#!/usr/bin/env python
# Copyright 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.
"""Test runner for the JSON models compliance tests

This is a test runner for all the JSON tests defined in
``tests/unit/protocols/``, including both the input/output tests.

You can use the normal ``python -m pytest tests/unit/test_protocols.py``
to run this test.  In addition, there are several env vars you can use during
development.

Tests are broken down by filename, test suite, testcase.  When a test fails
you'll see the protocol (filename), test suite, and test case number of the
failed test.

::

    Description           : Scalar members (0:0)  <--- (suite_id:test_id)
    Protocol:             : ec2                  <--- test file (ec2.json)
    Given                 : ...
    Response              : ...
    Expected serialization: ...
    Actual serialization  : ...
    Assertion message     : ...

To run tests from only a single file, you can set the
BOTOCORE_TEST env var::

    BOTOCORE_TEST=tests/unit/compliance/input/json.json pytest tests/unit/test_protocols.py

To run a single test suite you can set the BOTOCORE_TEST_ID env var:

    BOTOCORE_TEST=tests/unit/compliance/input/json.json BOTOCORE_TEST_ID=5 \
        pytest tests/unit/test_protocols.py

To run a single test case in a suite (useful when debugging a single test), you
can set the BOTOCORE_TEST_ID env var with the ``suite_id:test_id`` syntax.

    BOTOCORE_TEST_ID=5:1 pytest test/unit/test_protocols.py

"""

import copy
import os
from base64 import b64decode
from calendar import timegm
from enum import Enum

import pytest
from dateutil.tz import tzutc

from botocore.awsrequest import HeadersDict, prepare_request_dict
from botocore.compat import OrderedDict, json, urlsplit
from botocore.eventstream import EventStream
from botocore.model import NoShapeFoundError, OperationModel, ServiceModel
from botocore.parsers import (
    EC2QueryParser,
    JSONParser,
    QueryParser,
    RestJSONParser,
    RestXMLParser,
)
from botocore.serialize import (
    EC2Serializer,
    JSONSerializer,
    QuerySerializer,
    RestJSONSerializer,
    RestXMLSerializer,
)
from botocore.utils import parse_timestamp, percent_encode_sequence

TEST_DIR = os.path.join(
    os.path.dirname(os.path.abspath(__file__)), 'protocols'
)
NOT_SPECIFIED = object()
PROTOCOL_SERIALIZERS = {
    'ec2': EC2Serializer,
    'query': QuerySerializer,
    'json': JSONSerializer,
    'rest-json': RestJSONSerializer,
    'rest-xml': RestXMLSerializer,
}
PROTOCOL_PARSERS = {
    'ec2': EC2QueryParser,
    'query': QueryParser,
    'json': JSONParser,
    'rest-json': RestJSONParser,
    'rest-xml': RestXMLParser,
}
PROTOCOL_TEST_BLACKLIST = ['Idempotency token auto fill']


class TestType(Enum):
    # Tell test runner to ignore this class
    __test__ = False

    INPUT = "input"
    OUTPUT = "output"


def _compliance_tests(test_type=None):
    inp = test_type is None or test_type is TestType.INPUT
    out = test_type is None or test_type is TestType.OUTPUT

    for full_path in _walk_files():
        if full_path.endswith('.json'):
            for model, case, basename in _load_cases(full_path):
                if model.get('description') in PROTOCOL_TEST_BLACKLIST:
                    continue
                if 'params' in case and inp:
                    yield model, case, basename
                elif 'response' in case and out:
                    yield model, case, basename


@pytest.mark.parametrize(
    "json_description, case, basename", _compliance_tests(TestType.INPUT)
)
def test_input_compliance(json_description, case, basename):
    service_description = copy.deepcopy(json_description)
    service_description['operations'] = {
        case.get('name', 'OperationName'): case,
    }
    model = ServiceModel(service_description)
    protocol_type = model.metadata['protocol']
    try:
        protocol_serializer = PROTOCOL_SERIALIZERS[protocol_type]
    except KeyError:
        raise RuntimeError(f"Unknown protocol: {protocol_type}")
    serializer = protocol_serializer()
    serializer.MAP_TYPE = OrderedDict
    operation_model = OperationModel(case['given'], model)
    request = serializer.serialize_to_request(case['params'], operation_model)
    _serialize_request_description(request)
    client_endpoint = service_description.get('clientEndpoint')
    try:
        _assert_request_body_is_bytes(request['body'])
        _assert_requests_equal(request, case['serialized'])
        _assert_endpoints_equal(request, case['serialized'], client_endpoint)
    except AssertionError as e:
        _input_failure_message(protocol_type, case, request, e)


def _assert_request_body_is_bytes(body):
    if not isinstance(body, bytes):
        raise AssertionError(
            "Expected body to be serialized as type "
            f"bytes(), instead got: {type(body)}"
        )


def _assert_endpoints_equal(actual, expected, endpoint):
    if 'host' not in expected:
        return
    prepare_request_dict(actual, endpoint)
    actual_host = urlsplit(actual['url']).netloc
    assert_equal(actual_host, expected['host'], 'Host')


