#!/usr/bin/env python3
# -*- coding: utf-8 -*-

# PatchBay Canvas engine using QGraphicsView/Scene
# Copyright (C) 2010-2019 Filipe Coelho <falktx@falktx.com>
# Copyright (C) 2019-2024 Mathieu Picot <picotmathieu@gmail.com>
#
# 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 any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# For a full copy of the GNU General Public License see the doc/GPL.txt file.


# Imports (Globals)
import logging
import time
from typing import Optional

from qtpy.QtCore import (
    Signal, Slot, Qt, QPoint, QPointF, QRectF, QTimer) # type:ignore
from qtpy.QtGui import (
    QCursor, QPixmap, QPolygonF, QBrush, QPainter, QTransform)
from qtpy.QtWidgets import (
    QGraphicsRectItem, QGraphicsScene, QApplication,
    QGraphicsItem, QGraphicsView)

from patshared import PortMode
from .init_values import (
    AliasingReason,
    BoxHidding,
    CanvasItemType,
    GridStyle,
    Joining,
    Direction,
    canvas,
    options,
    Zv,
    MAX_PLUGIN_ID_ALLOWED)
from .box_widget import BoxWidget
from .box_widget_moth import BoxWidgetMoth
from .connectable_widget import ConnectableWidget
from .line_widget import LineWidget
from .grouped_lines_widget import GroupedLinesWidget
from .grid_widget import GridWidget
from .scene_view import PatchGraphicsView
from .utils import boxes_in_dict

_logger = logging.getLogger(__name__)


class RubberbandRect(QGraphicsRectItem):
    '''This class is used by rectangle selection when user
    press mouse button and move to select boxes.'''
    def __init__(self, scene: QGraphicsScene):
        QGraphicsRectItem.__init__(self, QRectF(0, 0, 0, 0))

        self.setZValue(Zv.RUBBERBAND.value)
        self.hide()

        scene.addItem(self)

    def type(self) -> CanvasItemType:
        return CanvasItemType.RUBBERBAND


class MovingBox:
    widget: BoxWidgetMoth
    from_pt: QPointF
    to_pt: QPointF
    final_rect: QRectF
    start_time: float
    is_joining: bool
    is_wrapping: bool
    hidding_state: BoxHidding
    needs_move: bool
    
    def __init__(self, widget: BoxWidgetMoth):
        self.widget = widget
        self.from_pt = QPointF(*widget.top_left())
        self.to_pt = QPointF(*widget.top_left())
        self.final_rect = widget.after_wrap_rect().translated(self.to_pt)
        self.start_time = 0.0
        self.is_joining = False
        self.is_wrapping = False
        self.hidding_state = BoxHidding.NONE
        self.needs_move = False
    
    def is_usefull(self) -> bool:
        if self.needs_move or self.is_wrapping:
            return True
        return self.hidding_state is not BoxHidding.NONE


class SelectingBoxes:
    '''Context for 'with' statment. Used when mutiple boxes are selected.'''
    def __init__(self, scene: 'PatchSceneMoth'):
        self.scene = scene
    
    def __enter__(self):
        self.scene.selecting_boxes = True
        
    def __exit__(self, *args, **kwargs):
        GroupedLinesWidget.reset_z_values_with_selection(
            self.scene.get_selected_boxes())
        self.scene.selecting_boxes = False
 

class PatchSceneMoth(QGraphicsScene):
    " This class is used for the scene. "
    " The child class in scene.py has all things to manage"
    " repulsives boxes."
    scale_changed = Signal(float)
    scene_group_moved = Signal(int, int, QPointF)
    plugin_selected = Signal(list)

    def __init__(self, view: PatchGraphicsView):
        QGraphicsScene.__init__(self)

        self._scale_area = False
        self._mouse_down_init = False
        self._mouse_rubberband = False
        self._mid_button_down = False
        self._pointer_border = QRectF(0.0, 0.0, 1.0, 1.0)
        self._scale_min = 0.1
        self._scale_max = 4.0

        self._rubberband = RubberbandRect(self)
        self._rubberband_selection = False
        self._rubberband_orig_point = QPointF(0, 0)
        self._press_point = QPointF(0, 0)

        self._view = view
        if not self._view:
            _logger.critical("Invalid view")
            return

        self._cursor_cut = None
        self._cursor_zoom_area = None

        self.prevent_box_user_move = False
        '''During view change, this attr must be set to True
        to prevent user to take and move a box.'''
        
        self.move_boxes = dict[BoxWidgetMoth, MovingBox]()
        self._MOVE_DURATION = 0.300 # 300ms
        self._MOVE_TIMER_INTERVAL = 20 # 20 ms step animation (50 Hz)
        self._move_timer_start_at = 0.0
        self._move_timer_last_time = 0.0
        self._move_box_timer = QTimer()
        self._move_box_timer.setInterval(self._MOVE_TIMER_INTERVAL)
        self._move_box_timer.timeout.connect(self.move_boxes_animation)

        self.resizing_scene = False
        self.translating_view = False
        self._last_border_translate = QPointF(0.0, 0.0)

        self._borders_nav_timer = QTimer()
        self._borders_nav_timer.setInterval(50)
        self._borders_nav_timer.timeout.connect(self._cursor_view_navigation)
        self._last_view_cpos = QPointF()
        self._allowed_nav_directions = set[Direction]()

        self.flying_connectable = None

        self.selecting_boxes = False
        '''While selecting multiple boxes, this could take a quite long time
        if there are many box selected, because of itemChange
        in BoxWidgetMoth. If this attribute is True, we can prevent
        actions for each box.
        
