# -*- coding: utf-8 -*-
"""
生成深色站反白版 logo（logo-light.png）：
1. flood-fill 镂空深蓝底（容差 84 = v1 验证成功参数，能吃掉 #000020 底色）
2. 不透明内容亮度反转 L' = 1 - L（黑字→白字，红/青/绿提亮，色相保留）
深色页黑字看不清、白底块又突兀，反白是深色站标准解法。
用法: uv run --with pillow python3 tools/make_logo_light.py
"""
import colorsys
from collections import deque

from PIL import Image

SRC = 'assets/img/logo.png'
OUT = 'assets/img/logo-light.png'
TOL = 84  # 曼哈顿距离容差（v1 实测：清除 83%、红色主体完整保留）

im = Image.open(SRC).convert('RGBA')
w, h = im.size
px = im.load()

# --- flood-fill 清底 ---
corners = [px[0, 0], px[w-1, 0], px[0, h-1], px[w-1, h-1]]
bg = tuple(sum(c[i] for c in corners) // 4 for i in range(3))

def is_bg(p):
    if p[3] < 10:
        return True
    return abs(p[0]-bg[0]) + abs(p[1]-bg[1]) + abs(p[2]-bg[2]) <= TOL

seen = [[False]*w for _ in range(h)]
q = deque()
for x in range(w):
    q.extend(((x, 0), (x, h-1)))
for y in range(h):
    q.extend(((0, y), (w-1, y)))
cleared = 0
while q:
    x, y = q.popleft()
    if x < 0 or x >= w or y < 0 or y >= h or seen[y][x]:
        continue
    seen[y][x] = True
    p = px[x, y]
    if not is_bg(p):
        continue
    px[x, y] = (0, 0, 0, 0)
    cleared += 1
    q.extend(((x+1, y), (x-1, y), (x, y+1), (x, y-1)))
ratio = cleared / (w * h)
assert 0.10 < ratio < 0.92, f'镂空异常: 清除 {ratio:.0%}'

# --- 暗部提亮、亮部保留（logo 含 ~20% 浅色元素，全量反转会把它们变黑） ---
# L' = max(L, 1-L)：暗像素翻到亮侧（黑→白），亮像素不动，色相全保留
opaque = [px[x, y] for y in range(h) for x in range(w) if px[x, y][3] > 128]
assert opaque, '镂空后内容为空'

for y in range(h):
    for x in range(w):
        r, g, b, a = px[x, y]
        if a == 0:
            continue
        hh, ll, ss = colorsys.rgb_to_hls(r / 255, g / 255, b / 255)
        r2, g2, b2 = colorsys.hls_to_rgb(hh, max(ll, 1 - ll), ss)
        px[x, y] = (round(r2 * 255), round(g2 * 255), round(b2 * 255), a)

im.save(OUT, 'PNG', optimize=True)

# 验证：反白后所有不透明像素亮度下限
final = [px[x, y] for y in range(h) for x in range(w) if px[x, y][3] > 128]
dark = sum(1 for p in final if 0.299*p[0]+0.587*p[1]+0.114*p[2] < 90) / len(final)
print(f'完成: {OUT} 镂空 {ratio:.0%}，暗部像素剩 {dark:.1%}（应为 0）')