class MockRawResponse:
    def __init__(self, data):
        self._data = b64decode(data)

    def stream(self):
        yield self._data


@pytest.mark.parametrize(
    "json_description, case, basename", _compliance_tests(TestType.OUTPUT)
)
def test_output_compliance(json_description, case, basename):
    service_description = copy.deepcopy(json_description)
    operation_name = case.get('name', 'OperationName')
    service_description['operations'] = {
        operation_name: case,
    }
    case['response']['context'] = {'operation_name': operation_name}
    try:
        model = ServiceModel(service_description)
        operation_model = OperationModel(case['given'], model)
        parser = PROTOCOL_PARSERS[model.metadata['protocol']](
            timestamp_parser=_compliance_timestamp_parser
        )
        # We load the json as utf-8, but the response parser is at the
        # botocore boundary, so it expects to work with bytes.
        body_bytes = case['response']['body'].encode('utf-8')
        case['response']['body'] = body_bytes
        # We need the headers to be case insensitive
        headers = HeadersDict(case['response']['headers'])
        case['response']['headers'] = headers
        # If this is an event stream fake the raw streamed response
        if operation_model.has_event_stream_output:
            case['response']['body'] = MockRawResponse(body_bytes)
        if 'error' in case:
            output_shape = operation_model.output_shape
            parsed = parser.parse(case['response'], output_shape)
            try:
                error_shape = model.shape_for(parsed['Error']['Code'])
            except NoShapeFoundError:
                error_shape = None
            if error_shape is not None:
                error_parse = parser.parse(case['response'], error_shape)
                parsed.update(error_parse)
        else:
            output_shape = operation_model.output_shape
            parsed = parser.parse(case['response'], output_shape)
        parsed = _fixup_parsed_result(parsed)
    except Exception as e:
        msg = (
            "\nFailed to run test  : {}\n"
            "Protocol            : {}\n"
            "Description         : {} ({}:{})\n".format(
                e,
                model.metadata['protocol'],
                case['description'],
                case['suite_id'],
                case['test_id'],
            )
        )
        raise AssertionError(msg)
    try:
        if 'error' in case:
            expected_result = {
                'Error': {
                    'Code': case.get('errorCode', ''),
                    'Message': case.get('errorMessage', ''),
                }
            }
            expected_result.update(case['error'])
        else:
            expected_result = case['result']
        assert_equal(parsed, expected_result, "Body")
    except Exception as e:
        _output_failure_message(
            model.metadata['protocol'], case, parsed, expected_result, e
        )


def _fixup_parsed_result(parsed):
    # This function contains all the transformation we need
    # to do from the response _our_ response parsers give
    # vs. the expected responses in the protocol tests.
    # These are implementation specific changes, not any
    # "we're not following the spec"-type changes.

    # 1. RequestMetadata.  We parse this onto the returned dict, but compliance
    # tests don't have any specs for how to deal with request metadata.
    if 'ResponseMetadata' in parsed:
        del parsed['ResponseMetadata']
    # 2. Binary blob types.  In the protocol test, blob types, when base64
    # decoded, always decode to something that can be expressed via utf-8.
    # This is not always the case.  In python3, the blob type is designed to
    # return a bytes (not str) object.  However, for these tests we'll work for
    # any bytes type, and decode it as utf-8 because we know that's safe for
    # the compliance tests.
    parsed = _convert_bytes_to_str(parsed)
    # 3. We need to expand the event stream object into the list of events
    for key, value in parsed.items():
        if isinstance(value, EventStream):
            parsed[key] = _convert_bytes_to_str(list(value))
            break
    # 4. We parse the entire error body into the "Error" field for rest-xml
    # which causes some modeled fields in the response to be placed under the
    # error key. We don't have enough information in the test suite to assert
    # these properly, and they probably shouldn't be there in the first place.
    if 'Error' in parsed:
        error_keys = list(parsed['Error'].keys())
        for key in error_keys:
            if key not in ['Code', 'Message']:
                del parsed['Error'][key]
    return parsed


def _convert_bytes_to_str(parsed):
    if isinstance(parsed, dict):
        new_dict = {}
        for key, value in parsed.items():
            new_dict[key] = _convert_bytes_to_str(value)
        return new_dict
    elif isinstance(parsed, bytes):
        return parsed.decode('utf-8')
    elif isinstance(parsed, list):
        new_list = []
        for item in parsed:
            new_list.append(_convert_bytes_to_str(item))
        return new_list
    else:
        return parsed


def _compliance_timestamp_parser(value):
    datetime = parse_timestamp(value)
    # Convert from our time zone to UTC
    datetime = datetime.astimezone(tzutc())
    # Convert to epoch.
    return int(timegm(datetime.timetuple()))