        Should be never directly set,
        use 'with SelectingBoxes(self):' instead.'''

        self._selected_boxes = list[BoxWidgetMoth]()
        '''Selected boxes saved here between mouse press event
        and context menu callback. By default with Qt, all items are
        unselected at right click elsewhere.'''

        self._grid_widget: Optional[GridWidget] = None

        self.sceneRectChanged.connect(self.update_grid_widget)
        # self.selectionChanged.connect(self._slot_selection_changed)

    def deplace_boxes_from_repulsers(self, repulser_boxes: list[BoxWidget],
                                     wanted_direction=Direction.NONE,
                                     new_scene_rect=None):
        '''Change the place of boxes in order to have no 
        box overlapping other boxes.'''
        # just for easier syntax, this method is overloaded in scene.py
        # but executed in this file too.
        pass

    def clear(self):
        # reimplement Qt function and fix missing rubberband after clear
        self.move_boxes.clear()
        
        QGraphicsScene.clear(self)
        self._rubberband = RubberbandRect(self)
        self._grid_widget = None
        self.update_theme()

    def clear_selection(self):
        with SelectingBoxes(self):
            self.clearSelection()

    def set_anti_aliasing(self, yesno: bool):
        if self._view is not None:
            self._view.setRenderHint(QPainter.RenderHint.Antialiasing, yesno)

    def screen_position(self, point: QPointF) -> QPoint:
        return self._view.mapToGlobal(self._view.mapFromScene(point))

    def get_device_pixel_ratio_f(self):
        return self._view.devicePixelRatioF()

    def get_scale_factor(self):
        return self._view.transform().m11()

    def fix_scale_factor(self, transform: Optional[QTransform]=None):
        fix, set_view, view = False, False, None

        if not transform:
            set_view = True
            view = self._view
            transform = view.transform()

        scale = transform.m11()
        if scale > self._scale_max:
            fix = True
            transform.reset()
            transform.scale(self._scale_max, self._scale_max)
        elif scale < self._scale_min:
            fix = True
            transform.reset()
            transform.scale(self._scale_min, self._scale_min)

        if set_view:
            if fix and view is not None:
                view.setTransform(transform)
            self.scale_changed.emit(transform.m11())

        return fix

    def _cursor_view_navigation(self):
        ''' This function is called every 50 ms when mouse
            left button is pressed. It moves the view if the mouse cursor
            is near a border of the view (in the limits of the scene size). '''
        # max speed of the drag when mouse is at a side pixel of the view  
        SPEED = 0.8
        
        # Acceleration, doesn't affect max speed
        POWER = 14

        view_width = self._view.width()
        view_height = self._view.height()
        if self._view.verticalScrollBar().isVisible():
            view_width -= self._view.verticalScrollBar().width()
        if self._view.horizontalScrollBar().isVisible():
            view_height -= self._view.horizontalScrollBar().height()
        
        view_cpos = self._view.mapFromGlobal(QCursor.pos())
        scene_cpos = self._view.mapToScene(view_cpos)
        
        # The scene relative area we want to be visible in the view 
        ensure_rect = QRectF(scene_cpos.x() - 1.0,
                             scene_cpos.y() - 1.0,
                             2.0, 2.0)
        
        # the scene relative area currently visible in the view
        vs_rect = QRectF(
            QPointF(self._view.mapToScene(0, 0)),
            QPointF(self._view.mapToScene(view_width - 1, view_height -1)))
        
        # The speed of the move depends on the scene size
        # to allow fast moves from one scene corner to another one.
        speed_hor = (SPEED * (self.sceneRect().width() - vs_rect.width())
                     / vs_rect.width()) 
        speed_ver = (SPEED * (self.sceneRect().height() - vs_rect.height())
                     / vs_rect.height())

        interval_hor = vs_rect.width() / 2
        interval_ver = vs_rect.height() / 2
        
        # Navigation is allowed in a direction only if mouse cursor has
        # already been moved in this direction, in order to prevent unintended
        # moves when user just pressed the mouse button.
        if self._last_view_cpos.isNull():
            self._allowed_nav_directions.clear()
        elif len(self._allowed_nav_directions) < 4:
            if view_cpos.x() < self._last_view_cpos.x():
                self._allowed_nav_directions.add(Direction.LEFT)
            elif view_cpos.x() > self._last_view_cpos.x():
                self._allowed_nav_directions.add(Direction.RIGHT)

            if view_cpos.y() < self._last_view_cpos.y():
                self._allowed_nav_directions.add(Direction.UP)
            elif view_cpos.y() > self._last_view_cpos.y():
                self._allowed_nav_directions.add(Direction.DOWN)

        self._last_view_cpos = view_cpos
        
        # Define the limits we want to see in the view
        # Note that the zone where there is no move is defined by the fact
        # the move in a direction is converted from float to int.
        # This way, a move lower than 1.0 pixel will be ignored.
        # By chance, the lower possible speed is good
        # 1.0 pixel * (1s / 0.050s) = 20 pixels/second. 
        
