QGIS/python/plugins/processing/gui/wrappers.py

# -*- coding: utf-8 -*-

"""
***************************************************************************
    wrappers.py
    ---------------------
    Date                 : May 2016
    Copyright            : (C) 2016 by Arnaud Morvan, Victor Olaya
    Email                : arnaud dot morvan at camptocamp dot com
                           volayaf at gmail dot 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.                                   *
*                                                                         *
***************************************************************************
"""
from builtins import str
from builtins import range


__author__ = 'Arnaud Morvan'
__date__ = 'May 2016'
__copyright__ = '(C) 2016, Arnaud Morvan'

# This will get replaced with a git SHA1 when you do a git archive

__revision__ = '$Format:%H$'


import locale
import os
from functools import cmp_to_key

from qgis.core import QgsCoordinateReferenceSystem, QgsVectorLayer, QgsApplication
from qgis.PyQt.QtWidgets import QCheckBox, QComboBox, QLineEdit, QPlainTextEdit, QWidget, QHBoxLayout, QToolButton
from qgis.gui import (QgsFieldExpressionWidget,
                      QgsExpressionLineEdit,
                      QgsProjectionSelectionWidget,
                      QgsGenericProjectionSelector,
                      QgsFieldComboBox,
                      QgsFieldProxyModel)
from qgis.PyQt.QtCore import pyqtSignal, QObject, QVariant

from processing.gui.NumberInputPanel import NumberInputPanel, ModellerNumberInputPanel
from processing.gui.InputLayerSelectorPanel import InputLayerSelectorPanel
from processing.modeler.MultilineTextPanel import MultilineTextPanel
from processing.gui.PointSelectionPanel import PointSelectionPanel
from processing.core.parameters import (ParameterBoolean,
                                        ParameterPoint,
                                        ParameterFile,
                                        ParameterRaster,
                                        ParameterVector,
                                        ParameterNumber,
                                        ParameterString,
                                        ParameterExpression,
                                        ParameterTable,
                                        ParameterTableField,
                                        ParameterExtent,
                                        ParameterFixedTable,
                                        ParameterCrs,
                                        _resolveLayers)
from processing.core.ProcessingConfig import ProcessingConfig
from processing.gui.FileSelectionPanel import FileSelectionPanel
from processing.core.outputs import (OutputFile, OutputRaster, OutputVector, OutputNumber,
                                     OutputString, OutputTable, OutputExtent)
from processing.tools import dataobjects
from processing.gui.MultipleInputPanel import MultipleInputPanel
from processing.gui.BatchInputSelectionPanel import BatchInputSelectionPanel
from processing.gui.FixedTablePanel import FixedTablePanel
from processing.gui.ExtentSelectionPanel import ExtentSelectionPanel
from processing.gui.StringInputPanel import StringInputPanel
from processing.gui.GeometryPredicateSelectionPanel import GeometryPredicateSelectionPanel


DIALOG_STANDARD = 'standard'
DIALOG_BATCH = 'batch'
DIALOG_MODELER = 'modeler'


class InvalidParameterValue(Exception):
    pass


dialogTypes = {"AlgorithmDialog": DIALOG_STANDARD,
               "ModelerParametersDialog": DIALOG_MODELER,
               "BatchAlgorithmDialog": DIALOG_BATCH}


def getExtendedLayerName(layer):
    authid = layer.crs().authid()
    if ProcessingConfig.getSetting(ProcessingConfig.SHOW_CRS_DEF) and authid is not None:
        return u'{} [{}]'.format(layer.name(), authid)
    else:
        return layer.name()


class WidgetWrapper(QObject):

    widgetValueHasChanged = pyqtSignal(object)

    def __init__(self, param, dialog, row=0, col=0):
        QObject.__init__(self)
        self.param = param
        self.dialog = dialog
        self.row = row
        self.col = col
        self.dialogType = dialogTypes.get(dialog.__class__.__name__, DIALOG_STANDARD)
        self.widget = self.createWidget()
        if param.default is not None:
            self.setValue(param.default)

