import threading
import time
import unittest.mock

from cherrypy.process import wspbus


msg = 'Listener %d on channel %s: %s.'


class PublishSubscribeTests(unittest.TestCase):

    def get_listener(self, channel, index):
        def listener(arg=None):
            self.responses.append(msg % (index, channel, arg))
        return listener

    def test_builtin_channels(self):
        b = wspbus.Bus()

        self.responses, expected = [], []

        for channel in b.listeners:
            for index, priority in enumerate([100, 50, 0, 51]):
                b.subscribe(channel,
                            self.get_listener(channel, index), priority)

        for channel in b.listeners:
            b.publish(channel)
            expected.extend([msg % (i, channel, None) for i in (2, 1, 3, 0)])
            b.publish(channel, arg=79347)
            expected.extend([msg % (i, channel, 79347) for i in (2, 1, 3, 0)])

        self.assertEqual(self.responses, expected)

    def test_custom_channels(self):
        b = wspbus.Bus()

        self.responses, expected = [], []

        custom_listeners = ('hugh', 'louis', 'dewey')
        for channel in custom_listeners:
            for index, priority in enumerate([None, 10, 60, 40]):
                b.subscribe(channel,
                            self.get_listener(channel, index), priority)

        for channel in custom_listeners:
            b.publish(channel, 'ah so')
            expected.extend([msg % (i, channel, 'ah so')
                            for i in (1, 3, 0, 2)])
            b.publish(channel)
            expected.extend([msg % (i, channel, None) for i in (1, 3, 0, 2)])

        self.assertEqual(self.responses, expected)

    def test_listener_errors(self):
        b = wspbus.Bus()

        self.responses, expected = [], []
        channels = [c for c in b.listeners if c != 'log']

        for channel in channels:
            b.subscribe(channel, self.get_listener(channel, 1))
            # This will break since the lambda takes no args.
            b.subscribe(channel, lambda: None, priority=20)

        for channel in channels:
            self.assertRaises(wspbus.ChannelFailures, b.publish, channel, 123)
            expected.append(msg % (1, channel, 123))

        self.assertEqual(self.responses, expected)


class BusMethodTests(unittest.TestCase):

    def log(self, bus):
        self._log_entries = []

        def logit(msg, level):
            self._log_entries.append(msg)
        bus.subscribe('log', logit)

    def assertLog(self, entries):
        self.assertEqual(self._log_entries, entries)

    def get_listener(self, channel, index):
        def listener(arg=None):
            self.responses.append(msg % (index, channel, arg))
        return listener

    def test_start(self):
        b = wspbus.Bus()
        self.log(b)

        self.responses = []
        num = 3
        for index in range(num):
            b.subscribe('start', self.get_listener('start', index))

        b.start()
        try:
            # The start method MUST call all 'start' listeners.
            self.assertEqual(
                set(self.responses),
                set([msg % (i, 'start', None) for i in range(num)]))
            # The start method MUST move the state to STARTED
            # (or EXITING, if errors occur)
            self.assertEqual(b.state, b.states.STARTED)
            # The start method MUST log its states.
            self.assertLog(['Bus STARTING', 'Bus STARTED'])
        finally:
            # Exit so the atexit handler doesn't complain.
            b.exit()

    def test_stop(self):
        b = wspbus.Bus()
        self.log(b)

        self.responses = []
        num = 3
        for index in range(num):
            b.subscribe('stop', self.get_listener('stop', index))

        b.stop()

        # The stop method MUST call all 'stop' listeners.
        self.assertEqual(set(self.responses),
                         set([msg % (i, 'stop', None) for i in range(num)]))
        # The stop method MUST move the state to STOPPED
        self.assertEqual(b.state, b.states.STOPPED)
        # The stop method MUST log its states.
        self.assertLog(['Bus STOPPING', 'Bus STOPPED'])

    def test_graceful(self):
        b = wspbus.Bus()
        self.log(b)

        self.responses = []
        num = 3
        for index in range(num):
            b.subscribe('graceful', self.get_listener('graceful', index))

        b.graceful()

