza (Pty) Ltd.
        email                : tim@kartoza.com
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
"""


import logging
import os
from builtins import object

from qgis.core import Qgis

from qgis.PyQt.QtCore import Qt, QSettings, QTranslator, qVersion, QCoreApplication, QUrl
from qgis.PyQt.QtGui import QIcon
from qgis.PyQt.QtWidgets import QAction, QProgressBar
from qgis.core import QgsProject, QgsMapLayer

from .stream_help_dialog import HelpDialog
from .stream_options_dialog import OptionsDialog
# Initialize Qt resources from file resources.py
# Import the code for the dialog
from .stream_utilities import is_line_layer, identify_features
from .utilities.resources import resources_path

# Import the PyQt and QGIS libraries
# this import required to enable PyQt API v2
# do it before Qt imports
# from pydev import pydevd  # pylint: disable=F0401

MENU_GROUP_LABEL = 'Stream feature extractor'
MENU_RUN_LABEL = 'Extract from current layer'
LOGGER = logging.getLogger('QGIS')


class StreamFeatureExtractor(object):
    """QGIS Plugin Implementation."""

    def __init__(self, iface):
        """Constructor.

        :param iface: An interface instance that will be passed to this class
            which provides the hook by which you can manipulate the QGIS
            application at run time.
        :type iface: QgsInterface
        """
        # Enable remote debugging - should normally be commented out.
        # pydevd.settrace(
        #    'localhost', port=5678, stdoutToServer=True,
        #     stderrToServer=True)

        # Save reference to the QGIS interface
        self.iface = iface
        # initialize plugin directory
        self.plugin_dir = os.path.dirname(__file__)
        # initialize locale
        self.locale = QSettings().value("locale/userLocale")[0:2]
        locale_path = os.path.join(
            self.plugin_dir,
            'i18n',
            '{}.qm'.format(self.locale))

        if os.path.exists(locale_path):
            self.translator = QTranslator()
            self.translator.load(locale_path)

            if qVersion() > '4.3.3':
                QCoreApplication.installTranslator(self.translator)

        # Declare instance attributes
        self.run_action = None
        self.options_action = None
        self.help_action = None
        self.message_bar = None

        # Declare instance attributes

        self.actions = []
        self.menu = self.tr(MENU_GROUP_LABEL)
        # TODO: We are going to let the user set this up in a future iteration
        self.toolbar = self.iface.addToolBar(MENU_GROUP_LABEL)
        self.toolbar.setObjectName('StreamFeatureExtractor')

        # To enable/disable the run menu option
        self.iface.currentLayerChanged.connect(self.layer_changed)
        LOGGER.debug('Stream feature extractor initialised')

    # noinspection PyMethodMayBeStatic
    def tr(self, message):
        """Get the translation for a string using Qt translation API.

        We implement this ourselves since we do not inherit QObject.

        :param message: String for translation.
        :type message: str, QString

        :returns: Translated version of message.
        :rtype: QString
        """
        # noinspection PyTypeChecker,PyArgumentList,PyCallByClass
        return QCoreApplication.translate('StreamFeatureExtractor', message)

    def add_action(
            self,
            icon_path,
            text,
            callback,
            enabled_flag=True,
            add_to_menu=True,
            add_to_toolbar=True,
            status_tip=None,
            whats_this=None,
            parent=None):
        """Add a toolbar icon to the InaSAFE toolbar.

        :param icon_path: Path to the icon for this action. Can be a resource
            path (e.g. ':/plugins/foo/bar.png') or a normal file system path.
        :type icon_path: str

        :param text: Text that should be shown in menu items for this action.
        :type text: str, QString

        :param callback: Function to be called when the action is triggered.
        :type callback: function

        :param enabled_flag: A flag indicating if the action should be enabled
            by default. Defaults to True.
        :type enabled_flag: bool

        :param add_to_menu: Flag indicating whether the action should also
            be added to the menu. Defaults to True.
        :type add_to_menu: bool

        :param add_to_toolbar: Flag indicating whether the action should also
            be added to the toolbar. Defaults to True.
        :type add_to_toolbar: bool

        :param status_tip: Optional text to show in a popup when mouse pointer
            hovers over the action.
        :type status_tip: str

        :param parent: Parent widget for the new action. Defaults None.
        :type parent: QWidget

        :param whats_this: Optional text to show in the status bar when the
            mouse pointer hovers over the action.

        :returns: The action that was created. Note that the action is also
            added to self.actions list.
        :rtype: QAction
        """

        icon = QIcon(icon_path)
        action = QAction(icon, text, parent)
        action.triggered.connect(callback)
        action.setEnabled(enabled_flag)

        if status_tip is not None:
            action.setStatusTip(status_tip)

        if whats_this is not None:
            action.setWhatsThis(whats_this)

        if add_to_toolbar:
            self.toolbar.addAction(action)

        if add_to_menu:
            self.iface.addPluginToVectorMenu(
                self.menu,
                action)

        self.actions.append(action)

        return action

    # noinspection PyPep8Naming
    def initGui(self):
        """Create the menu entries and toolbar icons inside the QGIS GUI."""
        self.menu = 'Stream feature extractor'
        icon_path = resources_path('icon.svg')
        self.run_action = self.add_action(
            icon_path,
            text=self.tr('Extract stream features from current layer', ),
            callback=self.run,
            parent=self.iface.mainWindow(),
            add_to_menu=True)
        self.actions.append(self.run_action)

