# Copyright (c) 2005 Antoon Pardon
#
# Modified 2010 by Damon Lynch to use python's higher performance deque, rather than a regular list
#
# 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.


import collections
from Queue import Queue

from threading import Lock
from thread import get_ident

from types import BooleanType as UnConnected

UnRegistered, Registered = False, True


class EOInformation(Exception):
    pass

class TubeAccess(Exception):
    pass

        
class Fifo:

    def __init__(self):
        self.fifo = collections.deque()

    def put(self, item):
        self.fifo.append(item)

    def get(self):
        return self.fifo.popleft()

    def size(self):
        return len(self.fifo)


class Tube:

    def __init__(self, maxsize, lck = Lock, container = None):
        if container is None:
            container = Fifo()
        self.readers = set()
        self.writers = set()
        self.container = container
        self.maxsize = maxsize
        self.cb_arglst = []
        self.cb_src = UnRegistered
        self.in_use = Lock()
        self.nowriter = lck()
        self.full = lck()
        self.empty = lck()
        self.empty.acquire()
        self.nowriter.acquire()

    def open(self, access = 'r', *to):
        thrd = get_ident()
        access = access.lower()
        self.in_use.acquire()
        if 'w' in access:
            if len(self.writers) == 0:
                for _ in self.readers:
                    self.nowriter.release()
            self.writers.add(thrd)
        if 'r' in access:
            self.readers.add(thrd)
            if len(self.writers) == 0:
                self.in_use.release()
                self.nowriter.acquire(*to)
            else:
                self.in_use.release()
        else:
            self.in_use.release()

    def close(self, access = 'rw'):
        thrd = get_ident()
        access = access.lower()
        self.in_use.acquire()
        if 'r' in access:
            self.readers.discard(thrd)
        if 'w' in access:
            self.writers.discard(thrd)
            if len(self.writers) == 0:
                if self.container.size() == 0:
                    self.empty.release()
                    if self.cb_src is Registered and len(self.readers) > 0:
                        self.cb_src = gob.idle_add(self._idle_callback)
                for _ in self.readers:
                    self.container.put(EOInformation)
        self.in_use.release()

    def size(self):
        self.in_use.acquire()
        size = self.container.size()
        self.in_use.release()
        return size

    def get(self, *to):
        thrd = get_ident()
        if thrd not in self.readers:
            raise TubeAccess, "Thread has no read access for tube"
        self.empty.acquire(*to)
        self.in_use.acquire()
        size = self.container.size()
        if size == self.maxsize:
            self.full.release()
        item = self.container.get()
        if size != 1:
            self.empty.release()
        elif type(self.cb_src) is not UnConnected:
            gob.source_remove(self.cb_src)
            self.cb_src = Registered
        self.in_use.release()
        if item is EOInformation:
            raise EOInformation
        else:
            return item

    def put(self, item, *to):
        thrd = get_ident()
        if thrd not in self.writers:
            raise TubeAccess, "Thread has no write access for tube"
        if thrd in self.readers:
            self._put_rw(item)
        else:
            self._put_wo(item, *to)

    def _put_wo(self, item, *to):
        self.full.acquire(*to)
        self.in_use.acquire()
        size = self.container.size()
        if size == 0:
            self.empty.release()
            if self.cb_src is Registered:
                self.cb_src = gob.idle_add(self._idle_callback)
        self.container.put(item)
        if size + 1 < self.maxsize:
            self.full.release()
        self.in_use.release()

    def _put_rw(self, item):
        self.in_use.acquire()
        size = self.container.size()
        if size == 0:
            self.empty.release()
            if self.cb_src is Registered:
                self.cb_src = gob.idle_add(self._idle_callback)
        self.container.put(item)
        self.in_use.release()

    def _idle_callback(self):
        self.in_use.acquire()
        lst = self.cb_arglst.pop(0)
        self.in_use.release()
        func = lst[0]
        lst[0] = self
        ret_val = func(*lst)
        self.in_use.acquire()
        if ret_val:
            lst[0] = func
            self.cb_arglst.append(lst)
        elif self.cb_arglst == []:
            self.cb_src = UnRegistered
        self.in_use.release()
        return self.cb_src is not UnRegistered


def tube_add_watch(tube, callback, *args):

    global gob 
    import gobject as gob

    tube.in_use.acquire()
    tube.cb_arglst.append([callback] + list(args))
    if tube.cb_src is UnRegistered:
        if tube.container.size() == 0:
            tube.cb_src = Registered
        else:
            tube.cb_src = gob.idle_add(tube._idle_callback)
    tube.in_use.release()

def tube_remove_watch(tube):
##    tube.in_use.acquire()
##    gob.source_remove(tube.cb_src)
##    tube._idle_callback.handler_block(tube.cb_src)
    pass