    def comboValue(self, validator=None, combobox=None):
        if not combobox:
            combobox = self.widget
        idx = combobox.findText(combobox.currentText())
        if idx < 0:
            v = combobox.currentText().strip()
            if validator is not None and not validator(v):
                raise InvalidParameterValue()
            return v
        return combobox.itemData(combobox.currentIndex())

    def createWidget(self):
        pass

    def setValue(self, value):
        pass

    def setComboValue(self, value, combobox=None):
        if not combobox:
            combobox = self.widget
        if isinstance(value, list):
            value = value[0]
        values = [combobox.itemData(i) for i in range(combobox.count())]
        try:
            idx = values.index(value)
            combobox.setCurrentIndex(idx)
            return
        except ValueError:
            pass
        if combobox.isEditable():
            if value is not None:
                combobox.setEditText(str(value))
        else:
            combobox.setCurrentIndex(0)

    def value(self):
        pass

    def postInitialize(self, wrappers):
        pass

    def refresh(self):
        pass


class BasicWidgetWrapper(WidgetWrapper):

    def createWidget(self):
        return QLineEdit()

    def setValue(self, value):
        self.widget.setText(value)

    def value(self):
        return self.widget.text()


class BooleanWidgetWrapper(WidgetWrapper):

    def createWidget(self):
        if self.dialogType == DIALOG_STANDARD:
            return QCheckBox()
        elif self.dialogType == DIALOG_BATCH:
            widget = QComboBox()
            widget.addItem(self.tr('Yes'))
            widget.addItem(self.tr('No'))
            if self.param.default:
                widget.setCurrentIndex(0)
            else:
                widget.setCurrentIndex(1)
            return widget
        else:
            widget = QComboBox()
            widget.addItem('Yes', True)
            widget.addItem('No', False)
            bools = self.dialog.getAvailableValuesOfType(ParameterBoolean, None)
            for b in bools:
                widget.addItem(self.dialog.resolveValueDescription(b), b)
            if self.param.default:
                widget.setCurrentIndex(0)
            else:
                widget.setCurrentIndex(1)
            return widget

    def setValue(self, value):
        if self.dialogType == DIALOG_STANDARD:
            self.widget.setChecked(value)
        else:
            self.setComboValue(value)

    def value(self):
        if self.dialogType == DIALOG_STANDARD:
            return self.widget.isChecked()
        elif self.dialogType == DIALOG_BATCH:
            return self.widget.currentIndex == 0
        else:
            return self.comboValue()


class CrsWidgetWrapper(WidgetWrapper):

    def createWidget(self):
        if self.dialogType == DIALOG_MODELER:
            self.combo = QComboBox()
            widget = QWidget()
            layout = QHBoxLayout()
            layout.setMargin(0)
            layout.setContentsMargins(0, 0, 0, 0)
            layout.setSpacing(1)
            layout.addWidget(self.combo)
            btn = QToolButton()
            btn.setIcon(QgsApplication.getThemeIcon("mActionSetProjection.svg"))
            btn.setToolTip(self.tr("Select CRS"))
            btn.clicked.connect(self.selectProjection)
            layout.addWidget(btn)

            widget.setLayout(layout)
            self.combo.setEditable(True)
            crss = self.dialog.getAvailableValuesOfType(ParameterCrs)
            for crs in crss:
                self.combo.addItem(self.dialog.resolveValueDescription(crs), crs)
            raster = self.dialog.getAvailableValuesOfType(ParameterRaster, OutputRaster)
            vector = self.dialog.getAvailableValuesOfType(ParameterVector, OutputVector)
            for r in raster:
                self.combo.addItem("Crs of layer " + self.dialog.resolveValueDescription(r), r)
            for v in vector:
                self.combo.addItem("Crs of layer " + self.dialog.resolveValueDescription(v), v)
            if not self.param.default:
                self.combo.setEditText(self.param.default)
            return widget
        else:

