# /*##########################################################################
#
# Copyright (c) 2014-2023 European Synchrotron Radiation Facility
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"""Implementation of the interaction for the :class:`Plot`."""

from __future__ import annotations

__authors__ = ["T. Vincent"]
__license__ = "MIT"
__date__ = "15/02/2019"


import math
import numpy
import time
import weakref
from typing import NamedTuple, Optional

from silx.gui import qt
from .. import colors
from . import items
from .Interaction import (
    ClickOrDrag,
    LEFT_BTN,
    RIGHT_BTN,
    MIDDLE_BTN,
    State,
    StateMachine,
)
from .PlotEvents import (
    prepareCurveSignal,
    prepareDrawingSignal,
    prepareHoverSignal,
    prepareImageSignal,
    prepareMarkerSignal,
    prepareMouseSignal,
)

from .backends.BackendBase import (
    CURSOR_POINTING,
    CURSOR_SIZE_HOR,
    CURSOR_SIZE_VER,
    CURSOR_SIZE_ALL,
)

from ._utils import (
    FLOAT32_SAFE_MIN,
    FLOAT32_MINPOS,
    FLOAT32_SAFE_MAX,
    applyZoomToPlot,
    EnabledAxes,
)


# Base class ##################################################################


class _PlotInteraction(object):
    """Base class for interaction handler.

    It provides a weakref to the plot and methods to set/reset overlay.
    """

    def __init__(self, plot):
        """Init.

        :param plot: The plot to apply modifications to.
        """
        self._needReplot = False
        self._selectionAreas = set()
        self._plot = weakref.ref(plot)  # Avoid cyclic-ref

    @property
    def plot(self):
        plot = self._plot()
        assert plot is not None
        return plot

    def setSelectionArea(self, points, fill, color, name="", shape="polygon"):
        """Set a polygon selection area overlaid on the plot.
        Multiple simultaneous areas are supported through the name parameter.

        :param points: The 2D coordinates of the points of the polygon
        :type points: An iterable of (x, y) coordinates
        :param str fill: The fill mode: 'hatch', 'solid' or 'none'
        :param color: RGBA color to use or None to disable display
        :type color: list or tuple of 4 float in the range [0, 1]
        :param name: The key associated with this selection area
        :param str shape: Shape of the area in 'polygon', 'polylines'
        """
        assert shape in ("polygon", "polylines")

        if color is None:
            return

        points = numpy.asarray(points)

        # TODO Not very nice, but as is for now
        legend = "__SELECTION_AREA__" + name

        fill = fill != "none"  # TODO not very nice either

        greyed = colors.greyed(color)[0]
        if greyed < 0.5:
            color2 = "white"
        else:
            color2 = "black"

        self.plot.addShape(
            points[:, 0],
            points[:, 1],
            legend=legend,
            replace=False,
            shape=shape,
            fill=fill,
            color=color,
            gapcolor=color2,
            linestyle="--",
            overlay=True,
        )

        self._selectionAreas.add(legend)

    def resetSelectionArea(self):
        """Remove all selection areas set by setSelectionArea."""
        for legend in self._selectionAreas:
            self.plot.remove(legend, kind="item")
        self._selectionAreas = set()


# Zoom/Pan ####################################################################


class _PlotInteractionWithClickEvents(ClickOrDrag, _PlotInteraction):
    """:class:`ClickOrDrag` state machine emitting click and double click events.

    Base class for :class:`Pan` and :class:`Zoom`
    """

    _DOUBLE_CLICK_TIMEOUT = 0.4

    def click(self, x, y, btn):
        """Handle clicks by sending events

        :param int x: Mouse X position in pixels
        :param int y: Mouse Y position in pixels
        :param btn: Clicked mouse button
        """
        if btn == LEFT_BTN:
            lastClickTime, lastClickPos = self._lastClick

            # Signal mouse double clicked event first
            if (time.time() - lastClickTime) <= self._DOUBLE_CLICK_TIMEOUT:
                # Use position of first click
                eventDict = prepareMouseSignal(
                    "mouseDoubleClicked", "left", *lastClickPos
                )
                self.plot.notify(**eventDict)

                self._lastClick = 0.0, None
            else:
                # Signal mouse clicked event
                dataPos = self.plot.pixelToData(x, y)
                assert dataPos is not None
                eventDict = prepareMouseSignal(
                    "mouseClicked", "left", dataPos[0], dataPos[1], x, y
                )
                self.plot.notify(**eventDict)

                self._lastClick = time.time(), (dataPos[0], dataPos[1], x, y)

        elif btn == RIGHT_BTN:
            # Signal mouse clicked event
            dataPos = self.plot.pixelToData(x, y)
            assert dataPos is not None
            eventDict = prepareMouseSignal(
                "mouseClicked", "right", dataPos[0], dataPos[1], x, y
            )
            self.plot.notify(**eventDict)

    def __init__(self, plot, **kwargs):
        """Init.

        :param plot: The plot to apply modifications to.
        """
        self._lastClick = 0.0, None

        _PlotInteraction.__init__(self, plot)
        ClickOrDrag.__init__(self, **kwargs)


# Pan #########################################################################


class Pan(_PlotInteractionWithClickEvents):
    """Pan plot content and zoom on wheel state machine."""

    def _pixelToData(self, x, y):
        xData, yData = self.plot.pixelToData(x, y)
        _, y2Data = self.plot.pixelToData(x, y, axis="right")
        return xData, yData, y2Data

    def beginDrag(self, x, y, btn):
        self._previousDataPos = self._pixelToData(x, y)

    def drag(self, x, y, btn):
        xData, yData, y2Data = self._pixelToData(x, y)
        lastX, lastY, lastY2 = self._previousDataPos

        xMin, xMax = self.plot.getXAxis().getLimits()
        yMin, yMax = self.plot.getYAxis().getLimits()
        y2Min, y2Max = self.plot.getYAxis(axis="right").getLimits()

        if self.plot.getXAxis()._isLogarithmic():
            try:
                dx = math.log10(xData) - math.log10(lastX)
                newXMin = pow(10.0, (math.log10(xMin) - dx))
                newXMax = pow(10.0, (math.log10(xMax) - dx))
            except (ValueError, OverflowError):
                newXMin, newXMax = xMin, xMax

            # Makes sure both values stays in positive float32 range
            if newXMin < FLOAT32_MINPOS or newXMax > FLOAT32_SAFE_MAX:
                newXMin, newXMax = xMin, xMax
        else:
            dx = xData - lastX
            newXMin, newXMax = xMin - dx, xMax - dx

            # Makes sure both values stays in float32 range
            if newXMin < FLOAT32_SAFE_MIN or newXMax > FLOAT32_SAFE_MAX:
                newXMin, newXMax = xMin, xMax

        if self.plot.getYAxis()._isLogarithmic():
            try:
                dy = math.log10(yData) - math.log10(lastY)
                newYMin = pow(10.0, math.log10(yMin) - dy)
                newYMax = pow(10.0, math.log10(yMax) - dy)

                dy2 = math.log10(y2Data) - math.log10(lastY2)
                newY2Min = pow(10.0, math.log10(y2Min) - dy2)
                newY2Max = pow(10.0, math.log10(y2Max) - dy2)
            except (ValueError, OverflowError):
                newYMin, newYMax = yMin, yMax
                newY2Min, newY2Max = y2Min, y2Max

