"""扫描器：扫全校合同 → 分级 → 写 alerts + 生成 renewal_tasks。

核心业务入口，cron 每日凌晨 02:00 调用。
"""

from __future__ import annotations

import sqlite3
from datetime import date
from typing import Tuple

from db import repository as repo
from service.task_generator import generate_task_for_contract
from util.constants import ALERT_LEVELS, DEFAULT_THRESHOLDS
from util.date_util import classify_alert, days_to, parse_iso_date
from util.logging_setup import get_skill_logger

logger = get_skill_logger()


def scan(
    conn: sqlite3.Connection,
    thresholds: Tuple[int, int, int] = DEFAULT_THRESHOLDS,
    today: date | None = None,
    scan_id: str | None = None,
) -> dict:
    """扫描全校合同，返回结构化结果。

    thresholds = (yellow_max, orange_max, red_max)，默认 (90, 60, 30)。

    返回：
        {
            "scanned_count": <int>,
            "yellow_count": <int>,
            "orange_count": <int>,
            "red_count": <int>,
            "generated_task_count": <int>,
            "scan_id": <str>,
            "thresholds": [yellow_max, orange_max, red_max],
        }
    """
    today = today or date.today()
    scan_id = scan_id or f"S{datetime_now_compact()}"

    contracts = repo.list_active_contracts(conn)
    counts = {f"{lvl}_count": 0 for lvl in ALERT_LEVELS}
    generated = 0

    logger.info("scan: start scan_id=%s thresholds=%s today=%s contracts=%d",
                scan_id, thresholds, today.isoformat(), len(contracts))

    with conn:
        for c in contracts:
            contract_end = parse_iso_date(c["contract_end"])
            days = days_to(contract_end, today)
            level = classify_alert(days, thresholds)
            if level is None:
                continue

            # 写 alert（alert_id 包含 scan_id 避免同一合同被多次扫描时冲突）
            alert_id = f"A-{c['contract_id']}-{scan_id}"
            repo.insert_alert(conn, alert_id, c["contract_id"], level, days, scan_id)
            counts[f"{level}_count"] += 1

            # 生成任务书
            task_id = f"T-{c['contract_id']}-{scan_id}"
            task = generate_task_for_contract(conn, c, alert_id, task_id)
            if task:
                generated += 1

    result = {
        "scanned_count": len(contracts),
        "yellow_count": counts["yellow_count"],
        "orange_count": counts["orange_count"],
        "red_count": counts["red_count"],
        "generated_task_count": generated,
        "scan_id": scan_id,
        "thresholds": list(thresholds),
        "today": today.isoformat(),
    }
    logger.info("scan: done %s", result)
    return result


def datetime_now_compact() -> str:
    """生成紧凑时间字符串，用于 alert_id / task_id / scan_id。"""
    from datetime import datetime
    return datetime.now().strftime("%Y%m%d%H%M%S")