# Source code for evennia.scripts.tickerhandler

    """
    TickerHandler

    This implements an efficient Ticker which uses a subscription
    model to 'tick' subscribed objects at regular intervals.

    The ticker mechanism is used by importing and accessing
    the instantiated TICKER_HANDLER instance in this module. This
    instance is run by the server; it will save its status across
    server reloads and be started automaticall on boot.

    Example:

    ```python
        from evennia.scripts.tickerhandler import TICKER_HANDLER

        # call tick myobj.at_tick(*args, **kwargs) every 15 seconds
        TICKER_HANDLER.add(15, myobj.at_tick, *args, **kwargs)
    ```

    You supply the interval to tick and a callable to call regularly with
    any extra args/kwargs. The callable should either be a stand-alone
    function in a module *or* the method on a *typeclassed* entity (that
    is, on an object that can be safely and stably returned from the
    database).  Functions that are dynamically created or sits on
    in-memory objects cannot be used by the tickerhandler (there is no way
    to reference them safely across reboots and saves).

    The handler will transparently set
    up and add new timers behind the scenes to tick at given intervals,
    using a TickerPool - all callables with the same interval will share
    the interval ticker.

    To remove:

    ```python
        TICKER_HANDLER.remove(15, myobj.at_tick)
    ```

    Both interval and callable must be given since a single object can be subscribed
    to many different tickers at the same time. You can also supply `idstring`
    as an identifying string if you ever want to tick the callable at the same interval
    but with different arguments (args/kwargs are not used for identifying the ticker). There
    is also `persistent=False` if you don't want to make a ticker that don't survive a reload.
    If either or both `idstring` or `persistent` has been changed from their defaults, they
    must be supplied to the `TICKER_HANDLER.remove` call to properly identify the ticker
    to remove.

    The TickerHandler's functionality can be overloaded by modifying the
    Ticker class and then changing TickerPool and TickerHandler to use the
    custom classes

    ```python
    class MyTicker(Ticker):
        # [doing custom stuff]

    class MyTickerPool(TickerPool):
        ticker_class = MyTicker
    class MyTickerHandler(TickerHandler):
        ticker_pool_class = MyTickerPool
    ```

    If one wants to duplicate TICKER_HANDLER's auto-saving feature in
    a  custom handler one can make a custom `AT_STARTSTOP_MODULE` entry to
    call the handler's `save()` and `restore()` methods when the server reboots.

    """
    import inspect

    from twisted.internet.defer import inlineCallbacks
    from django.core.exceptions import ObjectDoesNotExist
    from evennia.scripts.scripts import ExtendedLoopingCall
    from evennia.server.models import ServerConfig
    from evennia.utils.logger import log_trace, log_err
    from evennia.utils.dbserialize import dbserialize, dbunserialize, pack_dbobj
    from evennia.utils import variable_from_module, inherits_from

    _GA = object.__getattribute__
    _SA = object.__setattr__

    _ERROR_ADD_TICKER = """TickerHandler: Tried to add an invalid ticker:
    {store_key}
    Ticker was not added."""

    _ERROR_ADD_TICKER_SUB_SECOND = """You are trying to add a ticker running faster
    than once per second. This is not supported and also probably not useful:
    Spamming messages to the user faster than once per second serves no purpose in
    a text-game, and if you want to update some property, consider doing so
    on-demand rather than using a ticker.
    """

    class Ticker(object):
        """
        Represents a repeatedly running task that calls
        hooks repeatedly. Overload `_callback` to change the
        way it operates.
        """

        @inlineCallbacks
        def _callback(self):
            """
            This will be called repeatedly every `self.interval` seconds.
            `self.subscriptions` contain tuples of (obj, args, kwargs) for
            each subscribing object.

            If overloading, this callback is expected to handle all
            subscriptions when it is triggered. It should not return
            anything and should not traceback on poorly designed hooks.
            The callback should ideally work under @inlineCallbacks so it
            can yield appropriately.

            The _hook_key, which is passed down through the handler via
            kwargs is used here to identify which hook method to call.

