# Copyright 2012-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"). You
# may not use this file except in compliance with the License. A copy of
# the License is located at
#
# http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file is
# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
# ANY KIND, either express or implied. See the License for the specific
# language governing permissions and limitations under the License.

"""Signature Version 4 test suite.

AWS provides a test suite for signature version 4:

    http://docs.aws.amazon.com/general/latest/gr/signature-v4-test-suite.html

This module contains logic to run these tests.  The test files were
placed in ./aws4_testsuite, and we're using nose's test generators to
dynamically generate testcases based on these files.

"""
import os
import logging
import io
import datetime
from botocore.compat import six
from six import BytesIO
from six.moves import BaseHTTPServer

import nose.tools as t
from nose import with_setup
import mock

import botocore.auth
from botocore.awsrequest import AWSRequest
from botocore.credentials import Credentials

try:
    from urllib.parse import urlsplit
    from urllib.parse import parse_qsl
except ImportError:
    from urlparse import urlsplit
    from urlparse import parse_qsl


CREDENTIAL_SCOPE = "KEYNAME/20110909/us-west-1/s3/aws4_request"
SECRET_KEY = "wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY"
ACCESS_KEY = 'AKIDEXAMPLE'
DATE_STRING = 'Mon, 09 Sep 2011 23:36:00 GMT'

TESTSUITE_DIR = os.path.join(
    os.path.dirname(os.path.abspath(__file__)), 'aws4_testsuite')

# The following tests are not run.  Each test has a comment as
# to why the test is being ignored.
TESTS_TO_IGNORE = [
    # Bad POST syntax, python's HTTP parser chokes on this.
    'post-vanilla-query-space',
    # Bad POST syntax, python's HTTP parser chokes on this.
    'post-vanilla-query-nonunreserved',
    # Multiple query params of the same key not supported by
    # the SDKs.
    'get-vanilla-query-order-key-case',
    # Multiple query params of the same key not supported by
    # the SDKs.
    'get-vanilla-query-order-value',
]
if not six.PY3:
    TESTS_TO_IGNORE += [
        # NO support
        'get-header-key-duplicate',
        'get-header-value-order',
    ]

log = logging.getLogger(__name__)


class RawHTTPRequest(BaseHTTPServer.BaseHTTPRequestHandler):
    def __init__(self, raw_request):
        if isinstance(raw_request, six.text_type):
            raw_request = raw_request.encode('utf-8')
        self.rfile = BytesIO(raw_request)
        self.raw_requestline = self.rfile.readline()
        self.error_code = None
        self.error_message = None
        self.parse_request()

    def send_error(self, code, message):
        self.error_code = code
        self.error_message = message


def test_generator():
    datetime_patcher = mock.patch.object(
        botocore.auth.datetime, 'datetime',
        mock.Mock(wraps=datetime.datetime)
    )
    mocked_datetime = datetime_patcher.start()
    mocked_datetime.utcnow.return_value = datetime.datetime(2011, 9, 9, 23, 36)
    formatdate_patcher = mock.patch('botocore.auth.formatdate')
    formatdate = formatdate_patcher.start()
    # We have to change this because Sep 9, 2011 was actually
    # a Friday, but the tests have this set to a Monday.
    formatdate.return_value = 'Mon, 09 Sep 2011 23:36:00 GMT'
    for test_case in set(os.path.splitext(i)[0]
                         for i in os.listdir(TESTSUITE_DIR)):
        if test_case in TESTS_TO_IGNORE:
            log.debug("Skipping test: %s", test_case)
            continue
        yield (_test_signature_version_4, test_case)
    datetime_patcher.stop()
    formatdate_patcher.stop()


def create_request_from_raw_request(raw_request):
    raw_request = raw_request.replace('http/1.1', 'HTTP/1.1')
    request = AWSRequest()
    raw = RawHTTPRequest(raw_request)
    if raw.error_code is not None:
        raise Exception(raw.error_message)
    request.method = raw.command
    datetime_now = datetime.datetime(2011, 9, 9, 23, 36)
    request.context['timestamp'] = datetime_now.strftime('%Y%m%dT%H%M%SZ')
    for key, val in raw.headers.items():
        request.headers[key] = val
    request.data = raw.rfile.read()
    host = raw.headers.get('host', '')
    # For whatever reason, the BaseHTTPRequestHandler encodes
    # the first line of the response as 'iso-8859-1',
    # so we need decode this into utf-8.
    if isinstance(raw.path, six.text_type):
        raw.path = raw.path.encode('iso-8859-1').decode('utf-8')
    url = 'https://%s%s' % (host, raw.path)
    if '?' in url:
        split_url = urlsplit(url)
        params = dict(parse_qsl(split_url.query))
        request.url = split_url.path
        request.params = params
    else:
        request.url = url
    return request


def _test_signature_version_4(test_case):
    test_case = _SignatureTestCase(test_case)
    request = create_request_from_raw_request(test_case.raw_request)

    auth = botocore.auth.SigV4Auth(test_case.credentials, 'host', 'us-east-1')

    actual_canonical_request = auth.canonical_request(request)
    assert_equal(actual_canonical_request, test_case.canonical_request,
                 test_case.raw_request, 'canonical_request')

    actual_string_to_sign = auth.string_to_sign(request,
                                                actual_canonical_request)
    assert_equal(actual_string_to_sign, test_case.string_to_sign,
                 test_case.raw_request, 'string_to_sign')

    auth.add_auth(request)
    actual_auth_header = request.headers['Authorization']
    assert_equal(actual_auth_header, test_case.authorization_header,
                 test_case.raw_request, 'authheader')


def assert_equal(actual, expected, raw_request, part):
    if actual != expected:
        message = "The %s did not match" % part
        message += "\nACTUAL:%r !=\nEXPECT:%r" % (actual, expected)
        message += '\nThe raw request was:\n%s' % raw_request
        raise AssertionError(message)


class _SignatureTestCase(object):
    def __init__(self, test_case):
        p = os.path.join
        # We're using io.open() because we need to open these files with
        # a specific encoding, and in 2.x io.open is the best way to do this.
        self.raw_request = io.open(p(TESTSUITE_DIR, test_case + '.req'),
                                   encoding='utf-8').read()
        self.canonical_request = io.open(
            p(TESTSUITE_DIR, test_case + '.creq'),
            encoding='utf-8').read().replace('\r', '')
        self.string_to_sign = io.open(
            p(TESTSUITE_DIR, test_case + '.sts'),
            encoding='utf-8').read().replace('\r', '')
        self.authorization_header = io.open(
            p(TESTSUITE_DIR, test_case + '.authz'),
            encoding='utf-8').read().replace('\r', '')
        self.signed_request = io.open(p(TESTSUITE_DIR, test_case + '.sreq'),
                                      encoding='utf-8').read()

        self.credentials = Credentials(ACCESS_KEY, SECRET_KEY)
