# -*- coding: utf-8 -*-
#
# Licensed under the terms of the PyQwt License
# Copyright (C) 2003-2009 Gerard Vermeulen, for the original PyQwt example
# Copyright (c) 2015 Pierre Raybaut, for the PyQt5/PySide port and further
# developments (e.g. ported to PythonQwt API)
# (see LICENSE file for more details)

SHOW = True  # Show test in GUI-based test launcher

import os

import numpy as np
from qtpy.QtCore import QEvent, QObject, QPoint, QRect, QSize, Qt, Signal
from qtpy.QtGui import QBrush, QColor, QPainter, QPen
from qtpy.QtWidgets import QApplication, QMainWindow, QToolBar, QWhatsThis, QWidget

from qwt import (
    QwtPlot,
    QwtPlotCanvas,
    QwtPlotCurve,
    QwtPlotGrid,
    QwtScaleDiv,
    QwtScaleDraw,
    QwtSymbol,
)
from qwt.tests import utils

QT_API = os.environ["QT_API"]


class ColorBar(QWidget):
    colorSelected = Signal(QColor)

    def __init__(self, orientation, *args):
        QWidget.__init__(self, *args)
        self.__orientation = orientation
        self.__light = QColor(Qt.white)
        self.__dark = QColor(Qt.black)
        self.setCursor(Qt.PointingHandCursor)

    def setOrientation(self, orientation):
        self.__orientation = orientation
        self.update()

    def orientation(self):
        return self.__orientation

    def setRange(self, light, dark):
        self.__light = light
        self.__dark = dark
        self.update()

    def setLight(self, color):
        self.__light = color
        self.update()

    def setDark(self, color):
        self.__dark = color
        self.update()

    def light(self):
        return self.__light

    def dark(self):
        return self.__dark

    def mousePressEvent(self, event):
        if event.button() == Qt.LeftButton:
            pm = self.grab()
            color = QColor()
            color.setRgb(pm.toImage().pixel(event.x(), event.y()))
            self.colorSelected.emit(color)
            event.accept()

    def paintEvent(self, _):
        painter = QPainter(self)
        self.drawColorBar(painter, self.rect())

    def drawColorBar(self, painter, rect):
        h1, s1, v1, _ = self.__light.getHsv()
        h2, s2, v2, _ = self.__dark.getHsv()
        painter.save()
        painter.setClipRect(rect)
        painter.setClipping(True)
        painter.fillRect(rect, QBrush(self.__dark))
        sectionSize = 2
        if self.__orientation == Qt.Horizontal:
            numIntervals = rect.width() / sectionSize
        else:
            numIntervals = rect.height() / sectionSize
        section = QRect()
        for i in range(int(numIntervals)):
            if self.__orientation == Qt.Horizontal:
                section.setRect(
                    rect.x() + i * sectionSize, rect.y(), sectionSize, rect.heigh()
                )
            else:
                section.setRect(
                    rect.x(), rect.y() + i * sectionSize, rect.width(), sectionSize
                )
            ratio = float(i) / float(numIntervals)
            color = QColor()
            color.setHsv(
                h1 + int(ratio * (h2 - h1) + 0.5),
                s1 + int(ratio * (s2 - s1) + 0.5),
                v1 + int(ratio * (v2 - v1) + 0.5),
            )
            painter.fillRect(section, color)
        painter.restore()


class Plot(QwtPlot):
    def __init__(self, *args):
        QwtPlot.__init__(self, *args)

        self.setTitle("Interactive Plot")

        self.setCanvasColor(Qt.darkCyan)

        grid = QwtPlotGrid()
        grid.attach(self)
        grid.setMajorPen(QPen(Qt.white, 0, Qt.DotLine))

        self.setAxisScale(QwtPlot.xBottom, 0.0, 100.0)
        self.setAxisScale(QwtPlot.yLeft, 0.0, 100.0)

