from Constraint import Constraint

class XDistance(Constraint):
    def __init__(self, shape1, pt1, shape2, pt2, dist):
        self.shape1 = shape1
        self.pt1 = pt1
        self.shape2 = shape2
        self.pt2 = pt2
        self.dist = dist

    def toEqu(self):
        varrefs1 = self.shape1.toEqu(self.pt1)[0]
        varrefs2 = self.shape2.toEqu(self.pt2)[0]
        coeffs = []
        for i in range(len(varrefs1)):
            coeffs.append((-1 * varrefs1[i], (self.shape1, i)))
        for i in range(len(varrefs2)):
            coeffs.append((1 * varrefs2[i], (self.shape2, i)))
        return [(coeffs, self.dist)]