# (C) Copyright 2008-2021 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!

# ------------------------------------------------------------------------------
# Copyright (c) 2007, Riverbank Computing Limited
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD license.
# However, when used with the GPL version of PyQt the additional terms described
# in the PyQt GPL exception also apply

#
# Author: Riverbank Computing Limited
# ------------------------------------------------------------------------------

""" Defines the various list editors for the PyQt user interface toolkit.
"""


from pyface.qt import QtCore, QtGui

from pyface.api import ImageResource

from traits.api import (
    Any, Bool, Callable, Dict, Instance, List, Str, TraitError
)
from traits.trait_base import user_name_for, xgetattr

from traitsui.editors.list_editor import ListItemProxy

from .editor import Editor
from .helper import IconButton
from .menu import MakeMenu


class SimpleEditor(Editor):
    """ Simple style of editor for lists, which displays a list box with only
    one item visible at a time. A icon next to the list box displays a menu of
    operations on the list.

    """

    # -------------------------------------------------------------------------
    #  Trait definitions:
    # -------------------------------------------------------------------------

    #: The kind of editor to create for each list item
    kind = Str()

    #: Is the list of items being edited mutable?
    mutable = Bool(True)

    #: Is the editor scrollable?
    scrollable = Bool(True)

    #: Signal mapper allowing to identify which icon button requested a context
    #: menu
    mapper = Instance(QtCore.QSignalMapper)

    buttons = List([])

    _list_pane = Instance(QtGui.QWidget)

    # -------------------------------------------------------------------------
    #  Class constants:
    # -------------------------------------------------------------------------

    #: Whether the list is displayed in a single row
    single_row = True

    # -------------------------------------------------------------------------
    #  Normal list item menu:
    # -------------------------------------------------------------------------

    #: Menu for modifying the list
    list_menu = """
       Add &Before     [_menu_before]: self.add_before()
       Add &After      [_menu_after]:  self.add_after()
       ---
       &Delete         [_menu_delete]: self.delete_item()
       ---
       Move &Up        [_menu_up]:     self.move_up()
       Move &Down      [_menu_down]:   self.move_down()
       Move to &Top    [_menu_top]:    self.move_top()
       Move to &Bottom [_menu_bottom]: self.move_bottom()
    """

    # -------------------------------------------------------------------------
    #  Empty list item menu:
    # -------------------------------------------------------------------------

    empty_list_menu = """
       Add: self.add_empty()
    """

    def init(self, parent):
        """ Finishes initializing the editor by creating the underlying toolkit
            widget.
        """
        # Initialize the trait handler to use:
        trait_handler = self.factory.trait_handler
        if trait_handler is None:
            trait_handler = self.object.base_trait(self.name).handler
        self._trait_handler = trait_handler

        if self.scrollable:
            # Create a scrolled window to hold all of the list item controls:
            self.control = QtGui.QScrollArea()
            self.control.setFrameShape(QtGui.QFrame.NoFrame)
            self.control.setWidgetResizable(True)
            self._list_pane = QtGui.QWidget()
        else:
            self.control = QtGui.QWidget()
            self._list_pane = self.control
        self._list_pane.setSizePolicy(
            QtGui.QSizePolicy.Expanding, QtGui.QSizePolicy.Expanding
        )

        # Create a mapper to identify which icon button requested a contextmenu
        self.mapper = QtCore.QSignalMapper(self.control)

        # Create a widget with a grid layout as the container.
        layout = QtGui.QGridLayout(self._list_pane)
        layout.setAlignment(QtCore.Qt.AlignLeft | QtCore.Qt.AlignTop)
        layout.setContentsMargins(0, 0, 0, 0)
        layout.setSpacing(0)

        # Remember the editor to use for each individual list item:
        editor = self.factory.editor
        if editor is None:
            editor = trait_handler.item_trait.get_editor()
        self._editor = getattr(editor, self.kind)

        # Set up the additional 'list items changed' event handler needed for
        # a list based trait. Note that we want to fire the update_editor_item
        # only when the items in the list change and not when intermediate
        # traits change. Therefore, replace "." by ":" in the extended_name
        # when setting up the listener.
        extended_name = self.extended_name.replace(".", ":")
        self.context_object.on_trait_change(
            self.update_editor_item, extended_name + "_items?", dispatch="ui"
        )
        self.set_tooltip()

    def dispose(self):
        """ Disposes of the contents of an editor.
        """
        self._dispose_items()

        extended_name = self.extended_name.replace(".", ":")
        self.context_object.on_trait_change(
            self.update_editor_item, extended_name + "_items?", remove=True
        )

        super().dispose()

    def update_editor(self):
        """ Updates the editor when the object trait changes externally to the
            editor.
        """
        self.mapper = QtCore.QSignalMapper(self.control)
        # Disconnect the editor from any control about to be destroyed:
        self._dispose_items()

        list_pane = self._list_pane
        layout = list_pane.layout()

