from __future__ import with_statement

from unittest import TestCase
from os.path import join, abspath, dirname

from scrapy.spider import BaseSpider
from scrapy.http import Response, Request
from scrapy.contrib.downloadermiddleware.httpcompression import HttpCompressionMiddleware
from scrapy.tests import tests_datadir


SAMPLEDIR = join(tests_datadir, 'compressed')

FORMAT = {
        'gzip': ('html-gzip.bin', 'gzip'),
        'rawdeflate': ('html-rawdeflate.bin', 'deflate'),
        'zlibdeflate': ('html-zlibdeflate.bin', 'deflate'),
        }

class HttpCompressionTest(TestCase):

    def setUp(self):
        self.spider = BaseSpider()
        self.mw = HttpCompressionMiddleware()

    def _getresponse(self, coding):
        if coding not in FORMAT:
            raise ValueError()

        samplefile, contentencoding = FORMAT[coding]

        with open(join(SAMPLEDIR, samplefile), 'rb') as sample:
            body = sample.read()

        headers = {
                'Server': 'Yaws/1.49 Yet Another Web Server',
                'Date': 'Sun, 08 Mar 2009 00:41:03 GMT',
                'Content-Length': len(body),
                'Content-Type': 'text/html',
                'Content-Encoding': contentencoding,
                }

        response = Response('http://scrapytest.org/', body=body, headers=headers)
        response.request = Request('http://scrapytest.org', headers={'Accept-Encoding': 'gzip,deflate'})
        return response

    def test_process_request(self):
        request = Request('http://scrapytest.org')
        assert 'Accept-Encoding' not in request.headers
        self.mw.process_request(request, self.spider)
        self.assertEqual(request.headers.get('Accept-Encoding'), 'gzip,deflate')

    def test_process_response_gzip(self):
        response = self._getresponse('gzip')
        request = response.request

        self.assertEqual(response.headers['Content-Encoding'], 'gzip')
        newresponse = self.mw.process_response(request, response, self.spider)
        assert newresponse is not response
        assert newresponse.body.startswith('<!DOCTYPE')
        assert 'Content-Encoding' not in newresponse.headers

    def test_process_response_rawdeflate(self):
        response = self._getresponse('rawdeflate')
        request = response.request

        self.assertEqual(response.headers['Content-Encoding'], 'deflate')
        newresponse = self.mw.process_response(request, response, self.spider)
        assert newresponse is not response
        assert newresponse.body.startswith('<!DOCTYPE')
        assert 'Content-Encoding' not in newresponse.headers

    def test_process_response_zlibdelate(self):
        response = self._getresponse('zlibdeflate')
        request = response.request

        self.assertEqual(response.headers['Content-Encoding'], 'deflate')
        newresponse = self.mw.process_response(request, response, self.spider)
        assert newresponse is not response
        assert newresponse.body.startswith('<!DOCTYPE')
        assert 'Content-Encoding' not in newresponse.headers

    def test_process_response_plain(self):
        response = Response('http://scrapytest.org', body='<!DOCTYPE...')
        request = Request('http://scrapytest.org')

        assert not response.headers.get('Content-Encoding')
        newresponse = self.mw.process_response(request, response, self.spider)
        assert newresponse is response
        assert newresponse.body.startswith('<!DOCTYPE')

    def test_multipleencodings(self):
        response = self._getresponse('gzip')
        response.headers['Content-Encoding'] = ['uuencode', 'gzip']
        request = response.request
        newresponse = self.mw.process_response(request, response, self.spider)
        assert newresponse is not response
        self.assertEqual(newresponse.headers.getlist('Content-Encoding'), ['uuencode'])