# This file is part of MyPaint.
# -*- coding: utf-8 -*-
# Copyright (C) 2007-2013 by Martin Renold <martinxyz@gmx.ch>
# Copyright (C) 2013-2018 by the MyPaint Development Team.
#
# 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.


## Imports

from __future__ import division, print_function

# Know now that these are the rules of import.
# That we live by, by which we abide.
#
# Rule 1. You will not import mypaintlib before GTK and GLib.
# Rule 2. You **WILL NOT** import mypaintlib before GTK and GLib.
# Rule 2a. Not even to make the error message pretty in main.py or the
#          launch script.
# Rule 3. See rules 1 and 2.
# Rule 4. It's nice to divide the imports into blocks separated by
#         blank lines. Standard Python libs, then 3rd-party, then ours.

# Why the strict order for GLib/mypaintlib? For one thing, icon
# searching breaks unless Gtk is imported before mypaintlib on MSYS2's
# Windows-x86_64 (but not Windows-i686 or Linux-anything - go figure). I
# guess GTK is caching something internally, like GLib's g_get_*_dir()
# stuff, but wtf is libmypaint doing to break those?

import os
import sys
from os.path import join
from collections import namedtuple
import logging
import json

from gi.repository import GObject
from gi.repository import Gtk
from gi.repository import Gdk
from gi.repository import GdkPixbuf
from gi.repository import GLib
from gettext import gettext as _

import lib.observable
import lib.cache
import lib.document
from lib import brush
from lib import helpers
from lib import mypaintlib
from lib import brushsettings
import gui.compatibility as compat
import gui.device
from . import filehandling
from . import keyboard
from . import brushmanager
from . import document
from . import tileddrawwidget
from . import workspace  # noqa: F401
from . import topbar  # noqa: F401
from . import drawwindow  # noqa: F401
from . import backgroundwindow
from . import preferenceswindow
from . import brusheditor
from . import layerswindow  # noqa: F401
from . import previewwindow  # noqa: F401
from . import optionspanel  # noqa: F401
from . import framewindow  # noqa: F401
from . import scratchwindow  # noqa: F401
from . import inputtestwindow
from . import brushiconeditor
from . import history  # noqa: F401
from . import colortools  # noqa: F401
from . import brushmodifier
from . import blendmodehandler
from . import toolbar  # noqa: F401
from . import linemode
from . import colors  # noqa: F401
from . import colorpreview  # noqa: F401
from . import fill  # noqa: F401
from . import accelmap  # noqa: F401
from .brushcolor import BrushColorManager
from .overlays import LastPaintPosOverlay  # noqa: F401
from .overlays import ScaleOverlay  # noqa: F401
from .buttonmap import ButtonMapping
import lib.config
import lib.glib
import gui.cursor
import lib.fileutils
import gui.picker
import gui.userconfig
import gui.factoryaction  # registration only
import gui.autorecover
import lib.xml
import gui.profiling
from lib.pycompat import unicode

logger = logging.getLogger(__name__)

## Utility methods


def get_app():
    """Returns the `gui.application.Application` singleton object."""
    # Define this up front: gui.* requires the singleton object pretty much
    # everywhere, and the app instance carries them as members.
    return Application._INSTANCE


def _init_icons(icon_path, default_icon='org.mypaint.MyPaint'):
    """Set the icon theme search path, and GTK default window icon"""
    # Default location for our icons. The user's theme can override these.
    icon_theme = Gtk.IconTheme.get_default()
    icon_theme.append_search_path(icon_path)
    # Ensure that MyPaint has its icons.
    # Test a sample symbolic icon to make sure librsvg is installed and
    # GdkPixbuf's loader cache has been informed about it.
    icons_missing = False
    icon_tests = [
        (
            default_icon,
            "check that mypaint icons have been installed "
            "into {}".format(icon_path),
        ), (
            "mypaint-brush-symbolic",
            "check that librsvg is installed, and update loaders.cache",
        ),
    ]
    for icon_name, missing_msg in icon_tests:
        try:
            icon_theme.load_icon(icon_name, 32, 0)
        except Exception:
            logger.exception("Missing icon %r: %s", icon_name, missing_msg)
            icons_missing = True
    if icons_missing:
        logger.critical("Required icon(s) missing")
        logger.error('Icon search path: %r', icon_theme.get_search_path())
        logger.error(
            "MyPaint can't run sensibly without its icons; "
            "please check your installation. See "
            "https://github.com/mypaint/mypaint/wiki/FAQ-Missing-icons "
            "for possible solutions."
        )
        sys.exit(1)
    # Default icon for all windows
    Gtk.Window.set_default_icon_name(default_icon)