        # Create all of the list item trait editors:
        trait_handler = self._trait_handler
        resizable = (
            trait_handler.minlen != trait_handler.maxlen
        ) and self.mutable
        item_trait = trait_handler.item_trait

        is_fake = resizable and (len(self.value) == 0)
        if is_fake:
            self.empty_list()
        else:
            self.buttons = []
            # Asking the mapper to send the sender to the callback method
            self.mapper.mapped.connect(self.popup_menu)

        editor = self._editor
        for index, value in enumerate(self.value):
            row, column = divmod(index, self.factory.columns)

            # Account for the fact that we have <columns> number of
            # pairs
            column = column * 2

            if resizable:
                # Connecting the new button to the mapper
                control = IconButton("list_editor.png", self.mapper.map)
                self.buttons.append(control)
                # Setting the mapping and asking it to send the index of the
                # sender to the callback method.  Unfortunately just sending
                # the control does not work for PyQt (tested on 4.11)
                self.mapper.setMapping(control, index)

                layout.addWidget(control, row, column + 1)

            proxy = ListItemProxy(
                self.object, self.name, index, item_trait, value
            )
            if resizable:
                control.proxy = proxy
            peditor = editor(
                self.ui, proxy, "value", self.description, list_pane
            ).trait_set(object_name="")
            peditor.prepare(list_pane)
            pcontrol = peditor.control
            pcontrol.proxy = proxy

            if isinstance(pcontrol, QtGui.QWidget):
                layout.addWidget(pcontrol, row, column)
            else:
                layout.addLayout(pcontrol, row, column)

        # QScrollArea can have problems if the widget being scrolled is set too
        # early (ie. before it contains something).
        if self.scrollable and self.control.widget() is None:
            self.control.setWidget(list_pane)

    def update_editor_item(self, event):
        """ Updates the editor when an item in the object trait changes
        externally to the editor.
        """
        # If this is not a simple, single item update, rebuild entire editor:
        if (len(event.removed) != 1) or (len(event.added) != 1):
            self.update_editor()
            return

        # Otherwise, find the proxy for this index and update it with the
        # changed value:
        for control in self._list_pane.children():
            if isinstance(control, QtGui.QLayout):
                continue

            proxy = control.proxy
            if proxy.index == event.index:
                proxy.value = event.added[0]
                break

    def empty_list(self):
        """ Creates an empty list entry (so the user can add a new item).
        """
        # Connecting the new button to the mapper
        control = IconButton("list_editor.png", self.mapper.map)
        # Setting the mapping and asking it to send the index of the sender to
        # callback method. Unfortunately just sending the control does not
        # work for PyQt (tested on 4.11)
        self.mapper.setMapping(control, 0)
        self.mapper.mapped.connect(self.popup_empty_menu)
        control.is_empty = True
        self._cur_control = control
        self.buttons = [control]

        proxy = ListItemProxy(self.object, self.name, -1, None, None)
        pcontrol = QtGui.QLabel("   (Empty List)")
        pcontrol.proxy = control.proxy = proxy

        layout = self._list_pane.layout()
        layout.addWidget(control, 0, 1)
        layout.addWidget(pcontrol, 0, 0)

    def get_info(self):
        """ Returns the associated object list and current item index.
        """
        proxy = self._cur_control.proxy
        return (proxy.list, proxy.index)

    def popup_empty_menu(self, index):
        """ Displays the empty list editor popup menu.
        """
        self._cur_control = control = self.buttons[index]
        menu = MakeMenu(self.empty_list_menu, self, True, control).menu
        menu.exec_(control.mapToGlobal(QtCore.QPoint(4, 24)))

    def popup_menu(self, index):
        """ Displays the list editor popup menu.
        """
        self._cur_control = sender = self.buttons[index]

        proxy = sender.proxy
        menu = MakeMenu(self.list_menu, self, True, sender).menu
        len_list = len(proxy.list)
        not_full = len_list < self._trait_handler.maxlen

