# -*- coding: utf-8 -*-
"""裁掉配图四周的纯白边，避免插入 Word 后出现大片留白。

原图统一备份到 _bid_assets/_raw/，重复执行时从备份重新裁剪，不会越裁越小。
"""
import os
import shutil

from PIL import Image, ImageChops

HERE = os.path.dirname(os.path.abspath(__file__))
ASSETS = os.path.join(HERE, "_bid_assets")
RAW = os.path.join(ASSETS, "_raw")
os.makedirs(RAW, exist_ok=True)

PAD = 12  # 裁剪后保留的白边像素

# 个别抽取图自带「图 xxx」标题行，与 Word 图题重复，按比例切掉顶部
TOP_CROP_RATIO = {"s0_master_dataflow.png": 0.055}


def trim_box(im, tol=8):
    bg = Image.new("RGB", im.size, (255, 255, 255))
    diff = ImageChops.difference(im, bg).convert("L")
    box = diff.point(lambda v: 255 if v > tol else 0).getbbox()
    if not box:
        return im
    l, t, r, b = box
    return im.crop((max(0, l - PAD), max(0, t - PAD),
                    min(im.width, r + PAD), min(im.height, b + PAD)))


def trim(path, tol=8):
    """tol：接近纯白（每通道差值 ≤ tol）的像素一律视为背景。

    抽取自蓝图文档的图并非纯白底，直接与 #FFFFFF 比对会判定整幅都是内容。
    """
    im = Image.open(path).convert("RGB")
    bg = Image.new("RGB", im.size, (255, 255, 255))
    diff = ImageChops.difference(im, bg).convert("L")
    box = diff.point(lambda v: 255 if v > tol else 0).getbbox()
    if not box:
        return None
    l, t, r, b = box
    l, t = max(0, l - PAD), max(0, t - PAD)
    r, b = min(im.width, r + PAD), min(im.height, b + PAD)
    if (l, t, r, b) == (0, 0, im.width, im.height):
        return None
    return im.crop((l, t, r, b))


def main():
    # ui_* 是系统真实界面截图，边缘留白属于界面本身，不做裁剪
    names = sorted(n for n in os.listdir(ASSETS)
                   if n.lower().endswith(".png") and not n.startswith("ui_"))
    print(f"共 {len(names)} 张配图")
    for n in names:
        src = os.path.join(ASSETS, n)
        raw = os.path.join(RAW, n)
        if not os.path.exists(raw):
            shutil.copy2(src, raw)
        before = Image.open(raw).size
        out = trim(raw)
        ratio = TOP_CROP_RATIO.get(n)
        if ratio:
            im = out if out is not None else Image.open(raw).convert("RGB")
            cut = int(im.height * ratio)
            out = trim_box(im.crop((0, cut, im.width, im.height)))
        if out is None:
            print(f"  {n:<28} {before[0]}x{before[1]}  无需裁剪")
            continue
        out.save(src)
        print(f"  {n:<28} {before[0]}x{before[1]} → {out.width}x{out.height}")


if __name__ == "__main__":
    main()