        apply = False
        
        if (Direction.LEFT in self._allowed_nav_directions
                and scene_cpos.x() < vs_rect.center().x()):
            offset = vs_rect.center().x() - max(scene_cpos.x(), vs_rect.left())
            ratio_x = offset / interval_hor
            move_x = - speed_hor * ((ratio_x ** POWER) * interval_hor)
            left = vs_rect.left() + int(move_x)
            ensure_rect.moveLeft(max(left, self.sceneRect().left()))
            if int(move_x):
                apply = True

        elif (Direction.RIGHT in self._allowed_nav_directions
                and scene_cpos.x() > vs_rect.center().x()):
            offset = min(scene_cpos.x(), vs_rect.right()) - vs_rect.center().x()
            ratio_x = offset / interval_hor
            move_x = speed_hor * ((ratio_x ** POWER) * interval_hor)
            right = vs_rect.right() + int(move_x)
            ensure_rect.moveRight(min(right, self.sceneRect().right()))
            if int(move_x):
                apply = True
            
        if (Direction.UP in self._allowed_nav_directions
                and scene_cpos.y() < vs_rect.center().y()):
            offset = vs_rect.center().y() - max(scene_cpos.y(), vs_rect.top())
            ratio_y = offset / interval_ver
            move_y = - speed_ver * ((ratio_y ** POWER) * interval_ver)
            top = vs_rect.top() + int(move_y)
            ensure_rect.moveTop(max(top, self.sceneRect().top()))
            if int(move_y):
                apply = True
        
        elif (Direction.DOWN in self._allowed_nav_directions
                and scene_cpos.y() > vs_rect.center().y()):
            offset = min(scene_cpos.y(), vs_rect.bottom()) - vs_rect.center().y()
            ratio_y = offset / interval_ver
            move_y = speed_ver * ((ratio_y ** POWER) * interval_ver)
            bottom = vs_rect.bottom() + int(move_y)
            ensure_rect.moveBottom(min(bottom, self.sceneRect().bottom()))
            if int(move_y):
                apply = True
        
        if apply:
            canvas.qobject.start_aliasing_check(
                AliasingReason.NAV_ON_BORDERS)
            self._view.ensureVisible(ensure_rect, 0, 0)

    def _start_navigation_on_borders(self):
        if (options.borders_navigation
                and not self._borders_nav_timer.isActive()):
            self._last_view_cpos = QPointF()
            self._borders_nav_timer.start()

    def fix_temporary_scroll_bars(self):
        if self._view is None:
            return

        if self._view.horizontalScrollBar().isVisible():
            self._view.setHorizontalScrollBarPolicy(
                Qt.ScrollBarPolicy.ScrollBarAlwaysOn)
        else:
            self._view.setHorizontalScrollBarPolicy(
                Qt.ScrollBarPolicy.ScrollBarAlwaysOff)

        if self._view.verticalScrollBar().isVisible():
            self._view.setVerticalScrollBarPolicy(
                Qt.ScrollBarPolicy.ScrollBarAlwaysOn)
        else:
            self._view.setVerticalScrollBarPolicy(
                Qt.ScrollBarPolicy.ScrollBarAlwaysOff)

    def reset_scroll_bars(self):
        self._view.setHorizontalScrollBarPolicy(
            Qt.ScrollBarPolicy.ScrollBarAsNeeded)
        self._view.setVerticalScrollBarPolicy(
            Qt.ScrollBarPolicy.ScrollBarAsNeeded)

    def list_boxes_at(self, rect: QRectF):
        return [item for item in self.items(rect)
                if isinstance(item, BoxWidget)]

    def _start_move_timer(self):
        if self._move_box_timer.isActive():
            return

        self._move_timer_start_at = time.time()
        self._move_timer_last_time = self._move_timer_start_at
        self._move_box_timer.start()

    def move_boxes_animation(self):
        # Animation is nice but not the priority.
        # Do not ensure all steps are played
        # but just move the box where it has to go now.
        move_time = time.time()
        time_since_start = move_time - self._move_timer_start_at
        ratio = min(1.0, time_since_start / self._MOVE_DURATION)
        
        if self._move_timer_last_time == self._move_timer_start_at:
            # this is the first animation step
            if time_since_start > 0.33 * self._MOVE_DURATION:
                # this seems to be a big patch,
                # animation won't be pretty anyway,
                # let's finish it now.
                ratio = 1.0
        else:
            # this is not the first animation step.
            # If the timer called this method two times too late,
            # i.e. >40ms instead of 20ms after the previous step,
            # anti-aliasing is de-activated for a smoother animation.
            if (move_time - self._move_timer_last_time
                    > 0.002 * self._MOVE_TIMER_INTERVAL):
                canvas.set_aliasing_reason(AliasingReason.ANIMATION, True)

        self._move_timer_last_time = move_time

        lws = set[GroupedLinesWidget]()

        usefull = False

        for box, moving_box in self.move_boxes.items():
            if not usefull:
                usefull = moving_box.is_usefull()
                            
            if moving_box.needs_move:
                x = (moving_box.from_pt.x()
                        + ((moving_box.to_pt.x() - moving_box.from_pt.x())
                        * (ratio ** 0.6)))
                
                y = (moving_box.from_pt.y()
                        + ((moving_box.to_pt.y() - moving_box.from_pt.y())
                        * (ratio ** 0.6)))

                box.set_top_left((x, y))
                box.repaint_lines(fast_move=True)

            if moving_box.is_wrapping:
                box.animate_wrapping(ratio)
            
