import sys

from StringIO import StringIO

from django.test import TestCase

from django.db import models

from regressiontests.signals_regress.models import Author, Book

signal_output = []

def pre_save_test(signal, sender, instance, **kwargs):

    signal_output.append('pre_save signal, %s' % instance)

    if kwargs.get('raw'):

        signal_output.append('Is raw')

def post_save_test(signal, sender, instance, **kwargs):

    signal_output.append('post_save signal, %s' % instance)

    if 'created' in kwargs:

        if kwargs['created']:

            signal_output.append('Is created')

        else:

            signal_output.append('Is updated')

    if kwargs.get('raw'):

        signal_output.append('Is raw')

def pre_delete_test(signal, sender, instance, **kwargs):

    signal_output.append('pre_save signal, %s' % instance)

    signal_output.append('instance.id is not None: %s' % (instance.id != None))

def post_delete_test(signal, sender, instance, **kwargs):

    signal_output.append('post_delete signal, %s' % instance)

    signal_output.append('instance.id is not None: %s' % (instance.id != None))

class SignalsRegressTests(TestCase):

    """

    Testing signals before/after saving and deleting.

    """

    def get_signal_output(self, fn, *args, **kwargs):

        # Flush any existing signal output

        global signal_output

        signal_output = []

        fn(*args, **kwargs)

        return signal_output

    def setUp(self):

        # Save up the number of connected signals so that we can check at the end

        # that all the signals we register get properly unregistered (#9989)

        self.pre_signals = (len(models.signals.pre_save.receivers),

                       len(models.signals.post_save.receivers),

                       len(models.signals.pre_delete.receivers),

                       len(models.signals.post_delete.receivers))

        models.signals.pre_save.connect(pre_save_test)

        models.signals.post_save.connect(post_save_test)

        models.signals.pre_delete.connect(pre_delete_test)

        models.signals.post_delete.connect(post_delete_test)

    def tearDown(self):

        models.signals.post_delete.disconnect(post_delete_test)

        models.signals.pre_delete.disconnect(pre_delete_test)

        models.signals.post_save.disconnect(post_save_test)

        models.signals.pre_save.disconnect(pre_save_test)

        # Check that all our signals got disconnected properly.

        post_signals = (len(models.signals.pre_save.receivers),

                        len(models.signals.post_save.receivers),

                        len(models.signals.pre_delete.receivers),

                        len(models.signals.post_delete.receivers))

        self.assertEquals(self.pre_signals, post_signals)

    def test_model_signals(self):

        """ Model saves should throw some signals. """

        a1 = Author(name='Neal Stephenson')

        self.assertEquals(self.get_signal_output(a1.save), [

            "pre_save signal, Neal Stephenson",

            "post_save signal, Neal Stephenson",

            "Is created"

        ])

        b1 = Book(name='Snow Crash')

        self.assertEquals(self.get_signal_output(b1.save), [

            "pre_save signal, Snow Crash",

            "post_save signal, Snow Crash",

            "Is created"

        ])

    def test_m2m_signals(self):

        """ Assigning and removing to/from m2m shouldn't generate an m2m signal """

        b1 = Book(name='Snow Crash')

        self.get_signal_output(b1.save)

        a1 = Author(name='Neal Stephenson')

        self.get_signal_output(a1.save)

        self.assertEquals(self.get_signal_output(setattr, b1, 'authors', [a1]), [])

        self.assertEquals(self.get_signal_output(setattr, b1, 'authors', []), [])