"""web/detective 封面：1080x1920，雨夜推理主题——墨蓝夜雨、一盏路灯暖光、
雨丝竖线与居中标题《雨夜专案》。可复现脚本（固定 seed，无外部网络依赖）。

用法（PIL 探测顺序：系统 python3 → .venv-tts → 装 pillow 后任一）：
  python3 web/detective/gen/gen_cover.py
"""
import math
import os
import random

from PIL import Image, ImageDraw, ImageFilter, ImageFont

W, H = 1080, 1920
FONT_CANDIDATES = [
    "/home/xsl/SoundGame/web/rhythm/gen/NotoSansSC-Bold.ttf",
    "/home/xsl/SoundGame/app/src/reflex/gen/NotoSansSC-Bold.ttf",
]
OUT = os.path.join(os.path.dirname(os.path.abspath(__file__)), "..", "cover.png")


def load_font(size):
    for p in FONT_CANDIDATES:
        if os.path.exists(p):
            return ImageFont.truetype(p, size)
    raise SystemExit("未找到中文字体，请放一份 NotoSansSC-Bold.ttf 到 web/rhythm/gen/")


def main():
    rng = random.Random(918)  # 固定 seed：可复现
    img = Image.new("RGB", (W, H), (10, 12, 20))
    d = ImageDraw.Draw(img)

    # 背景竖向渐变：夜空墨蓝 -> 街面冷灰（雨夜街道）
    for y in range(H):
        t = y / H
        d.line([(0, y), (W, y)],
               fill=(int(14 + 10 * t), int(17 + 12 * t), int(26 + 18 * t)))

    # 一盏路灯暖光（左上，光晕压暗）——雨夜里唯一的暖色
    lx, ly = 250, 380
    lamp = Image.new("RGBA", (W, H), (0, 0, 0, 0))
    ld = ImageDraw.Draw(lamp)
    for r, alpha in [(420, 26), (300, 40), (190, 58), (110, 80)]:
        ld.ellipse([lx - r, ly - r, lx + r, ly + r], fill=(253, 230, 138, alpha))
    lamp = lamp.filter(ImageFilter.GaussianBlur(14))
    img.paste(lamp, (0, 0), lamp)
    d = ImageDraw.Draw(img)
    d.ellipse([lx - 26, ly - 26, lx + 26, ly + 26], fill=(255, 244, 214))

    # 雨丝：斜细线两景深（远淡近亮），风斜角 ~8°
    rain = Image.new("RGBA", (W, H), (0, 0, 0, 0))
    rd = ImageDraw.Draw(rain)
    for _ in range(90):  # 远景雨
        x = rng.randint(0, W + 200)
        y = rng.randint(0, H)
        ln = rng.randint(40, 90)
        rd.line([(x, y), (x - ln * 0.14, y + ln)],
                fill=(148, 163, 184, rng.randint(16, 34)), width=1)
    for _ in range(60):  # 近景雨
        x = rng.randint(0, W + 200)
        y = rng.randint(0, H)
        ln = rng.randint(90, 160)
        rd.line([(x, y), (x - ln * 0.14, y + ln)],
                fill=(203, 213, 225, rng.randint(28, 52)), width=2)
    img.paste(rain, (0, 0), rain)
    d = ImageDraw.Draw(img)

    # 中央：案卷卷宗剪影（翻开的两页，暗金色边线）——「卷宗六份」的具象
    cx, cy = W // 2, 640
    doc = Image.new("RGBA", (W, H), (0, 0, 0, 0))
    ddoc = ImageDraw.Draw(doc)
    ddoc.polygon([(cx - 40, cy - 120), (cx - 250, cy - 60), (cx - 250, cy + 190), (cx - 40, cy + 130)],
                 outline=(120, 113, 108, 220), width=4)
    ddoc.polygon([(cx + 40, cy - 120), (cx + 250, cy - 60), (cx + 250, cy + 190), (cx + 40, cy + 130)],
                 outline=(120, 113, 108, 220), width=4)
    # 页面行文线（证词的横线，右页夹一条对不上的红线）
    for i in range(5):
        yy = cy - 26 + i * 40
        ddoc.line([(cx - 215, yy - 28), (cx - 75, yy - 46)], fill=(148, 163, 184, 120), width=3)
        ddoc.line([(cx + 75, yy - 46), (cx + 215, yy - 28)], fill=(148, 163, 184, 120), width=3)
    ddoc.line([(cx + 92, cy + 62), (cx + 208, cy + 80)], fill=(248, 113, 113, 200), width=4)
    img.paste(doc, (0, 0), doc)
    d = ImageDraw.Draw(img)

    # 标题（居中）与副题
    f_title = load_font(172)
    f_sub = load_font(54)
    f_small = load_font(38)

    def ctext(y, s, font, fill, spacing=8):
        bbox = d.textbbox((0, 0), s, font=font)
        w = bbox[2] - bbox[0]
        x = (W - w) / 2
        for ch in s:
            d.text((x, y), ch, font=font, fill=fill)
            bb = d.textbbox((0, 0), ch, font=font)
            x += (bb[2] - bb[0]) + spacing

    ctext(1010, "雨夜专案", f_title, (237, 233, 254), spacing=16)
    ctext(1262, "证词会撒谎，证据不会", f_sub, (148, 163, 184))

    # 手势图例（极简两行）
    hints = ["左右滑 换卷宗", "单击 听取", "长按 指证", "上滑 进度", "下滑 菜单"]
    for i, s in enumerate(hints):
        col, row = i % 3, i // 3
        d.text((110 + col * 300, 1420 + row * 76), s, font=f_small, fill=(104, 122, 152))

    ctext(1700, "翻听六份卷宗，指出矛盾，锁定真凶。", f_small, (86, 102, 130))

    img.save(OUT)
    print(OUT, img.size)


if __name__ == "__main__":
    main()