            """
            self._to_add = []
            self._to_remove = []
            self._is_ticking = True
            for store_key, (args, kwargs) in self.subscriptions.items():
                callback = yield kwargs.pop("_callback", "at_tick")
                obj = yield kwargs.pop("_obj", None)
                try:
                    if callable(callback):
                        # call directly
                        yield callback(*args, **kwargs)
                        continue
                    # try object method
                    if not obj or not obj.pk:
                        # object was deleted between calls
                        self._to_remove.append(store_key)
                        continue
                    else:
                        yield _GA(obj, callback)(*args, **kwargs)
                except ObjectDoesNotExist:
                    log_trace("Removing ticker.")
                    self._to_remove.append(store_key)
                except Exception:
                    log_trace()
                finally:
                    # make sure to re-store
                    kwargs["_callback"] = callback
                    kwargs["_obj"] = obj
            # cleanup - we do this here to avoid changing the subscription dict while it loops
            self._is_ticking = False
            for store_key in self._to_remove:
                self.remove(store_key)
            for store_key, (args, kwargs) in self._to_add:
                self.add(store_key, *args, **kwargs)
            self._to_remove = []
            self._to_add = []

        def __init__(self, interval):
            """
            Set up the ticker

            Args:
                interval (int): The stepping interval.

            """
            self.interval = interval
            self.subscriptions = {}
            self._is_ticking = False
            self._to_remove = []
            self._to_add = []
            # set up a twisted asynchronous repeat call
            self.task = ExtendedLoopingCall(self._callback)

        def validate(self, start_delay=None):
            """
            Start/stop the task depending on how many subscribers we have
            using it.

            Args:
                start_delay (int): Time to way before starting.

            """
            subs = self.subscriptions
            if self.task.running:
                if not subs:
                    self.task.stop()
            elif subs:
                self.task.start(self.interval, now=False, start_delay=start_delay)

        def add(self, store_key, *args, **kwargs):
            """
            Sign up a subscriber to this ticker.
            Args:
                store_key (str): Unique storage hash for this ticker subscription.
                args (any, optional): Arguments to call the hook method with.

            Keyword Args:
                _start_delay (int): If set, this will be
                    used to delay the start of the trigger instead of
                    `interval`.

            """
            if self._is_ticking:
                # protects the subscription dict from
                # updating while it is looping
                self._to_add.append((store_key, (args, kwargs)))
            else:
                start_delay = kwargs.pop("_start_delay", None)
                self.subscriptions[store_key] = (args, kwargs)
                self.validate(start_delay=start_delay)

        def remove(self, store_key):
            """
            Unsubscribe object from this ticker

            Args:
                store_key (str): Unique store key.

            """
            if self._is_ticking:
                # this protects the subscription dict from
                # updating while it is looping
                self._to_remove.append(store_key)
            else:
                self.subscriptions.pop(store_key, False)
                self.validate()

        def stop(self):
            """
            Kill the Task, regardless of subscriptions.

            """
            self.subscriptions = {}
            self.validate()

    class TickerPool(object):
        """
        This maintains a pool of
        `evennia.scripts.scripts.ExtendedLoopingCall` tasks for calling
        subscribed objects at given times.

        """

        ticker_class = Ticker

        def __init__(self):
            """
            Initialize the pool.

            """
            self.tickers = {}

        def add(self, store_key, *args, **kwargs):
            """
            Add new ticker subscriber.

            Args:
                store_key (str): Unique storage hash.
                args (any, optional): Arguments to send to the hook method.

            """
            _, _, _, interval, _, _ = store_key
            if not interval:
                log_err(_ERROR_ADD_TICKER.format(store_key=store_key))
                return

            if interval not in self.tickers:
                self.tickers[interval] = self.ticker_class(interval)
            self.tickers[interval].add(store_key, *args, **kwargs)

        def remove(self, store_key):
            """
            Remove subscription from pool.

