#!/usr/bin/env python3
"""Rewrite catalog hostnames in a built ./site tree (HTML + PDF annotations).

Catalog HTML links are already relative. PDF annotations used to be baked as
https://zapier.georgelambert.org/… — this script retargets those (and any HTML
that still names a docs origin) when the tree is hosted on another name, e.g.
docs.verae-time.net.

It does **not** rewrite live service doors (portal/api/iam/…) or Forgejo.

Examples:

  # Lab catalog → future docs host (keep absolute URLs)
  python3 scripts/rewrite-docs-host.py \\
      --site ./site \\
      --from https://zapier.georgelambert.org \\
      --to https://docs.verae-time.net

  # Drop the host entirely (path-relative PDF links; any hostname at site root)
  python3 scripts/rewrite-docs-host.py --site ./site --relative

  python3 scripts/rewrite-docs-host.py --site ./site --from … --to … --dry-run
"""
from __future__ import annotations

import argparse
import os
import sys
from pathlib import Path

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


def _norm_origin(url: str) -> str:
    url = url.strip()
    if not url:
        return ""
    if "://" not in url:
        url = "https://" + url
    return url.rstrip("/") + "/"


def rewrite_html(site: Path, src: str, dst: str, dry: bool) -> int:
    n = 0
    src_bare = src.rstrip("/")
    dst_bare = dst.rstrip("/") or "/"
    for path in site.rglob("*"):
        if not path.is_file() or path.suffix.lower() not in {".html", ".htm", ".xml", ".svg", ".js", ".css", ".md"}:
            continue
        text = path.read_text(encoding="utf-8", errors="replace")
        if src not in text and src_bare not in text:
            continue
        new = text.replace(src, dst).replace(src_bare, dst_bare)
        if new == text:
            continue
        n += 1
        if dry:
            print(f"  html {path.relative_to(site)}")
        else:
            path.write_text(new, encoding="utf-8")
    return n


def rewrite_pdfs(site: Path, src: str, dst: str | None, dry: bool) -> int:
    try:
        from pypdf import PdfReader, PdfWriter
        from pypdf.generic import NameObject, create_string_object
    except ImportError:
        print("pypdf missing; pip install pypdf", file=sys.stderr)
        return 0
    n_pdf = 0
    n_uri = 0
    src_http = src.replace("https://", "http://", 1) if src.startswith("https://") else src
    for pdf in site.rglob("*.pdf"):
        try:
            reader = PdfReader(str(pdf))
        except Exception:
            continue
        changed = False
        for page in reader.pages:
            annots = page.get("/Annots")
            if not annots:
                continue
            for annot in annots:
                obj = annot.get_object()
                action = obj.get("/A")
                if not action:
                    continue
                uri = action.get("/URI")
                if not uri:
                    continue
                raw = str(uri)
                new = raw
                if raw.startswith(src) or raw.startswith(src_http):
                    rest = raw[len(src) :] if raw.startswith(src) else raw[len(src_http) :]
                    if dst:
                        new = dst + rest
                    else:
                        dest = site / rest.split("#", 1)[0]
                        frag = "#" + rest.split("#", 1)[1] if "#" in rest else ""
                        if not dest.exists():
                            dest = site / "index.html"
                        rel = os.path.relpath(dest.resolve(), pdf.parent.resolve())
                        new = Path(rel).as_posix() + frag
                if new != raw:
                    action[NameObject("/URI")] = create_string_object(new)
                    changed = True
                    n_uri += 1
        if changed:
            n_pdf += 1
            if dry:
                print(f"  pdf  {pdf.relative_to(site)}")
            else:
                writer = PdfWriter(clone_from=reader)
                tmp = pdf.with_suffix(".pdf.tmp")
                with tmp.open("wb") as fh:
                    writer.write(fh)
                tmp.replace(pdf)
    print(f"pdf annotations {n_uri} in {n_pdf} files")
    return n_pdf


def main() -> int:
    ap = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
    ap.add_argument("--site", type=Path, default=ROOT / "site", help="built catalog directory")
    ap.add_argument("--from", dest="src", default="https://zapier.georgelambert.org", help="current docs origin")
    g = ap.add_mutually_exclusive_group(required=True)
    g.add_argument("--to", help="new docs origin, e.g. https://docs.verae-time.net")
    g.add_argument("--relative", action="store_true", help="convert docs-origin URLs to path-relative links")
    ap.add_argument("--dry-run", action="store_true")
    args = ap.parse_args()
    site = args.site.resolve()
    if not site.is_dir():
        print(f"no site at {site}", file=sys.stderr)
        return 1
    src = _norm_origin(args.src)
    dst = None if args.relative else _norm_origin(args.to)
    print(f"{src} → {dst or 'relative paths'}  ({site})")
    # HTML: root-relative `/…` so nested pages still hit the site root on any host.
    html_dst = "/" if dst is None else dst
    n_html = rewrite_html(site, src, html_dst, args.dry_run)
    print(f"html/text files {n_html}")
    rewrite_pdfs(site, src, dst, args.dry_run)
    if args.dry_run:
        print("dry-run; nothing written")
    return 0


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