#!/usr/bin/env python3
"""Non-interactive replacement for the content repo's src/build_drawings.py.

Rebuilds contents/drawings/<id>.svg from contents/drawings/<id>.tex
(LuaLaTeX -> PDF -> pdftocairo -> SVG), run from the content repo root.

  build_drawings.py 502 503        build specific drawings
  build_drawings.py --stale        build drawings whose .tex is newer than the .svg
  build_drawings.py --all          build every drawing
  --preview DIR                    also write PNG previews into DIR (inside the container)
  -j N                             run N builds in parallel

Width: \\DARCimageOnly autoscales to a width in cm (default 9). To keep the size of the
existing drawing, the width is derived from the current SVG (pt -> cm); override with --width.
"""
import argparse
import os
import pathlib
import re
import subprocess
import sys
import tempfile
from concurrent.futures import ThreadPoolExecutor, as_completed

DRAWINGS = pathlib.Path("contents/drawings")
PHOTOS = pathlib.Path("contents/photos").resolve()


def width_from_svg(svg: pathlib.Path) -> float:
    """Width in cm of an existing SVG; 9 cm (the repo default) if unknown or ~9 cm."""
    try:
        head = svg.read_text(encoding="utf-8", errors="ignore")[:600]
        # poppler <= 22 writes "42.872pt", newer versions a bare number (same unit: pt)
        pt = float(re.search(r'width="([\d.]+)(?:pt)?"', head).group(1))
    except (OSError, AttributeError, ValueError):
        return 9.0
    cm = pt * 2.54 / 72
    if 8.85 <= cm <= 9.15:
        return 9.0
    return round(cm, 1)  # round (not ceil): stable when a drawing is rebuilt repeatedly


def build_drawing(drawing_id: str, width: float | None, preview: pathlib.Path | None = None) -> tuple[str, bool, str]:
    tex = DRAWINGS / f"{drawing_id}.tex"
    svg = DRAWINGS / f"{drawing_id}.svg"
    if not tex.is_file():
        return drawing_id, False, f"{tex} not found"
    latex = tex.read_text(encoding="utf-8")
    if "\\begin{document}" in latex or "\\begin{table}" in latex:
        return drawing_id, False, "contains a document environment"
    if width is None:
        width = width_from_svg(svg)

    with tempfile.TemporaryDirectory(prefix=f"build_{drawing_id}_", dir=".") as tmp:
        build = pathlib.Path(tmp)
        (build / "img").mkdir()
        (build / "img" / f"{drawing_id}include.tex").write_text(latex, encoding="utf-8")
        (build / f"{drawing_id}.tex").write_text(
            f"\\documentclass{{FiftyOhm}}\\DARCimageOnly{{{width}cm}}{{{drawing_id}include}}", encoding="utf-8"
        )
        (build / "foto").symlink_to(PHOTOS)
        (build / "img" / "foto").symlink_to(PHOTOS)

        # Run from the repo root so latexmk picks up ./latexmkrc (TEXINPUTS for FiftyOhm.cls);
        # its `$do_cd = 1` then runs LaTeX inside the build directory.
        run = subprocess.run(
            ["latexmk", "-lualatex", "-interaction=nonstopmode", "-halt-on-error", str(build / f"{drawing_id}.tex")],
            stdin=subprocess.DEVNULL, capture_output=True, text=True,
        )
        pdf = build / f"{drawing_id}.pdf"
        if run.returncode != 0 or not pdf.is_file():
            log = (build / f"{drawing_id}.log")
            tail = log.read_text(errors="ignore")[-1500:] if log.exists() else run.stdout[-1500:]
            return drawing_id, False, "latexmk failed:\n" + tail

        tmp_svg = build / f"{drawing_id}.svg"
        conv = subprocess.run(["pdftocairo", "-svg", str(pdf), str(tmp_svg)], capture_output=True, text=True)
        if conv.returncode != 0 or not tmp_svg.is_file():
            return drawing_id, False, "pdftocairo failed: " + conv.stderr
        if preview is not None:
            preview.mkdir(parents=True, exist_ok=True)
            subprocess.run(["pdftocairo", "-png", "-r", "130", "-singlefile", str(pdf), str(preview / drawing_id)], check=False)
        os.replace(tmp_svg, svg)  # only replace the SVG once a new one exists
    return drawing_id, True, f"{width} cm"


def stale_ids() -> list[str]:
    ids = []
    for tex in sorted(DRAWINGS.glob("*.tex")):
        svg = tex.with_suffix(".svg")
        if not svg.exists() or tex.stat().st_mtime > svg.stat().st_mtime:
            ids.append(tex.stem)
    return ids


def main() -> int:
    ap = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
    ap.add_argument("ids", nargs="*")
    ap.add_argument("--stale", action="store_true")
    ap.add_argument("--all", action="store_true")
    ap.add_argument("--width", type=float, help="override width in cm")
    ap.add_argument("--preview", type=pathlib.Path, help="also write a PNG preview of each drawing into this directory")
    ap.add_argument("-j", "--jobs", type=int, default=1)
    args = ap.parse_args()

    if not DRAWINGS.is_dir():
        print("Run from the content repo root (contents/drawings not found).", file=sys.stderr)
        return 2
    ids = list(args.ids)
    if args.all:
        ids = sorted(p.stem for p in DRAWINGS.glob("*.tex"))
    elif args.stale:
        ids = stale_ids()
    if not ids:
        print("Nothing to build.")
        return 0

    print(f"Building {len(ids)} drawing(s) with {args.jobs} job(s)")
    failed = []
    with ThreadPoolExecutor(max_workers=max(1, args.jobs)) as pool:
        futures = [pool.submit(build_drawing, i, args.width, args.preview) for i in ids]
        for n, fut in enumerate(as_completed(futures), 1):
            drawing_id, ok, info = fut.result()
            print(f"[{n}/{len(ids)}] {drawing_id}: {'ok ' + info if ok else 'FAILED ' + info}", flush=True)
            if not ok:
                failed.append(drawing_id)
    if failed:
        print(f"\n{len(failed)} failed: {' '.join(sorted(failed))}", file=sys.stderr)
        return 1
    return 0


if __name__ == "__main__":
    sys.exit(main())