            Args:
                store_key (str): Unique storage hash to remove

            """
            _, _, _, interval, _, _ = store_key
            if interval in self.tickers:
                self.tickers[interval].remove(store_key)
                if not self.tickers[interval]:
                    del self.tickers[interval]

        def stop(self, interval=None):
            """
            Stop all scripts in pool. This is done at server reload since
            restoring the pool will automatically re-populate the pool.

            Args:
                interval (int, optional): Only stop tickers with this
                    interval.

            """
            if interval and interval in self.tickers:
                self.tickers[interval].stop()
            else:
                for ticker in self.tickers.values():
                    ticker.stop()

    class TickerHandler(object):
        """
        The Tickerhandler maintains a pool of tasks for subscribing
        objects to various tick rates.  The pool maintains creation
        instructions and and re-applies them at a server restart.

        """

        ticker_pool_class = TickerPool

        def __init__(self, save_name="ticker_storage"):
            """
            Initialize handler

            save_name (str, optional): The name of the ServerConfig
                instance to store the handler state persistently.

            """
            self.ticker_storage = {}
            self.save_name = save_name
            self.ticker_pool = self.ticker_pool_class()

        def _get_callback(self, callback):
            """
            Analyze callback and determine its consituents

            Args:
                callback (function or method): This is either a stand-alone
                    function or class method on a typeclassed entitye (that is,
                    an entity that can be saved to the database).
            Returns:
                ret (tuple): This is a tuple of the form `(obj, path, callfunc)`,
                    where `obj` is the database object the callback is defined on
                    if it's a method (otherwise `None`) and vice-versa, `path` is
                    the python-path to the stand-alone function (`None` if a method).
                    The `callfunc` is either the name of the method to call or the
                    callable function object itself.
            Raises:
                TypeError: If the callback is of an unsupported type.

            """
            outobj, outpath, outcallfunc = None, None, None
            if callable(callback):
                if inspect.ismethod(callback):
                    outobj = callback.__self__
                    outcallfunc = callback.__func__.__name__
                elif inspect.isfunction(callback):
                    outpath = "%s.%s" % (callback.__module__, callback.__name__)
                    outcallfunc = callback
                else:
                    raise TypeError(f"{callback} is not a method or function.")
            else:
                raise TypeError(f"{callback} is not a callable function or method.")

            if outobj and not inherits_from(outobj, "evennia.typeclasses.models.TypedObject"):
                raise TypeError(
                    f"{callback} is a method on a normal object - it must "
                    "be either a method on a typeclass, or a stand-alone function."
                )

            return outobj, outpath, outcallfunc

        def _store_key(self, obj, path, interval, callfunc, idstring="", persistent=True):
            """
            Tries to create a store_key for the object.

            Args:
                obj (Object, tuple or None): Subscribing object if any. If a tuple, this is
                    a packed_obj tuple from dbserialize.
                path (str or None): Python-path to callable, if any.
                interval (int): Ticker interval. Floats will be converted to
                    nearest lower integer value.
                callfunc (callable or str): This is either the callable function or
                    the name of the method to call. Note that the callable is never
                    stored in the key; that is uniquely identified with the python-path.
                idstring (str, optional): Additional separator between
                    different subscription types.
                persistent (bool, optional): If this ticker should survive a system
                    shutdown or not.

            Returns:
                store_key (tuple): A tuple `(packed_obj, methodname, outpath, interval,
                    idstring, persistent)` that uniquely identifies the
                    ticker. Here, `packed_obj` is the unique string representation of the
                    object or `None`. The `methodname` is the string name of the method on
                    `packed_obj` to call, or `None` if `packed_obj` is unset. `path` is
                    the Python-path to a non-method callable, or `None`. Finally, `interval`
                    `idstring` and `persistent` are integers, strings and bools respectively.

            """
            if interval < 1:
                raise RuntimeError(_ERROR_ADD_TICKER_SUB_SECOND)

            interval = int(interval)
            persistent = bool(persistent)
            packed_obj = pack_dbobj(obj)
            methodname = callfunc if callfunc and isinstance(callfunc, str) else None
            outpath = path if path and isinstance(path, str) else None
            return (packed_obj, methodname, outpath, interval, idstring, persistent)

        def save(self):
            """
            Save ticker_storage as a serialized string into a temporary
            ServerConf field. Whereas saving is done on the fly, if called
            by server when it shuts down, the current timer of each ticker
            will be saved so it can start over from that point.