## Class definitions

_STATEDIRS_FIELDS = (
    "app_data",
    "app_icons",
    "user_data",
    "user_config",
)


class StateDirs (namedtuple("StateDirs", _STATEDIRS_FIELDS)):
    """Where MyPaint stores its config, read-only data etc.

    This caches some special paths that will never change for the
    lifetime of the application. An instance resides in the main
    Application object as `app.state_dirs`.

    :ivar unicode app_data:
        App-specific read-only data area.
        Path used for UI definition XML, and the default sets of
        backgrounds, palettes, and brush definitions.
        Often $PREFIX/share/.
    :ivar unicode app_icons:
        Extra search path for read-only themeable UI icons.
        This will be used in addition to $XDG_DATA_DIRS for the purposes of
        icon lookup. Normally it's $PREFIX/share/icons.
    :ivar unicode user_data:
        Read-write location of the user's app-specific data.
        For MyPaint, this means the user's brushes, backgrounds, and
        scratchpads. Commonly $XDG_DATA_HOME/mypaint, i.e.
        ~/.local/share/mypaint
    :ivar unicode user_config:
        Location of the user's app-specific config area.
        This is where MyPaint will save user preferences data and the
        keyboard accelerator map.
        Commonly $XDG_CONFIG_HOME/mypaint, i.e. ~/.config/mypaint

    """


class Application (object):
    """Main application singleton.

    This class serves as a global container for everything that needs
    to be shared in the GUI. Its constructor is the last part of the
    initialization, called by main.py or by the testing scripts.

    Access via `gui.application.get_app()`.

    """

    #: Singleton instance
    _INSTANCE = None

    def __init__(self, filenames, state_dirs, version, fullscreen=False):
        """Construct, but do not run.

        :param list filenames: The list of files to load (unicode required)
        :param StateDirs state_dirs: static special paths.
        :param unicode version: Version string for the about dialog.
        :param bool fullscreen: Go fullscreen after starting.

        Only the first filename listed will be loaded. If no files are
        listed, the autosave recovery dialog may be shown when the
        application starts up.

        """
        assert Application._INSTANCE is None
        super(Application, self).__init__()
        Application._INSTANCE = self

        self.state_dirs = state_dirs  #: Static special paths: see StateDirs

        self.version = version  #: version string for the app.

        # Create the user's config directory and any needed R/W data
        # storage areas.
        for basedir in [state_dirs.user_config, state_dirs.user_data]:
            if not os.path.isdir(basedir):
                os.makedirs(basedir)
                logger.info('Created basedir %r', basedir)
        for datasubdir in [u'backgrounds', u'brushes', u'scratchpads']:
            datadir = os.path.join(state_dirs.user_data, datasubdir)
            if not os.path.isdir(datadir):
                os.mkdir(datadir)
                logger.info('Created data subdir %r', datadir)

        _init_icons(state_dirs.app_icons)

        # Core actions and menu structure
        ui_dir = os.path.dirname(os.path.abspath(__file__))
        resources_xml = join(ui_dir, "resources.xml")
        self.builder = Gtk.Builder()
        self.builder.set_translation_domain("mypaint")
        self.builder.add_from_file(resources_xml)

        self.ui_manager = self.builder.get_object("app_ui_manager")
        signal_callback_objs = [self]