            widget = QgsProjectionSelectionWidget()
            if self.param.optional:
                widget.setOptionVisible(QgsProjectionSelectionWidget.CrsNotSet, True)

            if self.param.default:
                crs = QgsCoordinateReferenceSystem(self.param.default)
                widget.setCrs(crs)

            return widget

    def selectProjection(self):
        dialog = QgsGenericProjectionSelector(self.widget)
        current_crs = QgsCoordinateReferenceSystem(self.combo.currentText())
        if current_crs.isValid():
            dialog.setSelectedCrsId(current_crs.srsid())

        if dialog.exec_():
            self.setValue(dialog.selectedAuthId())

    def setValue(self, value):
        if self.dialogType == DIALOG_MODELER:
            self.setComboValue(value, self.combo)
        else:
            self.widget.setCrs(QgsCoordinateReferenceSystem(value))

    def value(self):
        if self.dialogType == DIALOG_MODELER:
            return self.comboValue(combobox=self.combo)
        else:
            crs = self.widget.crs()
            if crs.isValid():
                return self.widget.crs().authid()
            else:
                return None


class ExtentWidgetWrapper(WidgetWrapper):

    USE_MIN_COVERING_EXTENT = "[Use min covering extent]"

    def createWidget(self):
        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
            return ExtentSelectionPanel(self.dialog, self.param)
        else:
            widget = QComboBox()
            widget.setEditable(True)
            extents = self.dialog.getAvailableValuesOfType(ParameterExtent, OutputExtent)
            if self.param.optional:
                widget.addItem(self.USE_MIN_COVERING_EXTENT, None)
            raster = self.dialog.getAvailableValuesOfType(ParameterRaster, OutputRaster)
            vector = self.dialog.getAvailableValuesOfType(ParameterVector, OutputVector)
            for ex in extents:
                widget.addItem(self.dialog.resolveValueDescription(ex), ex)
            for r in raster:
                widget.addItem("Extent of " + self.dialog.resolveValueDescription(r), r)
            for v in vector:
                widget.addItem("Extent of " + self.dialog.resolveValueDescription(v), v)
            if not self.param.default:
                widget.setEditText(self.param.default)
            return widget

    def setValue(self, value):
        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
            self.widget.setExtentFromString(value)
        else:
            self.setComboValue(value)

    def value(self):
        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
            return self.widget.getValue()
        else:
            idx = self.widget.findText(self.widget.currentText())
            if idx < 0:
                s = str(self.widget.currentText()).strip()
                if s:
                    try:
                        tokens = s.split(',')
                        if len(tokens) != 4:
                            raise InvalidParameterValue()
                        for token in tokens:
                            float(token)
                    except:
                        raise InvalidParameterValue()
                elif self.param.optional:
                    s = None
                else:
                    raise InvalidParameterValue()
                return s
            else:
                return self.widget.itemData(self.widget.currentIndex())


class PointWidgetWrapper(WidgetWrapper):

    def createWidget(self):
        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
            return PointSelectionPanel(self.dialog, self.param.default)
        else:
            item = QComboBox()
            item.setEditable(True)
            points = self.dialog.getAvailableValuesOfType(ParameterPoint)
            for p in points:
                item.addItem(self.dialog.resolveValueDescription(p), p)
            item.setEditText(str(self.param.default))
            return item

    def setValue(self, value):
        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
            self.widget.setPointFromString(value)
        else:
            self.setComboValue(value)

    def value(self):
        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
            return self.widget.getValue()
        else:
            idx = self.widget.findText(self.widget.currentText())
            if idx < 0:
                s = str(self.widget.currentText()).strip()
                if s:
                    try:
                        tokens = s.split(',')
                        if len(tokens) != 2:
                            raise InvalidParameterValue()
                        for token in tokens:
                            float(token)
                    except:
                        raise InvalidParameterValue()
                elif self.param.optional:
                    s = None
                else:
                    raise InvalidParameterValue()
                return s
            else:
                return self.widget.itemData(self.widget.currentIndex())


