#04-数据更新与调度策略

import time
import logging
from functools import wraps

logger = logging.getLogger(__name__)

def fetch_with_retry(func, max_retries=3, base_delay=1.0,
                     backoff_factor=2.0, sleep_after=0.5):
    """
    带 retry 的 akshare 调用封装。
    - max_retries: 最大重试次数
    - base_delay: 首次重试延迟（秒）
    - backoff_factor: 退避因子，每次延迟乘以此系数
    - sleep_after: 成功后 sleep，避免触发限流
    """
    @wraps(func)
    def wrapper(*args, **kwargs):
        last_error = None
        for attempt in range(max_retries):
            try:
                result = func(*args, **kwargs)
                time.sleep(sleep_after)
                return result
            except Exception as e:
                last_error = e
                delay = base_delay * (backoff_factor ** attempt)
                logger.warning(
                    f"[{func.__name__}] 第 {attempt+1} 次失败: {e}, "
                    f"{delay}s 后重试"
                )
                time.sleep(delay)
        logger.error(f"[{func.__name__}] {max_retries} 次重试均失败: {last_error}")
        raise last_error
    return wrapper

from fetcher_common import get_last_local_date, compute_start_date

local_latest = get_last_local_date(conn, "index_daily", "index_code", "000300")
# local_latest = "2026-07-13"（昨日已更新）
start_date = compute_start_date(local_latest, default_days=30, mode="daily")
# start_date = "2026-07-14"（只拉今天的数据）

from fetcher_common import get_pending_targets

# 获取待更新的标的（跳过已完成的）
pending = get_pending_targets(conn, "fetch_index_daily", WATCH_INDEXES)
for index_code, symbol_em, name in pending:
    fetch_index_daily(conn, run_id, index_code, symbol_em, mode=mode)

try:
    conn.execute("BEGIN")
    conn.executemany("INSERT OR REPLACE INTO index_daily ...", records)
    conn.commit()
    mark_progress_done(conn, "fetch_index_daily", index_code, last_date, run_id)
except Exception:
    conn.execute("ROLLBACK")
    mark_progress_failed(conn, "fetch_index_daily", index_code, run_id)

import shutil
from datetime import datetime
from pathlib import Path

def backup_database(db_path: str, backup_dir: str):
    """更新前备份当前数据库"""
    ts = datetime.now().strftime("%Y%m%d_%H%M%S")
    backup_path = Path(backup_dir) / f"trend_invest_{ts}.db"
    shutil.copy2(db_path, backup_path)
    # 清理超过 30 天的旧备份
    cutoff = datetime.now() - timedelta(days=30)
    for old in Path(backup_dir).glob("trend_invest_*.db"):
        if datetime.fromtimestamp(old.stat().st_mtime) < cutoff:
            old.unlink()
    return backup_path

def fetch_index_daily(symbol: str, start_date: str, end_date: str):
    """主接口失败时自动切备用接口"""
    primary = lambda: ak.stock_zh_index_daily_em(symbol=symbol)
    fallback = lambda: ak.stock_zh_index_daily(symbol=symbol)

    for fetcher in [primary, fallback]:
        try:
            df = fetch_with_retry(fetcher)()
            if df is not None and len(df) > 0:
                return normalize_columns(df)  # 字段标准化
        except Exception as e:
            logger.warning(f"接口 {fetcher.__name__} 失败: {e}")
            continue

    raise RuntimeError(f"指数 {symbol} 日线获取全部失败")

EXPECTED_COLUMNS = {
    "stock_zh_a_hist": ["日期", "开盘", "收盘", "最高", "最低",
                        "成交量", "成交额", "振幅", "涨跌幅", "涨跌额", "换手率"],
}

def validate_columns(df, api_name: str):
    """校验返回字段是否符合预期"""
    expected = EXPECTED_COLUMNS.get(api_name, [])
    actual = list(df.columns)
    missing = set(expected) - set(actual)
    extra = set(actual) - set(expected)
    if missing:
        logger.warning(
            f"[{api_name}] 字段缺失: {missing}; 实际字段: {actual}"
        )
        return False
    if extra:
        logger.info(f"[{api_name}] 新增字段: {extra}")
    return True

failure_rate = failed_count / total_count
if failure_rate > 0.1:  # 超过 10% 失败
    logger.error(f"告警：本次更新失败率 {failure_rate:.1%}，请检查")
    # 可选：写入 alert 文件或发送通知