            if moving_box.hidding_state in (BoxHidding.HIDDING,
                                            BoxHidding.RESTORING):
                if moving_box.hidding_state is BoxHidding.HIDDING:
                    box.animate_hidding(ratio)
                else:
                    box.animate_restoring(ratio)
                    
                for lw in GroupedLinesWidget.widgets_for_box(
                        box._group_id, box._port_mode):
                    if lw not in lws:
                        lw.animate_hidding(ratio)
                        lws.add(lw)

        if not usefull:
            # stop animation now if all moving boxes have no change to make
            ratio = 1.0

        self.resize_the_scene(ratio)

        if ratio >= 1.0:
            # Animation is finished
            self._move_box_timer.stop()
            canvas.set_aliasing_reason(AliasingReason.ANIMATION, False)
            self.prevent_box_user_move = False
            GroupedLinesWidget.animation_finished()

            # box update positions is forbidden while widget is in self.move_boxes,
            # so we copy the list before to clear it,
            # then we can ask update_positions on widgets
            boxes = [b for b, mb in self.move_boxes.items()
                     if not (mb.is_joining or mb.hidding_state is BoxHidding.HIDDING)]
            
            self.move_boxes.clear()

            for box in boxes:
                if box.update_positions_pending:
                    box.update_positions()

            canvas.qobject.move_boxes_finished.emit()

    def add_box_to_animation(
            self, box_widget: BoxWidgetMoth, to_x: int, to_y: int,
            joining=Joining.NO_CHANGE, joined_rect=QRectF()):
        '''add a box to the move animation, to_x and to_y refer
        to the top left of the box at the end of animation.
        if joining is set to Joining.YES, joined_rect must be set'''

        moving_box = self.move_boxes.get(box_widget)
        if moving_box is None:
            # box is not already moving, create a MovingBox instance
            moving_box = MovingBox(box_widget)
            if joining is Joining.YES:
                moving_box.is_joining = True
            self.move_boxes[box_widget] = moving_box
        else:
            # box is already moving, check joining state and change it
            # if needed.
            if moving_box.is_joining and joining is Joining.NO:
                moving_box.is_joining = False
                canvas.qobject.rm_group_to_join(
                    box_widget.get_group_id())

        moving_box.from_pt = QPointF(*box_widget.top_left())
        moving_box.to_pt = QPointF(to_x, to_y)
        moving_box.needs_move = bool(moving_box.from_pt != moving_box.to_pt)
        
        if joining is Joining.YES or not box_widget.isVisible():
            moving_box.final_rect = joined_rect

        elif joining is Joining.NO_CHANGE and moving_box.is_joining:
            final_rect = QRectF(
                0.0, 0.0,
                moving_box.final_rect.width(),
                moving_box.final_rect.height())
            final_rect.translate(moving_box.to_pt)
            moving_box.final_rect = final_rect

        elif not moving_box.is_joining:
            aft_wrap_rect = box_widget.after_wrap_rect()
            final_rect = QRectF(
                0.0, 0.0, aft_wrap_rect.width(), aft_wrap_rect.height())
            final_rect.translate(moving_box.to_pt)
            moving_box.final_rect = final_rect
        
        else:
            # can not happens
            # would means moving_box.is_joining and joining is JOINING.NO,
            # It is prevented
            moving_box.final_rect = joined_rect

        if joining is not Joining.NO_CHANGE:
            moving_box.is_joining = True if joining is Joining.YES else False

        # save the group position
        group = canvas.get_group(box_widget._group_id)
        if group is not None:
            if moving_box.is_joining:
                if not joined_rect.isNull():
                    group.gpos.boxes[PortMode.BOTH].pos = (to_x, to_y)
            else:
                group.gpos.boxes[box_widget._port_mode].pos = (to_x, to_y)
            canvas.cb.group_pos_modified(group.group_id)

        moving_box.start_time = time.time() - self._move_timer_start_at

        if not self._move_box_timer.isActive():
            moving_box.start_time = 0.0
            
        self._start_move_timer()
            
        if canvas.aliasing_reason:
            # if antialiasing is already prevented
            # we need to keep it prevented at animation start
            canvas.set_aliasing_reason(AliasingReason.ANIMATION, True)

    def remove_box_from_animation(self, box_widget: BoxWidgetMoth):
        if self.prevent_box_user_move:
            # should not happens.
            # For now we can remove a box from animation
            # only by moving box manually,
            # and this is prevented by this attr in box_widget_moth.
            return

        if box_widget in self.move_boxes:
            self.move_boxes.pop(box_widget)

    def add_box_to_animation_wrapping(self, box_widget: BoxWidgetMoth, wrap: bool):  
        moving_box = self.move_boxes.get(box_widget)
        if moving_box is None:
            moving_box = MovingBox(box_widget)
            self.move_boxes[box_widget] = moving_box
        
        moving_box.start_time = time.time() - self._move_timer_start_at
    
        aft_wrap_rect = box_widget.after_wrap_rect()
        final_rect = QRectF(0.0, 0.0, aft_wrap_rect.width(), aft_wrap_rect.height())
        moving_box.final_rect = \
            final_rect.translated(moving_box.to_pt)
        moving_box.is_wrapping = True
        
        self._start_move_timer()

