# @author Bob Ippolito
#
# Copyright (c) 2005-2006, Bob Ippolito
# Copyright (c) 2007, Linden Research, Inc.
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

from eventlet.api import get_hub, getcurrent

""" If true, captures a stack trace for each timer when constructed.  This is
useful for debugging leaking timers, to find out where the timer was set up. """
_g_debug = False

class Timer(object):
    #__slots__ = ['seconds', 'tpl', 'called', 'cancelled', 'scheduled_time', 'greenlet', 'traceback', 'impltimer']
    def __init__(self, seconds, cb, *args, **kw):
        """Create a timer.
            seconds: The minimum number of seconds to wait before calling
            cb: The callback to call when the timer has expired
            *args: The arguments to pass to cb
            **kw: The keyword arguments to pass to cb

        This timer will not be run unless it is scheduled in a runloop by
        calling timer.schedule() or runloop.add_timer(timer).
        """
        self._cancelled = False
        self.seconds = seconds
        self.tpl = cb, args, kw
        self.called = False
        if _g_debug:
            import traceback, cStringIO
            self.traceback = cStringIO.StringIO()
            traceback.print_stack(file=self.traceback)

    @property
    def cancelled(self):
        return self._cancelled

    def __repr__(self):
        secs = getattr(self, 'seconds', None)
        cb, args, kw = getattr(self, 'tpl', (None, None, None))
        retval =  "Timer(%s, %s, *%s, **%s)" % (
            secs, cb, args, kw)
        if _g_debug and hasattr(self, 'traceback'):
            retval += '\n' + self.traceback.getvalue()
        return retval

    def copy(self):
        cb, args, kw = self.tpl
        return self.__class__(self.seconds, cb, *args, **kw)

    def schedule(self):
        """Schedule this timer to run in the current runloop.
        """
        self.called = False
        self.scheduled_time = get_hub().add_timer(self)
        return self

    def __call__(self, *args):
        if not self.called:
            self.called = True
            cb, args, kw = self.tpl
            try:
                cb(*args, **kw)
            finally:
                get_hub().timer_finished(self)

    def cancel(self):
        """Prevent this timer from being called. If the timer has already
        been called, has no effect.
        """
        self._cancelled = True
        self.called = True
        get_hub().timer_canceled(self)
        try:
            del self.tpl
        except AttributeError:
            pass

class LocalTimer(Timer):

    def __init__(self, *args, **kwargs):
        self.greenlet = getcurrent()
        Timer.__init__(self, *args, **kwargs)

    @property
    def cancelled(self):
        if self.greenlet is None or self.greenlet.dead:
            return True
        return self._cancelled

    def __call__(self, *args):
        if not self.called:
            self.called = True
            if self.greenlet is not None and self.greenlet.dead:
                return
            cb, args, kw = self.tpl
            try:
                cb(*args, **kw)
            finally:
                get_hub().timer_finished(self)

    def cancel(self):
        self.greenlet = None
        Timer.cancel(self)