            # Makes sure y and y2 stays in positive float32 range
            if (
                newYMin < FLOAT32_MINPOS
                or newYMax > FLOAT32_SAFE_MAX
                or newY2Min < FLOAT32_MINPOS
                or newY2Max > FLOAT32_SAFE_MAX
            ):
                newYMin, newYMax = yMin, yMax
                newY2Min, newY2Max = y2Min, y2Max
        else:
            dy = yData - lastY
            dy2 = y2Data - lastY2
            newYMin, newYMax = yMin - dy, yMax - dy
            newY2Min, newY2Max = y2Min - dy2, y2Max - dy2

            # Makes sure y and y2 stays in float32 range
            if (
                newYMin < FLOAT32_SAFE_MIN
                or newYMax > FLOAT32_SAFE_MAX
                or newY2Min < FLOAT32_SAFE_MIN
                or newY2Max > FLOAT32_SAFE_MAX
            ):
                newYMin, newYMax = yMin, yMax
                newY2Min, newY2Max = y2Min, y2Max

        self.plot.setLimits(newXMin, newXMax, newYMin, newYMax, newY2Min, newY2Max)

        self._previousDataPos = self._pixelToData(x, y)

    def endDrag(self, startPos, endPos, btn):
        del self._previousDataPos

    def cancel(self):
        pass


# Zoom ########################################################################


class AxesExtent(NamedTuple):
    xmin: float
    xmax: float
    ymin: float
    ymax: float
    y2min: float
    y2max: float


class Zoom(_PlotInteractionWithClickEvents):
    """Zoom-in/out state machine.

    Zoom-in on selected area, zoom-out on right click,
    and zoom on mouse wheel.
    """

    SURFACE_THRESHOLD = 5

    def __init__(self, plot, color):
        self.color = color
        self.enabledAxes = EnabledAxes()

        super(Zoom, self).__init__(plot)
        self.plot.getLimitsHistory().clear()

    def _getAxesExtent(
        self,
        x0: float,
        y0: float,
        x1: float,
        y1: float,
        enabledAxes: Optional[EnabledAxes] = None,
    ) -> AxesExtent:
        """Convert selection coordinates (pixels) to axes coordinates (data)

        This takes into account axes selected for zoom and aspect ratio.
        """
        if enabledAxes is None:
            enabledAxes = self.enabledAxes

        y2_0, y2_1 = y0, y1
        left, top, width, height = self.plot.getPlotBoundsInPixels()

        if not all(enabledAxes) and not self.plot.isKeepDataAspectRatio():
            # Handle axes disabled for zoom if plot is not keeping aspec ratio
            if not enabledAxes.xaxis:
                x0, x1 = left, left + width
            if not enabledAxes.yaxis:
                y0, y1 = top, top + height
            if not enabledAxes.y2axis:
                y2_0, y2_1 = top, top + height

        if self.plot.isKeepDataAspectRatio() and height != 0 and width != 0:
            ratio = width / height
            xextent, yextent = math.fabs(x1 - x0), math.fabs(y1 - y0)
            if xextent != 0 and yextent != 0:
                if xextent / yextent > ratio:
                    areaHeight = xextent / ratio
                    center = 0.5 * (y0 + y1)
                    y0 = center - numpy.sign(y1 - y0) * 0.5 * areaHeight
                    y1 = center + numpy.sign(y1 - y0) * 0.5 * areaHeight
                else:
                    areaWidth = yextent * ratio
                    center = 0.5 * (x0 + x1)
                    x0 = center - numpy.sign(x1 - x0) * 0.5 * areaWidth
                    x1 = center + numpy.sign(x1 - x0) * 0.5 * areaWidth

        # Convert to data space
        x0, y0 = self.plot.pixelToData(x0, y0, check=False)
        x1, y1 = self.plot.pixelToData(x1, y1, check=False)
        y2_0 = self.plot.pixelToData(None, y2_0, axis="right", check=False)[1]
        y2_1 = self.plot.pixelToData(None, y2_1, axis="right", check=False)[1]

        return AxesExtent(
            min(x0, x1),
            max(x0, x1),
            min(y0, y1),
            max(y0, y1),
            min(y2_0, y2_1),
            max(y2_0, y2_1),
        )

    def beginDrag(self, x, y, btn):
        dataPos = self.plot.pixelToData(x, y)
        assert dataPos is not None
        self.x0, self.y0 = x, y

    def drag(self, x1, y1, btn):
        if self.color is None:
            return  # Do not draw zoom area

        dataPos = self.plot.pixelToData(x1, y1)
        assert dataPos is not None

        if self.plot.isKeepDataAspectRatio() or not all(self.enabledAxes):
            # Patch enabledAxes to display the right Y axis area on the left Y axis
            # since the selection area is always displayed on the left Y axis
            isY2Visible = self.plot.getYAxis("right").isVisible()
            areaZoomEnabledAxes = EnabledAxes(
                self.enabledAxes.xaxis,
                self.enabledAxes.yaxis and (not isY2Visible or self.enabledAxes.y2axis),
                self.enabledAxes.y2axis,
            )
            extents = self._getAxesExtent(self.x0, self.y0, x1, y1, areaZoomEnabledAxes)
            areaCorners = (
                (extents.xmin, extents.ymin),
                (extents.xmax, extents.ymin),
                (extents.xmax, extents.ymax),
                (extents.xmin, extents.ymax),
            )

            if self.color != "video inverted":
                areaColor = list(self.color)
                areaColor[3] *= 0.25
            else:
                areaColor = [1.0, 1.0, 1.0, 1.0]

            self.setSelectionArea(
                areaCorners, fill="none", color=areaColor, name="zoomedArea"
            )

        corners = ((self.x0, self.y0), (self.x0, y1), (x1, y1), (x1, self.y0))
        corners = numpy.array(
            [self.plot.pixelToData(x, y, check=False) for (x, y) in corners]
        )

        self.setSelectionArea(corners, fill="none", color=self.color)

    def _zoom(self, x0, y0, x1, y1):
        """Zoom to the rectangle view x0,y0 x1,y1."""
        # Store current zoom state in stack
        self.plot.getLimitsHistory().push()

        extents = self._getAxesExtent(x0, y0, x1, y1)
        self.plot.setLimits(
            extents.xmin,
            extents.xmax,
            extents.ymin,
            extents.ymax,
            extents.y2min,
            extents.y2max,
        )

    def endDrag(self, startPos, endPos, btn):
        x0, y0 = startPos
        x1, y1 = endPos

        if abs(x0 - x1) * abs(y0 - y1) >= self.SURFACE_THRESHOLD:
            # Avoid empty zoom area
            self._zoom(x0, y0, x1, y1)

        self.resetSelectionArea()

    def cancel(self):
        if isinstance(self.state, self.states["drag"]):
            self.resetSelectionArea()


# Select ######################################################################


class Select(StateMachine, _PlotInteraction):
    """Base class for drawing selection areas."""

    def __init__(self, plot, parameters, states, state):
        """Init a state machine.

