import datetime
import os
import threading
import time
from module.logger import logger
from module.config.deep import deep_get
from module.notify import handle_notify


class CounterReachMaxCountException(Exception):
    ...


class Counter:
    def __init__(self, max_count):
        self.max_count = max_count
        self.current_count = 0

    def count_once(self):
        self.current_count += 1
        if self.current_count >= self.max_count:
            raise CounterReachMaxCountException()

    def reset(self):
        self.current_count = 0


class SchedulerWatcher:
    instance = None

    def __init__(self):
        self.alas_obj = None
        self.watcher: threading.Thread = None
        self.warning_count = None
        self.warning_time = None
        self.current_task = None
        self.min_timedelta = None

    def set_alas_obj(self, alas_obj):
        self.alas_obj = alas_obj

    def start_watch(self, min_timedelta, max_warning_count):
        if self.watcher is not None:
            if self.watcher.is_alive():
                return
        self.min_timedelta = datetime.timedelta(minutes=min_timedelta)
        self.warning_count = Counter(max_warning_count)
        logger.info(f"Scheduler watcher start")
        self.watcher = threading.Thread(target=self.watcher_thread, daemon=True)
        self.watcher.start()

    def request_extend_task_deadline(self):
        if self.watcher is None:
            return
        now = datetime.datetime.now()
        if self.warning_count.current_count > 0:
            self.warning_count.reset()
            self.warning_time = now + self.min_timedelta
            logger.info(f"Current task requests to extend the task deadline")
        else:
            if self.warning_time - now < datetime.timedelta(minutes=3):
                self.warning_time = now + self.min_timedelta
                logger.info(f"Current task requests to extend the task deadline")

    def no_task(self):
        if self.watcher is None:
            return
        self.current_task = None
        self.warning_time = None

    def switch_task(self, task):
        if self.watcher is None:
            return
        self.current_task = task
        self.warning_count.reset()
        self.warning_time = datetime.datetime.now() + self.min_timedelta

    def watcher_thread(self):
        while 1:
            time.sleep(60)
            if self.warning_time is None or self.current_task is None:
                continue

            now = datetime.datetime.now()
            if now > self.warning_time:
                try:
                    self.warning_count.count_once()
                    logger.warning(f"Current task reached time limit once")
                    self.warning_time = now + self.min_timedelta
                except CounterReachMaxCountException:
                    logger.error(f"Current task reached final time limit, assuming the scheduler is stuck")

                    config_data = self.alas_obj.config.data
                    is_instance_restart_enabled = deep_get(config_data, "Restart.InstanceRestart.Enabled", False)
                    if not is_instance_restart_enabled:
                        logger.error(f"Instance restart disabled, notify user")
                        err_push_config = deep_get(config_data, "Alas.Error.OnePushConfig")
                        handle_notify(
                            err_push_config,
                            title=f"Alas <{self.alas_obj.config_name}>: Scheduler Stuck",
                            content=f"Task {self.current_task} reached final time limit, assuming the scheduler is stuck",
                        )
                    os._exit(-1)

    @staticmethod
    def get_instance() -> "SchedulerWatcher":
        if SchedulerWatcher.instance is None:
            SchedulerWatcher.instance = SchedulerWatcher()
        return SchedulerWatcher.instance


def request_extend_task_deadline():
    ins = SchedulerWatcher.get_instance()
    ins.request_extend_task_deadline()


def no_task():
    ins = SchedulerWatcher.get_instance()
    ins.no_task()