from PIL import Image, ImageDraw, ImageFont, ImageFilter
import random


class ValidationCode(object):
    def __init__(self):
        super(ValidationCode, self).__init__()
    _letter_cases = "abcdefghjkmnpqrstuvwxy"       # 小写字母，取出干扰
    _upper_cases = _letter_cases.upper()           # 大写字母
    _numbers = ''.join(map(str, range(3, 10)))     # 数字
    init_chars = ''.join((_letter_cases, _upper_cases, _numbers))

    @staticmethod
    def create_validate_code(size=(140, 50), chars=init_chars, img_type="GIF", mode="RGB", bg_color=(255, 255, 255),
                             fg_color=(54, 127, 169), font_size=23, font_type="jigsaw_trouserdrop.ttf", length=4,
                             draw_lines=True, n_line=(1, 2), draw_points=True, point_chance=2):
        '''
        @todo: 生成验证码图片
        @param size: 图片的大小，格式（宽，高），默认为(120, 30)
        @param chars: 允许的字符集合，格式字符串
        @param img_type: 图片保存的格式，默认为GIF，可选的为GIF，JPEG，TIFF，PNG
        @param mode: 图片模式，默认为RGB
        @param bg_color: 背景颜色，默认为白色
        @param fg_color: 前景色，验证码字符颜色，默认为蓝色#0000FF
        @param font_size: 验证码字体大小
        @param font_type: 验证码字体，默认为 ae_AlArabiya.ttf
        @param length: 验证码字符个数
        @param draw_lines: 是否划干扰线
        @param n_lines: 干扰线的条数范围，格式元组，默认为(1, 2)，只有draw_lines为True时有效
        @param draw_points: 是否画干扰点
        @param point_chance: 干扰点出现的概率，大小范围[0, 100]
        @return: [0]: PIL Image实例
        @return: [1]: 验证码图片中的字符串
        '''
        width, height = size    # 宽，高
        img = Image.new(mode, size, bg_color)    # 创建图形
        draw = ImageDraw.Draw(img)    # 创建画笔

        def get_chars():
            '''生成给定长度的字符串，返回列表格式'''
            return random.sample(chars, length)

        def create_lines():
            '''绘制干扰线'''
            line_num = random.randint(*n_line)    # 干扰线条数
            for i in range(line_num):
                # 起始点
                begin = (random.randint(0, size[0]), random.randint(0, size[1]))
                # 结束点
                end = (random.randint(0, size[0]), random.randint(0, size[1]))
                draw.line([begin, end], fill=(0, 0, 0))

        def create_points():
            '''绘制干扰点'''
            chance = min(100, max(0, int(point_chance)))    # 大小限制在[0, 100]

            for w in range(0, width):
                for h in range(0, height):
                    tmp = random.randint(0, 100)
                    if tmp > 100 - chance:
                        draw.point((w, h), fill=(0, 0, 0))

        def create_strs():
            '''绘制验证码字符'''
            c_chars = get_chars()
            strs = '%s' % ''.join(c_chars)    # 每个字符前后以空格隔开
            font = ImageFont.truetype(font_type, font_size)
            font_width, font_height = font.getsize(strs)
            draw.text(((width - font_width) / 3 - 7, (height - font_height) / 3 - 7), strs, font=font, fill=fg_color)
            return ''.join(c_chars)

        if draw_lines:
            create_lines()
        if draw_points:
            create_points()
        strs = create_strs()
        # 图形扭曲参数
        params = [1 - float(random.randint(1, 2)) / 100, 0, 0, 0, 1 - float(random.randint(1, 10)) / 100,
                  float(random.randint(1, 2)) / 500, 0.001, float(random.randint(1, 2)) / 500]
        img = img.transform(size, Image.PERSPECTIVE, params)    # 创建扭曲
        img = img.filter(ImageFilter.EDGE_ENHANCE_MORE)    # 滤镜，边界加强（阈值更大）
        return img, strs


# def generate_validation_code(size=(140, 50), img_type="GIF", mode="RGB", bg_color=(255, 255, 255),
#                              fg_color=(54, 127, 169), font_size=23, font_type="jigsaw_trouserdrop.ttf", length=4,
#                              draw_lines=True, n_line=(1, 2), draw_points=True, point_chance=2):
#     code = ValidationCode()
#     return code.create_validate_code(size=size, img_type=img_type, mode=mode, bg_color=bg_color, fg_color=fg_color,
#                                      font_size=font_size, font_type=font_type, length=length, draw_lines=draw_lines,
#                                      n_line=n_line, draw_points=draw_points, point_chance=point_chance)