        :param plot: The plot to apply changes to.
        :param dict parameters: A dict of parameters such as color.
        :param dict states: The states of the state machine.
        :param str state: The name of the initial state.
        """
        _PlotInteraction.__init__(self, plot)
        self.parameters = parameters
        StateMachine.__init__(self, states, state)

    @property
    def color(self):
        return self.parameters.get("color", None)


class SelectPolygon(Select):
    """Drawing selection polygon area state machine."""

    DRAG_THRESHOLD_DIST = 4

    class Idle(State):
        def onPress(self, x, y, btn):
            if btn == LEFT_BTN:
                self.goto("select", x, y)
                return True

    class Select(State):
        def enterState(self, x, y):
            dataPos = self.machine.plot.pixelToData(x, y)
            assert dataPos is not None
            self._firstPos = dataPos
            self.points = [dataPos, dataPos]

            self.updateFirstPoint()

        def updateFirstPoint(self):
            """Update drawing first point, using self._firstPos"""
            x, y = self.machine.plot.dataToPixel(*self._firstPos, check=False)

            offset = self.machine.getDragThreshold()
            points = [
                (x - offset, y - offset),
                (x - offset, y + offset),
                (x + offset, y + offset),
                (x + offset, y - offset),
            ]
            points = [
                self.machine.plot.pixelToData(xpix, ypix, check=False)
                for xpix, ypix in points
            ]
            self.machine.setSelectionArea(
                points, fill=None, color=self.machine.color, name="first_point"
            )

        def updateSelectionArea(self):
            """Update drawing selection area using self.points"""
            self.machine.setSelectionArea(
                self.points, fill="hatch", color=self.machine.color
            )
            eventDict = prepareDrawingSignal(
                "drawingProgress", "polygon", self.points, self.machine.parameters
            )
            self.machine.plot.notify(**eventDict)

        def validate(self):
            if len(self.points) > 2:
                self.closePolygon()
            else:
                # It would be nice to have a cancel event.
                # The plot is not aware that the interaction was cancelled
                self.machine.cancel()

        def closePolygon(self):
            self.machine.resetSelectionArea()
            self.points[-1] = self.points[0]
            eventDict = prepareDrawingSignal(
                "drawingFinished", "polygon", self.points, self.machine.parameters
            )
            self.machine.plot.notify(**eventDict)
            self.goto("idle")

        def onWheel(self, x, y, angle):
            self.machine.onWheel(x, y, angle)
            self.updateFirstPoint()

        def onRelease(self, x, y, btn):
            if btn == LEFT_BTN:
                # checking if the position is close to the first point
                # if yes : closing the "loop"
                firstPos = self.machine.plot.dataToPixel(*self._firstPos, check=False)
                dx, dy = abs(firstPos[0] - x), abs(firstPos[1] - y)

                threshold = self.machine.getDragThreshold()

                # Only allow to close polygon after first point
                if len(self.points) > 2 and dx <= threshold and dy <= threshold:
                    self.closePolygon()
                    return False

                # Update polygon last point not too close to previous one
                dataPos = self.machine.plot.pixelToData(x, y)
                assert dataPos is not None
                self.updateSelectionArea()

                # checking that the new points isnt the same (within range)
                # of the previous one
                # This has to be done because sometimes the mouse release event
                # is caught right after entering the Select state (i.e : press
                # in Idle state, but with a slightly different position that
                # the mouse press. So we had the two first vertices that were
                # almost identical.
                previousPos = self.machine.plot.dataToPixel(
                    *self.points[-2], check=False
                )
                dx, dy = abs(previousPos[0] - x), abs(previousPos[1] - y)
                if dx >= threshold or dy >= threshold:
                    self.points.append(dataPos)
                else:
                    self.points[-1] = dataPos

                return True
            return False

        def onMove(self, x, y):
            firstPos = self.machine.plot.dataToPixel(*self._firstPos, check=False)
            dx, dy = abs(firstPos[0] - x), abs(firstPos[1] - y)
            threshold = self.machine.getDragThreshold()

            if dx <= threshold and dy <= threshold:
                x, y = firstPos  # Snap to first point

            dataPos = self.machine.plot.pixelToData(x, y)
            assert dataPos is not None
            self.points[-1] = dataPos
            self.updateSelectionArea()

    def __init__(self, plot, parameters):
        states = {"idle": SelectPolygon.Idle, "select": SelectPolygon.Select}
        super(SelectPolygon, self).__init__(plot, parameters, states, "idle")

    def cancel(self):
        if isinstance(self.state, self.states["select"]):
            self.resetSelectionArea()

    def getDragThreshold(self):
        """Return dragging ratio with device to pixel ratio applied.

        :rtype: float
        """
        ratio = self.plot.window().windowHandle().devicePixelRatio()
        return self.DRAG_THRESHOLD_DIST * ratio


class Select2Points(Select):
    """Base class for drawing selection based on 2 input points."""

    class Idle(State):
        def onPress(self, x, y, btn):
            if btn == LEFT_BTN:
                self.goto("start", x, y)
                return True

    class Start(State):
        def enterState(self, x, y):
            self.machine.beginSelect(x, y)

        def onMove(self, x, y):
            self.goto("select", x, y)

        def onRelease(self, x, y, btn):
            if btn == LEFT_BTN:
                self.goto("select", x, y)
                return True

    class Select(State):
        def enterState(self, x, y):
            self.onMove(x, y)

        def onMove(self, x, y):
            self.machine.select(x, y)

        def onRelease(self, x, y, btn):
            if btn == LEFT_BTN:
                self.machine.endSelect(x, y)
                self.goto("idle")

    def __init__(self, plot, parameters):
        states = {
            "idle": Select2Points.Idle,
            "start": Select2Points.Start,
            "select": Select2Points.Select,
        }
        super(Select2Points, self).__init__(plot, parameters, states, "idle")

    def beginSelect(self, x, y):
        pass

    def select(self, x, y):
        pass

    def endSelect(self, x, y):
        pass

    def cancelSelect(self):
        pass

    def cancel(self):
        if isinstance(self.state, self.states["select"]):
            self.cancelSelect()


class SelectEllipse(Select2Points):
    """Drawing ellipse selection area state machine."""

    def beginSelect(self, x, y):
        self.center = self.plot.pixelToData(x, y)
        assert self.center is not None

    def _getEllipseSize(self, pointInEllipse):
        """
        Returns the size from the center to the bounding box of the ellipse.

