"""Manual grid selection module"""

import pygame
import Image, ImageDraw
from math import atan, sin, cos, pi

class UserQuitError(Exception):
    pass

class Screen:
    def __init__(self, res):
        pygame.init()
        pygame.display.set_mode(res)
        pygame.display.set_caption("Imago manual mode")
        self._screen = pygame.display.get_surface()

    def display_picture(self, im):
        pg_img = pygame.image.frombuffer(im.tostring(), im.size, im.mode)
        self._screen.blit(pg_img, (0,0))
        pygame.display.flip()

def find_lines(im_orig):

    im = im_orig.copy()

    screen = Screen(im.size)

    done = False
    clock = pygame.time.Clock()
    draw = ImageDraw.Draw(im)
    hoshi = lambda c: draw.ellipse((c[0] - 1, c[1] - 1, c[0] + 1, c[1] + 1),
                 fill=(255, 64, 64))
    corners = []
    color=(64, 64, 255)
    line_width = 1
    lines_r = []

    while not done:
        for event in pygame.event.get():
            if event.type == pygame.QUIT or event.type == pygame.KEYDOWN:
                pygame.quit()
                if len(corners) == 4:
                    return lines_r
                else:
                    raise UserQuitError 
            if event.type == pygame.MOUSEBUTTONDOWN:
                if len(corners) >= 4: 
                    corners = []
                    im = im_orig.copy()
                    draw = ImageDraw.Draw(im)

                if len(corners) < 4:
                    corners.append(pygame.mouse.get_pos())
                    draw.point(corners[:-1], fill=color)
                    if len(corners) == 4:
                        l_vert, l_hor = lines(corners)
                        for l in l_vert:
                            draw.line(l, fill=color, width=line_width)
                        for l in l_hor:
                            draw.line(l, fill=color, width=line_width)
                        #TODO sort by distance
                        l_vert.sort()
                        l_hor.sort()
                        for i in [3, 9, 15]:
                            for j in [3, 9, 15]:
                                hoshi(intersection(line(l_vert[i][0], l_vert[i][1]),
                                                   line(l_hor[j][0], l_hor[j][1])))
                        lines_r = [[l2ad(l[0], l[1], im.size) for l in l_vert], 
                                   [l2ad(l[0], l[1], im.size) for l in l_hor]]

        screen.display_picture(im)
        clock.tick(15)

def lines(corners):
    cor_d = sorted([(corners[0][0] * c[1] - c[0] * corners[0][1], c) for c in
                    corners[1:]])
    corners = [corners[0]] + [c for _, c in cor_d]
    return (_lines(corners, 0) + [(corners[0], corners[3]),
                                  (corners[1], corners[2])],
            _lines(corners[1:4] + [corners[0]], 0) + 
            [(corners[0], corners[1]), (corners[2], corners[3])])

def _lines(corners, n):
    if n == 0:
        x = half_line(corners)
        return (_lines([corners[0], x[0], x[1], corners[3]], n + 1) + [x] + 
                _lines([x[0], corners[1], corners[2], x[1]], n + 1))
    else:
        x = half_line(corners)
        c = intersection(line(x[0], corners[2]), line(corners[1], corners[3]))
        d = intersection(line(corners[0], corners[3]), line(corners[1], corners[2]))
        l = (intersection(line(corners[0], corners[1]), line(c,d)),
             intersection(line(corners[2], corners[3]), line(c,d)))
        l2 = half_line([corners[0], l[0], l[1], corners[3]])
        if n == 1:
            return ([l, l2] + _lines([l[0], l2[0], l2[1], l[1]], 2)
                    + _lines([corners[0], l2[0], l2[1], corners[3]], 2)
                    + _lines([l[0], corners[1], corners[2], l[1]], 2))
        if n == 2:
            return [l, l2]


def half_line(corners):
    c = center(corners)
    d = intersection(line(corners[0], corners[3]), line(corners[1], corners[2]))
    if d:
        l = line(c, d)
    else:
        l = line(c, (c[0] + corners[0][0] - corners[3][0], 
                     c[1] + corners[0][1] - corners[3][1]))
    p1 = intersection(l, line(corners[0], corners[1]))
    p2 = intersection(l, line(corners[2], corners[3]))
    return (p1, p2)


def center(corners):
    return intersection(line(corners[0], corners[2]), 
                        line(corners[1], corners[3]))
def line(x, y):
    a = x[1] - y[1]
    b = y[0] - x[0]
    c = a * y[0] + b * y[1]
    return (a, b, c)

def intersection(p, q):
    det = p[0] * q[1] - p[1] * q[0]
    if det == 0:
        return None
    return (int(round(float(q[1] * p[2] - p[1] * q[2]) / det)), 
            int(round(float(p[0] * q[2] - q[0] * p[2]) / det)))

def l2ad(a, b, size):
    if (a[0] - b[0]) == 0:
        angle = pi / 2
    else:
        q = float(a[1] - b[1]) / (a[0] - b[0])
        angle = atan(q)

    if angle < 0:
        angle += pi
    if angle > pi:
        angle -= pi

    distance = (((a[0] - (size[0] / 2)) * sin(angle)) + 
                ((a[1] - (size[1] / 2)) * - cos(angle)))
    return (angle, distance)