#!/usr/bin/env python3
"""
查詢 TWSE 個股融資融券餘額（信用交易統計）

用法：
  python3 skills/stocks-query/scripts/twse-margin-trading.py 2330
  python3 skills/stocks-query/scripts/twse-margin-trading.py 3481

資料來源：證交所 TWSE 公開 API
"""

from __future__ import annotations

import json
import sys
import urllib.request
from datetime import datetime, timedelta


def fetch_margin(stock_no: str, date_str: str | None = None) -> dict:
    """從 TWSE 抓融資融券資料，自動往前回溯最多 10 天找到有資料的日期。"""
    if date_str:
        dates_to_try = [date_str]
    else:
        today = datetime.now()
        dates_to_try = [(today - timedelta(days=i)).strftime("%Y%m%d") for i in range(10)]

    for d in dates_to_try:
        url = (
            f"https://www.twse.com.tw/rwd/zh/marginTrading/MI_MARGN"
            f"?date={d}&selectType=ALL&response=json"
        )
        req = urllib.request.Request(url, headers={"User-Agent": "Mozilla/5.0"})
        try:
            with urllib.request.urlopen(req, timeout=30) as resp:
                data = json.loads(resp.read().decode("utf-8", errors="replace"))
        except Exception:
            continue

        if data.get("stat") != "OK":
            continue

        tables = data.get("tables", [])
        if not tables:
            continue

        # 找到個股那張表（title 含「融資融券」或欄位含「股票代號」）
        target_table = None
        for tbl in tables:
            fields = tbl.get("fields", [])
            if "股票代號" in fields:
                target_table = tbl
                break

        if not target_table:
            continue

        fields = target_table["fields"]
        for row in target_table.get("data", []):
            code = row[fields.index("股票代號")].strip()
            if code == stock_no:
                result = {"date": d}
                for i, field in enumerate(fields):
                    result[field.strip()] = row[i].strip().replace(",", "")
                return result

    raise RuntimeError(f"找不到 {stock_no} 的融資融券資料（已回溯 10 天）")


def print_summary(stock_no: str, d: dict) -> None:
    date_fmt = f"{d['date'][:4]}/{d['date'][4:6]}/{d['date'][6:]}"
    name = d.get("股票名稱", stock_no)
    print(f"{name}（{stock_no}）｜融資融券摘要")
    print(f"• 日期：{date_fmt}")

    # 融資
    margin_buy = d.get("融資買進", "-")
    margin_sell = d.get("融資賣出", "-")
    margin_cash = d.get("融資現償", "-")
    margin_balance = d.get("融資餘額", d.get("融資今日餘額", "-"))
    margin_limit = d.get("融資限額", "-")
    print(f"• 融資買進：{margin_buy}")
    print(f"• 融資賣出：{margin_sell}")
    print(f"• 融資現償：{margin_cash}")
    print(f"• 融資餘額：{margin_balance}")
    if margin_limit != "-":
        print(f"• 融資限額：{margin_limit}")

    # 融券
    short_sell = d.get("融券賣出", "-")
    short_buy = d.get("融券買進", "-")
    short_cash = d.get("融券現償", "-")
    short_balance = d.get("融券餘額", d.get("融券今日餘額", "-"))
    short_limit = d.get("融券限額", "-")
    print(f"• 融券賣出：{short_sell}")
    print(f"• 融券買進：{short_buy}")
    print(f"• 融券現償：{short_cash}")
    print(f"• 融券餘額：{short_balance}")
    if short_limit != "-":
        print(f"• 融券限額：{short_limit}")

    # 券資比
    try:
        mb = float(margin_balance) if margin_balance != "-" else 0
        sb = float(short_balance) if short_balance != "-" else 0
        if mb > 0:
            ratio = (sb / mb) * 100
            print(f"• 券資比：{ratio:.2f}%")
    except (ValueError, ZeroDivisionError):
        pass


if __name__ == "__main__":
    stock_no = sys.argv[1] if len(sys.argv) > 1 else "2330"
    try:
        data = fetch_margin(stock_no)
        print_summary(stock_no, data)
    except Exception as e:
        print(f"取得失敗：{e}", file=sys.stderr)
        sys.exit(1)