        :param Tuple[float,float] pointInEllipse: A point of the ellipse
        :rtype: Tuple[float,float]
        """
        x = abs(self.center[0] - pointInEllipse[0])
        y = abs(self.center[1] - pointInEllipse[1])
        if x == 0 or y == 0:
            return x, y
        # Ellipse definitions
        # e: eccentricity
        # a: length fron center to bounding box width
        # b: length fron center to bounding box height
        # Equations
        # (1) b < a
        # (2) For x,y a point in the ellipse: x^2/a^2 + y^2/b^2 = 1
        # (3) b = a * sqrt(1-e^2)
        # (4) e = sqrt(a^2 - b^2) / a

        # The eccentricity of the ellipse defined by a,b=x,y is the same
        # as the one we are searching for.
        swap = x < y
        if swap:
            x, y = y, x
        e = math.sqrt(x**2 - y**2) / x
        # From (2) using (3) to replace b
        # a^2 = x^2 + y^2 / (1-e^2)
        a = math.sqrt(x**2 + y**2 / (1.0 - e**2))
        b = a * math.sqrt(1 - e**2)
        if swap:
            a, b = b, a
        return a, b

    def select(self, x, y):
        dataPos = self.plot.pixelToData(x, y)
        assert dataPos is not None
        width, height = self._getEllipseSize(dataPos)

        # Circle used for circle preview
        nbpoints = 27.0
        angles = numpy.arange(nbpoints) * numpy.pi * 2.0 / nbpoints
        circleShape = numpy.array(
            (numpy.cos(angles) * width, numpy.sin(angles) * height)
        ).T
        circleShape += numpy.array(self.center)

        self.setSelectionArea(
            circleShape, shape="polygon", fill="hatch", color=self.color
        )

        eventDict = prepareDrawingSignal(
            "drawingProgress",
            "ellipse",
            (self.center, (width, height)),
            self.parameters,
        )
        self.plot.notify(**eventDict)

    def endSelect(self, x, y):
        self.resetSelectionArea()

        dataPos = self.plot.pixelToData(x, y)
        assert dataPos is not None
        width, height = self._getEllipseSize(dataPos)

        eventDict = prepareDrawingSignal(
            "drawingFinished",
            "ellipse",
            (self.center, (width, height)),
            self.parameters,
        )
        self.plot.notify(**eventDict)

    def cancelSelect(self):
        self.resetSelectionArea()


class SelectRectangle(Select2Points):
    """Drawing rectangle selection area state machine."""

    def beginSelect(self, x, y):
        self.startPt = self.plot.pixelToData(x, y)
        assert self.startPt is not None

    def select(self, x, y):
        dataPos = self.plot.pixelToData(x, y)
        assert dataPos is not None

        self.setSelectionArea(
            (
                self.startPt,
                (self.startPt[0], dataPos[1]),
                dataPos,
                (dataPos[0], self.startPt[1]),
            ),
            fill="hatch",
            color=self.color,
        )

        eventDict = prepareDrawingSignal(
            "drawingProgress", "rectangle", (self.startPt, dataPos), self.parameters
        )
        self.plot.notify(**eventDict)

    def endSelect(self, x, y):
        self.resetSelectionArea()

        dataPos = self.plot.pixelToData(x, y)
        assert dataPos is not None

        eventDict = prepareDrawingSignal(
            "drawingFinished", "rectangle", (self.startPt, dataPos), self.parameters
        )
        self.plot.notify(**eventDict)

    def cancelSelect(self):
        self.resetSelectionArea()


class SelectLine(Select2Points):
    """Drawing line selection area state machine."""

    def beginSelect(self, x, y):
        self.startPt = self.plot.pixelToData(x, y)
        assert self.startPt is not None

    def select(self, x, y):
        dataPos = self.plot.pixelToData(x, y)
        assert dataPos is not None

        self.setSelectionArea((self.startPt, dataPos), fill="hatch", color=self.color)

        eventDict = prepareDrawingSignal(
            "drawingProgress", "line", (self.startPt, dataPos), self.parameters
        )
        self.plot.notify(**eventDict)

    def endSelect(self, x, y):
        self.resetSelectionArea()

        dataPos = self.plot.pixelToData(x, y)
        assert dataPos is not None

        eventDict = prepareDrawingSignal(
            "drawingFinished", "line", (self.startPt, dataPos), self.parameters
        )
        self.plot.notify(**eventDict)

    def cancelSelect(self):
        self.resetSelectionArea()


class Select1Point(Select):
    """Base class for drawing selection area based on one input point."""

    class Idle(State):
        def onPress(self, x, y, btn):
            if btn == LEFT_BTN:
                self.goto("select", x, y)
                return True

    class Select(State):
        def enterState(self, x, y):
            self.onMove(x, y)

        def onMove(self, x, y):
            self.machine.select(x, y)

        def onRelease(self, x, y, btn):
            if btn == LEFT_BTN:
                self.machine.endSelect(x, y)
                self.goto("idle")

        def onWheel(self, x, y, angle):
            self.machine.onWheel(x, y, angle)  # Call select default wheel
            self.machine.select(x, y)

    def __init__(self, plot, parameters):
        states = {"idle": Select1Point.Idle, "select": Select1Point.Select}
        super(Select1Point, self).__init__(plot, parameters, states, "idle")

    def select(self, x, y):
        pass

    def endSelect(self, x, y):
        pass

    def cancelSelect(self):
        pass

    def cancel(self):
        if isinstance(self.state, self.states["select"]):
            self.cancelSelect()


class SelectHLine(Select1Point):
    """Drawing a horizontal line selection area state machine."""

    def _hLine(self, y):
        """Return points in data coords of the segment visible in the plot.

        Supports non-orthogonal axes.
        """
        left, _top, width, _height = self.plot.getPlotBoundsInPixels()

        dataPos1 = self.plot.pixelToData(left, y, check=False)
        dataPos2 = self.plot.pixelToData(left + width, y, check=False)
        return dataPos1, dataPos2

    def select(self, x, y):
        points = self._hLine(y)
        self.setSelectionArea(points, fill="hatch", color=self.color)

        eventDict = prepareDrawingSignal(
            "drawingProgress", "hline", points, self.parameters
        )
        self.plot.notify(**eventDict)

    def endSelect(self, x, y):
        self.resetSelectionArea()

        eventDict = prepareDrawingSignal(
            "drawingFinished", "hline", self._hLine(y), self.parameters
        )
        self.plot.notify(**eventDict)

    def cancelSelect(self):
        self.resetSelectionArea()


class SelectVLine(Select1Point):
    """Drawing a vertical line selection area state machine."""

    def _vLine(self, x):
        """Return points in data coords of the segment visible in the plot.