        self.options_action = self.add_action(
            icon_path,
            text=self.tr('Options ...', ),
            callback=self.show_options,
            parent=self.iface.mainWindow(),
            add_to_menu=True,
            add_to_toolbar=False)
        self.actions.append(self.options_action)

        self.help_action = self.add_action(
            icon_path,
            text=self.tr('Help ...', ),
            callback=self.show_help,
            parent=self.iface.mainWindow(),
            add_to_menu=True,
            add_to_toolbar=False)
        self.actions.append(self.help_action)

        if self.iface.activeLayer() is not None:
            self.layer_changed(self.iface.activeLayer())
        else:
            self.run_action.setEnabled(False)

    def unload(self):
        """Removes the plugin menu item and icon from QGIS GUI."""
        for action in self.actions:
            self.iface.removePluginVectorMenu(
                self.menu,
                action)
            self.iface.removeToolBarIcon(action)

    def _load_nodes_with_style(self, nodes):
        """Set the style for the layer (must be before addMapLayer call).

        Try to get one for the current locale, and fall back to default
        if none available. To add new locales. clone styles/nodes.qml and
        rename it nodes-<locale>.qml.

        :param nodes: An extracted nodes layer.
        :type nodes: QgsVectorLayer, QgsMapLayer
        """
        style_path = os.path.join(
            os.path.dirname(__file__), 'styles/nodes-%s.qml' % self.locale)
        if not os.path.exists(style_path):
            style_path = os.path.join(
                os.path.dirname(__file__), 'styles/nodes.qml')
        nodes.loadNamedStyle(style_path)
        QgsProject.instance().addMapLayer(nodes)

    def run(self):
        """Run method that performs all the real work."""
        message_bar = self.iface.messageBar().createMessage(
            self.tr('Extracting stream features'),
            self.tr('Please stand by while calculation is in progress.'),
            self.iface.mainWindow())

        progress_bar = QProgressBar()
        progress_bar.setAlignment(Qt.AlignLeft | Qt.AlignVCenter)
        # Need to implement a separate worker thread if we want cancel
        # cancel_button = QPushButton()
        # cancel_button.setText(self.tr('Cancel'))
        # cancel_button.clicked.connect(worker.kill)
        message_bar.layout().addWidget(progress_bar)
        # message_bar.layout().addWidget(cancel_button)
        self.iface.messageBar().pushWidget(
            message_bar, Qgis.Info)
        self.message_bar = message_bar

        def progress_callback(current, maximum, message=None):
            """GUI based callback implementation for showing progress.

            :param current: Current progress.
            :type current: int

            :param maximum: Maximum range (point at which task is complete.
            :type maximum: int

            :param message: Optional message to display in the progress bar
            :type message: str, QString
            """
            if message is not None:
                message_bar.setText(message)
            if progress_bar is not None:
                progress_bar.setMaximum(maximum)
                progress_bar.setValue(current)

        settings = QSettings()
        distance = settings.value(
            'stream-feature-extractor/search-distance', 0, type=float)
        load_intermediate_layer = settings.value(
            'stream-feature-extractor/load-intermediate-layer',
            False,
            type=bool)
        # noinspection PyBroadException
        try:
            intermediate_layer, nodes = identify_features(
                self.iface.activeLayer(),
                threshold=distance,
                callback=progress_callback)
        except Exception as exception:
            LOGGER.exception(f"A failure occurred calling identify_features. {exception}")
            self.iface.messageBar().popWidget(message_bar)
            self.iface.messageBar().pushMessage(
                self.tr('Feature extraction error.'),
                self.tr('Please check logs for details.'),
                level=Qgis.Critical,
                duration=5)
            return

        # Get rid of the message bar again.
        self.iface.messageBar().popWidget(message_bar)

        self._load_nodes_with_style(nodes)

        if load_intermediate_layer:
            QgsProject.instance().addMapLayer(intermediate_layer)

        # QgsMapLayerRegistry.instance().addMapLayers([layer])
        self.iface.messageBar().pushMessage(
            self.tr('Extraction completed.'),
            self.tr('Use "Layer->Save as" to save the results permanently.'),
            level=Qgis.Info,
            duration=10)

    def show_help(self):
        """Display application help to the user."""
        locale_path = os.path.join(
            self.plugin_dir,
            'help',
            '{}'.format(self.locale))

        if os.path.exists(locale_path):
            help_file = 'file:///%s/help/%s/index.html' % (os.path.dirname(
                __file__), self.locale)
        else:
            help_file = 'file:///%s/help/en/index.html' % os.path.dirname(
                __file__)
        LOGGER.debug('Opening this help file:\n%s' % help_file)
        results_dialog = HelpDialog()
        results_dialog.web_view.load(QUrl(help_file))
        results_dialog.exec_()

    @staticmethod
    def show_options():
        """Show dialog with plugin options."""
        # show the dialog
        dialog = OptionsDialog()
        result = dialog.exec_()
        # See if OK was pressed
        if result:
            pass
        else:
            pass

    def layer_changed(self, layer):
        """Enable or disable extract features action when active layer changes.

        :param layer: The layer that is now active.
        :type layer: QgsMapLayer
        """
        flag = is_line_layer(layer)
        self.run_action.setEnabled(flag)