        # Avoid jumping when label with 3 digits
        # appear/disappear when scrolling vertically
        scaleDraw = self.axisScaleDraw(QwtPlot.yLeft)
        scaleDraw.setMinimumExtent(
            scaleDraw.extent(self.axisWidget(QwtPlot.yLeft).font())
        )

        self.plotLayout().setAlignCanvasToScales(True)

        self.__insertCurve(Qt.Vertical, Qt.blue, 30.0)
        self.__insertCurve(Qt.Vertical, Qt.magenta, 70.0)
        self.__insertCurve(Qt.Horizontal, Qt.yellow, 30.0)
        self.__insertCurve(Qt.Horizontal, Qt.white, 70.0)

        self.replot()

        scaleWidget = self.axisWidget(QwtPlot.yLeft)
        scaleWidget.setMargin(10)

        self.__colorBar = ColorBar(Qt.Vertical, scaleWidget)
        self.__colorBar.setRange(QColor(Qt.red), QColor(Qt.darkBlue))
        self.__colorBar.setFocusPolicy(Qt.TabFocus)
        self.__colorBar.colorSelected.connect(self.setCanvasColor)

        # we need the resize events, to lay out the color bar
        scaleWidget.installEventFilter(self)

        # we need the resize events, to lay out the wheel
        self.canvas().installEventFilter(self)

        scaleWidget.setWhatsThis(
            "Selecting a value at the scale will insert a new curve."
        )
        self.__colorBar.setWhatsThis(
            "Selecting a color will change the background of the plot."
        )
        self.axisWidget(QwtPlot.xBottom).setWhatsThis(
            "Selecting a value at the scale will insert a new curve."
        )

    def setCanvasColor(self, color):
        self.setCanvasBackground(color)
        self.replot()

    def scrollLeftAxis(self, value):
        self.setAxisScale(QwtPlot.yLeft, value, value + 100)
        self.replot()

    def eventFilter(self, obj, event):
        if event.type() == QEvent.Resize:
            size = event.size()
            if obj == self.axisWidget(QwtPlot.yLeft):
                margin = 2
                x = size.width() - obj.margin() + margin
                w = obj.margin() - 2 * margin
                y = int(obj.startBorderDist())
                h = int(size.height() - obj.startBorderDist() - obj.endBorderDist())
                self.__colorBar.setGeometry(x, y, w, h)
        return QwtPlot.eventFilter(self, obj, event)

    def insertCurve(self, axis, base):
        if axis == QwtPlot.yLeft or axis == QwtPlot.yRight:
            o = Qt.Horizontal
        else:
            o = Qt.Vertical
        self.__insertCurve(o, QColor(Qt.red), base)
        self.replot()

    def __insertCurve(self, orientation, color, base):
        curve = QwtPlotCurve()
        curve.attach(self)
        curve.setPen(QPen(color))
        curve.setSymbol(
            QwtSymbol(QwtSymbol.Ellipse, QBrush(Qt.gray), QPen(color), QSize(8, 8))
        )
        fixed = base * np.ones(10, float)
        changing = np.arange(0, 95.0, 10.0, float) + 5.0
        if orientation == Qt.Horizontal:
            curve.setData(changing, fixed)
        else:
            curve.setData(fixed, changing)


class CanvasPicker(QObject):
    def __init__(self, plot):
        QObject.__init__(self, plot)
        self.__selectedCurve = None
        self.__selectedPoint = -1
        self.__plot = plot
        canvas = plot.canvas()
        canvas.installEventFilter(self)
        # We want the focus, but no focus rect.
        # The selected point will be highlighted instead.
        canvas.setFocusPolicy(Qt.StrongFocus)
        canvas.setCursor(Qt.PointingHandCursor)
        canvas.setFocusIndicator(QwtPlotCanvas.ItemFocusIndicator)
        canvas.setFocus()
        canvas.setWhatsThis(
            "All points can be moved using the left mouse button "
            "or with these keys:\n\n"
            "- Up: Select next curve\n"
            "- Down: Select previous curve\n"
            '- Left, "-": Select next point\n'
            '- Right, "+": Select previous point\n'
            "- 7, 8, 9, 4, 6, 1, 2, 3: Move selected point"
        )
        self.__shiftCurveCursor(True)

    def event(self, event):
        if event.type() == QEvent.User:
            self.__showCursor(True)
            return True
        return QObject.event(self, event)