        Supports non-orthogonal axes.
        """
        _left, top, _width, height = self.plot.getPlotBoundsInPixels()

        dataPos1 = self.plot.pixelToData(x, top, check=False)
        dataPos2 = self.plot.pixelToData(x, top + height, check=False)
        return dataPos1, dataPos2

    def select(self, x, y):
        points = self._vLine(x)
        self.setSelectionArea(points, fill="hatch", color=self.color)

        eventDict = prepareDrawingSignal(
            "drawingProgress", "vline", points, self.parameters
        )
        self.plot.notify(**eventDict)

    def endSelect(self, x, y):
        self.resetSelectionArea()

        eventDict = prepareDrawingSignal(
            "drawingFinished", "vline", self._vLine(x), self.parameters
        )
        self.plot.notify(**eventDict)

    def cancelSelect(self):
        self.resetSelectionArea()


class DrawFreeHand(Select):
    """Interaction for drawing pencil. It display the preview of the pencil
    before pressing the mouse.
    """

    class Idle(State):
        def onPress(self, x, y, btn):
            if btn == LEFT_BTN:
                self.goto("select", x, y)
                return True

        def onMove(self, x, y):
            self.machine.updatePencilShape(x, y)

        def onLeave(self):
            self.machine.cancel()

    class Select(State):
        def enterState(self, x, y):
            self.__isOut = False
            self.machine.setFirstPoint(x, y)

        def onMove(self, x, y):
            self.machine.updatePencilShape(x, y)
            self.machine.select(x, y)

        def onRelease(self, x, y, btn):
            if btn == LEFT_BTN:
                if self.__isOut:
                    self.machine.resetSelectionArea()
                self.machine.endSelect(x, y)
                self.goto("idle")

        def onEnter(self):
            self.__isOut = False

        def onLeave(self):
            self.__isOut = True

    def __init__(self, plot, parameters):
        # Circle used for pencil preview
        angle = numpy.arange(13.0) * numpy.pi * 2.0 / 13.0
        size = parameters.get("width", 1.0) * 0.5
        self._circle = size * numpy.array((numpy.cos(angle), numpy.sin(angle))).T

        states = {"idle": DrawFreeHand.Idle, "select": DrawFreeHand.Select}
        super(DrawFreeHand, self).__init__(plot, parameters, states, "idle")

    @property
    def width(self):
        return self.parameters.get("width", None)

    def setFirstPoint(self, x, y):
        self._points = []
        self.select(x, y)

    def updatePencilShape(self, x, y):
        center = self.plot.pixelToData(x, y, check=False)
        assert center is not None

        polygon = center + self._circle

        self.setSelectionArea(polygon, fill="none", color=self.color)

    def select(self, x, y):
        pos = self.plot.pixelToData(x, y, check=False)
        if len(self._points) > 0:
            if self._points[-1] == pos:
                # Skip same points
                return
        self._points.append(pos)
        eventDict = prepareDrawingSignal(
            "drawingProgress", "polylines", self._points, self.parameters
        )
        self.plot.notify(**eventDict)

    def endSelect(self, x, y):
        pos = self.plot.pixelToData(x, y, check=False)
        if len(self._points) > 0:
            if self._points[-1] != pos:
                # Append if different
                self._points.append(pos)

        eventDict = prepareDrawingSignal(
            "drawingFinished", "polylines", self._points, self.parameters
        )
        self.plot.notify(**eventDict)
        self._points = None

    def cancelSelect(self):
        self.resetSelectionArea()

    def cancel(self):
        self.resetSelectionArea()


class SelectFreeLine(ClickOrDrag, _PlotInteraction):
    """Base class for drawing free lines with tools such as pencil."""

    def __init__(self, plot, parameters):
        """Init a state machine.

        :param plot: The plot to apply changes to.
        :param dict parameters: A dict of parameters such as color.
        """
        # self.DRAG_THRESHOLD_SQUARE_DIST = 1  # Disable first move threshold
        self._points = []
        ClickOrDrag.__init__(self)
        _PlotInteraction.__init__(self, plot)
        self.parameters = parameters

    @property
    def color(self):
        return self.parameters.get("color", None)

    def click(self, x, y, btn):
        if btn == LEFT_BTN:
            self._processEvent(x, y, isLast=True)

    def beginDrag(self, x, y, btn):
        self._processEvent(x, y, isLast=False)

    def drag(self, x, y, btn):
        self._processEvent(x, y, isLast=False)

    def endDrag(self, startPos, endPos, btn):
        x, y = endPos
        self._processEvent(x, y, isLast=True)

    def cancel(self):
        self.resetSelectionArea()
        self._points = []

    def _processEvent(self, x, y, isLast):
        dataPos = self.plot.pixelToData(x, y, check=False)
        isNewPoint = not self._points or dataPos != self._points[-1]

        if isNewPoint:
            self._points.append(dataPos)

        if isNewPoint or isLast:
            eventDict = prepareDrawingSignal(
                "drawingFinished" if isLast else "drawingProgress",
                "polylines",
                self._points,
                self.parameters,
            )
            self.plot.notify(**eventDict)

        if not isLast:
            self.setSelectionArea(
                self._points, fill="none", color=self.color, shape="polylines"
            )
        else:
            self.cancel()


# ItemInteraction #############################################################


class ItemsInteraction(ClickOrDrag, _PlotInteraction):
    """Interaction with items (markers, curves and images).

    This class provides selection and dragging of plot primitives
    that support those interaction.
    It is also meant to be combined with the zoom interaction.
    """

    class Idle(ClickOrDrag.Idle):
        def __init__(self, *args, **kw):
            super(ItemsInteraction.Idle, self).__init__(*args, **kw)
            self._hoverMarker = None

        def enterState(self):
            widget = self.machine.plot.getWidgetHandle()
            if widget is None or not widget.isVisible():
                return
            position = widget.mapFromGlobal(qt.QCursor.pos())
            self.onMove(position.x(), position.y())

        def onMove(self, x, y):
            marker = self.machine.plot._getMarkerAt(x, y)

            if marker is not None:
                dataPos = self.machine.plot.pixelToData(x, y)
                assert dataPos is not None
                eventDict = prepareHoverSignal(
                    marker.getName(),
                    "marker",
                    dataPos,
                    (x, y),
                    marker.isDraggable(),
                    marker.isSelectable(),
                )
                self.machine.plot.notify(**eventDict)

            if marker != self._hoverMarker:
                self._hoverMarker = marker
                self.machine._setCursorForMarker(marker)

            return True

    def __init__(self, plot):
        self._pan = Pan(plot)

        _PlotInteraction.__init__(self, plot)
        ClickOrDrag.__init__(
            self, clickButtons=(LEFT_BTN, RIGHT_BTN), dragButtons=(LEFT_BTN, MIDDLE_BTN)
        )

    def _setCursorForMarker(self, marker: Optional[items.MarkerBase] = None):
        """Set mouse cursor for given marker"""
        if marker is None:
            cursor = None

        elif marker.isDraggable():
            if isinstance(marker, items.YMarker):
                cursor = CURSOR_SIZE_VER
            elif isinstance(marker, items.XMarker):
                cursor = CURSOR_SIZE_HOR
            else:
                cursor = CURSOR_SIZE_ALL

        elif marker.isSelectable():
            cursor = CURSOR_POINTING

        else:
            cursor = None

        self.plot.setGraphCursorShape(cursor)

    def click(self, x, y, btn):
        """Handle mouse click

        :param x: X position of the mouse in pixels
        :param y: Y position of the mouse in pixels
        :param btn: Pressed button id
        :return: True if click is catched by an item, False otherwise
        """
        # Signal mouse clicked event
        dataPos = self.plot.pixelToData(x, y)
        assert dataPos is not None
        eventDict = prepareMouseSignal(
            "mouseClicked", btn, dataPos[0], dataPos[1], x, y
        )
        self.plot.notify(**eventDict)

        eventDict = self._handleClick(x, y, btn)
        if eventDict is not None:
            self.plot.notify(**eventDict)

    def _handleClick(self, x, y, btn):
        """Perform picking and prepare event if click is handled here

