"""
普通字符验证码生成器

生成风格：
- 浅色随机背景 (RGB 各通道 230-255)
- 每个字符随机深色 (蓝/红/绿/紫/棕等)
- 字符数量 4-5 个
- 字符有 ±15° 随机旋转
- 2-5 条浅色干扰线
- 少量噪点
- 可选轻微高斯模糊
"""

import random

from PIL import Image, ImageDraw, ImageFilter, ImageFont

from config import GENERATE_CONFIG, NORMAL_CHARS
from generators.base import BaseCaptchaGenerator

# 系统可用字体列表（粗体/常规混合，增加多样性）
_FONT_PATHS = [
    "/usr/share/fonts/TTF/DejaVuSans-Bold.ttf",
    "/usr/share/fonts/TTF/DejaVuSerif-Bold.ttf",
    "/usr/share/fonts/TTF/DejaVuSansMono-Bold.ttf",
    "/usr/share/fonts/liberation/LiberationSans-Bold.ttf",
    "/usr/share/fonts/liberation/LiberationMono-Bold.ttf",
    "/usr/share/fonts/liberation/LiberationSerif-Bold.ttf",
    "/usr/share/fonts/gnu-free/FreeSansBold.otf",
    "/usr/share/fonts/gnu-free/FreeMonoBold.otf",
]

# 深色调色板 (R, G, B)
_DARK_COLORS = [
    (0, 0, 180),      # 蓝
    (180, 0, 0),      # 红
    (0, 130, 0),      # 绿
    (130, 0, 130),    # 紫
    (120, 60, 0),     # 棕
    (0, 100, 100),    # 青
    (80, 80, 0),      # 橄榄
    (0, 0, 0),        # 黑
    (100, 0, 50),     # 暗玫红
    (50, 50, 150),    # 钢蓝
]


class NormalCaptchaGenerator(BaseCaptchaGenerator):
    """普通字符验证码生成器。"""

    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["normal"]
        self.chars = NORMAL_CHARS
        self.width, self.height = self.cfg["image_size"]

        # 预加载可用字体
        self._fonts: list[str] = []
        for p in _FONT_PATHS:
            try:
                ImageFont.truetype(p, 20)
                self._fonts.append(p)
            except OSError:
                continue
        if not self._fonts:
            raise RuntimeError("未找到任何可用字体，无法生成验证码")

    # ----------------------------------------------------------
    # 公共接口
    # ----------------------------------------------------------
    def generate(self, text: str | None = None) -> tuple[Image.Image, str]:
        rng = self.rng

        # 1. 随机文本
        if text is None:
            length = rng.randint(*self.cfg["char_count_range"])
            text = "".join(rng.choices(self.chars, k=length))

        # 2. 浅色背景
        bg_lo, bg_hi = self.cfg["bg_color_range"]
        bg = tuple(rng.randint(bg_lo, bg_hi) for _ in range(3))
        img = Image.new("RGB", (self.width, self.height), bg)

        # 3. 逐字符绘制（旋转后粘贴）
        self._draw_text(img, text, rng)

        # 4. 干扰线
        self._draw_noise_lines(img, rng)

        # 5. 噪点
        self._draw_noise_points(img, rng)

        # 6. 轻微高斯模糊
        if self.cfg["blur_radius"] > 0:
            img = img.filter(ImageFilter.GaussianBlur(radius=self.cfg["blur_radius"]))

        return img, text

    # ----------------------------------------------------------
    # 私有方法
    # ----------------------------------------------------------
    def _draw_text(self, img: Image.Image, text: str, rng: random.Random) -> None:
        """逐字符旋转并粘贴到画布上。"""
        n = len(text)
        # 每个字符的水平可用宽度
        slot_w = self.width // n
        font_size = int(min(slot_w * 0.9, self.height * 0.7))
        font_size = max(font_size, 12)

        for i, ch in enumerate(text):
            font_path = rng.choice(self._fonts)
            font = ImageFont.truetype(font_path, font_size)
            color = rng.choice(_DARK_COLORS)

            # 绘制单字符到临时透明图层
            bbox = font.getbbox(ch)
            cw = bbox[2] - bbox[0] + 4
            ch_h = bbox[3] - bbox[1] + 4
            char_img = Image.new("RGBA", (cw, ch_h), (0, 0, 0, 0))
            ImageDraw.Draw(char_img).text((-bbox[0] + 2, -bbox[1] + 2), ch, fill=color, font=font)

            # 随机旋转
            angle = rng.randint(*self.cfg["rotation_range"])
            char_img = char_img.rotate(angle, resample=Image.BICUBIC, expand=True)

            # 粘贴位置
            x = slot_w * i + (slot_w - char_img.width) // 2
            y = (self.height - char_img.height) // 2 + rng.randint(-3, 3)
            x = max(0, min(x, self.width - char_img.width))
            y = max(0, min(y, self.height - char_img.height))

            img.paste(char_img, (x, y), char_img)

    def _draw_noise_lines(self, img: Image.Image, rng: random.Random) -> None:
        """绘制浅色干扰线。"""
        draw = ImageDraw.Draw(img)
        lo, hi = self.cfg["noise_line_range"]
        num = rng.randint(lo, hi)
        for _ in range(num):
            x1, y1 = rng.randint(0, self.width), rng.randint(0, self.height)
            x2, y2 = rng.randint(0, self.width), rng.randint(0, self.height)
            color = tuple(rng.randint(150, 220) for _ in range(3))
            draw.line([(x1, y1), (x2, y2)], fill=color, width=rng.randint(1, 2))

    def _draw_noise_points(self, img: Image.Image, rng: random.Random) -> None:
        """绘制噪点。"""
        draw = ImageDraw.Draw(img)
        for _ in range(self.cfg["noise_point_num"]):
            x = rng.randint(0, self.width - 1)
            y = rng.randint(0, self.height - 1)
            color = tuple(rng.randint(0, 200) for _ in range(3))
            draw.point((x, y), fill=color)