    def add_box_to_animation_hidding(self, box_widget: BoxWidget):
        moving_box = self.move_boxes.get(box_widget)
        if moving_box is None:
            moving_box = MovingBox(box_widget)
            self.move_boxes[box_widget] = moving_box
        
        moving_box.start_time = time.time() - self._move_timer_start_at
        moving_box.final_rect = QRectF()
        moving_box.hidding_state = BoxHidding.HIDDING
        
        for port_mode in PortMode.OUTPUT, PortMode.INPUT:
            if port_mode not in box_widget.get_port_mode():
                continue

            for lw in GroupedLinesWidget.widgets_for_box(
                    box_widget.get_group_id(), port_mode):
                lw.set_mode_hidding(port_mode, BoxHidding.HIDDING)
        
        self._start_move_timer()

    def add_box_to_animation_restore(self, box_widget: BoxWidget):
        moving_box = self.move_boxes.get(box_widget)
        if moving_box is None:
            moving_box = MovingBox(box_widget)
            self.move_boxes[box_widget] = moving_box

        moving_box.start_time = time.time() - self._move_timer_start_at
        moving_box.from_pt = moving_box.to_pt

        aft_wrap_rect = box_widget.after_wrap_rect()
        final_rect = QRectF(
            0.0, 0.0, aft_wrap_rect.width(), aft_wrap_rect.height())
        moving_box.final_rect = \
            final_rect.translated(moving_box.to_pt)

        if moving_box.hidding_state is BoxHidding.NONE:
            box_widget.animate_restoring(0.0)
        moving_box.hidding_state = BoxHidding.RESTORING

        for port_mode in PortMode.OUTPUT, PortMode.INPUT:
            if port_mode not in box_widget._port_mode:
                continue

            for lw in GroupedLinesWidget.widgets_for_box(
                    box_widget._group_id, port_mode):
                lw.set_mode_hidding(port_mode, BoxHidding.RESTORING)

        self._start_move_timer()

    def remove_box(self, box_widget: BoxWidget):
        if box_widget in self.move_boxes:
            self.move_boxes.pop(box_widget)
        
        self.removeItem(box_widget)

    def center_view_on(self, widget):
        self._view.centerOn(widget)

    def get_connectable_item_at(
            self, pos: QPointF, origin: ConnectableWidget) \
                -> Optional[ConnectableWidget]:
        for item in self.items(pos, Qt.ItemSelectionMode.ContainsItemShape,
                               Qt.SortOrder.AscendingOrder):
            if isinstance(item, ConnectableWidget) and item is not origin:
                return item

    def get_box_at(self, pos: QPointF) -> Optional[BoxWidget]:
        for item in self.items(pos, Qt.ItemSelectionMode.ContainsItemShape,
                               Qt.SortOrder.AscendingOrder):
            if isinstance(item, BoxWidget):
                return item

    def get_selected_boxes(self) -> list[BoxWidget]:
        return [i for i in self.selectedItems() if isinstance(i, BoxWidget)]

    def removeItem(self, item: QGraphicsItem):
        for child_item in item.childItems():
            QGraphicsScene.removeItem(self, child_item)
        QGraphicsScene.removeItem(self, item)

    def update_limits(self):
        w0 = canvas.size_rect.width()
        h0 = canvas.size_rect.height()
        w1 = self._view.width()
        h1 = self._view.height()
        self._scale_min = w1/w0 if w0/h0 > w1/h1 else h1/h0

    def update_theme(self):
        if canvas.theme.scene_background_image is not None:
            bg_brush = QBrush()
            bg_brush.setTextureImage(canvas.theme.scene_background_image)
            self.setBackgroundBrush(bg_brush)
        else:
            self.setBackgroundBrush(canvas.theme.scene_background_color)
        
        self._rubberband.setPen(canvas.theme.rubberband.fill_pen)
        self._rubberband.setBrush(canvas.theme.rubberband.background_color)

        cur_color = ("black" if canvas.theme.scene_background_color.blackF() < 0.5
                     else "white")
        self._cursor_cut = QCursor(QPixmap(f":/cursors/cut-{cur_color}.png"), 1, 1)
        self._cursor_zoom_area = QCursor(
            QPixmap(f":/cursors/zoom-area-{cur_color}.png"), 8, 7)
        
        self.update_grid_style()

    def drawBackground(self, painter, rect):
        painter.save()
        painter.setPen(Qt.PenStyle.NoPen)
        
        if (canvas.theme.scene_background_image is not None
                and not canvas.theme.scene_background_image.isNull()):
            canvas.theme.scene_background_image.setDevicePixelRatio(3.0)
            bg_brush = QBrush()
            bg_brush.setTextureImage(canvas.theme.scene_background_image)
            painter.setBrush(bg_brush)
            painter.drawRect(rect)

        painter.setBrush(canvas.theme.scene_background_color)        
        painter.drawRect(rect)
        painter.restore()

    def get_new_scene_rect(self, anim_ratio: Optional[float]=None) -> QRectF:
        full_rect = QRectF()

        if anim_ratio is None or anim_ratio >= 1.0:
            for widget in canvas.list_boxes():
                full_rect |= widget.rect_needed_in_scene()

            return full_rect
        
        futur_rect = QRectF()
        
        for widget in canvas.list_boxes():
            move_box = self.move_boxes.get(widget)
            if move_box is None:
                full_rect |= widget.rect_needed_in_scene()
            
            else:
                if move_box.hidding_state is BoxHidding.RESTORING:
                    continue
                