            """
            if self.ticker_storage:
                # get the current times so the tickers can be restarted with a delay later
                start_delays = dict(
                    (interval, ticker.task.next_call_time())
                    for interval, ticker in self.ticker_pool.tickers.items()
                )

                # remove any subscriptions that lost its object in the interim
                to_save = {
                    store_key: (args, kwargs)
                    for store_key, (args, kwargs) in self.ticker_storage.items()
                    if (
                        (
                            store_key[1]
                            and ("_obj" in kwargs and kwargs["_obj"].pk)
                            and hasattr(kwargs["_obj"], store_key[1])
                        )
                        or store_key[2]  # a valid method with existing obj
                    )
                }  # a path given

                # update the timers for the tickers
                for store_key, (args, kwargs) in to_save.items():
                    interval = store_key[1]
                    # this is a mutable, so it's updated in-place in ticker_storage
                    kwargs["_start_delay"] = start_delays.get(interval, None)
                ServerConfig.objects.conf(key=self.save_name, value=dbserialize(to_save))
            else:
                # make sure we have nothing lingering in the database
                ServerConfig.objects.conf(key=self.save_name, delete=True)

        def restore(self, server_reload=True):
            """
            Restore ticker_storage from database and re-initialize the
            handler from storage. This is triggered by the server at
            restart.

            Args:
                server_reload (bool, optional): If this is False, it means
                    the server went through a cold reboot and all
                    non-persistent tickers must be killed.

            """
            # load stored command instructions and use them to re-initialize handler
            restored_tickers = ServerConfig.objects.conf(key=self.save_name)
            if restored_tickers:
                # the dbunserialize will convert all serialized dbobjs to real objects

                restored_tickers = dbunserialize(restored_tickers)
                self.ticker_storage = {}
                for store_key, (args, kwargs) in restored_tickers.items():
                    try:
                        # at this point obj is the actual object (or None) due to how
                        # the dbunserialize works
                        obj, callfunc, path, interval, idstring, persistent = store_key
                        if not persistent and not server_reload:
                            # this ticker will not be restarted
                            continue
                        if isinstance(callfunc, str) and not obj:
                            # methods must have an existing object
                            continue
                        # we must rebuild the store_key here since obj must not be
                        # stored as the object itself for the store_key to be hashable.
                        store_key = self._store_key(obj, path, interval, callfunc, idstring, persistent)

                        if obj and callfunc:
                            kwargs["_callback"] = callfunc
                            kwargs["_obj"] = obj
                        elif path:
                            modname, varname = path.rsplit(".", 1)
                            callback = variable_from_module(modname, varname)
                            kwargs["_callback"] = callback
                            kwargs["_obj"] = None
                        else:
                            # Neither object nor path - discard this ticker
                            log_err("Tickerhandler: Removing malformed ticker: %s" % str(store_key))
                            continue
                    except Exception:
                        # this suggests a malformed save or missing objects
                        log_trace("Tickerhandler: Removing malformed ticker: %s" % str(store_key))
                        continue
                    # if we get here we should create a new ticker
                    self.ticker_storage[store_key] = (args, kwargs)
                    self.ticker_pool.add(store_key, *args, **kwargs)

        def add(self, interval=60, callback=None, idstring="", persistent=True, *args, **kwargs):
            """
            Add subscription to tickerhandler

            Args:
                interval (int, optional): Interval in seconds between calling
                    `callable(*args, **kwargs)`
                callable (callable function or method, optional): This
                    should either be a stand-alone function or a method on a
                    typeclassed entity (that is, one that can be saved to the
                    database).
                idstring (str, optional): Identifier for separating
                    this ticker-subscription from others with the same
                    interval. Allows for managing multiple calls with
                    the same time interval and callback.
                persistent (bool, optional): A ticker will always survive
                    a server reload. If this is unset, the ticker will be
                    deleted by a server shutdown.
                args, kwargs (optional): These will be passed into the
                    callback every time it is called. This must be data possible
                    to pickle!

