from pycs.ui.AnnotatedImageView import AnnotatedImageView


class AnnotatedInteractiveImageView(AnnotatedImageView):
    def __init__(self, parent, click_handler=None):
        super().__init__(parent)
        self.__click_handler = click_handler

    def mousePressEvent(self, event):
        """
        handle click event, get point and emit to parent node
        :param event:
        :return:
        """

        # do not execute if no click handler is given
        if self.__click_handler is None:
            return

        # get clicked point
        pos = event.pos()
        point_x, point_y = pos.x() / self.width(), pos.y() / self.height()

        # get image and box dimensions
        image_width, image_height = self._image.width(), self._image.height()
        box_width, box_height = self.width(), self.height()

        maximum_width, maximum_height = max(image_width, box_width), max(image_height, box_height)

        # determine orientation
        # horizontal
        if image_width / image_height >= box_width / box_height:
            # calculate top margin
            image_height, box_height = maximum_width / image_width * image_height, maximum_width / box_width * box_height
            top = (box_height - image_height) / 2

            # click is inside the image
            if top <= point_y * box_height <= box_height - top:
                off = top / box_height
                rat = 1 - 2 * off
                self.__click_handler(point_x, (point_y - off) / rat, event)

        # vertical
        else:
            # calculate left margin
            image_width, box_width = maximum_height / image_height * image_width, maximum_height / box_height * box_width
            left = (box_width - image_width) / 2

            if left <= point_x * box_width <= box_width - left:
                off = left / box_width
                rat = 1 - 2 * off
                self.__click_handler((point_x - off) / rat, point_y, event)