        :param x: X position of the mouse in pixels
        :param y: Y position of the mouse in pixels
        :param btn: Pressed button id
        :return: event description to send of None if not handling event.
        :rtype: dict or None
        """

        if btn == LEFT_BTN:
            result = self.plot._pickTopMost(x, y, lambda i: i.isSelectable())
            if result is None:
                return None

            item = result.getItem()

            if isinstance(item, items.MarkerBase):
                xData, yData = item.getPosition()
                if xData is None:
                    xData = [0, 1]
                if yData is None:
                    yData = [0, 1]

                eventDict = prepareMarkerSignal(
                    "markerClicked",
                    "left",
                    item.getName(),
                    "marker",
                    item.isDraggable(),
                    item.isSelectable(),
                    (xData, yData),
                    (x, y),
                    None,
                )
                return eventDict

            elif isinstance(item, items.Curve):
                dataPos = self.plot.pixelToData(x, y)
                assert dataPos is not None

                xData = item.getXData(copy=False)
                yData = item.getYData(copy=False)

                indices = result.getIndices(copy=False)
                eventDict = prepareCurveSignal(
                    "left",
                    item,
                    xData[indices],
                    yData[indices],
                    dataPos[0],
                    dataPos[1],
                    x,
                    y,
                )
                return eventDict

            elif isinstance(item, items.ImageBase):
                dataPos = self.plot.pixelToData(x, y)
                assert dataPos is not None

                indices = result.getIndices(copy=False)
                row, column = indices[0][0], indices[1][0]
                eventDict = prepareImageSignal(
                    "left", item, column, row, dataPos[0], dataPos[1], x, y
                )
                return eventDict

        return None

    def _signalMarkerMovingEvent(self, eventType, marker, x, y):
        assert marker is not None

        xData, yData = marker.getPosition()
        if xData is None:
            xData = [0, 1]
        if yData is None:
            yData = [0, 1]

        posDataCursor = self.plot.pixelToData(x, y)
        assert posDataCursor is not None

        eventDict = prepareMarkerSignal(
            eventType,
            "left",
            marker.getName(),
            "marker",
            marker.isDraggable(),
            marker.isSelectable(),
            (xData, yData),
            (x, y),
            posDataCursor,
        )
        self.plot.notify(**eventDict)

    @staticmethod
    def __isDraggableItem(item):
        return isinstance(item, items.DraggableMixIn) and item.isDraggable()

    def __terminateDrag(self, x, y):
        """Finalize a drag operation by reseting to initial state"""
        self._setCursorForMarker(self.plot._getMarkerAt(x, y))
        self.draggedItemRef = None

    def beginDrag(self, x, y, btn):
        """Handle begining of drag interaction

        :param x: X position of the mouse in pixels
        :param y: Y position of the mouse in pixels
        :param str btn: The mouse button for which a drag is starting.
        :return: True if drag is catched by an item, False otherwise
        """
        if btn == LEFT_BTN:
            self._lastPos = self.plot.pixelToData(x, y)
            assert self._lastPos is not None

            result = self.plot._pickTopMost(x, y, self.__isDraggableItem)
            item = result.getItem() if result is not None else None

            self.draggedItemRef = None if item is None else weakref.ref(item)

            if item is None:
                self.__terminateDrag(x, y)
                return False

            if isinstance(item, items.MarkerBase):
                self._signalMarkerMovingEvent("markerMoving", item, x, y)
                item._startDrag()

            return True
        elif btn == MIDDLE_BTN:
            self._pan.beginDrag(x, y, btn)
            return True

    def drag(self, x, y, btn):
        if btn == LEFT_BTN:
            dataPos = self.plot.pixelToData(x, y)
            assert dataPos is not None

            item = None if self.draggedItemRef is None else self.draggedItemRef()
            if item is not None:
                item.drag(self._lastPos, dataPos)

                if isinstance(item, items.MarkerBase):
                    self._signalMarkerMovingEvent("markerMoving", item, x, y)

            self._lastPos = dataPos
        elif btn == MIDDLE_BTN:
            self._pan.drag(x, y, btn)

    def endDrag(self, startPos, endPos, btn):
        if btn == LEFT_BTN:
            item = None if self.draggedItemRef is None else self.draggedItemRef()
            if isinstance(item, items.MarkerBase):
                posData = list(item.getPosition())
                if posData[0] is None:
                    posData[0] = 1.0
                if posData[1] is None:
                    posData[1] = 1.0

                eventDict = prepareMarkerSignal(
                    "markerMoved",
                    "left",
                    item.getLegend(),
                    "marker",
                    item.isDraggable(),
                    item.isSelectable(),
                    posData,
                )
                self.plot.notify(**eventDict)
                item._endDrag()

            self.__terminateDrag(*endPos)
        elif btn == MIDDLE_BTN:
            self._pan.endDrag(startPos, endPos, btn)

    def cancel(self):
        self._pan.cancel()
        widget = self.plot.getWidgetHandle()
        if widget is None or not widget.isVisible():
            return
        position = widget.mapFromGlobal(qt.QCursor.pos())
        self.__terminateDrag(position.x(), position.y())


class ItemsInteractionForCombo(ItemsInteraction):
    """Interaction with items to combine through :class:`FocusManager`."""

    class Idle(ItemsInteraction.Idle):
        @staticmethod
        def __isItemSelectableOrDraggable(item):
            return item.isSelectable() or (
                isinstance(item, items.DraggableMixIn) and item.isDraggable()
            )

        def onPress(self, x, y, btn):
            if btn == LEFT_BTN:
                result = self.machine.plot._pickTopMost(
                    x, y, self.__isItemSelectableOrDraggable
                )
                if result is not None:  # Request focus and handle interaction
                    self.goto("clickOrDrag", x, y, btn)
                    return True
                else:  # Do not request focus
                    return False
            else:
                return super().onPress(x, y, btn)


# FocusManager ################################################################


class FocusManager(StateMachine):
    """Manages focus across multiple event handlers

