# -*- coding: utf-8 -*-
"""定时调度器: 支持间隔调度与 5 段 cron 表达式"""
import threading
from datetime import datetime, timedelta

import store


# ---------------- cron 工具 ----------------

def _field(f, lo, hi):
    out = set()
    for part in str(f).split(","):
        part = part.strip()
        if not part:
            continue
        if "/" in part:
            rng, step = part.split("/")
            step = int(step)
            if rng == "*":
                out.update(range(lo, hi + 1, step))
            elif "-" in rng:
                a, b = map(int, rng.split("-"))
                out.update(range(a, b + 1, step))
            else:
                out.update(range(int(rng), hi + 1, step))
        elif "-" in part:
            a, b = map(int, part.split("-"))
            out.update(range(a, b + 1))
        elif part == "*":
            out.update(range(lo, hi + 1))
        else:
            out.add(int(part))
    return out


def cron_next(expr, base=None):
    """计算 cron 表达式(分 时 日 月 周, 周:0/7=周日)的下一次执行时间"""
    base = base or datetime.now()
    parts = str(expr).strip().split()
    if len(parts) != 5:
        raise ValueError("cron 表达式必须为 5 段: 分 时 日 月 周")
    mins = _field(parts[0], 0, 59)
    hours = _field(parts[1], 0, 23)
    doms = _field(parts[2], 1, 31)
    mons = _field(parts[3], 1, 12)
    dows = _field(parts[4], 0, 7)
    dows = {d % 7 for d in dows}          # cron 0/7=周日 -> python 0=周一..6=周日
    t = base.replace(second=0, microsecond=0) + timedelta(minutes=1)
    for _ in range(366 * 24 * 60):        # 一年窗口
        if (t.minute in mins and t.hour in hours and t.day in doms
                and t.month in mons and t.weekday() in dows):
            return t
        t += timedelta(minutes=1)
    return None


def interval_delta(sch):
    unit = sch.get("interval_unit", "hours")
    val = int(sch.get("interval_value", 24) or 24)
    if unit == "minutes":
        return timedelta(minutes=val)
    if unit == "days":
        return timedelta(days=val)
    return timedelta(hours=val)


# ---------------- 调度器线程 ----------------

class Scheduler(threading.Thread):
    """每 30 秒检查一次所有定时任务, 到点则触发一次爬取"""

    def __init__(self, spawn):
        """
        spawn: callable(task) -> 启动一次运行 (由 app 提供)
        """
        super().__init__(daemon=True, name="scheduler")
        self._spawn = spawn
        self._stop = threading.Event()

    def stop(self):
        self._stop.set()

    def run(self):
        while not self._stop.wait(30):
            try:
                self._tick()
            except Exception:
                pass

    def _tick(self):
        now = datetime.now()
        for task in store.load_tasks():
            sch = task.get("schedule") or {}
            if task.get("mode") != "scheduled" or not sch.get("enabled"):
                continue
            nxt = sch.get("next_run")
            if not nxt:
                continue
            try:
                due = datetime.strptime(nxt, "%Y-%m-%d %H:%M:%S")
            except Exception:
                continue
            if due > now:
                continue
            runs = store.get_runs(task["id"])
            if runs and runs[-1].get("status") == "running":
                continue                     # 上次还没跑完, 跳过本次
            self._spawn(task)
            try:
                if sch.get("type") == "cron":
                    nn = cron_next(sch.get("cron", "0 * * * *"), now)
                else:
                    nn = now + interval_delta(sch)
                sch["next_run"] = nn.strftime("%Y-%m-%d %H:%M:%S") if nn else None
                sch["last_run"] = now.strftime("%Y-%m-%d %H:%M:%S")
                sch["runs_count"] = sch.get("runs_count", 0) + 1
                store.upsert_task(task)
                try:
                    import db
                    db.upsert_task(task)
                except Exception:
                    pass
            except Exception:
                pass