                full_rect |= widget.rect_needed_in_scene()
        
        for widget in canvas.list_boxes():
            futur_rect |= widget.rect_needed_in_scene(futur=True)
            
        if futur_rect is None or full_rect is None:
            return full_rect
        
        rect = QRectF(full_rect)
        rect.setLeft(full_rect.left() * (1.0 - anim_ratio)
                     + futur_rect.left() * anim_ratio)
        rect.setRight(full_rect.right() * (1.0 - anim_ratio)
                      + futur_rect.right() * anim_ratio)
        rect.setTop(full_rect.top() * (1.0 - anim_ratio)
                    + futur_rect.top() * anim_ratio)
        rect.setBottom(full_rect.bottom() * (1.0 - anim_ratio)
                       + futur_rect.bottom() * anim_ratio)
        
        return rect

    def resize_the_scene(self, anim_ratio: Optional[float]=None):
        if not options.elastic:
            return

        scene_rect = self.get_new_scene_rect(anim_ratio)
        
        if not scene_rect.isNull():
            self.resizing_scene = True
            self.setSceneRect(scene_rect)
            self.resizing_scene = False

    def set_elastic(self, yesno: bool):
        options.elastic = True
        self.resize_the_scene()
        options.elastic = yesno

        if not yesno:
            # resize the scene to a null QRectF to auto set sceneRect
            # always growing with items
            self.setSceneRect(QRectF())

            # add a fake item with the current canvas scene size
            # (calculated with items), and remove it.
            fake_item = QGraphicsRectItem(self.get_new_scene_rect())
            self.addItem(fake_item)
            self.update()
            self.removeItem(fake_item)

    def set_cursor(self, cursor: QCursor):
        if self._view is None:
            return
        
        self._view.viewport().setCursor(cursor)

    def unset_cursor(self):
        if self._view is None:
            return
        
        self._view.viewport().unsetCursor()

    def zoom_ratio(self, percent: float, force=False):
        ratio = percent / 100.0
        transform = self._view.transform()
        
        if not force and ratio == transform.m11():
            return
        
        transform.reset()
        transform.scale(ratio, ratio)
        self._view.setTransform(transform)

        for box in canvas.list_boxes():
            if box.top_icon:
                box.top_icon.update_zoom(ratio)

        self.scale_changed.emit(transform.m11())

    def zoom_fit(self):
        if self._view is None:
            return

        full_rect = QRectF()
        
        for item in self.items():
            if isinstance(item, BoxWidget) and item.isVisible():
                rect = item.sceneBoundingRect()
                
                if full_rect.isNull():
                    full_rect = rect
                    continue
                
                full_rect.setLeft(min(full_rect.left(), rect.left()))
                full_rect.setRight(max(full_rect.right(), rect.right()))
                full_rect.setTop(min(full_rect.top(), rect.top()))
                full_rect.setBottom(max(full_rect.bottom(), rect.bottom()))
                
        if full_rect.isNull():
            return
        
        self._view.fitInView(full_rect, Qt.AspectRatioMode.KeepAspectRatio)
        self.fix_scale_factor()
        self.scale_changed.emit(self._view.transform().m11())

    def zoom_in(self):
        view = self._view
        transform = view.transform()
        if transform.m11() < self._scale_max:
            transform.scale(1.2, 1.2)
            if transform.m11() > self._scale_max:
                transform.reset()
                transform.scale(self._scale_max, self._scale_max)
            view.setTransform(transform)
        self.scale_changed.emit(transform.m11())

    def zoom_out(self):
        view = self._view
        transform = view.transform()
        if transform.m11() > self._scale_min:
            transform.scale(0.833333333333333, 0.833333333333333)
            if transform.m11() < self._scale_min:
                transform.reset()
                transform.scale(self._scale_min, self._scale_min)
            view.setTransform(transform)
        self.scale_changed.emit(transform.m11())

    def zoom_reset(self):
        transform = self._view.transform()
        transform.reset()

        default_scale = options.default_zoom / 100
        transform.scale(default_scale, default_scale)
        self._view.setTransform(transform)
        self.scale_changed.emit(default_scale)

    @Slot()
    def _slot_selection_changed(self):
        items_list = self.selectedItems()

        if len(items_list) == 0:
            self.plugin_selected.emit([])
            return

        plugin_list = []

        for item in items_list:
            if item and item.isVisible():
                group_item = None

                if isinstance(item, BoxWidget):
                    group_item = item
                elif isinstance(item, ConnectableWidget):
                    group_item = item.parentItem()

                if group_item is not None and group_item._plugin_id >= 0:
                    plugin_id = group_item._plugin_id
                    if plugin_id > MAX_PLUGIN_ID_ALLOWED:
                        plugin_id = 0
                    plugin_list.append(plugin_id)

        self.plugin_selected.emit(plugin_list)

    def _trigger_rubberband_scale(self):
        # TODO, should enable an auto-zoom on 
        # Ctrl+Right clic + drag (rubberband)
        self._scale_area = True

        if self._cursor_zoom_area:
            self.set_cursor(self._cursor_zoom_area)

    def get_zoom_scale(self):
        return self._view.transform().m11()

    def keyPressEvent(self, event):
        if not self._view:
            event.ignore()
            return

        if event.key() == Qt.Key.Key_Control:
            if self._mid_button_down:
                self._start_connection_cut()

        elif event.key() == Qt.Key.Key_Home:
            event.accept()
            self.zoom_fit()
            return

        elif (QApplication.keyboardModifiers()
                & Qt.KeyboardModifier.ControlModifier):
            if event.key() == Qt.Key.Key_Plus:
                event.accept()
                self.zoom_in()
                return

            if event.key() == Qt.Key.Key_Minus:
                event.accept()
                self.zoom_out()
                return

            if event.key() == Qt.Key.Key_1:
                event.accept()
                self.zoom_reset()
                return

