from __future__ import annotations

import re
from pathlib import Path
from typing import Iterable

try:
    # Optional, nur Fallback
    from wordfreq import top_n_list  # type: ignore
except Exception:  # pragma: no cover
    top_n_list = None  # type: ignore


ALLOWED_FIVE_LETTER = re.compile(r"^[a-zäöüß]{5}$")


def is_valid_five_letter_word(word: str) -> bool:
    return bool(ALLOWED_FIVE_LETTER.match(word))


def clean_token(token: str) -> str:
    # entferne Klammerzusätze wie (ugs.), (fachspr.), etc.
    no_paren = re.sub(r"\([^)]*\)", "", token)
    # entferne Auslassungszeichen (Präfix-/Suffix-Markierungen)
    no_ellipsis = no_paren.replace("...", "").replace("…", "")
    # nur Buchstaben (inkl. äöüß) behalten
    letters_only = re.sub(r"[^A-Za-zÄÖÜäöüß]", "", no_ellipsis)
    return letters_only.strip().lower()


def extract_from_openthesaurus(path: Path) -> list[str]:
    words: set[str] = set()
    with path.open("r", encoding="utf-8") as f:
        for raw_line in f:
            line = raw_line.strip()
            if not line or line.startswith("#"):
                continue
            parts = line.split(";")
            for part in parts:
                # Einträge mit Auslassungen überspringen (keine vollständigen Wörter)
                if "..." in part or "…" in part:
                    continue
                token = clean_token(part)
                if is_valid_five_letter_word(token):
                    words.add(token)
    return sorted(words)


def extract_from_wordfreq(limit: int = 500_000) -> list[str]:
    if top_n_list is None:
        return []
    candidates = top_n_list("de", limit)
    words = {clean_token(w) for w in candidates}
    return sorted(w for w in words if is_valid_five_letter_word(w))


def main() -> None:
    root = Path(__file__).resolve().parents[1]
    source_ot = root / "data" / "openthesaurus.txt"
    out_path = root / "data" / "words_de_5.txt"
    out_path.parent.mkdir(parents=True, exist_ok=True)

    if source_ot.exists():
        words = extract_from_openthesaurus(source_ot)
        source = "OpenThesaurus"
    else:
        words = extract_from_wordfreq()
        source = "wordfreq"

    with out_path.open("w", encoding="utf-8") as f:
        for w in words:
            f.write(w + "\n")

    print(f"Gespeichert: {len(words)} Wörter (Quelle: {source}) -> {out_path}")


if __name__ == "__main__":
    main()