#!/usr/bin/env python3
"""Render a .humans/ HTML page to a self-contained PDF via headless Chrome.

The pages in `.humans/` reference screenshots relatively
(`../tools/tailor/screenshots/...`), so the HTML only works from inside a repo
checkout. The PDF embeds those images, which makes it the thing you actually
send to someone.

The HTML stays the source of truth: edit the page, re-run this, commit both.

    python tools/humans_to_pdf.py .humans/marvelous-designer.html
    python tools/humans_to_pdf.py --all
"""
from __future__ import annotations

import argparse
import subprocess
import sys
import tempfile
from pathlib import Path

CHROME_CANDIDATES = [
    r"C:\Program Files\Google\Chrome\Application\chrome.exe",
    r"C:\Program Files (x86)\Google\Chrome\Application\chrome.exe",
    r"C:\Program Files\Microsoft\Edge\Application\msedge.exe",
    r"C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe",
    "/Applications/Google Chrome.app/Contents/MacOS/Google Chrome",
    "/usr/bin/google-chrome",
    "/usr/bin/chromium",
]


def find_chrome() -> Path:
    for c in CHROME_CANDIDATES:
        p = Path(c)
        if p.exists():
            return p
    raise SystemExit("error: no Chrome or Edge found; tried:\n  "
                     + "\n  ".join(CHROME_CANDIDATES))


def to_pdf(html: Path, chrome: Path) -> Path:
    out = html.with_suffix(".pdf")
    # Chrome refuses to reuse a running profile, so give it a throwaway one.
    with tempfile.TemporaryDirectory() as profile:
        cmd = [
            str(chrome),
            "--headless=new",
            "--disable-gpu",
            f"--user-data-dir={profile}",
            "--no-pdf-header-footer",       # drop the URL/date furniture
            "--virtual-time-budget=15000",  # let local images decode first
            f"--print-to-pdf={out}",
            html.resolve().as_uri(),
        ]
        r = subprocess.run(cmd, capture_output=True, text=True, timeout=180)
    if not out.exists():
        sys.stderr.write(r.stderr or "")
        raise SystemExit(f"error: Chrome produced no PDF for {html}")
    return out


def main() -> int:
    ap = argparse.ArgumentParser(description=__doc__,
                                 formatter_class=argparse.RawDescriptionHelpFormatter)
    ap.add_argument("page", type=Path, nargs="?", help="HTML page under .humans/")
    ap.add_argument("--all", action="store_true", help="render every .humans/*.html")
    args = ap.parse_args()

    repo = Path(__file__).resolve().parent.parent
    if args.all:
        pages = sorted((repo / ".humans").glob("*.html"))
    elif args.page:
        pages = [args.page]
    else:
        ap.error("give a page, or --all")

    if not pages:
        print("nothing to render")
        return 0

    chrome = find_chrome()
    print(f"using {chrome.name}")
    for html in pages:
        if not html.is_file():
            print(f"  skip (missing): {html}")
            continue
        out = to_pdf(html, chrome)
        print(f"  {out.stat().st_size / 1048576:.2f} MB  {out}")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())