        self._menu_before.enabled(not_full)
        self._menu_after.enabled(not_full)
        self._menu_delete.enabled(len_list > self._trait_handler.minlen)
        self._menu_up.enabled(index > 0)
        self._menu_top.enabled(index > 0)
        self._menu_down.enabled(index < (len_list - 1))
        self._menu_bottom.enabled(index < (len_list - 1))

        menu.exec_(sender.mapToGlobal(QtCore.QPoint(4, 24)))

    def add_item(self, offset):
        """ Adds a new value at the specified list index.
        """
        list, index = self.get_info()
        index += offset
        item_trait = self._trait_handler.item_trait
        if self.factory.item_factory:
            value = self.factory.item_factory(
                *self.factory.item_factory_args,
                **self.factory.item_factory_kwargs
            )
        else:
            value = item_trait.default_value_for(self.object, self.name)
        try:
            self.value = list[:index] + [value] + list[index:]
        # if the default new item is invalid, we just don't add it to the list.
        # traits will still give an error message, but we don't want to crash
        except TraitError:
            from traitsui.api import raise_to_debug
            raise_to_debug()
        self.update_editor()

    def add_before(self):
        """ Inserts a new item before the current item.
        """
        self.add_item(0)

    def add_after(self):
        """ Inserts a new item after the current item.
        """
        self.add_item(1)

    def add_empty(self):
        """ Adds a new item when the list is empty.
        """
        list, index = self.get_info()
        self.add_item(0)

    def delete_item(self):
        """ Delete the current item.
        """
        list, index = self.get_info()
        self.value = list[:index] + list[index + 1 :]
        self.update_editor()

    def move_up(self):
        """ Move the current item up one in the list.
        """
        list, index = self.get_info()
        self.value = (
            list[: index - 1]
            + [list[index], list[index - 1]]
            + list[index + 1 :]
        )
        self.update_editor()

    def move_down(self):
        """ Moves the current item down one in the list.
        """
        list, index = self.get_info()
        self.value = (
            list[:index] + [list[index + 1], list[index]] + list[index + 2 :]
        )
        self.update_editor()

    def move_top(self):
        """ Moves the current item to the top of the list.
        """
        list, index = self.get_info()
        self.value = [list[index]] + list[:index] + list[index + 1 :]
        self.update_editor()

    def move_bottom(self):
        """ Moves the current item to the bottom of the list.
        """
        list, index = self.get_info()
        self.value = list[:index] + list[index + 1 :] + [list[index]]
        self.update_editor()

    # -- Private Methods ------------------------------------------------------

    def _dispose_items(self):
        """ Disposes of each current list item.
        """
        layout = self._list_pane.layout()
        child = layout.takeAt(0)
        while child is not None:
            control = child.widget()
            if control is not None:
                editor = getattr(control, "_editor", None)
                if editor is not None:
                    editor.dispose()
                    editor.control = None
                control.deleteLater()
            child = layout.takeAt(0)
        del child

    # -- Trait initializers ----------------------------------------------------

    def _kind_default(self):
        """ Returns a default value for the 'kind' trait.
        """
        return self.factory.style + "_editor"

    def _mutable_default(self):
        """ Trait handler to set the mutable trait from the factory.
        """
        return self.factory.mutable

    def _scrollable_default(self):
        return self.factory.scrollable

class CustomEditor(SimpleEditor):
    """ Custom style of editor for lists, which displays the items as a series
    of text fields. If the list is editable, an icon next to each item displays
    a menu of operations on the list.
    """

    # -------------------------------------------------------------------------
    #  Class constants:
    # -------------------------------------------------------------------------

    #: Whether the list is displayed in a single row. This value overrides the
    #: default.
    single_row = False


class TextEditor(CustomEditor):

    #: The kind of editor to create for each list item. This value overrides the
    #: default.
    kind = "text_editor"


class ReadonlyEditor(CustomEditor):

    #: Is the list of items being edited mutable? This value overrides the
    #: default.
    mutable = False


class NotebookEditor(Editor):
    """ An editor for lists that displays the list as a "notebook" of tabbed
    pages.
    """

    #: The "Close Tab" button.
    close_button = Any()

    #: Maps tab names to QWidgets representing the tab contents
    #: TODO: It would be nice to be able to reuse self._pages for this, but
    #: its keys are not quite what we want.
    _pagewidgets = Dict()

    #: Maps names of tabs to their menu QAction instances; used to toggle
    #: checkboxes
    _action_dict = Dict()

    # -------------------------------------------------------------------------
    #  Trait definitions:
    # -------------------------------------------------------------------------

