from .auxiliary import Position

class Snap(object):
    """Snap-to-edges manager"""
    def __init__(self, size, tolerance, list):
        self.tolerance = tolerance

        self.horizontal = set()
        self.vertical = set()
        for i in list:
            self.vertical.add(i[0].left)
            self.vertical.add(i[0].left+i[1].width)
            self.horizontal.add(i[0].top)
            self.horizontal.add(i[0].top+i[1].height)

            self.vertical.add(i[0].left-size.width)
            self.vertical.add(i[0].left+i[1].width-size.width)
            self.horizontal.add(i[0].top-size.height)
            self.horizontal.add(i[0].top+i[1].height-size.height)

    def suggest(self, position):
        vertical = [x for x in self.vertical if abs(x-position[0])<self.tolerance]
        horizontal = [y for y in self.horizontal if abs(y-position[1])<self.tolerance]

        if vertical:
            position = Position((vertical[0], position[1]))
        if horizontal:
            position = Position((position[0], horizontal[0]))

        return position