# Import PyQt libs
from PyQt5.QtCore import (
    pyqtSignal,
    Qt,
    )
from PyQt5.QtGui import QColor
# Import PyQgis libs
from qgis.core import (
    QgsRectangle,
    QgsPointXY,
    QgsWkbTypes,
    QgsCoordinateReferenceSystem,
    QgsCoordinateTransform,
    )
from qgis.gui import (
    QgsMapTool,
    QgsMapMouseEvent,
    QgsRubberBand,
    )



class RectangleFeatureTool(QgsMapTool):
    signal = pyqtSignal()
    def __init__(self, project, canvas):
        super().__init__(canvas)
        self.project = project
        self.canvas = canvas

        # initiate variable to calculate the extent
        self.start_point = None
        self.end_point = None
        self.new_extent = None

        # flag to check if the left mouse button was pressed
        self.is_left_button_pressed = False
        # create a rubber line object
        # to display the geometry of the dragged object on the canvas
        self.rubber_band = QgsRubberBand(self.canvas, QgsWkbTypes.PolygonGeometry)
        self.rubber_band.setColor(QColor(255, 0, 0, 50))
        self.rubber_band.setWidth(2)

    # Mouse button pressed.
    def canvasPressEvent(self, event: QgsMapMouseEvent):
        if event.button() == Qt.LeftButton:
            self.start_point = self.toMapCoordinates(event.pos())
            self.end_point = self.start_point
            self.is_left_button_pressed = True

    # The cursor moves across the screen.
    def canvasMoveEvent(self, event: QgsMapMouseEvent):
        # if the left mouse button is pressed
        if self.is_left_button_pressed:
            self.end_point = self.toMapCoordinates(event.pos())
            # draw a rectangle on the canvas
            self.showRect(self.start_point, self.end_point)

    # The mouse button is released.
    def canvasReleaseEvent(self, event: QgsMapMouseEvent):
        # if the left mouse button was released
        if event.button() == Qt.LeftButton:
            if event.type() == 3:
                # get the rectangle created from the click point and
                # left mouse button release points
                self.new_extent = self.rectangle()
                self.signal.emit()
        # toggle the flag, the left mouse button is no longer held down
        self.is_left_button_pressed = False
        self.rubber_band.reset()  # remove rubber band from canvas
        sourceCrs = QgsCoordinateReferenceSystem(self.project.crs())
        destCrs = QgsCoordinateReferenceSystem(4326)
        tr = QgsCoordinateTransform(sourceCrs, destCrs, self.project)

    # Draw the rectangle on the canvas
    def showRect(self, startPoint, endPoint):
        # Reset the last drawn rectangle
        self.rubber_band.reset(QgsWkbTypes.PolygonGeometry)
        # Make sure the mouse has moved
        if startPoint.x() == endPoint.x() or startPoint.y() == endPoint.y():
            return

        # Create the rectangle
        point1 = QgsPointXY(startPoint.x(), startPoint.y())
        point2 = QgsPointXY(startPoint.x(), endPoint.y())
        point3 = QgsPointXY(endPoint.x(), endPoint.y())
        point4 = QgsPointXY(endPoint.x(), startPoint.y())

        self.rubber_band.addPoint(point1, False)
        self.rubber_band.addPoint(point2, False)
        self.rubber_band.addPoint(point3, False)
        self.rubber_band.addPoint(point4, True)  # true to update canvas
        self.rubber_band.show()

    def rectangle(self):
        if self.start_point is None or self.end_point is None:
            return None
        elif self.start_point.x() == self.end_point.x() or self.start_point.y() == self.end_point.y():
            return None
        return QgsRectangle(self.start_point, self.end_point)

    def deactivate(self):
        # unload the map tool on the mouse
        QgsMapTool.deactivate(self)
        self.deactivated.emit()