        QGraphicsScene.keyPressEvent(self, event)

    def keyReleaseEvent(self, event):
        if event.key() == Qt.Key.Key_Control:
            # Connection cut mode off
            if self._mid_button_down:
                self.unset_cursor()

        QGraphicsScene.keyReleaseEvent(self, event)

    def _start_connection_cut(self):
        if self._cursor_cut:
            self.set_cursor(self._cursor_cut)

    def zoom_wheel(self, delta: int):
        transform = self._view.transform()
        scale = transform.m11()

        if ((delta > 0 and scale < self._scale_max)
                or (delta < 0 and scale > self._scale_min)):
            # prevent too large unzoom
            if delta < 0:
                rect = self.sceneRect()

                top_left_vw = self._view.mapFromScene(rect.topLeft())
                if (top_left_vw.x() > self._view.width() / 4
                        and top_left_vw.y() > self._view.height() / 4):
                    return

            # Apply scale
            factor = 1.4142135623730951 ** (delta / 240.0)
            transform.scale(factor, factor)
            self.fix_scale_factor(transform)
            self._view.setTransform(transform)
            self.scale_changed.emit(transform.m11())

            # Update box icons especially when they are not scalable
            # eg. coming from system theme
            for box in canvas.list_boxes():
                if box.top_icon:
                    box.top_icon.update_zoom(scale * factor)

    def update_grid_widget(self):
        if self._view.transforming:
            return
        
        if self._grid_widget is not None:
            self._grid_widget.update_path()

    def update_grid_style(self):
        if self._grid_widget is not None:
            self.removeItem(self._grid_widget)
        
        if options.grid_style is GridStyle.NONE:
            self._grid_widget = None
        else:
            self._grid_widget = GridWidget(self, style=options.grid_style)
            self._grid_widget.update_path()
            self._grid_widget.setZValue(Zv.GRID.value)
            self.addItem(self._grid_widget)

        self.update()

    def invert_boxes_selection(self):
        selected_boxes = set(self.get_selected_boxes())

        with SelectingBoxes(self):
            for box in canvas.list_boxes():
                if box in selected_boxes:
                    box.setSelected(False)
                elif box.isVisible():
                    box.setSelected(True)

    def mouseDoubleClickEvent(self, event):
        if event.button() == Qt.MouseButton.LeftButton and not canvas.menu_shown:
            # parse items under mouse to prevent CallbackAct.DOUBLE_CLICK
            # if mouse is on a box
            
            has_box = False
            items = self.items(
                event.scenePos(), Qt.ItemSelectionMode.ContainsItemShape,
                Qt.SortOrder.AscendingOrder)

            for item in items:
                if isinstance(item, ConnectableWidget):
                    # start a flying connection with mouse button not pressed,
                    # here we just change the cursor
                    # and define the ConnectableWidget.
                    self.flying_connectable = item
                    self.set_cursor(QCursor(Qt.CursorShape.CrossCursor))
                    self._start_navigation_on_borders()
                    return

                if not has_box:
                    has_box = isinstance(item, BoxWidget)
            
            if not has_box:
                canvas.cb.bg_double_click()

        QGraphicsScene.mouseDoubleClickEvent(self, event)

    def mousePressEvent(self, event):
        if self.flying_connectable:
            if event.button() == Qt.MouseButton.LeftButton:
                self.flying_connectable.mouseReleaseEvent(event)
                self.flying_connectable = None
                self.set_cursor(Qt.CursorShape.ArrowCursor) # type:ignore
                return

            if event.button() == Qt.MouseButton.RightButton:
                self.flying_connectable.mousePressEvent(event)
                return

        ctrl_pressed = bool(
            QApplication.keyboardModifiers()
            & Qt.KeyboardModifier.ControlModifier)
        alt_or_meta_pressed = bool(
            QApplication.keyboardModifiers()
            & (Qt.KeyboardModifier.AltModifier
               | Qt.KeyboardModifier.MetaModifier))
        self._mouse_down_init = bool(
            (event.button() == Qt.MouseButton.LeftButton
                and not alt_or_meta_pressed)
            or (event.button() == Qt.MouseButton.RightButton and ctrl_pressed))
        
        self._press_point = event.scenePos()
        self._mouse_rubberband = False

        # There is no more possibility to use trigger disconnect
        # with Ctrl + Middle click
        # because connection objects are now grouped.
        # we keep the code here,
        # it may be possible to re-implement it,
        # if really wanted by some users.