class FileWidgetWrapper(WidgetWrapper):

    def createWidget(self):
        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
            return FileSelectionPanel(self.param.isFolder, self.param.ext)
        else:
            widget = QComboBox()
            widget.setEditable(True)
            files = self.dialog.getAvailableValuesOfType(ParameterFile, OutputFile)
            for f in files:
                widget.addItem(self.dialog.resolveValueDescription(f), f)
            return widget

    def setValue(self, value):
        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
            self.widget.setText(value)
        else:
            self.setComboValue(value)

    def value(self):
        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
            return self.widget.getValue()
        else:
            return self.comboValue()


class FixedTableWidgetWrapper(WidgetWrapper):

    def createWidget(self):
        return FixedTablePanel(self.param)

    def setValue(self, value):
        pass

    def value(self):
        if self.dialogType == DIALOG_MODELER:
            table = self.widget.table
            if not bool(table) and not self.param.optional:
                raise InvalidParameterValue()
            return ParameterFixedTable.tableToString(table)
        else:
            return self.widget.table


class MultipleInputWidgetWrapper(WidgetWrapper):

    def _getOptions(self):
        if self.param.datatype == dataobjects.TYPE_VECTOR_ANY:
            options = self.dialog.getAvailableValuesOfType(ParameterVector, OutputVector)
        elif self.param.datatype == dataobjects.TYPE_VECTOR_POINT:
            options = self.dialog.getAvailableValuesOfType(ParameterVector, OutputVector,
                                                           [dataobjects.TYPE_VECTOR_POINT, dataobjects.TYPE_VECTOR_ANY])
        elif self.param.datatype == dataobjects.TYPE_VECTOR_LINE:
            options = self.dialog.getAvailableValuesOfType(ParameterVector, OutputVector,
                                                           [dataobjects.TYPE_VECTOR_LINE, dataobjects.TYPE_VECTOR_ANY])
        elif self.param.datatype == dataobjects.TYPE_VECTOR_POLYGON:
            options = self.dialog.getAvailableValuesOfType(ParameterVector, OutputVector,
                                                           [dataobjects.TYPE_VECTOR_POLYGON, dataobjects.TYPE_VECTOR_ANY])
        elif self.param.datatype == dataobjects.TYPE_RASTER:
            options = self.dialog.getAvailableValuesOfType(ParameterRaster, OutputRaster)
        else:
            options = self.dialog.getAvailableValuesOfType(ParameterFile, OutputFile)
        options = sorted(options, key=lambda opt: self.dialog.resolveValueDescription(opt))
        return options

    def createWidget(self):
        if self.dialogType == DIALOG_STANDARD:
            if self.param.datatype == dataobjects.TYPE_FILE:
                return MultipleInputPanel(datatype=dataobjects.TYPE_FILE)
            else:
                if self.param.datatype == dataobjects.TYPE_RASTER:
                    options = dataobjects.getRasterLayers(sorting=False)
                elif self.param.datatype == dataobjects.TYPE_VECTOR_ANY:
                    options = dataobjects.getVectorLayers(sorting=False)
                else:
                    options = dataobjects.getVectorLayers([self.param.datatype], sorting=False)
                opts = [getExtendedLayerName(opt) for opt in options]
                return MultipleInputPanel(opts)
        elif self.dialogType == DIALOG_BATCH:
            widget = BatchInputSelectionPanel(self.param, self.row, self.col, self.dialog)
            widget.valueChanged.connect(lambda: self.widgetValueHasChanged.emit(self))
            return widget
        else:
            options = [self.dialog.resolveValueDescription(opt) for opt in self._getOptions()]
            return MultipleInputPanel(options)

