#!/usr/bin/env python3
"""Split the original PSD scan artwork for deterministic, code-driven motion."""
import argparse
import hashlib
import json
from pathlib import Path

from PIL import Image, ImageDraw
from psd_tools import PSDImage

ROOT = Path(__file__).resolve().parents[1]


def main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("psd", type=Path)
    args = parser.parse_args()
    psd = PSDImage.open(args.psd)
    page = psd[9]
    if page.name != "扫描" or page[2][1].name != "矩形 661":
        raise ValueError("Unexpected scan layout; nothing exported")
    left, top, right, bottom = page.bbox
    viewport = (left, top + 248, right, bottom)
    source = page[2][2]
    source.visible = False
    base = page.composite(viewport=viewport).convert("RGB")
    # Recover the connected white face from the unmodified cached PSD pixels.
    # Disconnected frame/text/icon whites must never become part of the mask.
    candidate = Image.eval(base.convert("L"), lambda v: 255 if v > 245 else 0)
    ImageDraw.floodfill(candidate, (540, 720), 128)
    mask = Image.eval(candidate, lambda v: 255 if v == 128 else 0)
    if mask.getbbox() is None or mask.getpixel((540, 1200)) != 255:
        raise ValueError(f"PSD white face was lost to cross-layer clipping: bbox={mask.getbbox()}, seed={base.getpixel((540, 720))}, lower={base.getpixel((540, 1200))}")
    target = ROOT / "h5/assets/img/ui-20261012"
    target.mkdir(parents=True, exist_ok=True)
    alpha_mask = Image.new("RGBA", mask.size, (255, 255, 255, 0))
    alpha_mask.putalpha(mask)
    assets = []
    for name, image in [("scan-base.webp", base), ("scan-face-mask.png", alpha_mask)]:
        output = target / name
        if output.suffix == ".webp":
            image.save(output, lossless=True, method=6)
        else:
            image.save(output, optimize=True)
        data = output.read_bytes()
        assets.append({"file": str(output.relative_to(ROOT)), "size": list(image.size),
                       "bytes": len(data), "sha256": hashlib.sha256(data).hexdigest()})
        print(f"Exported {name}: {image.size}, {len(data)} bytes", flush=True)
    digest = hashlib.sha256()
    with args.psd.open("rb") as stream:
        for chunk in iter(lambda: stream.read(8 * 1024 * 1024), b""):
            digest.update(chunk)
    manifest = {"source": str(args.psd), "source_sha256": digest.hexdigest(),
                "source_page": "9", "hidden_scan_layer": "9/2/2", "viewport": list(viewport),
                "face_bbox": list(mask.getbbox()), "cycle_ms": 1000, "yellow": "#F5F078",
                "assets": assets}
    design = ROOT / "design/ui-20261012"
    (design / "scan-motion-manifest.json").write_text(json.dumps(manifest, ensure_ascii=False, indent=2) + "\n")


if __name__ == "__main__":
    main()