from qgis.gui import QgsMapTool
from qgis.PyQt.QtCore import pyqtSignal
from qgis.PyQt.QtGui import QCursor
from qgis.PyQt.QtCore import Qt


class PointCaptureTool(QgsMapTool):
    """
    Outil de capture d'un point sur la carte QGIS.
    Émet pointCaptured(x, y, crs) au clic gauche.
    Se désactive automatiquement après un clic.
    """
    pointCaptured = pyqtSignal(float, float, object)

    def __init__(self, canvas, previous_tool=None):
        super().__init__(canvas)
        self.canvas = canvas
        self.previous_tool = previous_tool
        self.setCursor(QCursor(Qt.CrossCursor))

    def canvasReleaseEvent(self, event):
        if event.button() == Qt.LeftButton:
            point = self.toMapCoordinates(event.pos())
            crs = self.canvas.mapSettings().destinationCrs()
            self.pointCaptured.emit(point.x(), point.y(), crs)
            # Restaurer l'outil précédent
            if self.previous_tool:
                self.canvas.setMapTool(self.previous_tool)
            else:
                self.canvas.unsetMapTool(self)

    def keyPressEvent(self, event):
        if event.key() == Qt.Key_Escape:
            if self.previous_tool:
                self.canvas.setMapTool(self.previous_tool)
            else:
                self.canvas.unsetMapTool(self)