    def refresh(self):
        if self.param.datatype != dataobjects.TYPE_FILE:
            if self.param.datatype == dataobjects.TYPE_RASTER:
                options = dataobjects.getRasterLayers(sorting=False)
            elif self.param.datatype == dataobjects.TYPE_VECTOR_ANY:
                options = dataobjects.getVectorLayers(sorting=False)
            else:
                options = dataobjects.getVectorLayers([self.param.datatype], sorting=False)
            opts = [self.getExtendedLayerName(opt) for opt in options]
            self.widget.updateForOptions(opts)

    def setValue(self, value):
        if self.dialogType == DIALOG_STANDARD:
            pass  # TODO
        elif self.dialogType == DIALOG_BATCH:
            return self.widget.setText(value)
        else:
            options = self._getOptions()
            selected = []
            for i, opt in enumerate(options):
                if opt in value:
                    selected.append(i)
            self.widget.setSelectedItems(selected)

    def value(self):
        if self.dialogType == DIALOG_STANDARD:
            if self.param.datatype == dataobjects.TYPE_FILE:
                return self.param.setValue(self.widget.selectedoptions)
            else:
                if self.param.datatype == dataobjects.TYPE_RASTER:
                    options = dataobjects.getRasterLayers(sorting=False)
                elif self.param.datatype == dataobjects.TYPE_VECTOR_ANY:
                    options = dataobjects.getVectorLayers(sorting=False)
                else:
                    options = dataobjects.getVectorLayers([self.param.datatype], sorting=False)
                return [options[i] for i in self.widget.selectedoptions]
        elif self.dialogType == DIALOG_BATCH:
            return self.widget.getText()
        else:
            options = self._getOptions()
            values = [options[i] for i in self.widget.selectedoptions]
            if len(values) == 0 and not self.param.optional:
                raise InvalidParameterValue()
            return values


class NumberWidgetWrapper(WidgetWrapper):

    def createWidget(self):
        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
            return NumberInputPanel(self.param)
        else:
            return ModellerNumberInputPanel(self.param, self.dialog)

    def setValue(self, value):
        self.widget.setValue(value)

    def value(self):
        return self.widget.getValue()


class RasterWidgetWrapper(WidgetWrapper):

    NOT_SELECTED = '[Not selected]'

    def createWidget(self):
        if self.dialogType == DIALOG_STANDARD:
            layers = dataobjects.getRasterLayers()
            items = []
            if self.param.optional:
                items.append((self.NOT_SELECTED, None))
            for layer in layers:
                items.append((getExtendedLayerName(layer), layer))
            return InputLayerSelectorPanel(items, self.param)
        elif self.dialogType == DIALOG_BATCH:
            return BatchInputSelectionPanel(self.param, self.row, self.col, self.dialog)
        else:
            widget = QComboBox()
            widget.setEditable(True)
            files = self.dialog.getAvailableValuesOfType(ParameterRaster, OutputRaster)
            for f in files:
                widget.addItem(self.dialog.resolveValueDescription(f), f)
            if self.param.optional:
                widget.setEditText("")
            return widget

    def refresh(self):
        items = []
        layers = dataobjects.getRasterLayers()
        if self.param.optional:
            items.append((self.NOT_SELECTED, None))
        for layer in layers:
            items.append((getExtendedLayerName(layer), layer))
        self.widget.update(items)

    def setValue(self, value):
        if self.dialogType == DIALOG_STANDARD:
            pass  # TODO
        elif self.dialogType == DIALOG_BATCH:
            self.widget.setText(value)
        else:
            self.setComboValue(value)

    def value(self):
        if self.dialogType == DIALOG_STANDARD:
            return self.widget.getValue()
        elif self.dialogType == DIALOG_BATCH:
            return self.widget.getText()
        else:
            def validator(v):
                if not bool(v):
                    return self.param.optional
                else:
                    return os.path.exists(v)
            return self.comboValue(validator)