        # if event.button() == Qt.MidButton:
        #     if ctrl_pressed:
        #         self._mid_button_down = True
        #         self._start_connection_cut()

        #         pos = event.scenePos()
        #         self._pointer_border.moveTo(floor(pos.x()), floor(pos.y()))

        #         for item in self.items(self._pointer_border):
        #             if isinstance(item, (ConnectableWidget, LineWidget)):
        #                 item.trigger_disconnect()

        self._selected_boxes = [
            b for b in self.selectedItems()
            if isinstance(b, BoxWidgetMoth) and b.isVisible()]

        QGraphicsScene.mousePressEvent(self, event)
        canvas.menu_shown = False

        if (self._view.dragMode() != QGraphicsView.DragMode.ScrollHandDrag
                and event.buttons() == Qt.MouseButton.LeftButton):
            # Middle click and move changes the view drag mode
            # and fake a left button.
            # we don't want navigation on borders in case of middle click.
            self._start_navigation_on_borders()

    def mouseMoveEvent(self, event):
        if self.flying_connectable is not None:
            self.flying_connectable.mouseMoveEvent(event)
            return
        
        if self._mouse_down_init:
            self._mouse_down_init = False
            self._mouse_rubberband = False
            for item in self.items(self._press_point):
                if isinstance(item, (BoxWidget, ConnectableWidget)):
                    break
            else:
                if event.buttons() != 0:
                    self._mouse_rubberband = True
            
        if self._mouse_rubberband:
            event.accept()
            pos = event.scenePos()
            pos_x = pos.x()
            pos_y = pos.y()
            if not self._rubberband_selection:
                self._rubberband.show()
                self._rubberband_selection = True
                self._rubberband_orig_point = self._press_point
            rubb_orig_point = self._rubberband_orig_point

            x = min(pos_x, rubb_orig_point.x())
            y = min(pos_y, rubb_orig_point.y())

            line_hinting = canvas.theme.rubberband.fill_pen.widthF() / 2.0
            self._rubberband.setRect(
                x + line_hinting, y + line_hinting,
                abs(pos_x - rubb_orig_point.x()),
                abs(pos_y - rubb_orig_point.y()))

        if (self._mid_button_down
                and (QApplication.keyboardModifiers()
                     & Qt.KeyboardModifier.ControlModifier)):
            for item in self.items(
                    QPolygonF([event.scenePos(), event.lastScenePos(),
                               event.scenePos()])):
                if isinstance(item, LineWidget):
                    item.trigger_disconnect()
        
        QGraphicsScene.mouseMoveEvent(self, event)

    def mouseReleaseEvent(self, event):
        if self.flying_connectable:
            QGraphicsScene.mouseReleaseEvent(self, event)
            canvas.set_aliasing_reason(AliasingReason.NAV_ON_BORDERS, False)
            return
        
        if self._scale_area and not self._rubberband_selection:
            self._scale_area = False
            self.unset_cursor()

        if self._rubberband_selection:
            if self._scale_area:
                self._scale_area = False
                self.unset_cursor()

                rect = self._rubberband.rect()
                self._view.fitInView(
                    rect.x(), rect.y(),
                    rect.width(), rect.height(),
                    Qt.AspectRatioMode.KeepAspectRatio)
                self.fix_scale_factor()

            else:
                with SelectingBoxes(self):
                    for item in self.items():
                        if isinstance(item, BoxWidget):
                            item_rect = item.sceneBoundingRect()
                            if self._rubberband.rect().contains(item_rect):
                                item.setSelected(True)

            self._rubberband.hide()
            self._rubberband.setRect(0, 0, 0, 0)
            self._rubberband_selection = False

        else:
            for item in self.get_selected_boxes():
                item.check_item_pos()
                self.scene_group_moved.emit(
                    item._group_id, item._port_mode,
                    item.scenePos())

            if len(self.selectedItems()) > 1:
                self.update()

        self._mouse_down_init = False
        self._mouse_rubberband = False

        if event.button() == Qt.MouseButton.LeftButton:
            self._borders_nav_timer.stop()
            canvas.set_aliasing_reason(AliasingReason.NAV_ON_BORDERS, False)

        if event.button() == Qt.MouseButton.MiddleButton:
            event.accept()

            self._mid_button_down = False

            # Connection cut mode off
            if (QApplication.keyboardModifiers()
                    & Qt.KeyboardModifier.ControlModifier):
                self.unset_cursor()
            return

        QGraphicsScene.mouseReleaseEvent(self, event)

    def wheelEvent(self, event):
        if not self._view:
            event.ignore()
            return

        canvas.qobject.start_aliasing_check(AliasingReason.VIEW_MOVE)

        if (QApplication.keyboardModifiers()
                & Qt.KeyboardModifier.ControlModifier):
            self.zoom_wheel(event.delta())
            event.accept()
            return

        QGraphicsScene.wheelEvent(self, event)

    def contextMenuEvent(self, event):
        if canvas.is_line_mov:
            event.ignore()
            return
        
        for item in self.items(event.scenePos()):
            if isinstance(item, (BoxWidget, ConnectableWidget)):
                break
        else:
            if (QApplication.keyboardModifiers()
                    & Qt.KeyboardModifier.ControlModifier):
                event.accept()
                self._trigger_rubberband_scale()
                return

            with SelectingBoxes(self):
                for sel_box in self._selected_boxes:
                    sel_box.setSelected(True)

            event.accept()
            screen_pos = event.screenPos()
            scene_pos = event.scenePos()

            canvas.cb.bg_right_click(
                screen_pos.x(), screen_pos.y(),
                scene_pos.x(), scene_pos.y(),
                boxes_in_dict(self._selected_boxes))
            return

        QGraphicsScene.contextMenuEvent(self, event)