"""为存在价格断层的板块挑选替补：先抓日线，再做断层扫描 + 规模/成交额提示。

用法： py -3.14 -B labs/analysis/etf/pick_alt.py
"""

import json
import sys
import urllib.request
from pathlib import Path

HERE = Path(__file__).resolve().parent
sys.path.insert(0, str(HERE))
try:
    sys.stdout.reconfigure(encoding="utf-8", errors="replace")
except Exception:
    pass

from backtest import CACHE, DAILY_URL  # noqa: E402

# 板块 -> 需要考察的替补（按规模顺序）
ALTS = {
    "CPO/通信": ["515050.SH", "159583.SZ", "159994.SZ", "159695.SZ"],
    "半导体": ["159516.SZ", "588170.SH", "159995.SZ", "159558.SZ", "512480.SH"],
}


def fetch(code: str) -> list[dict]:
    request = urllib.request.Request(f"{DAILY_URL}?code={code}", headers={"User-Agent": "Mozilla/5.0"})
    with urllib.request.urlopen(request, timeout=30) as response:
        rows = json.load(response)
    CACHE.mkdir(parents=True, exist_ok=True)
    (CACHE / f"{code}.json").write_text(json.dumps(rows), encoding="utf-8")
    return sorted(rows, key=lambda r: str(r["trade_date"]))


def gaps(rows: list[dict]) -> list[tuple[str, float]]:
    out = []
    for prev, cur in zip(rows, rows[1:]):
        a, b = float(prev["close"]), float(cur["close"])
        if a > 0 and abs(b / a - 1) * 100 > 15:
            out.append((str(cur["trade_date"]), (b / a - 1) * 100))
    return out


for sector, codes in ALTS.items():
    print(f"\n== {sector} 替补 ==")
    for code in codes:
        try:
            rows = fetch(code)
        except Exception as exc:
            print(f"  {code}: 抓取失败 {exc}")
            continue
        closes = [float(r["close"]) for r in rows]
        bad = gaps(rows)
        flag = "OK" if not bad else f"断层 {len(bad)} 处(最大 {max(abs(g[1]) for g in bad):.1f}%)"
        print(f"  {code:11} 根数={len(rows):4} 最新={closes[-1]:7.3f} "
              f"区间={min(closes):6.3f}~{max(closes):6.3f} {flag}")