        Gdk.set_program_class('MyPaint')

        self.pixmaps = PixbufDirectory(join(state_dirs.app_data, u'pixmaps'))
        self.cursor_color_picker = Gdk.Cursor.new_from_pixbuf(
            Gdk.Display.get_default(),
            self.pixmaps.cursor_color_picker,
            3, 15,
        )
        self.cursor_color_picker_h = Gdk.Cursor.new_from_pixbuf(
            Gdk.Display.get_default(),
            self.pixmaps.cursor_color_picker_h,
            3, 15,
        )
        self.cursor_color_picker_c = Gdk.Cursor.new_from_pixbuf(
            Gdk.Display.get_default(),
            self.pixmaps.cursor_color_picker_c,
            3, 15,
        )
        self.cursor_color_picker_y = Gdk.Cursor.new_from_pixbuf(
            Gdk.Display.get_default(),
            self.pixmaps.cursor_color_picker_y,
            3, 15,
        )
        self.cursors = gui.cursor.CustomCursorMaker(self)

        # App-level settings
        self._preferences = lib.observable.ObservableDict()
        self.load_settings()

        # Set up compatibility mode (most of it)
        self.compat_mode = None
        self.reset_compat_mode(update=False)
        compat.update_default_layer_type(self)

        # Unmanaged main brush.
        # Always the same instance (we can attach settings_observers).
        # This brush is where temporary changes (color, size...) happen.
        self.brush = brush.BrushInfo()
        self.brush.load_defaults()

        # Global pressure mapping function, ignored unless set
        self.pressure_mapping = None

        # Fake inputs to send when using a mouse.  Adjustable
        # via slider and/or hotkeys
        self.fakepressure = 0.5
        self.fakerotation = 0.5

        # Keyboard manager
        self.kbm = keyboard.KeyboardManager(self)

        # File I/O
        self.filehandler = filehandling.FileHandler(self)

        # Picking grabs
        self.context_grab = gui.picker.ContextPickingGrabPresenter()
        self.context_grab.app = self
        self.color_grab = gui.picker.ColorPickingGrabPresenter()
        self.color_grab.app = self

        # Load the main interface
        mypaint_main_xml = join(ui_dir, "mypaint.glade")
        self.builder.add_from_file(mypaint_main_xml)

        # Main drawing window
        self.drawWindow = self.builder.get_object("drawwindow")
        signal_callback_objs.append(self.drawWindow)

        # Workspace widget. Manages layout of toolwindows, and autohide in
        # fullscreen.
        wkspace = self.builder.get_object("app_workspace")
        wkspace.build_from_layout(self.preferences["workspace.layout"])
        wkspace.floating_window_created += self._floating_window_created_cb
        fs_autohide_action = self.builder.get_object("FullscreenAutohide")
        fs_autohide_action.set_active(wkspace.autohide_enabled)
        self.workspace = wkspace

        # Working document: viewer widget
        app_canvas = self.builder.get_object("app_canvas")

        # Working document: model and controller
        cache_size = self.preferences.get(
            'ui.rendered_tile_cache_size', lib.cache.DEFAULT_CACHE_SIZE
        )
        model = lib.document.Document(self.brush, cache_size=cache_size)
        self.doc = document.Document(self, app_canvas, model)
        app_canvas.set_model(model)

        signal_callback_objs.append(self.doc)
        signal_callback_objs.append(self.doc.modes)

        self.scratchpad_filename = ""
        scratchpad_model = lib.document.Document(
            self.brush, painting_only=True,
            cache_size=lib.cache.DEFAULT_CACHE_SIZE/4
        )
        scratchpad_tdw = tileddrawwidget.TiledDrawWidget()
        scratchpad_tdw.scroll_on_allocate = False
        scratchpad_tdw.set_model(scratchpad_model)
        self.scratchpad_doc = document.Document(self, scratchpad_tdw,
                                                scratchpad_model)

        self.brushmanager = brushmanager.BrushManager(
            lib.config.mypaint_brushdir,
            join(self.state_dirs.user_data, 'brushes'),
            self,
        )

        signal_callback_objs.append(self.filehandler)
        self.brushmodifier = brushmodifier.BrushModifier(self)
        signal_callback_objs.append(self.brushmodifier)
        self.blendmodemanager = blendmodehandler.BlendModeManager(self)
        signal_callback_objs.append(self.blendmodemanager)
        self.blendmodemanager.register(self.brushmodifier.bm)

        self.line_mode_settings = linemode.LineModeSettings(self)

