"""한국어 TTS용 간단한 텍스트 정규화."""
from __future__ import annotations

import re


_RE_MULTI_SPACE = re.compile(r"\s+")
_RE_EMAIL = re.compile(r"[\w.+-]+@[\w.-]+\.\w+")
_RE_URL = re.compile(r"https?://\S+")


def _digits_to_korean(num_str: str) -> str:
    """정수 문자열을 한글 읽기로 변환 (간단 버전)."""
    if not num_str.isdigit():
        return num_str
    n = int(num_str.replace(",", ""))
    if n == 0:
        return "영"
    units = ["", "만", "억", "조"]
    small = ["", "일", "이", "삼", "사", "오", "육", "칠", "팔", "구"]
    ten = ["", "십", "백", "천"]

    def chunk_to_korean(x: int) -> str:
        if x == 0:
            return ""
        parts: list[str] = []
        s = f"{x:04d}"
        for i, d in enumerate(s):
            di = int(d)
            if di == 0:
                continue
            if i == 0 and di == 1 and len(s) > 1:
                parts.append(ten[3 - i])
            elif di == 1 and i > 0:
                parts.append(ten[3 - i])
            else:
                parts.append(small[di] + ten[3 - i])
        return "".join(parts)

    if n < 10000:
        return chunk_to_korean(n)

    result: list[str] = []
    u = 0
    while n > 0 and u < len(units):
        part = n % 10000
        n //= 10000
        if part:
            result.append(chunk_to_korean(part) + units[u])
        u += 1
    return "".join(reversed(result)) or num_str


def _replace_numbers(text: str) -> str:
    def repl(m: re.Match[str]) -> str:
        raw = m.group(0).replace(",", "")
        return _digits_to_korean(raw)

    return re.sub(r"\d[\d,]*", repl, text)


def preprocess_korean(text: str) -> str:
    t = text.strip()
    t = _RE_URL.sub(" 링크 ", t)
    t = _RE_EMAIL.sub(" 이메일 ", t)
    t = t.replace("&", " 앤드 ")
    t = t.replace("%", " 퍼센트 ")
    t = _replace_numbers(t)
    t = _RE_MULTI_SPACE.sub(" ", t)
    return t.strip()


def split_sentences(text: str, max_chars: int = 120) -> list[str]:
    """긴 텍스트를 문장 단위로 분리."""
    parts = re.split(r"(?<=[.!?…])\s+|\n+", preprocess_korean(text))
    chunks: list[str] = []
    buf = ""
    for p in parts:
        p = p.strip()
        if not p:
            continue
        if len(buf) + len(p) + 1 <= max_chars:
            buf = f"{buf} {p}".strip() if buf else p
        else:
            if buf:
                chunks.append(buf)
            if len(p) <= max_chars:
                buf = p
            else:
                for i in range(0, len(p), max_chars):
                    chunks.append(p[i : i + max_chars])
                buf = ""
    if buf:
        chunks.append(buf)
    return chunks or [text]