"""Hough transform module."""

from math import pi

from PIL import Image

import pcf

class Hough:
    def __init__(self, size, dt, init_angle, image):
        self.size = size
        self.dt = dt
        self.initial_angle = init_angle
        self.image = image

    @classmethod
    def Transform(cls, image):
        size = image.size
        dt = pi / size[1]
        initial_angle = (pi / 4) + (dt / 2)
        image_s = pcf.hough(size, image.tostring(), initial_angle, dt)
        image_t = Image.fromstring('L', size, image_s)
        return cls(size, dt, initial_angle, image_t)

    def apply_filter(self, filter_f):
        return Hough(self.size, self.dt, self.initial_angle,
                     filter_f(self.image))

    def lines_from_list(self, p_list):
        lines = []
        for p in p_list:
            lines.append(self.angle_distance(p))
        return lines

    def all_lines_h(self):
        im_l = self.image.load()
        lines1 = []
        for x in xrange(self.size[0] / 2):
            for y in xrange(self.size[1]):
                if im_l[x, y]:
                    lines1.append(self.angle_distance((x, y)))
        lines2 = []
        for x in xrange(self.size[0] / 2, self.size[0]):
            for y in xrange(self.size[1]):
                if im_l[x, y]:
                    lines2.append(self.angle_distance((x, y)))
        return [lines1, lines2]

    def all_lines(self):
        im_l = self.image.load()
        lines = []
        for x in xrange(self.size[0]):
            for y in xrange(self.size[1]):
                if im_l[x, y]:
                    lines.append(self.angle_distance((x, y)))
        return lines
    
    def angle_distance(self, point):
        return (self.dt * point[1] + self.initial_angle,
                point[0] - self.size[0] / 2)