import json
import sys
from pathlib import Path

from PIL import Image, ImageOps
from pptx import Presentation
from pptx.util import Inches


def main() -> None:
    if len(sys.argv) != 3:
        raise SystemExit("Usage: python html_to_ppt_make.py <image-dir> <output-pptx>")

    image_dir = Path(sys.argv[1])
    output_pptx = Path(sys.argv[2])
    output_pptx.parent.mkdir(parents=True, exist_ok=True)

    labels_path = image_dir / "slides.json"
    labels = {}
    if labels_path.exists():
        labels = {item["index"]: item["label"] for item in json.loads(labels_path.read_text(encoding="utf-8"))}

    image_paths = sorted(image_dir.glob("slide_*.png"))
    if not image_paths:
        raise SystemExit(f"No slide PNGs found in {image_dir}")

    prs = Presentation()
    prs.slide_width = Inches(13.333333)
    prs.slide_height = Inches(7.5)

    blank_layout = prs.slide_layouts[6]
    for image_path in image_paths:
        slide_num = int(image_path.stem.split("_")[-1])
        slide = prs.slides.add_slide(blank_layout)
        picture = slide.shapes.add_picture(
            str(image_path),
            0,
            0,
            width=prs.slide_width,
            height=prs.slide_height,
        )
        picture.name = labels.get(slide_num, image_path.stem)

    prs.save(output_pptx)

    montage_path = output_pptx.with_suffix(".preview.png")
    thumbs = []
    for image_path in image_paths:
        img = Image.open(image_path).convert("RGB")
        img.thumbnail((384, 216), Image.Resampling.LANCZOS)
        thumbs.append(ImageOps.expand(img, border=2, fill=(30, 30, 30)))

    cols = 5
    rows = (len(thumbs) + cols - 1) // cols
    montage = Image.new("RGB", (cols * 388, rows * 220), (12, 15, 24))
    for idx, thumb in enumerate(thumbs):
        x = (idx % cols) * 388
        y = (idx // cols) * 220
        montage.paste(thumb, (x, y))
    montage.save(montage_path)

    print(f"pptx={output_pptx}")
    print(f"preview={montage_path}")
    print(f"slides={len(image_paths)}")


if __name__ == "__main__":
    main()