# -*- coding: utf-8 -*-
"""
生成 App 图标资源（Android / iOS / Web 通用）。

背景：
  品牌原图 AI-accounting-soft-uniApp/static/images/logo.png 是「熊头+3只狗+5个大字」
  的贴纸海报，带虚化底纹，不适合直接当图标（缩小后文字糊成一团、背景去不干净）。
  因此改用同画风的专用图标素材（熊头单主体），由本脚本完成：
    1. 去除素材右下角的 AI 生成水印（用上方像素向下延展填充，适配平滑渐变底）
    2. 居中裁切、按比例缩放
    3. 输出两种产物

产物：
  assets/icon/app_icon.png     1024x1024，无透明通道 → iOS / Android 传统图标 / Web
  assets/icon/app_icon_fg.png  1024x1024，带透明通道 → Android 自适应图标前景层
  assets/images/logo.png        512x512，带透明通道 → App 内品牌标识（登录页圆形 Logo）

  登录页的 Logo 用透明底：外层是白色圆形，放进不透明的方图会露出四角（方图
  对角线比圆直径长），看起来像贴了张方照片。

用法：
  python tools/make_app_icon.py            # 生成正式产物
  python tools/make_app_icon.py --preview  # 只输出效果预览图
"""
from __future__ import annotations

import argparse
from pathlib import Path

import numpy as np
from PIL import Image, ImageDraw

ROOT = Path(__file__).resolve().parent.parent
DEFAULT_SRC = ROOT / "assets" / "icon" / "_source" / "raw_bear.png"
OUT_DIR = ROOT / "assets" / "icon"
LOGO_OUT = ROOT / "assets" / "images" / "logo.png"

CANVAS = 1024
BG_COLOR = (255, 246, 236)   # 暖奶油色，与品牌焦糖色 #C8956E 同色系
ICON_FILL = 0.74             # 正式图标里主体的占比
FG_FILL = 0.60               # 自适应图标前景层占比（Android 安全区为画布的 66%）
LOGO_CANVAS = 512            # 登录页最大显示 120pt，512 够 4x 屏
LOGO_FILL = 0.86             # 品牌标识的占比，比自适应前景层饱满一些
BG_THRESH = 70               # 判定「这是背景」的色差阈值（各通道绝对差之和）

# 水印区域（右下角），留够边距避免碰到主体
WM_BOX = (850, 912, 1024, 1024)


def remove_watermark(im: Image.Image, box: tuple[int, int, int, int]) -> Image.Image:
    """把 box 区域用其上方一行的像素向下延展填充，抹掉水印。"""
    x0, y0, x1, y1 = box
    row = im.crop((x0, y0 - 1, x1, y0)).resize((x1 - x0, y1 - y0), Image.NEAREST)
    out = im.copy()
    out.paste(row, (x0, y0))
    return out


def background_mask(im: Image.Image, thresh: int) -> np.ndarray:
    """返回「属于背景」的布尔矩阵：与四角平均色的色差小于阈值。"""
    arr = np.asarray(im).astype(np.int16)
    h, w, _ = arr.shape
    corners = np.stack([
        arr[0, 0], arr[0, w - 1], arr[h - 1, 0], arr[h - 1, w - 1],
        arr[2, 2], arr[2, w - 3], arr[h - 3, 2], arr[h - 3, w - 3],
    ]).astype(np.int16)
    seed = corners.mean(axis=0)
    diff = np.abs(arr - seed).sum(axis=2)
    return diff <= thresh


def to_foreground(im: Image.Image, mask: np.ndarray) -> Image.Image:
    """按背景掩码抠出主体，返回带 alpha 的图。"""
    rgba = im.convert("RGBA")
    a = np.asarray(rgba).copy()
    a[..., 3] = np.where(mask, 0, 255)
    out = Image.fromarray(a, "RGBA")
    bbox = out.getbbox()
    return out.crop(bbox) if bbox else out


def fit(art: Image.Image, size: int, fill: float, bg: tuple[int, int, int, int] | None) -> Image.Image:
    """等比缩放 art 至画布 size 的 fill 比例，居中合成。bg=None 表示透明底。"""
    box = int(size * fill)
    scale = min(box / art.width, box / art.height)
    art = art.convert("RGBA").resize(
        (max(1, round(art.width * scale)), max(1, round(art.height * scale))),
        Image.LANCZOS,
    )
    canvas = Image.new("RGBA", (size, size), bg if bg else (0, 0, 0, 0))
    canvas.alpha_composite(art, ((size - art.width) // 2, (size - art.height) // 2))
    return canvas


def build(src: Path):
    im = Image.open(src).convert("RGB")
    print(f"source: {src.name} {im.size}")

    cleaned = remove_watermark(im, WM_BOX)
    mask = background_mask(cleaned, BG_THRESH)
    print(f"background pixels: {mask.mean():.1%}")

