# -*- coding: utf-8 -*-
import random
from captcha.conf import settings
from django.core.urlresolvers import reverse


def math_challenge():
    operators = ('+', '*', '-',)
    operands = (random.randint(1, 10), random.randint(1, 10))
    operator = random.choice(operators)
    if operands[0] < operands[1] and '-' == operator:
        operands = (operands[1], operands[0])
    challenge = '%d%s%d' % (operands[0], operator, operands[1])
    return '%s=' % (challenge), eval(challenge)


def random_char_challenge():
    chars, ret = u'abcdefghijklmnopqrstuvwxyz', u''
    for i in range(settings.CAPTCHA_LENGTH):
        ret += random.choice(chars)
    return ret.upper(), ret


def unicode_challenge():
    chars, ret = u'äàáëéèïíîöóòüúù', u''
    for i in range(settings.CAPTCHA_LENGTH):
        ret += random.choice(chars)
    return ret.upper(), ret


def word_challenge():
    fd = open(settings.CAPTCHA_WORDS_DICTIONARY, 'rb')
    l = fd.readlines()
    fd.close()
    while True:
        word = random.choice(l).strip()
        if len(word) >= settings.CAPTCHA_DICTIONARY_MIN_LENGTH and len(word) <= settings.CAPTCHA_DICTIONARY_MAX_LENGTH:
            break
    return word.upper(), word.lower()


def huge_words_and_punctuation_challenge():
    "Yay, undocumneted. Mostly used to test Issue 39 - http://code.google.com/p/django-simple-captcha/issues/detail?id=39"
    fd = open(settings.CAPTCHA_WORDS_DICTIONARY, 'rb')
    l = fd.readlines()
    fd.close()
    word = ''
    while True:
        word1 = random.choice(l).strip()
        word2 = random.choice(l).strip()
        punct = random.choice(settings.CAPTCHA_PUNCTUATION)
        word = '%s%s%s' % (word1, punct, word2)
        if len(word) >= settings.CAPTCHA_DICTIONARY_MIN_LENGTH and len(word) <= settings.CAPTCHA_DICTIONARY_MAX_LENGTH:
            break
    return word.upper(), word.lower()


def noise_arcs(draw, image):
    size = image.size
    draw.arc([-20, -20, size[0], 20], 0, 295, fill=settings.CAPTCHA_FOREGROUND_COLOR)
    draw.line([-20, 20, size[0] + 20, size[1] - 20], fill=settings.CAPTCHA_FOREGROUND_COLOR)
    draw.line([-20, 0, size[0] + 20, size[1]], fill=settings.CAPTCHA_FOREGROUND_COLOR)
    return draw


def noise_dots(draw, image):
    size = image.size
    for p in range(int(size[0] * size[1] * 0.1)):
        draw.point((random.randint(0, size[0]), random.randint(0, size[1])), fill=settings.CAPTCHA_FOREGROUND_COLOR)
    return draw


def post_smooth(image):
    try:
        import ImageFilter
    except ImportError:
        from PIL import ImageFilter
    return image.filter(ImageFilter.SMOOTH)


def captcha_image_url(key):
    """ Return url to image. Need for ajax refresh and, etc"""
    return reverse('captcha-image', args=[key])
