#!/usr/bin/env python3
"""
page_index.py — write a table-of-contents page into a space. Offline.

The wiki this feeds is flat: a title like `Simple Chains/Ideas/Chain core` has
hierarchy in its name and nowhere else, and Gitea will not draw you a tree from
it. An index page is therefore not a nicety, it is the navigation.

Written as an ordinary page in the space, so it is pushed by the same command
as everything else and needs no special case anywhere downstream. Links are
written by TITLE rather than by URL — the wiki resolves those itself, and a
link written that way survives every filename-escaping rule this layer
deliberately refuses to model.

    page_index.py --space claude-skills/tea --prefix "Simple Chains"
        -> Simple-Chains.md, title `Simple Chains`

    page_index.py --space claude-skills/tea --title Home
        -> Home.md, title `Home`, listing the whole space

Usage:
    page_index.py [--space SPACE] [--prefix TITLE] [--title TITLE]
                  [--dry-run] [--out DIR]
"""
import argparse
import os
import sys

sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
import page  # noqa: E402


def die(msg, code=1):
    sys.stderr.write("%s: %s\n" % (os.path.basename(sys.argv[0]), msg))
    sys.exit(code)


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--space", default="local")
    ap.add_argument("--prefix", default="",
                    help="index only this subtree; also the index's own title")
    ap.add_argument("--title", help="title for the index page "
                                    "(default: --prefix, else Home)")
    ap.add_argument("--dry-run", action="store_true")
    ap.add_argument("--out", help="wiki cache root (default: <repo>/tmp/wiki)")
    a = ap.parse_args()

    root = a.out or page.WIKI_ROOT
    space_dir = page.space_root(a.space, root)
    if not os.path.isdir(space_dir):
        die("no such space: %s (looked in %s)" % (a.space, space_dir))

    manifest = page.load_manifest(a.space, root)
    prefix = page.sanitize_title(a.prefix) if a.prefix else ""
    title = a.title or prefix or "Home"

    body = page.render_index(manifest, prefix, heading=title)
    relpath = page.path_for_title(title)

    if a.dry_run:
        sys.stdout.write(body)
        print("-> %s (%s)" % (relpath, title))
        return 0

    dest = os.path.join(space_dir, relpath)
    os.makedirs(os.path.dirname(dest), exist_ok=True)
    with open(dest, "w", encoding="utf-8") as f:
        f.write(body)

    # Carries the entry's passthrough keys forward: rebuilding an index must
    # update the page that is already published, never publish a second one.
    prior = manifest["pages"].get(relpath, {})
    e = dict(prior)
    e.update(page.entry(title, prior.get("order")))
    manifest["pages"][relpath] = e
    page.save_manifest(manifest, root)

    n = len(page.children_of(manifest, prefix) if prefix
            else page.sorted_pages(manifest))
    print("%s -> %s (%d entr%s)" % (title, relpath, n - 1,
                                    "y" if n - 1 == 1 else "ies"))
    return 0


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