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

# Copyright (c) 2016 - 2019 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing a dialog to select from a list of strings.
"""

from __future__ import unicode_literals

from PyQt5.QtCore import pyqtSlot, Qt
from PyQt5.QtWidgets import QDialog, QDialogButtonBox, QAbstractItemView, \
    QListWidgetItem

from .Ui_E5ListSelectionDialog import Ui_E5ListSelectionDialog


class E5ListSelectionDialog(QDialog, Ui_E5ListSelectionDialog):
    """
    Class implementing a dialog to select from a list of strings.
    """
    def __init__(self, entries,
                 selectionMode=QAbstractItemView.ExtendedSelection,
                 title="", message="", checkBoxSelection=False, parent=None):
        """
        Constructor
        
        @param entries list of entries to select from
        @type list of str
        @param selectionMode selection mode for the list
        @type QAbstractItemView.SelectionMode
        @param title tirle of the dialog
        @type str
        @param message message to be show in the dialog
        @type str
        @param checkBoxSelection flag indicating to select items via their
            checkbox
        @type bool
        @param parent reference to the parent widget
        @type QWidget
        """
        super(E5ListSelectionDialog, self).__init__(parent)
        self.setupUi(self)
        
        if title:
            self.setWindowTitle(title)
        if message:
            self.messageLabel.setText(message)
        
        self.__checkCount = 0
        self.__isCheckBoxSelection = checkBoxSelection
        if self.__isCheckBoxSelection:
            self.selectionList.setSelectionMode(QAbstractItemView.NoSelection)
            for entry in entries:
                itm = QListWidgetItem(entry)
                itm.setFlags(Qt.ItemIsUserCheckable | Qt.ItemIsEnabled)
                itm.setCheckState(Qt.Unchecked)
                self.selectionList.addItem(itm)
        else:
            self.selectionList.setSelectionMode(selectionMode)
            self.selectionList.addItems(entries)
        
        self.buttonBox.button(QDialogButtonBox.Ok).setEnabled(False)
    
    @pyqtSlot()
    def on_selectionList_itemSelectionChanged(self):
        """
        Private slot handling a change of the selection.
        """
        if not self.__isCheckBoxSelection:
            self.buttonBox.button(QDialogButtonBox.Ok).setEnabled(
                len(self.selectionList.selectedItems()) > 0)
    
    def on_selectionList_itemChanged(self, itm):
        """
        Private slot handling a change of an item.
        
        @param itm reference to the changed item
        @type QListWidgetItem
        """
        if self.__isCheckBoxSelection:
            if itm.checkState() == Qt.Checked:
                self.__checkCount += 1
            else:
                self.__checkCount -= 1
            self.buttonBox.button(QDialogButtonBox.Ok).setEnabled(
                self.__checkCount > 0)
    
    def getSelection(self):
        """
        Public method to retrieve the selected items.
        
        @return selected entries
        @rtype list of str
        """
        entries = []
        if self.__isCheckBoxSelection:
            for row in range(self.selectionList.count()):
                item = self.selectionList.item(row)
                if item.checkState() == Qt.Checked:
                    entries.append(item.text())
        else:
            for item in self.selectionList.selectedItems():
                entries.append(item.text())
        return entries