    On press an event handler can acquire focus.
    By default it looses focus when all buttons are released.
    """

    class Idle(State):
        def onPress(self, x, y, btn):
            if btn == LEFT_BTN:
                for eventHandler in self.machine.eventHandlers:
                    requestFocus = eventHandler.handleEvent("press", x, y, btn)
                    if requestFocus:
                        self.goto("focus", eventHandler, btn)
                        break

        def _processEvent(self, *args):
            for eventHandler in self.machine.eventHandlers:
                consumeEvent = eventHandler.handleEvent(*args)
                if consumeEvent:
                    break

        def onMove(self, x, y):
            self._processEvent("move", x, y)

        def onRelease(self, x, y, btn):
            if btn == LEFT_BTN:
                self._processEvent("release", x, y, btn)

        def onWheel(self, x, y, angle):
            self._processEvent("wheel", x, y, angle)

    class Focus(State):
        def enterState(self, eventHandler, btn):
            self.eventHandler = eventHandler
            self.focusBtns = {btn}

        def validate(self):
            self.eventHandler.validate()
            self.goto("idle")

        def onPress(self, x, y, btn):
            if btn == LEFT_BTN:
                self.focusBtns.add(btn)
                self.eventHandler.handleEvent("press", x, y, btn)

        def onMove(self, x, y):
            self.eventHandler.handleEvent("move", x, y)

        def onRelease(self, x, y, btn):
            if btn == LEFT_BTN:
                self.focusBtns.discard(btn)
                requestFocus = self.eventHandler.handleEvent("release", x, y, btn)
                if len(self.focusBtns) == 0 and not requestFocus:
                    self.goto("idle")

        def onWheel(self, x, y, angleInDegrees):
            self.eventHandler.handleEvent("wheel", x, y, angleInDegrees)

    def __init__(self, eventHandlers=()):
        self.eventHandlers = list(eventHandlers)

        states = {"idle": FocusManager.Idle, "focus": FocusManager.Focus}
        super(FocusManager, self).__init__(states, "idle")

    def cancel(self):
        for handler in self.eventHandlers:
            handler.cancel()


class ZoomAndSelect(ItemsInteraction):
    """Combine Zoom and ItemInteraction state machine.

    :param plot: The Plot to which this interaction is attached
    :param color: The color to use for the zoom area bounding box
    """

    def __init__(self, plot, color):
        super(ZoomAndSelect, self).__init__(plot)
        self._zoom = Zoom(plot, color)
        self._doZoom = False

    @property
    def color(self):
        """Color of the zoom area"""
        return self._zoom.color

    @property
    def zoomEnabledAxes(self) -> EnabledAxes:
        """Whether or not to apply zoom for each axis"""
        return self._zoom.enabledAxes

    @zoomEnabledAxes.setter
    def zoomEnabledAxes(self, enabledAxes: EnabledAxes):
        self._zoom.enabledAxes = enabledAxes

    def click(self, x, y, btn):
        """Handle mouse click

        :param x: X position of the mouse in pixels
        :param y: Y position of the mouse in pixels
        :param btn: Pressed button id
        :return: True if click is catched by an item, False otherwise
        """
        eventDict = self._handleClick(x, y, btn)

        if eventDict is not None:
            # Signal mouse clicked event
            dataPos = self.plot.pixelToData(x, y)
            assert dataPos is not None
            clickedEventDict = prepareMouseSignal(
                "mouseClicked", btn, dataPos[0], dataPos[1], x, y
            )
            self.plot.notify(**clickedEventDict)

            self.plot.notify(**eventDict)

        else:
            self._zoom.click(x, y, btn)

    def beginDrag(self, x, y, btn):
        """Handle start drag and switching between zoom and item drag.

        :param x: X position in pixels
        :param y: Y position in pixels
        :param str btn: The mouse button for which a drag is starting.
        """
        self._doZoom = not super(ZoomAndSelect, self).beginDrag(x, y, btn)
        if self._doZoom:
            self._zoom.beginDrag(x, y, btn)

    def drag(self, x, y, btn):
        """Handle drag, eventually forwarding to zoom.

        :param x: X position in pixels
        :param y: Y position in pixels
        :param str btn: The mouse button for which a drag is in progress.
        """
        if self._doZoom:
            return self._zoom.drag(x, y, btn)
        else:
            return super(ZoomAndSelect, self).drag(x, y, btn)

    def endDrag(self, startPos, endPos, btn):
        """Handle end of drag, eventually forwarding to zoom.

        :param startPos: (x, y) position at the beginning of the drag
        :param endPos: (x, y) position at the end of the drag
        :param str btn: The mouse button for which a drag is done.
        """
        if self._doZoom:
            return self._zoom.endDrag(startPos, endPos, btn)
        else:
            return super(ZoomAndSelect, self).endDrag(startPos, endPos, btn)


class PanAndSelect(ItemsInteraction):
    """Combine Pan and ItemInteraction state machine.

    :param plot: The Plot to which this interaction is attached
    """

    def __init__(self, plot):
        super(PanAndSelect, self).__init__(plot)
        self._pan = Pan(plot)
        self._doPan = False

    def click(self, x, y, btn):
        """Handle mouse click

        :param x: X position of the mouse in pixels
        :param y: Y position of the mouse in pixels
        :param btn: Pressed button id
        :return: True if click is catched by an item, False otherwise
        """
        eventDict = self._handleClick(x, y, btn)

        if eventDict is not None:
            # Signal mouse clicked event
            dataPos = self.plot.pixelToData(x, y)
            assert dataPos is not None
            clickedEventDict = prepareMouseSignal(
                "mouseClicked", btn, dataPos[0], dataPos[1], x, y
            )
            self.plot.notify(**clickedEventDict)

            self.plot.notify(**eventDict)

        else:
            self._pan.click(x, y, btn)

    def beginDrag(self, x, y, btn):
        """Handle start drag and switching between zoom and item drag.

        :param x: X position in pixels
        :param y: Y position in pixels
        :param str btn: The mouse button for which a drag is starting.
        """
        self._doPan = not super(PanAndSelect, self).beginDrag(x, y, btn)
        if self._doPan:
            self._pan.beginDrag(x, y, btn)

    def drag(self, x, y, btn):
        """Handle drag, eventually forwarding to zoom.

        :param x: X position in pixels
        :param y: Y position in pixels
        :param str btn: The mouse button for which a drag is in progress.
        """
        if self._doPan:
            return self._pan.drag(x, y, btn)
        else:
            return super(PanAndSelect, self).drag(x, y, btn)

    def endDrag(self, startPos, endPos, btn):
        """Handle end of drag, eventually forwarding to zoom.

        :param startPos: (x, y) position at the beginning of the drag
        :param endPos: (x, y) position at the end of the drag
        :param str btn: The mouse button for which a drag is done.
        """
        if self._doPan:
            return self._pan.endDrag(startPos, endPos, btn)
        else:
            return super(PanAndSelect, self).endDrag(startPos, endPos, btn)