        # Button press mapping
        self.button_mapping = ButtonMapping()

        # Monitors pluggings and uses of input device, configures them,
        # and switches between device-specific brushes.
        self.device_monitor = gui.device.Monitor(self)

        if not self.preferences.get("scratchpad.last_opened_scratchpad", None):
            self.preferences["scratchpad.last_opened_scratchpad"] \
                = self.filehandler.get_scratchpad_autosave()
        self.scratchpad_filename \
            = self.preferences["scratchpad.last_opened_scratchpad"]

        self.brush_color_manager = BrushColorManager(self)
        self.brush_color_manager.set_picker_cursor(self.cursor_color_picker)
        self.brush_color_manager.set_data_path(self.datapath)

        #: Mapping of setting cname to a GtkAdjustment which controls the base
        #: value of that setting for the app's current brush.
        self.brush_adjustment = {}
        self.init_brush_adjustments()
        # Extend with some fake inputs that act kind of like brush settings
        self.fake_adjustment = {}

        # Connect signals defined in resources.xml
        callback_finder = CallbackFinder(signal_callback_objs)
        self.builder.connect_signals(callback_finder)

        self.kbm.start_listening()
        self.filehandler.doc = self.doc
        self.filehandler.filename = None
        Gtk.AccelMap.load(join(self.user_confpath, 'accelmap.conf'))

        # Load the default background image
        self.doc.reset_background()

        # Non-dockable subwindows
        # Loading is deferred as late as possible
        self._subwindow_classes = {
            # action-name: action-class
            "BackgroundWindow": backgroundwindow.BackgroundWindow,
            "BrushEditorWindow": brusheditor.BrushEditorWindow,
            "PreferencesWindow": preferenceswindow.PreferencesWindow,
            "InputTestWindow": inputtestwindow.InputTestWindow,
            "BrushIconEditorWindow": brushiconeditor.BrushIconEditorWindow,
        }
        self._subwindows = {}

        # Statusbar init
        statusbar = self.builder.get_object("app_statusbar")
        self.statusbar = statusbar
        context_id = statusbar.get_context_id("transient-message")
        self._transient_msg_context_id = context_id
        self._transient_msg_remove_timeout_id = None

        # Profiling & debug stuff
        self.profiler = gui.profiling.Profiler()

        # Show main UI.
        self.drawWindow.show_all()
        GLib.idle_add(self._at_application_start, filenames, fullscreen)

    @property
    def preferences(self):
        """Application-level settings, as an observable dict object.

        :rtype: lib.observable.ObservableDict

        """
        return self._preferences

    def _at_application_start(self, filenames, fullscreen):
        col = self.brush_color_manager.get_color()
        self.brushmanager.select_initial_brush()
        self.brush_color_manager.set_color(col)

        # Complete the compatibility mode setup
        compat.update_default_pigment_setting(self)

        if filenames:
            # Open only the first file, no matter how many has been specified
            # If the file does not exist just set it as the file to save to
            fn = filenames[0]
            if not os.path.exists(fn):
                self.filehandler.filename = fn
            else:
                self.filehandler.open_file(fn)

        # Load last scratchpad
        sp_autosave_key = "scratchpad.last_opened_scratchpad"
        autosave_name = self.preferences[sp_autosave_key]
        if not autosave_name:
            autosave_name = self.filehandler.get_scratchpad_autosave()
            self.preferences[sp_autosave_key] = autosave_name
            self.scratchpad_filename = autosave_name
        if os.path.isfile(autosave_name):
            try:
                self.filehandler.open_scratchpad(autosave_name)
            except AttributeError:
                pass

        self.apply_settings()
        self.drawWindow.present()

