"""品种推荐：计算、按资金过滤、SQLite 缓存。"""
from __future__ import annotations

import json
from datetime import datetime
from typing import Callable, Optional

from product_recommend import list_product_recommendations

RECOMMEND_CACHE_SQL = """
CREATE TABLE IF NOT EXISTS product_recommend_cache (
    id INTEGER PRIMARY KEY CHECK (id = 1),
    capital REAL NOT NULL DEFAULT 0,
    rows_json TEXT NOT NULL DEFAULT '[]',
    updated_at TEXT
)
"""


def ensure_recommend_tables(conn) -> None:
    conn.execute(RECOMMEND_CACHE_SQL)


def filter_affordable_recommendations(rows: list[dict]) -> list[dict]:
    """仅保留当前资金可开 1 手的品种（不含资金不足、无行情）。"""
    return [r for r in rows if r.get("status") in ("ok", "margin_ok")]


def refresh_recommend_cache(
    conn,
    capital: float,
    quote_fn: Callable[[str], Optional[dict]],
) -> list[dict]:
    """后台拉行情、筛选并写入数据库。"""
    ensure_recommend_tables(conn)
    all_rows = list_product_recommendations(capital, quote_fn)
    rows = filter_affordable_recommendations(all_rows)
    now = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    conn.execute(
        """INSERT INTO product_recommend_cache (id, capital, rows_json, updated_at)
           VALUES (1, ?, ?, ?)
           ON CONFLICT(id) DO UPDATE SET
             capital=excluded.capital,
             rows_json=excluded.rows_json,
             updated_at=excluded.updated_at""",
        (float(capital or 0), json.dumps(rows, ensure_ascii=False), now),
    )
    conn.commit()
    return rows


def load_recommend_cache(conn) -> dict:
    """优先从数据库读取推荐列表。"""
    ensure_recommend_tables(conn)
    row = conn.execute("SELECT capital, rows_json, updated_at FROM product_recommend_cache WHERE id=1").fetchone()
    if not row:
        return {"capital": 0.0, "rows": [], "updated_at": None}
    try:
        rows = json.loads(row["rows_json"] or "[]")
    except (TypeError, ValueError, json.JSONDecodeError):
        rows = []
    return {
        "capital": float(row["capital"] or 0),
        "rows": rows if isinstance(rows, list) else [],
        "updated_at": row["updated_at"],
    }