# Interaction mode control ####################################################

# Mapping of draw modes: event handler
_DRAW_MODES = {
    "polygon": SelectPolygon,
    "rectangle": SelectRectangle,
    "ellipse": SelectEllipse,
    "line": SelectLine,
    "vline": SelectVLine,
    "hline": SelectHLine,
    "polylines": SelectFreeLine,
    "pencil": DrawFreeHand,
}


class DrawMode(FocusManager):
    """Interactive mode for draw and select"""

    def __init__(self, plot, shape, label, color, width):
        eventHandlerClass = _DRAW_MODES[shape]
        parameters = {
            "shape": shape,
            "label": label,
            "color": color,
            "width": width,
        }
        super().__init__(
            (
                Pan(plot, clickButtons=(), dragButtons=(MIDDLE_BTN,)),
                eventHandlerClass(plot, parameters),
            )
        )

    def getDescription(self):
        """Returns the dict describing this interactive mode"""
        params = self.eventHandlers[1].parameters.copy()
        params["mode"] = "draw"
        return params


class DrawSelectMode(FocusManager):
    """Interactive mode for draw and select"""

    def __init__(self, plot, shape, label, color, width):
        eventHandlerClass = _DRAW_MODES[shape]
        self._pan = Pan(plot)
        self._panStart = None
        parameters = {
            "shape": shape,
            "label": label,
            "color": color,
            "width": width,
        }
        super().__init__(
            (ItemsInteractionForCombo(plot), eventHandlerClass(plot, parameters))
        )

    def handleEvent(self, eventName, *args, **kwargs):
        # Hack to add pan interaction to select-draw
        # See issue Refactor PlotWidget interaction #3292
        if eventName == "press" and args[2] == MIDDLE_BTN:
            self._panStart = args[:2]
            self._pan.beginDrag(*args)
            return  # Consume middle click events
        elif eventName == "release" and args[2] == MIDDLE_BTN:
            self._panStart = None
            self._pan.endDrag(self._panStart, args[:2], MIDDLE_BTN)
            return  # Consume middle click events
        elif self._panStart is not None and eventName == "move":
            x, y = args[:2]
            self._pan.drag(x, y, MIDDLE_BTN)

        super().handleEvent(eventName, *args, **kwargs)

    def getDescription(self):
        """Returns the dict describing this interactive mode"""
        params = self.eventHandlers[1].parameters.copy()
        params["mode"] = "select-draw"
        return params


class PlotInteraction(qt.QObject):
    """PlotWidget user interaction handler.

    :param plot: The :class:`PlotWidget` to apply interaction to
    """

    sigChanged = qt.Signal()
    """Signal emitted when the interaction configuration has changed"""

    _DRAW_MODES = {
        "polygon": SelectPolygon,
        "rectangle": SelectRectangle,
        "ellipse": SelectEllipse,
        "line": SelectLine,
        "vline": SelectVLine,
        "hline": SelectHLine,
        "polylines": SelectFreeLine,
        "pencil": DrawFreeHand,
    }

    def __init__(self, parent):
        super().__init__(parent)
        self.__zoomOnWheel = True
        self.__zoomEnabledAxes = EnabledAxes()

        # Default event handler
        self._eventHandler = ItemsInteraction(parent)

    def isZoomOnWheelEnabled(self) -> bool:
        """Returns whether or not wheel interaction triggers zoom"""
        return self.__zoomOnWheel

    def setZoomOnWheelEnabled(self, enabled: bool):
        """Toggle zoom on wheel interaction"""
        if enabled != self.__zoomOnWheel:
            self.__zoomOnWheel = enabled
            self.sigChanged.emit()

    def setZoomEnabledAxes(self, xaxis: bool, yaxis: bool, y2axis: bool):
        """Toggle zoom interaction for each axis

        This is taken into account only if the plot does not keep aspect ratio.
        """
        zoomEnabledAxes = EnabledAxes(xaxis, yaxis, y2axis)
        if zoomEnabledAxes != self.__zoomEnabledAxes:
            self.__zoomEnabledAxes = zoomEnabledAxes
            if isinstance(self._eventHandler, ZoomAndSelect):
                self._eventHandler.zoomEnabledAxes = zoomEnabledAxes
            self.sigChanged.emit()

    def getZoomEnabledAxes(self) -> EnabledAxes:
        """Returns axes for which zoom is enabled"""
        return self.__zoomEnabledAxes

    def _getInteractiveMode(self):
        """Returns the current interactive mode as a dict.

        The returned dict contains at least the key 'mode'.
        Mode can be: 'draw', 'pan', 'select', 'select-draw', 'zoom'.
        It can also contains extra keys (e.g., 'color') specific to a mode
        as provided to :meth:`_setInteractiveMode`.
        """
        if isinstance(self._eventHandler, ZoomAndSelect):
            return {"mode": "zoom", "color": self._eventHandler.color}

        elif isinstance(self._eventHandler, (DrawMode, DrawSelectMode)):
            return self._eventHandler.getDescription()

        elif isinstance(self._eventHandler, PanAndSelect):
            return {"mode": "pan"}

        else:
            return {"mode": "select"}

    def _validate(self):
        """Validate the current interaction if possible

        If was designed to close the polygon interaction.
        """
        self._eventHandler.validate()

    def _setInteractiveMode(
        self, mode, color="black", shape="polygon", label=None, width=None
    ):
        """Switch the interactive mode.

        :param str mode: The name of the interactive mode.
                         In 'draw', 'pan', 'select', 'select-draw', 'zoom'.
        :param color: Only for 'draw' and 'zoom' modes.
                      Color to use for drawing selection area. Default black.
                      If None, selection area is not drawn.
        :type color: Color description: The name as a str or
                     a tuple of 4 floats or None.
        :param str shape: Only for 'draw' mode. The kind of shape to draw.
                          In 'polygon', 'rectangle', 'line', 'vline', 'hline',
                          'polylines'.
                          Default is 'polygon'.
        :param str label: Only for 'draw' mode.
        :param float width: Width of the pencil. Only for draw pencil mode.
        """
        assert mode in ("draw", "pan", "select", "select-draw", "zoom")

        plotWidget = self.parent()
        assert plotWidget is not None

        if isinstance(color, numpy.ndarray) or color not in (None, "video inverted"):
            color = colors.rgba(color)

        if mode in ("draw", "select-draw"):
            self._eventHandler.cancel()
            handlerClass = DrawMode if mode == "draw" else DrawSelectMode
            self._eventHandler = handlerClass(plotWidget, shape, label, color, width)

        elif mode == "pan":
            # Ignores color, shape and label
            self._eventHandler.cancel()
            self._eventHandler = PanAndSelect(plotWidget)

        elif mode == "zoom":
            # Ignores shape and label
            self._eventHandler.cancel()
            self._eventHandler = ZoomAndSelect(plotWidget, color)
            self._eventHandler.zoomEnabledAxes = self.getZoomEnabledAxes()

        else:  # Default mode: interaction with plot objects
            # Ignores color, shape and label
            self._eventHandler.cancel()
            self._eventHandler = ItemsInteraction(plotWidget)

        self.sigChanged.emit()

    def handleEvent(self, event, *args, **kwargs):
        """Forward event to current interactive mode state machine."""
        if event == "wheel":  # Handle wheel events directly
            self._onWheel(*args, **kwargs)
            return

        self._eventHandler.handleEvent(event, *args, **kwargs)

    def _onWheel(self, x: float, y: float, angle: float):
        """Handle wheel events"""
        if not self.isZoomOnWheelEnabled():
            return

        plotWidget = self.parent()
        if plotWidget is None:
            return

        # All axes are enabled if keep aspect ratio is on
        enabledAxes = (
            EnabledAxes()
            if plotWidget.isKeepDataAspectRatio()
            else self.getZoomEnabledAxes()
        )
        if enabledAxes.isDisabled():
            return

        scale = 1.1 if angle > 0 else 1.0 / 1.1
        applyZoomToPlot(plotWidget, scale, (x, y), enabledAxes)