    #: Is the notebook editor scrollable? This values overrides the default:
    scrollable = True

    #: The currently selected notebook page object:
    selected = Any()

    def init(self, parent):
        """ Finishes initializing the editor by creating the underlying toolkit
            widget.
        """
        self._uis = []

        # Create a tab widget to hold each separate object's view:
        self.control = QtGui.QTabWidget()
        self.control.currentChanged.connect(self._tab_activated)

        # minimal dock_style handling
        if self.factory.dock_style == "tab":
            self.control.setDocumentMode(True)
            self.control.tabBar().setDocumentMode(True)
        elif self.factory.dock_style == "vertical":
            self.control.setTabPosition(QtGui.QTabWidget.West)

        # Create the button to close tabs, if necessary:
        if self.factory.deletable:
            button = QtGui.QToolButton()
            button.setAutoRaise(True)
            button.setToolTip("Remove current tab ")
            button.setIcon(ImageResource("closetab").create_icon())

            self.control.setCornerWidget(button, QtCore.Qt.TopRightCorner)
            button.clicked.connect(self.close_current)
            self.close_button = button

        if self.factory.show_notebook_menu:
            # Create the necessary attributes to manage hiding and revealing of
            # tabs via a context menu
            self._context_menu = QtGui.QMenu()
            self.control.customContextMenuRequested.connect(
                self._context_menu_requested
            )
            self.control.setContextMenuPolicy(QtCore.Qt.CustomContextMenu)

        # Set up the additional 'list items changed' event handler needed for
        # a list based trait. Note that we want to fire the update_editor_item
        # only when the items in the list change and not when intermediate
        # traits change. Therefore, replace "." by ":" in the extended_name
        # when setting up the listener.
        extended_name = self.extended_name.replace(".", ":")
        self.context_object.on_trait_change(
            self.update_editor_item, extended_name + "_items?", dispatch="ui"
        )

        # Set of selection synchronization:
        self.sync_value(self.factory.selected, "selected")

    def update_editor(self):
        """ Updates the editor when the object trait changes externally to the
            editor.
        """
        # Destroy the views on each current notebook page:
        self.close_all()

        # Create a tab page for each object in the trait's value:
        for object in self.value:
            ui, view_object, monitoring = self._create_page(object)

            # Remember the page for later deletion processing:
            self._uis.append([ui.control, ui, view_object, monitoring])

        if self.selected:
            self._selected_changed(self.selected)

    def update_editor_item(self, event):
        """ Handles an update to some subset of the trait's list.
        """
        index = event.index

        # Delete the page corresponding to each removed item:
        page_name = self.factory.page_name[1:]

        for i in event.removed:
            page, ui, view_object, monitoring = self._uis[index]
            if monitoring:
                view_object.on_trait_change(
                    self.update_page_name, page_name, remove=True
                )
            ui.dispose()
            self.control.removeTab(self.control.indexOf(page))

            if self.factory.show_notebook_menu:
                for name, tmp in self._pagewidgets.items():
                    if tmp is page:
                        del self._pagewidgets[name]
                self._context_menu.removeAction(self._action_dict[name])
                del self._action_dict[name]

            del self._uis[index]

        # Add a page for each added object:
        first_page = None
        for object in event.added:
            ui, view_object, monitoring = self._create_page(object)
            self._uis[index:index] = [
                [ui.control, ui, view_object, monitoring]
            ]
            index += 1

            if first_page is None:
                first_page = ui.control

        if first_page is not None:
            self.control.setCurrentWidget(first_page)

    def close_current(self, force=False):
        """ Closes the currently selected tab:
        """
        widget = self.control.currentWidget()
        for i in range(len(self._uis)):
            page, ui, _, _ = self._uis[i]
            if page is widget:
                if force or ui.handler.close(ui.info, True):
                    del self.value[i]
                break

        if self.factory.show_notebook_menu:
            # Find the name associated with this widget, so we can purge its action
            # from the menu
            for name, tmp in self._pagewidgets.items():
                if tmp is widget:
                    break
            else:
                # Hmm... couldn't find the widget, assume that we don't need to do
                # anything.
                return

            action = self._action_dict[name]
            self._context_menu.removeAction(action)
            del self._action_dict[name]
            del self._pagewidgets[name]
        return

    def close_all(self):
        """ Closes all currently open notebook pages.
        """
        page_name = self.factory.page_name[1:]

        for _, ui, view_object, monitoring in self._uis:
            if monitoring:
                view_object.on_trait_change(
                    self.update_page_name, page_name, remove=True
                )
            ui.dispose()

