# (C) Copyright 2005-2022 Enthought, Inc., Austin, TX
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!

""" The preference dialog. """


import wx


from traits.api import Any, Dict, Float, Instance, Str


from pyface.preference.preference_node import PreferenceNode
from pyface.ui.wx.heading_text import HeadingText
from pyface.ui.wx.layered_panel import LayeredPanel
from pyface.ui.wx.split_dialog import SplitDialog
from pyface.ui.wx.viewer.tree_viewer import TreeViewer
from pyface.viewer.default_tree_content_provider import (
    DefaultTreeContentProvider,
)


class PreferenceDialog(SplitDialog):
    """ The preference dialog. """

    # 'Dialog' interface ---------------------------------------------------

    # The dialog title.
    title = Str("Preferences")

    # 'SplitDialog' interface ---------------------------------------------#

    # The ratio of the size of the left/top pane to the right/bottom pane.
    ratio = Float(0.25)

    # 'PreferenceDialog' interface -----------------------------------------

    # The root of the preference hierarchy.
    root = Instance(PreferenceNode)

    # Private interface ----------------------------------------------------

    # The preference pages in the dialog (they are created lazily).
    _pages = Dict()

    # The current visible preference page.
    _current_page = Any()

    # ------------------------------------------------------------------------
    # Protected 'Dialog' interface.
    # ------------------------------------------------------------------------

    def _create_buttons(self, parent):
        """ Creates the buttons. """

        sizer = wx.BoxSizer(wx.HORIZONTAL)

        # 'Done' button.
        done = wx.Button(parent, wx.ID_OK, "Done")
        done.SetDefault()
        parent.Bind(wx.EVT_BUTTON, self._wx_on_ok, wx.ID_OK)
        sizer.Add(done)

        return sizer

    # ------------------------------------------------------------------------
    # Protected 'SplitDialog' interface.
    # ------------------------------------------------------------------------

    def _create_lhs(self, parent):
        """ Creates the panel containing the preference page tree. """

        return self._create_tree(parent)

    def _create_rhs(self, parent):
        """ Creates the panel containing the selected preference page. """

        panel = wx.Panel(parent, -1, style=wx.CLIP_CHILDREN)
        sizer = wx.BoxSizer(wx.VERTICAL)
        panel.SetSizer(sizer)
        panel.SetAutoLayout(True)

        # The 'pretty' title bar ;^)
        self.__title = HeadingText(parent=panel, create=False)
        self.__title.create()
        sizer.Add(
            self.__title.control,
            0,
            wx.EXPAND | wx.BOTTOM | wx.LEFT | wx.RIGHT,
            5,
        )

        # The preference page of the node currently selected in the tree.
        self._layered_panel = LayeredPanel(
            parent=panel,
            create=False,
            min_width=-1,
            min_height=-1,
        )
        self._layered_panel.create()
        sizer.Add(
            self._layered_panel.control,
            1,
            wx.EXPAND | wx.TOP | wx.LEFT | wx.RIGHT,
            5,
        )

        # The 'Restore Defaults' button etc.
        buttons = self._create_page_buttons(panel)
        sizer.Add(buttons, 0, wx.ALIGN_RIGHT | wx.TOP | wx.RIGHT, 5)

        # A separator.
        line = wx.StaticLine(panel, -1)
        sizer.Add(line, 0, wx.EXPAND | wx.TOP | wx.LEFT | wx.RIGHT, 5)

        # Resize the panel to fit the sizer's minimum size.
        sizer.Fit(panel)

        return panel

    # ------------------------------------------------------------------------
    # Private interface.
    # ------------------------------------------------------------------------

    def _create_tree(self, parent):
        """ Creates the preference page tree. """

        tree_viewer = TreeViewer(
            parent,
            input=self.root,
            show_images=False,
            show_root=False,
            content_provider=DefaultTreeContentProvider(),
        )

        tree_viewer.observe(self._on_selection_changed, "selection")

        return tree_viewer.control

    def _create_page_buttons(self, parent):
        """ Creates the 'Restore Defaults' button, etc.

        At the moment the "etc." is an optional 'Help' button.

        """

        self._button_sizer = sizer = wx.BoxSizer(wx.HORIZONTAL)

        # 'Help' button. Comes first so 'Restore Defaults' doesn't jump around.
        self._help = help = wx.Button(parent, -1, "Help")
        parent.Bind(wx.EVT_BUTTON, self._on_help, help.GetId())
        sizer.Add(help, 0, wx.RIGHT, 5)

        # 'Restore Defaults' button.
        restore = wx.Button(parent, -1, "Restore Defaults")
        parent.Bind(wx.EVT_BUTTON, self._on_restore_defaults, restore.GetId())
        sizer.Add(restore)

        return sizer

    # ------------------------------------------------------------------------
    # wx event handlers.
    # ------------------------------------------------------------------------

    def _on_restore_defaults(self, event):
        """ Called when the 'Restore Defaults' button is pressed. """

        page = self._pages[self._layered_panel.current_layer_name]
        page.restore_defaults()

    def _on_help(self, event):
        """ Called when the 'Help' button is pressed. """

        page = self._pages[self._layered_panel.current_layer_name]
        page.show_help_topic()

        return

    # ------------------------------------------------------------------------
    # Trait event handlers.
    # ------------------------------------------------------------------------

    def _on_selection_changed(self, event):
        """ Called when a node in the tree is selected. """
        selection = event.new
        if len(selection) > 0:
            # The tree is in single selection mode.
            node = selection[0]

            # We only show the help button if the selected node has a help
            # topic Id.
            if len(node.help_id) > 0:
                self._button_sizer.Show(self._help, True)

            else:
                self._button_sizer.Show(self._help, False)

            # Show the selected preference page.
            layered_panel = self._layered_panel
            parent = self._layered_panel.control

            # If we haven't yet displayed the node's preference page during the
            # lifetime of this dialog, then we have to create it.
            if not layered_panel.has_layer(node.name):
                page = node.create_page()
                layered_panel.add_layer(node.name, page.create_control(parent))
                self._pages[node.name] = page

            layered_panel.show_layer(node.name)
            self.__title.text = node.name

        return
