from point import Point

# parent class of all lattices
class Lattice():
    def __init__(self,**kwargs):
        self.type=kwargs.get("type","")

    # lattice point nearest to point
    # overwrite in subclasses
    def nearest(self,point):
        return point

    # delta to nearest point
    def nearest_delta(self,point):
        return self.nearest(point)-point

    # draw lattice
    # overwrite in subclasses
    def draw(self,painter):
        return

    # return the lattice according to a specification
    def new(spec):
        specs=spec.split(":")
        # check type of lattice
        if specs[0]=="square":
            return Lattice_square.new_square(specs[1:],spec)
        else:
            return(None,"error: unrecognized lattice type: '"+specs[0]+"'")


# square lattice
class Lattice_square(Lattice):
    def __init__(self,**kwargs):

        self.spacing=kwargs.get("spacing",1.)

        super(Lattice_square,self).__init__(**kwargs,type="square")

    # lattice point nearest to point
    def nearest(self,point):
        return Point(round(point.x/self.spacing)*self.spacing,round(point.y/self.spacing)*self.spacing)

    # draw
    def draw(self,painter):
        painter.draw_grid(Point(self.spacing/2,self.spacing/2),self.spacing)

    # return the lattice according to a specification
    def new_square(specs,spec):
        # no optional args
        if len(specs)==0:
            return (Lattice_square(),"")
        if len(specs)>1:
            return (None,"error: '"+spec+"' is not a valid specification for the square lattice: should be 'square[:spacing]'")
        try:
            spacing=float(specs[0])
            return (Lattice_square(spacing=spacing),"")
        except:
            return (None,"error: '"+spec+"' is not a valid specification for the square lattice: should be 'square[:spacing]'")