        # The graceful method MUST call all 'graceful' listeners.
        self.assertEqual(
            set(self.responses),
            set([msg % (i, 'graceful', None) for i in range(num)]))
        # The graceful method MUST log its states.
        self.assertLog(['Bus graceful'])

    def test_exit(self):
        b = wspbus.Bus()
        self.log(b)

        self.responses = []
        num = 3
        for index in range(num):
            b.subscribe('stop', self.get_listener('stop', index))
            b.subscribe('exit', self.get_listener('exit', index))

        b.exit()

        # The exit method MUST call all 'stop' listeners,
        # and then all 'exit' listeners.
        self.assertEqual(set(self.responses),
                         set([msg % (i, 'stop', None) for i in range(num)] +
                             [msg % (i, 'exit', None) for i in range(num)]))
        # The exit method MUST move the state to EXITING
        self.assertEqual(b.state, b.states.EXITING)
        # The exit method MUST log its states.
        self.assertLog(
            ['Bus STOPPING', 'Bus STOPPED', 'Bus EXITING', 'Bus EXITED'])

    def test_wait(self):
        b = wspbus.Bus()

        def f(method):
            time.sleep(0.2)
            getattr(b, method)()

        flow = [
            ('start', [b.states.STARTED]),
            ('stop', [b.states.STOPPED]),
            ('start', [b.states.STARTING, b.states.STARTED]),
            ('exit', [b.states.EXITING]),
        ]

        for method, states in flow:
            threading.Thread(target=f, args=(method,)).start()
            b.wait(states)

            # The wait method MUST wait for the given state(s).
            if b.state not in states:
                self.fail('State %r not in %r' % (b.state, states))

    def test_wait_publishes_periodically(self):
        bus = wspbus.Bus()
        callback = unittest.mock.MagicMock()
        bus.subscribe('main', callback)

        def set_start():
            time.sleep(0.05)
            bus.start()
        threading.Thread(target=set_start).start()
        bus.wait(bus.states.STARTED, interval=0.01, channel='main')
        assert callback.call_count > 3

    def test_block(self):
        b = wspbus.Bus()
        self.log(b)

        def f():
            time.sleep(0.2)
            b.exit()

        def g():
            time.sleep(0.4)
        threading.Thread(target=f).start()
        threading.Thread(target=g).start()
        threads = [t for t in threading.enumerate() if not t.daemon]
        self.assertEqual(len(threads), 3)

        b.block()

        # The block method MUST wait for the EXITING state.
        self.assertEqual(b.state, b.states.EXITING)
        # The block method MUST wait for ALL non-main, non-daemon threads to
        # finish.
        threads = [t for t in threading.enumerate() if not t.daemon]
        self.assertEqual(len(threads), 1)
        # The last message will mention an indeterminable thread name; ignore
        # it
        self.assertEqual(self._log_entries[:-1],
                         ['Bus STOPPING', 'Bus STOPPED',
                          'Bus EXITING', 'Bus EXITED',
                          'Waiting for child threads to terminate...'])

    def test_start_with_callback(self):
        b = wspbus.Bus()
        self.log(b)
        try:
            events = []

            def f(*args, **kwargs):
                events.append(('f', args, kwargs))

            def g():
                events.append('g')
            b.subscribe('start', g)
            b.start_with_callback(f, (1, 3, 5), {'foo': 'bar'})
            # Give wait() time to run f()
            time.sleep(0.2)

            # The callback method MUST wait for the STARTED state.
            self.assertEqual(b.state, b.states.STARTED)
            # The callback method MUST run after all start methods.
            self.assertEqual(events, ['g', ('f', (1, 3, 5), {'foo': 'bar'})])
        finally:
            b.exit()

    def test_log(self):
        b = wspbus.Bus()
        self.log(b)
        self.assertLog([])

        # Try a normal message.
        expected = []
        for msg in ["O mah darlin'"] * 3 + ['Clementiiiiiiiine']:
            b.log(msg)
            expected.append(msg)
            self.assertLog(expected)

        # Try an error message
        try:
            foo
        except NameError:
            b.log('You are lost and gone forever', traceback=True)
            lastmsg = self._log_entries[-1]
            if 'Traceback' not in lastmsg or 'NameError' not in lastmsg:
                self.fail('Last log message %r did not contain '
                          'the expected traceback.' % lastmsg)
        else:
            self.fail('NameError was not raised as expected.')


if __name__ == '__main__':
    unittest.main()