    solid_subject = Image.fromarray(
        np.where(mask[..., None], np.array(BG_COLOR, np.uint8), np.asarray(cleaned)).astype(np.uint8),
        "RGB",
    )
    bbox = background_mask(solid_subject, BG_THRESH)
    ys, xs = np.nonzero(~bbox)
    subject = solid_subject.crop((xs.min(), ys.min(), xs.max() + 1, ys.max() + 1))
    fg_subject = to_foreground(cleaned, mask)
    print(f"subject bbox: {subject.size}   fg bbox: {fg_subject.size}")

    icon = fit(subject, CANVAS, ICON_FILL, (*BG_COLOR, 255)).convert("RGB")
    fg = fit(fg_subject, CANVAS, FG_FILL, None)
    logo = fit(fg_subject, LOGO_CANVAS, LOGO_FILL, None)
    return icon, fg, logo


def checkerboard(size: int, square: int = 16) -> Image.Image:
    board = Image.new("RGB", (size, size), (255, 255, 255))
    d = ImageDraw.Draw(board)
    for y in range(0, size, square):
        for x in range(0, size, square):
            if (x // square + y // square) % 2:
                d.rectangle([x, y, x + square - 1, y + square - 1], fill=(205, 205, 205))
    return board


def preview(icon: Image.Image, fg: Image.Image) -> None:
    cell = 240
    sheet = Image.new("RGB", (cell * 4 + 50, cell + 50), (235, 235, 235))

    sheet.paste(icon.resize((cell, cell), Image.LANCZOS), (10, 30))

    tiny = icon.resize((48, 48), Image.LANCZOS).resize((cell, cell), Image.NEAREST)
    sheet.paste(tiny, (cell + 20, 30))

    adaptive = Image.new("RGB", (CANVAS, CANVAS), BG_COLOR)
    adaptive.paste(fg, (0, 0), fg)
    circ = Image.new("L", (CANVAS, CANVAS), 0)
    ImageDraw.Draw(circ).ellipse([60, 60, CANVAS - 60, CANVAS - 60], fill=255)
    circle_bg = Image.new("RGB", (CANVAS, CANVAS), (255, 255, 255))
    circle_bg.paste(adaptive, (0, 0), circ)
    sheet.paste(circle_bg.resize((cell, cell), Image.LANCZOS), (cell * 2 + 30, 30))

    board = checkerboard(cell)
    board.paste(fg.resize((cell, cell), Image.LANCZOS), (0, 0), fg.resize((cell, cell), Image.LANCZOS))
    sheet.paste(board, (cell * 3 + 40, 30))

    d = ImageDraw.Draw(sheet)
    for i, label in enumerate(["1: icon 1024", "2: at 48px", "3: adaptive(circle)", "4: fg alpha"]):
        d.text((10 + (cell + 10) * i, 10), label, fill=(0, 0, 0))

    out = ROOT / "tools" / "_preview.png"
    sheet.save(out)
    print("preview ->", out)


CHECK_TARGETS = [
    "assets/icon/app_icon.png",
    "assets/icon/app_icon_fg.png",
    "assets/images/logo.png",
    "ios/Runner/Assets.xcassets/AppIcon.appiconset/Icon-App-1024x1024@1x.png",
    "android/app/src/main/res/mipmap-xxxhdpi/ic_launcher.png",
    "android/app/src/main/res/drawable-xxxhdpi/ic_launcher_foreground.png",
    "web/icons/Icon-512.png",
]


def check() -> None:
    """核对已生成的图标：iOS 的 1024 图必须是 RGB（无 alpha），否则上架报 ITMS-90717。"""
    for rel in CHECK_TARGETS:
        p = ROOT / rel
        if not p.exists():
            print(f"MISSING  {rel}")
            continue
        with Image.open(p) as im:
            flag = ""
            if "ios" in rel and im.mode != "RGB":
                flag = "  <-- 必须无 alpha！"
            print(f"{im.mode:<6} {str(im.size):<12} {rel}{flag}")


def main() -> None:
    ap = argparse.ArgumentParser()
    ap.add_argument("--src", type=Path, default=DEFAULT_SRC)
    ap.add_argument("--preview", action="store_true", help="只输出效果预览图")
    ap.add_argument("--check", action="store_true", help="核对已生成的图标产物")
    args = ap.parse_args()

    if args.check:
        check()
        return

    icon, fg, logo = build(args.src)
    if args.preview:
        preview(icon, fg)
        return

    OUT_DIR.mkdir(parents=True, exist_ok=True)
    icon.save(OUT_DIR / "app_icon.png", "PNG", optimize=True)
    fg.save(OUT_DIR / "app_icon_fg.png", "PNG", optimize=True)
    LOGO_OUT.parent.mkdir(parents=True, exist_ok=True)
    logo.save(LOGO_OUT, "PNG", optimize=True)
    print("->", OUT_DIR / "app_icon.png", icon.size)
    print("->", OUT_DIR / "app_icon_fg.png", fg.size)
    print("->", LOGO_OUT, logo.size)


if __name__ == "__main__":
    main()