import random
from PIL import Image, ImageDraw, ImageFont
import time
import os
import string

class GetCaptcha:
    size = (100, 40)
    source = tuple(string.digits + string.ascii_letters)
    number = 4
    background_color = (250, 250, 250)
    fontsize = 25
    font_path = os.path.join(os.path.dirname(__file__), 'verdana.ttf')
    random.seed(time.time())
    fontcolor = (random.randint(0, 80), random.randint(0, 80), random.randint(0, 80))
    draw_line = True
    line_number = 3
    line_color = (random.randint(0, 250), random.randint(0, 255), random.randint(0, 250))
    draw_point = True
    rotate = True

    @classmethod
    def image_rotate(cls, original_image):
        image = original_image.rotate(random.randint(-15, 15), expand=0)
        back_ground = Image.new('RGBA', cls.size,cls.background_color)
        return Image.composite(image, back_ground, image)

    @classmethod
    def draw_text(cls):
        """return a captcha include digit and letter"""
        return ''.join(random.sample(cls.source, cls.number))

    @classmethod
    def __draw_line(cls, draw, width, height):
        begin = (random.randint(0, width), random.randint(0, height))
        end = (random.randint(0, width), random.randint(0, height))
        draw.line([begin, end], fill=cls.line_color)

    @classmethod
    def __draw_point(cls, draw, point_size, width, height):
        size = min(100, max(0, int(point_size)))
        for w in range(width):
            for h in range(height):
                tmp = random.randint(0, 100)
                if tmp > 100 - size:        # make sure would not point too much
                    draw.point((w, h), fill=(150, 150, 150))

    @classmethod
    def draw_captcha(cls):
        width, height = cls.size
        image = Image.new('RGBA', (width, height), cls.background_color)
        font = ImageFont.truetype(cls.font_path, cls.fontsize)
        draw = ImageDraw.Draw(image)
        text = cls.draw_text()
        font_width, font_height = font.getsize(text)
        draw.text(((width - font_width) / 2, (height - font_height) / 2), text, font=font, fill=cls.fontcolor)

        if cls.draw_line:
            for x in range(0, cls.line_number):
                cls.__draw_line(draw, width, height)

        if cls.draw_point:
            cls.__draw_point(draw, 5, width, height)

        return (text, cls.image_rotate(image))

if __name__ == "__main__":
    captcha = GetCaptcha()
    text, image = captcha.draw_captcha()
    image.save('code.png', "PNG")

def captcha_view(request):
    text, image = GetCaptcha.draw_captcha()
    output = BytesIO()
    image.save(output,'png')
    output.seek(0)
    response = HttpResponse()
    response['content/type'] = "image/png"
    response.write(output.read())
    return response