        # Reset the list of ui's and dictionary of page name counts:
        self._uis = []
        self._pages = {}

        self.control.clear()

    def dispose(self):
        """ Disposes of the contents of an editor.
        """
        self.context_object.on_trait_change(
            self.update_editor_item, self.name + "_items?", remove=True
        )
        self.close_all()

        super().dispose()

    def update_page_name(self, object, name, old, new):
        """ Handles the trait defining a particular page's name being changed.
        """
        for i, value in enumerate(self._uis):
            page, ui, _, _ = value
            if object is ui.info.object:
                name = None
                handler = getattr(
                    self.ui.handler,
                    "%s_%s_page_name" % (self.object_name, self.name),
                    None,
                )

                if handler is not None:
                    name = handler(self.ui.info, object)

                if name is None:
                    name = str(
                        xgetattr(object, self.factory.page_name[1:], "???")
                    )
                self.control.setTabText(self.control.indexOf(page), name)
                break

    def _create_page(self, object):
        # Create the view for the object:
        view_object = object
        factory = self.factory
        if factory.factory is not None:
            view_object = factory.factory(object)
        ui = view_object.edit_traits(
            parent=self.control, view=factory.view, kind=factory.ui_kind
        ).trait_set(parent=self.ui)

        # Get the name of the page being added to the notebook:
        name = ""
        monitoring = False
        prefix = "%s_%s_page_" % (self.object_name, self.name)
        page_name = factory.page_name
        if page_name[0:1] == ".":
            name = xgetattr(view_object, page_name[1:], None)
            monitoring = name is not None
            if monitoring:
                handler_name = None
                method = getattr(self.ui.handler, prefix + "name", None)
                if method is not None:
                    handler_name = method(self.ui.info, object)
                if handler_name is not None:
                    name = handler_name
                else:
                    name = str(name) or "???"
                view_object.on_trait_change(
                    self.update_page_name, page_name[1:], dispatch="ui"
                )
            else:
                name = ""
        elif page_name != "":
            name = page_name

        if name == "":
            name = user_name_for(view_object.__class__.__name__)

        # Make sure the name is not a duplicate:
        if not monitoring:
            self._pages[name] = count = self._pages.get(name, 0) + 1
            if count > 1:
                name += " %d" % count

        # Return the control for the ui, and whether or not its name is being
        # monitored:
        image = None
        method = getattr(self.ui.handler, prefix + "image", None)
        if method is not None:
            image = method(self.ui.info, object)

        if image is None:
            self.control.addTab(ui.control, name)
        else:
            self.control.addTab(ui.control, image, name)

        if self.factory.show_notebook_menu:
            newaction = self._context_menu.addAction(name)
            newaction.setText(name)
            newaction.setCheckable(True)
            newaction.setChecked(True)
            newaction.triggered.connect(
                lambda e, name=name: self._menu_action(e, name=name)
            )
            self._action_dict[name] = newaction
            self._pagewidgets[name] = ui.control

        return (ui, view_object, monitoring)

    def _tab_activated(self, idx):
        """ Handles a notebook tab being "activated" (i.e. clicked on) by the
            user.
        """
        widget = self.control.widget(idx)
        for page, ui, _, _ in self._uis:
            if page is widget:
                self.selected = ui.info.object
                break

    def _selected_changed(self, selected):
        """ Handles the **selected** trait being changed.
        """
        for page, ui, _, _ in self._uis:
            if ui.info and selected is ui.info.object:
                self.control.setCurrentWidget(page)
                break
            deletable = self.factory.deletable
            deletable_trait = self.factory.deletable_trait
            if deletable and deletable_trait:
                enabled = xgetattr(selected, deletable_trait, True)
                self.close_button.setEnabled(enabled)

    def _context_menu_requested(self, event):
        self._context_menu.popup(self.control.mapToGlobal(event))

    def _menu_action(self, event, name=""):
        """ Qt signal handler for when a item in a context menu is actually
        selected.  Not that we get this even after the underlying value has
        already changed.
        """
        action = self._action_dict[name]
        checked = action.isChecked()
        if not checked:
            for ndx in range(self.control.count()):
                if self.control.tabText(ndx) == name:
                    self.control.removeTab(ndx)
        else:
            # TODO: Fix tab order based on the context_object's list
            self.control.addTab(self._pagewidgets[name], name)