"""
3D 滑块验证码生成器

生成滑块拼图验证码：纹理背景 + 拼图缺口 + 拼图块在左侧。
用户需将拼图块滑动到缺口位置。

标签 = 缺口 x 坐标偏移（整数）
文件名格式: {offset}_{index:06d}.png
"""

import random

from PIL import Image, ImageDraw, ImageFilter

from config import GENERATE_CONFIG
from generators.base import BaseCaptchaGenerator


class ThreeDSliderGenerator(BaseCaptchaGenerator):
    """3D 滑块验证码生成器。"""

    def __init__(self, seed: int | None = None):
        from config import RANDOM_SEED
        super().__init__(seed=seed if seed is not None else RANDOM_SEED)

        self.cfg = GENERATE_CONFIG["3d_slider"]
        self.width, self.height = self.cfg["image_size"]

    def generate(self, text: str | None = None) -> tuple[Image.Image, str]:
        rng = self.rng
        pw, ph = self.cfg["puzzle_size"]
        gap_x_lo, gap_x_hi = self.cfg["gap_x_range"]

        # 缺口位置
        gap_x = rng.randint(gap_x_lo, gap_x_hi)
        gap_y = rng.randint(10, self.height - ph - 10)

        if text is None:
            text = str(gap_x)

        # 1. 生成纹理背景
        img = self._textured_background(rng)

        # 2. 从缺口位置截取拼图块内容
        piece_content = img.crop((gap_x, gap_y, gap_x + pw, gap_y + ph)).copy()

        # 3. 绘制缺口 (半透明灰色区域)
        overlay = Image.new("RGBA", img.size, (0, 0, 0, 0))
        overlay_draw = ImageDraw.Draw(overlay)
        overlay_draw.rectangle(
            [gap_x, gap_y, gap_x + pw, gap_y + ph],
            fill=(80, 80, 80, 160),
            outline=(60, 60, 60, 200),
            width=2,
        )
        img = img.convert("RGBA")
        img = Image.alpha_composite(img, overlay)
        img = img.convert("RGB")

        # 4. 绘制拼图块在左侧
        piece_x = self.cfg["piece_left_margin"]
        piece_img = Image.new("RGBA", (pw + 4, ph + 4), (0, 0, 0, 0))
        piece_draw = ImageDraw.Draw(piece_img)
        # 阴影
        piece_draw.rectangle([2, 2, pw + 3, ph + 3], fill=(0, 0, 0, 80))
        # 内容
        piece_img.paste(piece_content, (0, 0))
        # 边框
        piece_draw.rectangle([0, 0, pw - 1, ph - 1], outline=(255, 255, 255, 200), width=2)

        img_rgba = img.convert("RGBA")
        img_rgba.paste(piece_img, (piece_x, gap_y), piece_img)
        img = img_rgba.convert("RGB")

        # 5. 轻微模糊
        img = img.filter(ImageFilter.GaussianBlur(radius=0.3))

        return img, text

    def _textured_background(self, rng: random.Random) -> Image.Image:
        """生成带纹理的彩色背景。"""
        img = Image.new("RGB", (self.width, self.height))
        draw = ImageDraw.Draw(img)

        # 渐变底色
        base_r, base_g, base_b = rng.randint(100, 180), rng.randint(100, 180), rng.randint(100, 180)
        for y in range(self.height):
            ratio = y / max(self.height - 1, 1)
            r = int(base_r + 30 * ratio)
            g = int(base_g - 20 * ratio)
            b = int(base_b + 10 * ratio)
            draw.line([(0, y), (self.width, y)], fill=(r, g, b))

        # 添加纹理噪声
        noise_intensity = self.cfg["bg_noise_intensity"]
        for _ in range(self.width * self.height // 8):
            x = rng.randint(0, self.width - 1)
            y = rng.randint(0, self.height - 1)
            pixel = img.getpixel((x, y))
            noise = tuple(
                max(0, min(255, c + rng.randint(-noise_intensity, noise_intensity)))
                for c in pixel
            )
            draw.point((x, y), fill=noise)

        # 随机色块 (模拟图案)
        for _ in range(rng.randint(3, 6)):
            x1, y1 = rng.randint(0, self.width - 30), rng.randint(0, self.height - 20)
            x2, y2 = x1 + rng.randint(15, 40), y1 + rng.randint(10, 25)
            color = tuple(rng.randint(60, 220) for _ in range(3))
            draw.rectangle([x1, y1, x2, y2], fill=color)

        return img