"""股票代码规范化工具。"""

from __future__ import annotations

import re

SUPPORTED_MARKETS = {"SH", "SZ", "BJ"}


def normalize_ts_code(value: str | None) -> str:
    """把常见 A 股代码输入规范成 Tushare 格式。

    支持:
      - 603779 -> 603779.SH
      - 300750 -> 300750.SZ
      - 430047 -> 430047.BJ
      - sh600519 / sz000001 / bj430047
      - 600519.sh -> 600519.SH
    """
    text = str(value or "").strip().upper()
    if not text:
        return ""

    compact_match = re.fullmatch(r"(SH|SZ|BJ)(\d{6})", text)
    if compact_match:
        market, code = compact_match.groups()
        return f"{code}.{market}"

    dotted_match = re.fullmatch(r"(\d{6})\.(SH|SZ|BJ)", text)
    if dotted_match:
        code, market = dotted_match.groups()
        return f"{code}.{market}"

    if re.fullmatch(r"\d{6}", text):
        if text.startswith(("6", "9")):
            return f"{text}.SH"
        if text.startswith(("0", "2", "3")):
            return f"{text}.SZ"
        if text.startswith(("4", "8")):
            return f"{text}.BJ"

    return text


def split_ts_code(value: str | None) -> tuple[str, str]:
    """返回 (code, market)，无法识别时抛出带上下文的 ValueError。"""
    normalized = normalize_ts_code(value)
    if "." not in normalized:
        raise ValueError(f"无效股票代码格式: {value!r}")

    code, market = normalized.split(".", 1)
    if not re.fullmatch(r"\d{6}", code) or market not in SUPPORTED_MARKETS:
        raise ValueError(f"无效股票代码格式: {value!r}")
    return code, market