        # Handle fullscreen command line option
        if fullscreen:
            self.drawWindow.fullscreen_cb()

        if not filenames:
            autosave_recovery = gui.autorecover.Presenter(self)
            autosave_recovery.run(startup=True)

    def save_settings(self):
        """Saves the current settings to persistent storage."""
        self.brushmanager.save_brushes_for_devices()
        self.brushmanager.save_brush_history()
        self.filehandler.save_scratchpad(self.scratchpad_filename)
        settingspath = join(self.user_confpath, u'settings.json')
        logger.debug("Writing app settings to %r", settingspath)
        json_data = json.dumps(self.preferences, indent=2)
        if isinstance(json_data, unicode):
            # Py3. Let's write UTF-8 bytes, just like the stuff Py2's
            # json.dumps() with a default encoding arg does.
            json_data = json_data.encode("utf-8")
        assert isinstance(json_data, bytes)
        with open(settingspath, 'wb') as f:
            f.write(json_data)

    def apply_settings(self):
        """Applies the current settings.

        Called at startup and from the prefs dialog.
        """
        self._apply_pressure_mapping_settings()
        self._apply_button_mapping_settings()
        self._apply_autosave_settings()
        self.preferences_window.update_ui()

    def load_settings(self):
        """Loads the settings from persistent storage.

        Uses defaults if not explicitly configured.

        """
        default_config = gui.userconfig.default_configuration()
        self.preferences.clear()
        self.preferences.update(default_config.copy())
        user_config = gui.userconfig.get_json_config(self.user_confpath)
        self.preferences.update(user_config)
        key = "input.button_mapping"
        if 'ColorPickerPopup' in self.preferences[key].values():
            # old config file; users who never assigned any buttons would
            # end up with Ctrl-Click color picker broken after upgrade
            self.preferences[key] = default_config[key]

    def reset_compat_mode(self, update=True):
        """Reset compatibility mode to configured default"""
        compat.set_compat_mode(
            self, self.preferences[compat.DEFAULT_COMPAT], update=update)

    def add_action_group(self, ag):
        self.ui_manager.insert_action_group(ag, -1)

    def find_action(self, name):
        for ag in self.ui_manager.get_action_groups():
            result = ag.get_action(name)
            if result is not None:
                return result

    ## Brush settings: GtkAdjustments for base values

    def init_brush_adjustments(self):
        """Initializes the base value adjustments for all brush settings"""
        assert not self.brush_adjustment
        changed_cb = self._brush_adjustment_value_changed_cb
        for s in brushsettings.settings_visible:
            adj = Gtk.Adjustment(value=s.default, lower=s.min, upper=s.max,
                                 step_increment=0.01, page_increment=0.1)
            self.brush_adjustment[s.cname] = adj
            adj.connect("value-changed", changed_cb, s.cname)
        self.brush.observers.append(self._brush_modified_cb)

    def _brush_adjustment_value_changed_cb(self, adj, cname):
        """Updates a brush setting when the user tweaks it using a scale"""
        newvalue = adj.get_value()
        if self.brush.get_base_value(cname) != newvalue:
            self.brush.set_base_value(cname, newvalue)

    def _brush_modified_cb(self, settings):
        """Updates the brush's base setting adjustments on brush changes"""
        for cname in settings:
            adj = self.brush_adjustment.get(cname, None)
            if adj is None:
                continue
            value = self.brush.get_base_value(cname)
            adj.set_value(value)

    ## Button mappings, global pressure curve

    def _apply_button_mapping_settings(self):
        self.button_mapping.update(self.preferences["input.button_mapping"])

    def _apply_pressure_mapping_settings(self):
        p = self.preferences['input.global_pressure_mapping']
        if len(p) == 2 and abs(p[0][1]-1.0)+abs(p[1][1]-0.0) < 0.0001:
            # 1:1 mapping (mapping disabled)
            self.pressure_mapping = None
        else:
            # This mapping is still required for certain problematic hw
            # See https://github.com/mypaint/mypaint/issues/275
            m = mypaintlib.MappingWrapper(1)
            m.set_n(0, len(p))
            for i, (x, y) in enumerate(p):
                m.set_point(0, i, x, 1.0-y)

            def mapping(pressure):
                return m.calculate_single_input(pressure)
            self.pressure_mapping = mapping

