#!/usr/bin/env python3
"""render_check.py — rasterize PDF pages to PNG for visual verification.

Cross-platform: uses pypdfium2 (already pulled in with pdfplumber), so it needs
no poppler/pdftoppm. On Windows this is the practical way to do the "ALWAYS
verify visually" step from SKILL.md.

Usage:
    python render_check.py Output.pdf                # every page -> Output_p1.png, ...
    python render_check.py Output.pdf 1 2 5          # only pages 1, 2, 5 (1-based)
    python render_check.py Output.pdf 1 2 --scale 2  # higher resolution
"""
import sys, pathlib

try:
    import pypdfium2 as pdfium
except Exception:
    sys.exit("Missing pypdfium2 (it installs alongside pdfplumber).\n"
             "    pip install pypdfium2")


def main():
    args = list(sys.argv[1:])
    if not args:
        sys.exit("Usage: python render_check.py <pdf> [pages...] [--scale N]")

    scale = 1.5
    if "--scale" in args:
        i = args.index("--scale")
        try:
            scale = float(args[i + 1])
        except (IndexError, ValueError):
            sys.exit("--scale needs a number, e.g. --scale 2")
        del args[i:i + 2]

    pdf_path = args[0]
    if not pathlib.Path(pdf_path).exists():
        sys.exit(f"PDF not found: {pdf_path}")
    pages = [int(a) for a in args[1:]]

    pdf = pdfium.PdfDocument(pdf_path)
    n = len(pdf)
    idxs = [p - 1 for p in pages] if pages else range(n)
    stem = pathlib.Path(pdf_path).with_suffix("")
    for i in idxs:
        if i < 0 or i >= n:
            print(f"  ! page {i + 1} out of range (1..{n})")
            continue
        out = f"{stem}_p{i + 1}.png"
        pdf[i].render(scale=scale).to_pil().save(out)
        print("wrote", out)


if __name__ == "__main__":
    main()