    def eventFilter(self, object, event):
        if event.type() == QEvent.FocusIn:
            self.__showCursor(True)
        if event.type() == QEvent.FocusOut:
            self.__showCursor(False)
        if event.type() == QEvent.Paint:
            QApplication.postEvent(self, QEvent(QEvent.User))
        elif event.type() == QEvent.MouseButtonPress:
            self.__select(event.position())
            return True
        elif event.type() == QEvent.MouseMove:
            self.__move(event.position())
            return True
        if event.type() == QEvent.KeyPress:
            delta = 5
            key = event.key()
            if key == Qt.Key_Up:
                self.__shiftCurveCursor(True)
                return True
            elif key == Qt.Key_Down:
                self.__shiftCurveCursor(False)
                return True
            elif key == Qt.Key_Right or key == Qt.Key_Plus:
                if self.__selectedCurve:
                    self.__shiftPointCursor(True)
                else:
                    self.__shiftCurveCursor(True)
                return True
            elif key == Qt.Key_Left or key == Qt.Key_Minus:
                if self.__selectedCurve:
                    self.__shiftPointCursor(False)
                else:
                    self.__shiftCurveCursor(True)
                return True
            if key == Qt.Key_1:
                self.__moveBy(-delta, delta)
            elif key == Qt.Key_2:
                self.__moveBy(0, delta)
            elif key == Qt.Key_3:
                self.__moveBy(delta, delta)
            elif key == Qt.Key_4:
                self.__moveBy(-delta, 0)
            elif key == Qt.Key_6:
                self.__moveBy(delta, 0)
            elif key == Qt.Key_7:
                self.__moveBy(-delta, -delta)
            elif key == Qt.Key_8:
                self.__moveBy(0, -delta)
            elif key == Qt.Key_9:
                self.__moveBy(delta, -delta)
        return False

    def __select(self, pos):
        found, distance, point = None, 1e100, -1
        for curve in self.__plot.itemList():
            if isinstance(curve, QwtPlotCurve):
                i, d = curve.closestPoint(pos)
                if d < distance:
                    found = curve
                    point = i
                    distance = d
        self.__showCursor(False)
        self.__selectedCurve = None
        self.__selectedPoint = -1
        if found and distance < 10:
            self.__selectedCurve = found
            self.__selectedPoint = point
            self.__showCursor(True)

    def __moveBy(self, dx, dy):
        if dx == 0 and dy == 0:
            return
        curve = self.__selectedCurve
        if not curve:
            return
        s = curve.sample(self.__selectedPoint)
        x = self.__plot.transform(curve.xAxis(), s.x()) + dx
        y = self.__plot.transform(curve.yAxis(), s.y()) + dy
        self.__move(QPoint(x, y))

    def __move(self, pos):
        curve = self.__selectedCurve
        if not curve:
            return
        xData = np.zeros(curve.dataSize(), float)
        yData = np.zeros(curve.dataSize(), float)
        for i in range(curve.dataSize()):
            if i == self.__selectedPoint:
                xData[i] = self.__plot.invTransform(curve.xAxis(), pos.x())
                yData[i] = self.__plot.invTransform(curve.yAxis(), pos.y())
            else:
                s = curve.sample(i)
                xData[i] = s.x()
                yData[i] = s.y()
        curve.setData(xData, yData)
        self.__showCursor(True)
        self.__plot.replot()

    def __showCursor(self, showIt):
        curve = self.__selectedCurve
        if not curve:
            return
        symbol = curve.symbol()
        brush = symbol.brush()
        if showIt:
            symbol.setBrush(symbol.brush().color().darker(180))
        curve.directPaint(self.__selectedPoint, self.__selectedPoint)
        if showIt:
            symbol.setBrush(brush)

    def __shiftCurveCursor(self, up):
        curves = [
            curve for curve in self.__plot.itemList() if isinstance(curve, QwtPlotCurve)
        ]
        if not curves:
            return
        if self.__selectedCurve in curves:
            index = curves.index(self.__selectedCurve)
            if up:
                index += 1
            else:
                index -= 1
            # keep index within [0, len(curves))
            index += len(curves)
            index %= len(curves)
        else:
            index = 0
        self.__showCursor(False)
        self.__selectedPoint = 0
        self.__selectedCurve = curves[index]
        self.__showCursor(True)

