"""Wiki page titles and transliterated wiki filenames."""

from __future__ import annotations

import hashlib
import re

from export1c_help.discover import HelpPage

_INVALID = re.compile(r'[\\/:*?"<>|#\[\]]+')
_SPACES = re.compile(r"\s+")
_NON_SLUG = re.compile(r"[^a-z0-9._-]+")
_DASH_RUNS = re.compile(r"-+")
_MAX_SLUG = 48

_TRANSLIT = {
    "а": "a",
    "б": "b",
    "в": "v",
    "г": "g",
    "д": "d",
    "е": "e",
    "ё": "e",
    "ж": "zh",
    "з": "z",
    "и": "i",
    "й": "y",
    "к": "k",
    "л": "l",
    "м": "m",
    "н": "n",
    "о": "o",
    "п": "p",
    "р": "r",
    "с": "s",
    "т": "t",
    "у": "u",
    "ф": "f",
    "х": "h",
    "ц": "ts",
    "ч": "ch",
    "ш": "sh",
    "щ": "sch",
    "ъ": "",
    "ы": "y",
    "ь": "",
    "э": "e",
    "ю": "yu",
    "я": "ya",
}


def sanitize_title(title: str) -> str:
    title = _SPACES.sub(" ", title).strip()
    title = _INVALID.sub(" ", title)
    title = _SPACES.sub(" ", title).strip()
    return title or "untitled"


def _short_hash(s: str) -> str:
    return hashlib.sha1(s.encode("utf-8")).hexdigest()[:8]


def _translit_slug(title: str) -> str:
    chars: list[str] = []
    for ch in title.lower():
        chars.append(_TRANSLIT.get(ch, ch))
    raw = "".join(chars).replace(" ", "-")
    raw = _NON_SLUG.sub("-", raw)
    raw = _DASH_RUNS.sub("-", raw).strip("-._")
    return raw or "page"


def wiki_filename(title: str, *, meta_key: str | None = None) -> str:
    """
    Build ASCII transliterated ``slug.md`` with bounded slug length.
    """
    slug = _translit_slug(sanitize_title(title))
    if len(slug) <= _MAX_SLUG:
        return f"{slug}.md"
    suffix = "-" + _short_hash(meta_key or title)
    keep = max(8, _MAX_SLUG - len(suffix))
    slug = slug[:keep].rstrip("-._") or "page"
    return f"{slug}{suffix}.md"


def decode_wiki_filename(name: str) -> str:
    return name[:-3] if name.endswith(".md") else name


def assign_titles(
    pages: list[HelpPage],
    h1_by_meta: dict[str, str | None],
) -> tuple[dict[str, str], dict[str, str]]:
    """Returns (meta_key → title, meta_key → filename)."""
    used_title: set[str] = set()
    used_file: set[str] = set()
    titles: dict[str, str] = {}
    files: dict[str, str] = {}

    for p in pages:
        h1 = h1_by_meta.get(p.meta_key)
        base = sanitize_title(h1 or p.synonym or p.meta_key)
        title = base
        n = 2
        while title.casefold() in used_title:
            if p.is_form and p.form_name and n == 2:
                title = sanitize_title(f"{base} — {p.form_name}")
            elif n == 2:
                title = sanitize_title(f"{base} — {p.object_name}")
            else:
                title = sanitize_title(f"{base} ({n})")
            n += 1
            if n > 5000:
                title = sanitize_title(p.meta_key)
                break

        fname = wiki_filename(title, meta_key=p.meta_key)
        if fname.casefold() in used_file:
            fname = wiki_filename(
                f"{title}-{_short_hash(p.meta_key)}",
                meta_key=p.meta_key,
            )
        guard = 0
        while fname.casefold() in used_file:
            fname = f"page-{_short_hash(p.meta_key + str(guard))}.md"
            guard += 1

        used_title.add(title.casefold())
        used_file.add(fname.casefold())
        titles[p.meta_key] = title
        files[p.meta_key] = fname

    return titles, files