    def _apply_autosave_settings(self):
        active = self.preferences["document.autosave_backups"]
        interval = self.preferences["document.autosave_interval"]
        logger.debug(
            "Applying autosave settings: active=%r, interval=%r",
            active, interval,
        )
        model = self.doc.model
        model.autosave_backups = active
        model.autosave_interval = interval

    def save_gui_config(self):
        Gtk.AccelMap.save(join(self.user_confpath, 'accelmap.conf'))
        wkspace = self.workspace
        self.preferences["workspace.layout"] = wkspace.get_layout()
        self.save_settings()

    def message_dialog(self, text,
                       secondary_text=None, long_text=None, title=None,
                       investigate_dir=None, investigate_str=None, **kwds):
        """Utility function to show a message/information dialog"""
        d = Gtk.MessageDialog(
            transient_for=self.drawWindow,
            buttons=Gtk.ButtonsType.NONE,
            **kwds
        )
        # Auxiliary actions first...
        if investigate_dir and os.path.isdir(investigate_dir):
            if not investigate_str:
                tmpl = _(u"Open Folder “{folder_basename}”…")
                investigate_str = tmpl.format(
                    folder_basename = os.path.basename(investigate_dir),
                )
            d.add_button(investigate_str, -1)
        # ... so that the main actions end up in the bottom-right of the
        # dialog (reversed for rtl scripts), where the eye ends up
        # naturally at the end of the flow.
        d.add_button(_("OK"), Gtk.ResponseType.OK)
        markup = lib.xml.escape(unicode(text))
        d.set_markup(markup)
        if title is not None:
            d.set_title(unicode(title))
        if secondary_text is not None:
            secondary_markup = lib.xml.escape(unicode(secondary_text))
            d.format_secondary_markup(secondary_markup)
        if long_text is not None:
            buf = Gtk.TextBuffer()
            buf.set_text(unicode(long_text))
            tv = Gtk.TextView.new_with_buffer(buf)
            tv.show()
            tv.set_editable(False)
            tv.set_wrap_mode(Gtk.WrapMode.WORD_CHAR)
            scrolls = Gtk.ScrolledWindow()
            scrolls.show()
            scrolls.set_policy(Gtk.PolicyType.AUTOMATIC, Gtk.PolicyType.ALWAYS)
            scrolls.add(tv)
            scrolls.set_size_request(-1, 300)
            scrolls.set_shadow_type(Gtk.ShadowType.IN)
            d.get_message_area().pack_start(scrolls, True, True, 0)
        response = d.run()
        d.destroy()
        if response == -1:
            lib.fileutils.startfile(investigate_dir, "open")

    def show_transient_message(self, text, seconds=5):
        """Display a brief, impermanent status message"""
        context_id = self._transient_msg_context_id
        self.statusbar.remove_all(context_id)
        self.statusbar.push(context_id, unicode(text))
        timeout_id = self._transient_msg_remove_timeout_id
        if timeout_id is not None:
            GLib.source_remove(timeout_id)
        timeout_id = GLib.timeout_add_seconds(
            interval=seconds,
            function=self._transient_msg_remove_timer_cb,
        )
        self._transient_msg_remove_timeout_id = timeout_id

    def _transient_msg_remove_timer_cb(self, *_ignored):
        context_id = self._transient_msg_context_id
        self.statusbar.remove_all(context_id)
        self._transient_msg_remove_timeout_id = None
        return False

    ## Subwindows

    @property
    def background_window(self):
        """The background switcher subwindow."""
        return self.get_subwindow("BackgroundWindow")

    @property
    def brush_settings_window(self):
        """The brush settings editor subwindow."""
        return self.get_subwindow("BrushEditorWindow")

    @property
    def brush_icon_editor_window(self):
        """The brush icon editor subwindow."""
        return self.get_subwindow("BrushIconEditorWindow")

    @property
    def brush_editor_window(self):
        """The brush editor subwindow."""
        return self.get_subwindow("BrushEditorWindow")

    @property
    def preferences_window(self):
        """The preferences subwindow."""
        return self.get_subwindow("PreferencesWindow")