class SelectionWidgetWrapper(WidgetWrapper):

    def createWidget(self):
        if self.param.multiple:
            return MultipleInputPanel(options=self.param.options)
        else:
            widget = QComboBox()
            widget.addItems(self.param.options)
            if self.param.default:
                widget.setCurrentIndex(self.param.default)
            return widget

    def setValue(self, value):
        if self.param.multiple:
            self.widget.setSelectedItems(value)
        else:
            self.widget.setCurrentIndex(int(value))

    def value(self):
        if self.param.multiple:
            return self.widget.selectedoptions
        else:
            return self.widget.currentIndex()


class VectorWidgetWrapper(WidgetWrapper):

    NOT_SELECTED = '[Not selected]'

    def createWidget(self):
        if self.dialogType == DIALOG_STANDARD:
            layers = dataobjects.getVectorLayers(self.param.datatype)
            items = []
            if self.param.optional:
                items.append((self.NOT_SELECTED, None))
            for layer in layers:
                items.append((getExtendedLayerName(layer), layer))
            widget = InputLayerSelectorPanel(items, self.param)
            widget.name = self.param.name
            widget.valueChanged.connect(lambda: self.widgetValueHasChanged.emit(self))
            return widget
        elif self.dialogType == DIALOG_BATCH:
            widget = BatchInputSelectionPanel(self.param, self.row, self.col, self.dialog)
            widget.valueChanged.connect(lambda: self.widgetValueHasChanged.emit(self))
            return widget
        else:
            widget = QComboBox()
            layers = self.dialog.getAvailableValuesOfType(ParameterVector, OutputVector)
            widget.setEditable(True)
            for layer in layers:
                widget.addItem(self.dialog.resolveValueDescription(layer), layer)
            if self.param.optional:
                widget.setEditText("")
            return widget

    def _populate(self, widget):
        items = []
        layers = dataobjects.getVectorLayers(self.param.datatype)
        layers.sort(key=lambda lay: lay.name())
        if self.param.optional:
            items.append((self.NOT_SELECTED, None))
        for layer in layers:
            items.append((getExtendedLayerName(layer), layer))
        self.widget.update(items)

    def refresh(self):
        self._populate(self.widget)

    def setValue(self, value):
        if self.dialogType == DIALOG_STANDARD:
            pass  # TODO
        elif self.dialogType == DIALOG_BATCH:
            self.widget.setValue(value)
        else:
            self.setComboValue(value)

    def value(self):
        if self.dialogType == DIALOG_STANDARD:
            try:
                return self.widget.itemData(self.widget.currentIndex())
            except:
                return self.widget.getValue()
        elif self.dialogType == DIALOG_BATCH:
            return self.widget.value()
        else:
            def validator(v):
                if not bool(v):
                    return self.param.optional
                else:
                    return os.path.exists(v)
            return self.comboValue(validator)


class StringWidgetWrapper(WidgetWrapper):

    def createWidget(self):
        if self.dialogType == DIALOG_STANDARD:
            if self.param.multiline:
                widget = QPlainTextEdit()
                if self.param.default:
                    widget.setPlainText(self.param.default)
            else:
                widget = StringInputPanel(self.param)
                if self.param.default:
                    widget.setValue(self.param.default)
        elif self.dialogType == DIALOG_BATCH:
            widget = QLineEdit()
            if self.param.default:
                widget.setText(self.param.default)
        else:
            # strings, numbers, files and table fields are all allowed input types
            strings = self.dialog.getAvailableValuesOfType([ParameterString, ParameterNumber, ParameterFile,
                                                            ParameterTableField, ParameterExpression], OutputString)
            options = [(self.dialog.resolveValueDescription(s), s) for s in strings]
            if self.param.multiline:
                widget = MultilineTextPanel(options)
                widget.setText(self.param.default or "")
            else:
                widget = QComboBox()
                widget.setEditable(True)
                for desc, val in options:
                    widget.addItem(desc, val)
                widget.setEditText(self.param.default or "")
        return widget

