import sys
import unittest

from django.http import HttpResponse
from django.test.client import Client
from django.test.testcases import TestCase as DjangoTestCase
from django.core.urlresolvers import reverse
from django.template import TemplateDoesNotExist

from anyjson import deserialize as JSON_load
from billiard.utils.functional import curry

from celery import conf
from celery import states
from celery.utils import gen_unique_id, get_full_cls_name
from celery.backends import default_backend
from celery.exceptions import RetryTaskError
from celery.decorators import task
from celery.datastructures import ExceptionInfo

def reversestar(name, **kwargs):
    return reverse(name, kwargs=kwargs)

task_is_successful = curry(reversestar, "celery-is_task_successful")
task_status = curry(reversestar, "celery-task_status")
task_apply = curry(reverse, "celery-apply")

scratch = {}
@task()
def mytask(x, y):
    ret = scratch["result"] = int(x) * int(y)
    return ret


def create_exception(name, base=Exception):
    return type(name, (base, ), {})


def catch_exception(exception):
    try:
        raise exception
    except exception.__class__, exc:
        exc = default_backend.prepare_exception(exc)
        return exc, ExceptionInfo(sys.exc_info()).traceback


class ViewTestCase(DjangoTestCase):

    def assertJSONEquals(self, json, py):
        json = isinstance(json, HttpResponse) and json.content or json
        try:
            self.assertEquals(JSON_load(json), py)
        except TypeError, exc:
            raise TypeError("%s: %s" % (exc, json))


class TestTaskApply(ViewTestCase):

    def test_apply(self):
        conf.ALWAYS_EAGER = True
        try:
            ret = self.client.get(task_apply(kwargs={"task_name":
                mytask.name}) + "?x=4&y=4")
            self.assertEquals(scratch["result"], 16)
        finally:
            conf.ALWAYS_EAGER = False

    def test_apply_raises_404_on_unregistered_task(self):
        conf.ALWAYS_EAGER = True
        try:
            name = "xxx.does.not.exist"
            action = curry(self.client.get, task_apply(kwargs={
                        "task_name": name}) + "?x=4&y=4")
            self.assertRaises(TemplateDoesNotExist, action)
        finally:
            conf.ALWAYS_EAGER = False


class TestTaskStatus(ViewTestCase):

    def assertStatusForIs(self, status, res, traceback=None):
        uuid = gen_unique_id()
        default_backend.store_result(uuid, res, status,
                                     traceback=traceback)
        json = self.client.get(task_status(task_id=uuid))
        expect = dict(id=uuid, status=status, result=res)
        if status in default_backend.EXCEPTION_STATES:
            instore = default_backend.get_result(uuid)
            self.assertEquals(str(instore.args), str(res.args))
            expect["result"] = str(res.args[0])
            expect["exc"] = get_full_cls_name(res.__class__)
            expect["traceback"] = traceback

        self.assertJSONEquals(json, dict(task=expect))

    def test_task_status_success(self):
        self.assertStatusForIs(states.SUCCESS, "The quick brown fox")

    def test_task_status_failure(self):
        exc, tb = catch_exception(KeyError("foo"))
        self.assertStatusForIs(states.FAILURE, exc, tb)

    def test_task_status_retry(self):
        oexc, _ = catch_exception(KeyError("Resource not available"))
        exc, tb = catch_exception(RetryTaskError(str(oexc), oexc))
        self.assertStatusForIs(states.RETRY, exc, tb)


class TestTaskIsSuccessful(ViewTestCase):

    def assertStatusForIs(self, status, outcome):
        uuid = gen_unique_id()
        result = gen_unique_id()
        default_backend.store_result(uuid, result, status)
        json = self.client.get(task_is_successful(task_id=uuid))
        self.assertJSONEquals(json, {"task": {"id": uuid,
                                              "executed": outcome}})

    def test_is_successful_success(self):
        self.assertStatusForIs(states.SUCCESS, True)

    def test_is_successful_pending(self):
        self.assertStatusForIs(states.PENDING, False)

    def test_is_successful_failure(self):
        self.assertStatusForIs(states.FAILURE, False)

    def test_is_successful_retry(self):
        self.assertStatusForIs(states.RETRY, False)