import os
import sys
from twisted.trial.unittest import TestCase, SkipTest

from scrapy.contrib.downloadermiddleware.httpproxy import HttpProxyMiddleware
from scrapy.core.exceptions import NotConfigured
from scrapy.http import Response, Request
from scrapy.spider import BaseSpider
from scrapy.conf import settings

spider = BaseSpider()

class TestDefaultHeadersMiddleware(TestCase):

    failureException = AssertionError

    def setUp(self):
        self._oldenv = os.environ.copy()

    def tearDown(self):
        os.environ = self._oldenv

    def test_no_proxies(self):
        os.environ = {}
        self.assertRaises(NotConfigured, HttpProxyMiddleware)

    def test_no_enviroment_proxies(self):
        os.environ = {'dummy_proxy': 'reset_env_and_do_not_raise'}
        mw = HttpProxyMiddleware()

        for url in ('http://e.com', 'https://e.com', 'file:///tmp/a'):
            req = Request(url)
            assert mw.process_request(req, spider) is None
            self.assertEquals(req.url, url)
            self.assertEquals(req.meta, {})

    def test_enviroment_proxies(self):
        os.environ['http_proxy'] = http_proxy = 'https://proxy.for.http:3128'
        os.environ['https_proxy'] = https_proxy = 'http://proxy.for.https:8080'
        os.environ.pop('file_proxy', None)
        mw = HttpProxyMiddleware()

        for url, proxy in [('http://e.com', http_proxy),
                ('https://e.com', https_proxy), ('file://tmp/a', None)]:
            req = Request(url)
            assert mw.process_request(req, spider) is None
            self.assertEquals(req.url, url)
            self.assertEquals(req.meta.get('proxy'), proxy)

    def test_proxy_auth(self):
        os.environ['http_proxy'] = 'https://user:pass@proxy:3128'
        mw = HttpProxyMiddleware()
        req = Request('http://scrapytest.org')
        assert mw.process_request(req, spider) is None
        self.assertEquals(req.meta, {'proxy': 'https://proxy:3128'})
        self.assertEquals(req.headers.get('Proxy-Authorization'), 'Basic dXNlcjpwYXNz')

    def test_proxy_already_seted(self):
        os.environ['http_proxy'] = http_proxy = 'https://proxy.for.http:3128'
        mw = HttpProxyMiddleware()
        req = Request('http://noproxy.com', meta={'proxy': None})
        assert mw.process_request(req, spider) is None
        assert 'proxy' in req.meta and req.meta['proxy'] is None


    def test_no_proxy(self):
        if sys.version_info < (2, 6):
            raise SkipTest('no_proxy is not supported in python < 2.6')
        os.environ['http_proxy'] = http_proxy = 'https://proxy.for.http:3128'
        mw = HttpProxyMiddleware()

        os.environ['no_proxy'] = '*'
        req = Request('http://noproxy.com')
        assert mw.process_request(req, spider) is None
        assert 'proxy' not in req.meta

        os.environ['no_proxy'] = 'other.com'
        req = Request('http://noproxy.com')
        assert mw.process_request(req, spider) is None
        assert 'proxy' in req.meta

        os.environ['no_proxy'] = 'other.com,noproxy.com'
        req = Request('http://noproxy.com')
        assert mw.process_request(req, spider) is None
        assert 'proxy' not in req.meta