            Returns:
                store_key (tuple): The immutable store-key for this ticker. This can
                    be stored and passed into `.remove(store_key=store_key)` later to
                    easily stop this ticker later.

            Notes:
                The callback will be identified by type and stored either as
                as combination of serialized database object + methodname or
                as a python-path to the module + funcname. These strings will
                be combined iwth `interval` and `idstring` to define a
                unique storage key for saving. These must thus all be supplied
                when wanting to modify/remove the ticker later.

            """
            obj, path, callfunc = self._get_callback(callback)
            store_key = self._store_key(obj, path, interval, callfunc, idstring, persistent)
            kwargs["_obj"] = obj
            kwargs["_callback"] = callfunc  # either method-name or callable
            self.ticker_storage[store_key] = (args, kwargs)
            self.ticker_pool.add(store_key, *args, **kwargs)
            self.save()
            return store_key

        def remove(self, interval=60, callback=None, idstring="", persistent=True, store_key=None):
            """
            Remove ticker subscription from handler.

            Args:
                interval (int, optional): Interval of ticker to remove.
                callback (callable function or method): Either a function or
                    the method of a typeclassed object.
                idstring (str, optional): Identifier id of ticker to remove.
                persistent (bool, optional): Whether this ticker is persistent or not.
                store_key (str, optional): If given, all other kwargs are ignored and only
                    this is used to identify the ticker.

            Raises:
                KeyError: If no matching ticker was found to remove.

            Notes:
                The store-key is normally built from the interval/callback/idstring/persistent values;
                but if the `store_key` is explicitly given, this is used instead.

            """
            if isinstance(callback, int):
                raise RuntimeError(
                    "TICKER_HANDLER.remove has changed: "
                    "the interval is now the first argument, callback the second."
                )
            if not store_key:
                obj, path, callfunc = self._get_callback(callback)
                store_key = self._store_key(obj, path, interval, callfunc, idstring, persistent)
            to_remove = self.ticker_storage.pop(store_key, None)
            if to_remove:
                self.ticker_pool.remove(store_key)
                self.save()
            else:
                raise KeyError(f"No Ticker was found matching the store-key {store_key}.")

        def clear(self, interval=None):
            """
            Stop/remove tickers from handler.

            Args:
                interval (int): Only stop tickers with this interval.

            Notes:
                This is the only supported way to kill tickers related to
                non-db objects.

            """
            self.ticker_pool.stop(interval)
            if interval:
                self.ticker_storage = dict(
                    (store_key, store_value)
                    for store_key, store_value in self.ticker_storage.items()
                    if store_key[3] != interval
                )
            else:
                self.ticker_storage = {}
            self.save()

        def all(self, interval=None):
            """
            Get all subscriptions.

            Args:
                interval (int): Limit match to tickers with this interval.

            Returns:
                tickers (list): If `interval` was given, this is a list of
                    tickers using that interval.
                tickerpool_layout (dict): If `interval` was *not* given,
                    this is a dict {interval1: [ticker1, ticker2, ...],  ...}

            """
            if interval is None:
                # return dict of all, ordered by interval
                return dict(
                    (interval, ticker.subscriptions)
                    for interval, ticker in self.ticker_pool.tickers.items()
                )
            else:
                # get individual interval
                ticker = self.ticker_pool.tickers.get(interval, None)
                if ticker:
                    return {interval: ticker.subscriptions}
                return None

        def all_display(self):
            """
            Get all tickers on an easily displayable form.

            Returns:
                tickers (dict): A list of all storekeys

            """
            store_keys = []
            for ticker in self.ticker_pool.tickers.values():
                for (
                    (objtup, callfunc, path, interval, idstring, persistent),
                    (args, kwargs),
                ) in ticker.subscriptions.items():
                    store_keys.append(
                        (kwargs.get("_obj", None), callfunc, path, interval, idstring, persistent)
                    )
            return store_keys

    # main tickerhandler
    TICKER_HANDLER = TickerHandler()