from twisted.trial import unittest
from twisted.python import log as txlog
from twisted.python.failure import Failure
from twisted.internet import defer, reactor

from scrapy.xlib.pydispatch import dispatcher
from scrapy.utils.signal import send_catch_log, send_catch_log_deferred
from scrapy import log

class SendCatchLogTest(unittest.TestCase):

    @defer.inlineCallbacks
    def test_send_catch_log(self):
        test_signal = object()
        handlers_called = set()

        def log_received(event):
            handlers_called.add(log_received)
            assert "error_handler" in event['message'][0]
            assert event['logLevel'] == log.ERROR

        txlog.addObserver(log_received)
        dispatcher.connect(self.error_handler, signal=test_signal)
        dispatcher.connect(self.ok_handler, signal=test_signal)
        result = yield defer.maybeDeferred(self._get_result, test_signal, arg='test', \
            handlers_called=handlers_called)

        assert self.error_handler in handlers_called
        assert self.ok_handler in handlers_called
        assert log_received in handlers_called
        self.assertEqual(result[0][0], self.error_handler)
        self.assert_(isinstance(result[0][1], Failure))
        self.assertEqual(result[1], (self.ok_handler, "OK"))

        txlog.removeObserver(log_received)
        self.flushLoggedErrors()
        dispatcher.disconnect(self.error_handler, signal=test_signal)
        dispatcher.disconnect(self.ok_handler, signal=test_signal)

    def _get_result(self, signal, *a, **kw):
        return send_catch_log(signal, *a, **kw)

    def error_handler(self, arg, handlers_called):
        handlers_called.add(self.error_handler)
        a = 1/0

    def ok_handler(self, arg, handlers_called):
        handlers_called.add(self.ok_handler)
        assert arg == 'test'
        return "OK"


class SendCatchLogDeferredTest(SendCatchLogTest):

    def _get_result(self, signal, *a, **kw):
        return send_catch_log_deferred(signal, *a, **kw)


class SendCatchLogDeferredTest2(SendCatchLogTest):

    def ok_handler(self, arg, handlers_called):
        handlers_called.add(self.ok_handler)
        assert arg == 'test'
        d = defer.Deferred()
        reactor.callLater(0, d.callback, "OK")
        return d

    def _get_result(self, signal, *a, **kw):
        return send_catch_log_deferred(signal, *a, **kw)

class SendCatchLogTest2(unittest.TestCase):

    def test_error_logged_if_deferred_not_supported(self):
        test_signal = object()
        test_handler = lambda: defer.Deferred()
        log_events = []
        txlog.addObserver(log_events.append)
        dispatcher.connect(test_handler, test_signal)
        send_catch_log(test_signal)
        self.assertTrue(log_events)
        self.assertIn("Cannot return deferreds from signal handler", str(log_events))
        txlog.removeObserver(log_events.append)
        self.flushLoggedErrors()
        dispatcher.disconnect(test_handler, test_signal)