def _output_failure_message(
    protocol_type, case, actual_parsed, expected_result, error
):
    j = _try_json_dump
    error_message = (
        "\nDescription           : {} ({}:{})\n"
        "Protocol:             : {}\n"
        "Given                 : {}\n"
        "Response              : {}\n"
        "Expected serialization: {}\n"
        "Actual serialization  : {}\n"
        "Assertion message     : {}\n".format(
            case['description'],
            case['suite_id'],
            case['test_id'],
            protocol_type,
            j(case['given']),
            j(case['response']),
            j(expected_result),
            j(actual_parsed),
            error,
        )
    )
    raise AssertionError(error_message)


def _input_failure_message(protocol_type, case, actual_request, error):
    j = _try_json_dump
    error_message = (
        "\nDescription           : {} ({}:{})\n"
        "Protocol:             : {}\n"
        "Given                 : {}\n"
        "Params                : {}\n"
        "Expected serialization: {}\n"
        "Actual serialization  : {}\n"
        "Assertion message     : {}\n".format(
            case['description'],
            case['suite_id'],
            case['test_id'],
            protocol_type,
            j(case['given']),
            j(case['params']),
            j(case['serialized']),
            j(actual_request),
            error,
        )
    )
    raise AssertionError(error_message)


def _try_json_dump(obj):
    try:
        return json.dumps(obj)
    except (ValueError, TypeError):
        return str(obj)


def assert_equal(first, second, prefix):
    # A better assert equals.  It allows you to just provide
    # prefix instead of the entire message.
    try:
        assert first == second
    except Exception:
        try:
            better = f"{prefix} (actual != expected)\n{json.dumps(first, indent=2)} !=\n{json.dumps(second, indent=2)}"
        except (ValueError, TypeError):
            better = f"{prefix} (actual != expected)\n{first} !=\n{second}"
        raise AssertionError(better)


def _serialize_request_description(request_dict):
    if isinstance(request_dict.get('body'), dict):
        # urlencode the request body.
        encoded = percent_encode_sequence(request_dict['body']).encode('utf-8')
        request_dict['body'] = encoded
    if isinstance(request_dict.get('query_string'), dict):
        encoded = percent_encode_sequence(request_dict.get('query_string'))
        if encoded:
            # 'requests' automatically handle this, but we in the
            # test runner we need to handle the case where the url_path
            # already has query params.
            if '?' not in request_dict['url_path']:
                request_dict['url_path'] += f'?{encoded}'
            else:
                request_dict['url_path'] += f'&{encoded}'


def _assert_requests_equal(actual, expected):
    assert_equal(
        actual['body'], expected.get('body', '').encode('utf-8'), 'Body value'
    )
    actual_headers = HeadersDict(actual['headers'])
    expected_headers = HeadersDict(expected.get('headers', {}))
    excluded_headers = expected.get('forbidHeaders', [])
    _assert_expected_headers_in_request(
        actual_headers, expected_headers, excluded_headers
    )
    assert_equal(actual['url_path'], expected.get('uri', ''), "URI")
    if 'method' in expected:
        assert_equal(actual['method'], expected['method'], "Method")


def _assert_expected_headers_in_request(actual, expected, excluded_headers):
    for header, value in expected.items():
        assert header in actual
        assert actual[header] == value
    for header in excluded_headers:
        assert header not in actual


def _walk_files():
    # Check for a shortcut when running the tests interactively.
    # If a BOTOCORE_TEST env var is defined, that file is used as the
    # only test to run.  Useful when doing feature development.
    single_file = os.environ.get('BOTOCORE_TEST')
    if single_file is not None:
        yield os.path.abspath(single_file)
    else:
        for root, _, filenames in os.walk(TEST_DIR):
            for filename in filenames:
                yield os.path.join(root, filename)


def _load_cases(full_path):
    # During developement, you can set the BOTOCORE_TEST_ID
    # to run a specific test suite or even a specific test case.
    # The format is BOTOCORE_TEST_ID=suite_id:test_id or
    # BOTOCORE_TEST_ID=suite_id
    suite_id, test_id = _get_suite_test_id()
    all_test_data = json.load(open(full_path), object_pairs_hook=OrderedDict)
    basename = os.path.basename(full_path)
    for i, test_data in enumerate(all_test_data):
        if suite_id is not None and i != suite_id:
            continue
        cases = test_data.pop('cases')
        description = test_data['description']
        for j, case in enumerate(cases):
            if test_id is not None and j != test_id:
                continue
            case['description'] = description
            case['suite_id'] = i
            case['test_id'] = j
            yield (test_data, case, basename)


def _get_suite_test_id():
    if 'BOTOCORE_TEST_ID' not in os.environ:
        return None, None
    test_id = None
    suite_id = None
    split = os.environ['BOTOCORE_TEST_ID'].split(':')
    try:
        if len(split) == 2:
            suite_id, test_id = int(split[0]), int(split[1])
        else:
            suite_id = int(split([0]))
    except TypeError:
        # Same exception, just give a better error message.
        raise TypeError(
            "Invalid format for BOTOCORE_TEST_ID, should be "
            "suite_id[:test_id], and both values should be "
            "integers."
        )
    return suite_id, test_id