    def __shiftPointCursor(self, up):
        curve = self.__selectedCurve
        if not curve:
            return
        if up:
            index = self.__selectedPoint + 1
        else:
            index = self.__selectedPoint - 1
        # keep index within [0, curve.dataSize())
        index += curve.dataSize()
        index %= curve.dataSize()
        if index != self.__selectedPoint:
            self.__showCursor(False)
            self.__selectedPoint = index
            self.__showCursor(True)


class ScalePicker(QObject):
    clicked = Signal(int, float)

    def __init__(self, plot):
        QObject.__init__(self, plot)
        for axis_id in QwtPlot.AXES:
            scaleWidget = plot.axisWidget(axis_id)
            if scaleWidget:
                scaleWidget.installEventFilter(self)

    def eventFilter(self, object, event):
        if event.type() == QEvent.MouseButtonPress:
            self.__mouseClicked(object, event.position())
            return True
        return QObject.eventFilter(self, object, event)

    def __mouseClicked(self, scale, pos):
        rect = self.__scaleRect(scale)
        margin = 10
        rect.setRect(
            rect.x() - margin,
            rect.y() - margin,
            rect.width() + 2 * margin,
            rect.height() + 2 * margin,
        )
        if rect.contains(pos):
            value = 0.0
            axis = -1
        sd = scale.scaleDraw()
        if scale.alignment() == QwtScaleDraw.LeftScale:
            value = sd.scaleMap().invTransform(pos.y())
            axis = QwtPlot.yLeft
        elif scale.alignment() == QwtScaleDraw.RightScale:
            value = sd.scaleMap().invTransform(pos.y())
            axis = QwtPlot.yRight
        elif scale.alignment() == QwtScaleDraw.BottomScale:
            value = sd.scaleMap().invTransform(pos.x())
            axis = QwtPlot.xBottom
        elif scale.alignment() == QwtScaleDraw.TopScale:
            value = sd.scaleMap().invTransform(pos.x())
            axis = QwtPlot.xBottom
        self.clicked.emit(axis, value)

    def __scaleRect(self, scale):
        bld = scale.margin()
        mjt = scale.scaleDraw().tickLength(QwtScaleDiv.MajorTick)
        sbd = scale.startBorderDist()
        ebd = scale.endBorderDist()
        if scale.alignment() == QwtScaleDraw.LeftScale:
            return QRect(
                scale.width() - bld - mjt, sbd, mjt, scale.height() - sbd - ebd
            )
        elif scale.alignment() == QwtScaleDraw.RightScale:
            return QRect(bld, sbd, mjt, scale.height() - sbd - ebd)
        elif scale.alignment() == QwtScaleDraw.BottomScale:
            return QRect(sbd, bld, scale.width() - sbd - ebd, mjt)
        elif scale.alignment() == QwtScaleDraw.TopScale:
            return QRect(
                sbd, scale.height() - bld - mjt, scale.width() - sbd - ebd, mjt
            )
        else:
            return QRect()


class EventFilterWindow(QMainWindow):
    def __init__(self, parent=None):
        super(EventFilterWindow, self).__init__(parent=parent)
        toolBar = QToolBar(self)
        toolBar.addAction(QWhatsThis.createAction(toolBar))
        self.addToolBar(toolBar)
        plot = Plot()
        self.setCentralWidget(plot)
        plot.setWhatsThis(
            "An useless plot to demonstrate how to use event filtering.\n\n"
            "You can click on the color bar, the scales or move the slider.\n"
            "All points can be moved using the mouse or the keyboard."
        )
        CanvasPicker(plot)
        scalePicker = ScalePicker(plot)
        scalePicker.clicked.connect(plot.insertCurve)


def test_eventfilter():
    """Event filter example"""
    utils.test_widget(EventFilterWindow, size=(540, 400))


if __name__ == "__main__":
    test_eventfilter()