    def setValue(self, value):
        if self.dialogType == DIALOG_STANDARD:
            pass  # TODO
        elif self.dialogType == DIALOG_BATCH:
            self.widget.setText(value)
        else:
            if self.param.multiline:
                self.widget.setValue(value)
            else:
                self.setComboValue(value)

    def value(self):
        if self.dialogType in DIALOG_STANDARD:
            if self.param.multiline:
                text = self.widget.toPlainText()
            else:
                text = self.widget.getValue()
            return text
        if self.dialogType == DIALOG_BATCH:
            return self.widget.text()
        else:
            if self.param.multiline:
                value = self.widget.getValue()
                option = self.widget.getOption()
                if option == MultilineTextPanel.USE_TEXT:
                    if value == '':
                        if self.param.optional:
                            return None
                        else:
                            raise InvalidParameterValue()
                    else:
                        return value
                else:
                    return value
            else:
                def validator(v):
                    return bool(v) or self.param.optional
                return self.comboValue(validator)


class ExpressionWidgetWrapper(WidgetWrapper):

    def createWidget(self):
        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
            if self.param.parent_layer:
                widget = QgsFieldExpressionWidget()
            else:
                widget = QgsExpressionLineEdit()
            if self.param.default:
                widget.setExpression(self.param.default)
        else:
            strings = self.dialog.getAvailableValuesOfType([ParameterExpression, ParameterString, ParameterNumber], OutputString)
            options = [(self.dialog.resolveValueDescription(s), s) for s in strings]
            widget = QComboBox()
            widget.setEditable(True)
            for desc, val in options:
                widget.addItem(desc, val)
            widget.setEditText(self.param.default or "")
        return widget

    def postInitialize(self, wrappers):
        for wrapper in wrappers:
            if wrapper.param.name == self.param.parent_layer:
                if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
                    self.setLayer(wrapper.value())
                    wrapper.widgetValueHasChanged.connect(self.parentLayerChanged)
                break

    def parentLayerChanged(self, wrapper):
        self.setLayer(wrapper.value())

    def setLayer(self, layer):
        if isinstance(layer, str):
            layer = dataobjects.getObjectFromUri(_resolveLayers(layer))
        self.widget.setLayer(layer)

    def setValue(self, value):
        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
            self.widget.setExpression(value)
        else:
            self.setComboValue(value)

    def value(self):
        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
            try:
                return self.widget.asExpression()
            except:
                return self.widget.expression()
        else:
            def validator(v):
                return bool(v) or self.param.optional
            return self.comboValue(validator)


class TableWidgetWrapper(WidgetWrapper):

    NOT_SELECTED = '[Not selected]'

    def createWidget(self):
        if self.dialogType == DIALOG_STANDARD:
            widget = QComboBox()
            layers = dataobjects.getTables()
            layers.sort(key=lambda lay: lay.name())
            if self.param.optional:
                widget.addItem(self.NOT_SELECTED, None)
            for layer in layers:
                widget.addItem(layer.name(), layer)
            widget.currentIndexChanged.connect(lambda: self.widgetValueHasChanged.emit(self))
            widget.name = self.param.name
            return widget
        elif self.dialogType == DIALOG_BATCH:
            return BatchInputSelectionPanel(self.param, self.row, self.col, self.dialog)
        else:
            widget = QComboBox()
            tables = self.dialog.getAvailableValuesOfType(ParameterTable, OutputTable)
            layers = self.dialog.getAvailableValuesOfType(ParameterVector, OutputVector)
            if self.param.optional:
                widget.addItem(self.NOT_SELECTED, None)
            for table in tables:
                widget.addItem(self.dialog.resolveValueDescription(table), table)
            for layer in layers:
                widget.addItem(self.dialog.resolveValueDescription(layer), layer)
            return widget