    @property
    def input_test_window(self):
        """The input test window."""
        return self.get_subwindow("InputTestWindow")

    def get_subwindow(self, name):
        """Get a subwindow by its name."""
        if name in self._subwindows:
            window = self._subwindows[name]
        elif name in self._subwindow_classes:
            window_class = self._subwindow_classes[name]
            window = window_class()
            window.__toggle_action = self.find_action(name)
            window.connect("hide", self._subwindow_hide_cb)
            self._subwindows[name] = window
        else:
            raise ValueError("Unknown subwindow %r" % name)
        return window

    def has_subwindow(self, name):
        """True if the named subwindow is known."""
        return name in self._subwindow_classes

    def _subwindow_hide_cb(self, subwindow):
        """Toggles off a subwindow's related action when it's hidden."""
        action = subwindow.__toggle_action
        if action and action.get_active():
            action.set_active(False)

    def autorecover_cb(self, action):
        autosave_recovery = gui.autorecover.Presenter(self)
        autosave_recovery.run(startup=False)

    ## Workspace callbacks

    def _floating_window_created_cb(self, wkspace, floatwin):
        """Adds newly created `workspace.ToolStackWindow`s to the kbm."""
        self.kbm.add_window(floatwin)

    ## Stroke loading support

    # App-wide, while the single painting brush still lives here.

    def restore_brush_from_stroke_info(self, strokeinfo):
        """Restores the app brush from a stroke

        :param strokeinfo: Stroke details from the stroke map
        :type strokeinfo: lib.strokemap.StrokeShape
        """
        mb = brushmanager.ManagedBrush(self.brushmanager)
        mb.brushinfo.load_from_string(strokeinfo.brush_string)
        self.brushmanager.select_brush(mb)
        self.brushmodifier.restore_context_of_selected_brush()

    ## Compatibility properties for special unchanging paths

    @property
    def user_confpath(self):
        """Dir for read/write user configs (prefer app.paths.user_config)."""
        return self.state_dirs.user_config

    @property
    def user_datapath(self):
        """Dir for read/write user data (prefer app.paths.user_data)."""
        return self.state_dirs.user_data

    @property
    def datapath(self):
        """Dir holding read-only app data (prefer app.paths.app_data)."""
        return self.state_dirs.app_data

    ## Profiling and debugging

    def start_profiling_cb(self, action):
        """Starts profiling, or stops it (and tries to show the results)"""
        self.profiler.toggle_profiling()

    def print_memory_leak_cb(self, action):
        helpers.record_memory_leak_status(print_diff=True)

    def run_garbage_collector_cb(self, action):
        helpers.run_garbage_collector()

    def crash_program_cb(self, action):
        """Tests exception handling."""
        raise Exception("This is a crash caused by the user.")


class PixbufDirectory (object):

    def __init__(self, dirname):
        super(PixbufDirectory, self).__init__()
        self.dirname = dirname
        self.cache = {}

    def __getattr__(self, name):
        if name not in self.cache:
            pixbuf_file = join(self.dirname, name + '.png')
            try:
                pixbuf = GdkPixbuf.Pixbuf.new_from_file(pixbuf_file)
            except GObject.GError as e:
                raise AttributeError(str(e))
            self.cache[name] = pixbuf
        return self.cache[name]


class CallbackFinder (object):
    """Finds callbacks amongst a list of objects.

    It's not possible to call `GtkBuilder.connect_signals()` more than once,
    but we use more tnan one backend object. Thus, this little workaround is
    necessary during construction.

    See http://stackoverflow.com/questions/4637792

    """

    def __init__(self, objects):
        super(CallbackFinder, self).__init__()
        self._objs = list(objects)

    def __getattr__(self, name):
        name = str(name)
        found = [getattr(obj, name) for obj in self._objs
                 if hasattr(obj, name)]
        if len(found) == 1:
            return found[0]
        elif len(found) > 1:
            logger.warning("ambiguity: %r resolves to %r", name, found)
            logger.warning("using first match only.")
            return found[0]
        else:
            raise AttributeError(
                "No method named %r was defined on any of %r"
                % (name, self._objs))
