""" Help pages
"""

from qtpy.QtCore import Qt, QUrl
from qtpy.QtGui import QIcon, QKeySequence
from qtpy.QtWidgets import (QAction, QApplication, QDialog, QLabel, 
                            QTextBrowser, QToolBar, QVBoxLayout)

class HelpBrowser(QDialog):
    def __init__(self, helpbase, page, parent=None, xlength=600, ylength=550):
        super(HelpBrowser, self).__init__(parent)
        self.setAttribute(Qt.WA_DeleteOnClose)
        self.setAttribute(Qt.WA_GroupLeader)
        self.xlength = xlength
        self.ylength = ylength

        back_action = QAction(QIcon(":/back.png"), "&Back", self)
        back_action.setShortcut(QKeySequence.Back)
        home_action = QAction(QIcon(":/home.png"), "&Home", self)
        home_action.setShortcut("Home")
        self.page_label = QLabel()

        tool_bar = QToolBar()
        tool_bar.addAction(back_action)
        tool_bar.addAction(home_action)
        tool_bar.addWidget(self.page_label)
        self.text_browser = QTextBrowser()

        layout = QVBoxLayout()
        layout.addWidget(tool_bar)
        layout.addWidget(self.text_browser, 1)
        self.setLayout(layout)

        back_action.triggered.connect(self.text_browser.backward)
        home_action.triggered.connect(self.text_browser.home)
        self.text_browser.sourceChanged.connect(self.update_page_title)

        self.text_browser.setSearchPaths([":/help", helpbase])
        self.text_browser.setSource(QUrl(page))
        self.resize(self.xlength, self.ylength)
        self.setWindowTitle("{0} Help".format(parent.pymodule))
        QApplication.processEvents()

    def update_page_title(self):
        self.page_label.setText(self.text_browser.documentTitle())