    def setValue(self, value):
        if self.dialogType == DIALOG_STANDARD:
            pass  # TODO
        elif self.dialogType == DIALOG_BATCH:
            return self.widget.setText(value)
        else:
            self.setComboValue(value)

    def value(self):
        if self.dialogType == DIALOG_STANDARD:
            try:
                return self.widget.itemData(self.widget.currentIndex())
            except:
                return self.widget.getValue()
        elif self.dialogType == DIALOG_BATCH:
            return self.widget.value()
        else:
            def validator(v):
                return bool(v) or self.param.optional
            return self.comboValue(validator)


class TableFieldWidgetWrapper(WidgetWrapper):

    NOT_SET = '[Not set]'

    def createWidget(self):
        self._layer = None

        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
            if self.param.multiple:
                return MultipleInputPanel(options=[])
            else:
                widget = QgsFieldComboBox()
                widget.setAllowEmptyFieldName(self.param.optional)
                if self.param.datatype == ParameterTableField.DATA_TYPE_NUMBER:
                    widget.setFilters(QgsFieldProxyModel.Numeric)
                elif self.param.datatype == ParameterTableField.DATA_TYPE_STRING:
                    widget.setFilters(QgsFieldProxyModel.String)

                return widget
        else:
            widget = QComboBox()
            widget.setEditable(True)
            fields = self.dialog.getAvailableValuesOfType(ParameterTableField, None)
            if self.param.optional:
                widget.addItem(self.NOT_SET, None)
            for f in fields:
                widget.addItem(self.dialog.resolveValueDescription(f), f)
            return widget

    def postInitialize(self, wrappers):
        for wrapper in wrappers:
            if wrapper.param.name == self.param.parent:
                if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
                    self.setLayer(wrapper.value())
                    wrapper.widgetValueHasChanged.connect(self.parentValueChanged)
                break

    def parentValueChanged(self, wrapper):
        self.setLayer(wrapper.value())

    def setLayer(self, layer):
        if isinstance(layer, str):
            layer = dataobjects.getObjectFromUri(_resolveLayers(layer))
        self._layer = layer
        self.refreshItems()

    def refreshItems(self):
        if self.param.multiple:
            self.widget.updateForOptions(self.getFields())
        else:
            self.widget.setLayer(self._layer)
            self.widget.setCurrentIndex(0)

    def getFields(self):
        if self._layer is None:
            return []
        fieldTypes = []
        if self.param.datatype == ParameterTableField.DATA_TYPE_STRING:
            fieldTypes = [QVariant.String]
        elif self.param.datatype == ParameterTableField.DATA_TYPE_NUMBER:
            fieldTypes = [QVariant.Int, QVariant.Double, QVariant.LongLong,
                          QVariant.UInt, QVariant.ULongLong]

        fieldNames = set()
        for field in self._layer.fields():
            if not fieldTypes or field.type() in fieldTypes:
                fieldNames.add(str(field.name()))
        return sorted(list(fieldNames), key=cmp_to_key(locale.strcoll))

    def setValue(self, value):
        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
            if self.param.multiple:
                options = self.widget.options
                selected = []
                for i, opt in enumerate(options):
                    if opt in value:
                        selected.append(i)
                self.widget.setSelectedItems(selected)
            else:
                self.widget.setField(value)
        else:
            self.setComboValue(value)

    def value(self):
        if self.dialogType in (DIALOG_STANDARD, DIALOG_BATCH):
            if self.param.multiple:
                return [self.widget.options[i] for i in self.widget.selectedoptions]
            else:
                f = self.widget.field()
                if self.param.optional and not f:
                    return None
                return f
        else:
            def validator(v):
                return bool(v) or self.param.optional
            return self.comboValue(validator)


def GeometryPredicateWidgetWrapper(WidgetWrapper):

    def createWidget(self):
        return GeometryPredicateSelectionPanel()

    def setValue(self, value):
        self.widget.setValue(value)

    def value(self):
        return self.widget.value()