"""东方财富 CHOICE API 股东户数抓取工具。
- 输入: 股票代码列表 (如 ['603233.SH'])
- 输出: pandas DataFrame (按报告期末的股东户数变化)
- 不需要登录, 不需要 cookie, 无文件落盘
"""
from __future__ import annotations

import pandas as pd

from utils._emchoice import fetch_report


_REPORT_NAME = "RPT_F10_EH_HOLDERNUM"
_COLUMNS = "CHOICEF9_EH_HOLDERNUM"


def _build_params(
    secucode: str,
    start_date: str,
    end_date: str,
) -> dict[str, str]:
    """构造 RPT_F10_EH_HOLDERNUM 查询参数."""
    return {
        "source": "CHOICE",
        "reportName": _REPORT_NAME,
        "columns": _COLUMNS,
        "quoteColumns": "",
        "filter": f'(SECUCODE="{secucode}")(END_DATE>=\'{start_date}\')(END_DATE<=\'{end_date}\')',
        "pageNumber": "",
        "pageSize": "",
        "sortColumns": "END_DATE",
        "client": "SW",
        "sortTypes": "-1",
    }


def _fetch_one(secucode: str, years: int) -> pd.DataFrame:
    """拉一只股票的股东户数."""
    today = pd.Timestamp.today()
    start = (today - pd.DateOffset(years=years)).strftime("%Y-%m-%d")
    end = today.strftime("%Y-%m-%d")

    rows = fetch_report(_build_params(secucode, start, end))
    df = pd.DataFrame(rows)
    if not df.empty:
        df["SECUCODE"] = secucode
    return df


def get_holder_num(secucodes: list[str], years: int = 3) -> pd.DataFrame:
    """抓取指定股票的股东户数并按股票合并。"""
    codes = [code.strip() for code in secucodes if code.strip()]
    if not codes:
        return pd.DataFrame()

    frames: list[pd.DataFrame] = []
    for code in codes:
        df = _fetch_one(code, years)
        if not df.empty:
            frames.append(df)

    if not frames:
        return pd.DataFrame()
    return pd.concat(frames, ignore_index=True)