"""Common tests to run for all backends (BaseCache subclasses)"""
import json
from datetime import datetime
from io import BytesIO
from threading import Thread
from time import sleep, time
from typing import Dict, Type
from urllib.parse import parse_qs, urlparse

import pytest
import requests
from requests.models import PreparedRequest

from requests_cache import ALL_METHODS, CachedResponse, CachedSession
from requests_cache.backends.base import BaseCache
from requests_cache.serializers import SERIALIZERS, SerializerPipeline, safe_pickle_serializer
from tests.conftest import (
    CACHE_NAME,
    ETAG,
    EXPIRED_DT,
    HTTPBIN_FORMATS,
    HTTPBIN_METHODS,
    HTTPDATE_STR,
    LAST_MODIFIED,
    N_ITERATIONS,
    N_THREADS,
    USE_PYTEST_HTTPBIN,
    assert_delta_approx_equal,
    httpbin,
)

# Handle optional dependencies if they're not installed; if so, skips will be shown in pytest output
TEST_SERIALIZERS = SERIALIZERS.copy()
try:
    TEST_SERIALIZERS['safe_pickle'] = safe_pickle_serializer(secret_key='hunter2')
except ImportError:
    TEST_SERIALIZERS['safe_pickle'] = 'safe_pickle_placeholder'


class BaseCacheTest:
    """Base class for testing cache backend classes"""

    backend_class: Type[BaseCache] = None
    init_kwargs: Dict = {}

    def init_session(self, cache_name=CACHE_NAME, clear=True, **kwargs) -> CachedSession:
        kwargs.setdefault('allowable_methods', ALL_METHODS)
        kwargs.setdefault('serializer', 'pickle')
        backend = self.backend_class(cache_name, **self.init_kwargs, **kwargs)
        if clear:
            backend.clear()

        return CachedSession(backend=backend, **self.init_kwargs, **kwargs)

    @classmethod
    def teardown_class(cls):
        cls().init_session(clear=True)

    @pytest.mark.parametrize('serializer', TEST_SERIALIZERS.values())
    @pytest.mark.parametrize('method', HTTPBIN_METHODS)
    @pytest.mark.parametrize('field', ['params', 'data', 'json'])
    def test_all_methods(self, field, method, serializer):
        """Test all relevant combinations of methods X data fields X serializers.
        Requests with different request params, data, or json should be cached under different keys.
        """
        if not isinstance(serializer, SerializerPipeline):
            pytest.skip(f'Dependencies not installed for {serializer}')

        url = httpbin(method.lower())
        session = self.init_session(serializer=serializer)
        for params in [{'param_1': 1}, {'param_1': 2}, {'param_2': 2}]:
            assert session.request(method, url, **{field: params}).from_cache is False
            assert session.request(method, url, **{field: params}).from_cache is True

    @pytest.mark.parametrize('serializer', TEST_SERIALIZERS.values())
    @pytest.mark.parametrize('response_format', HTTPBIN_FORMATS)
    def test_all_response_formats(self, response_format, serializer):
        """Test that all relevant combinations of response formats X serializers are cached correctly"""
        if not isinstance(serializer, SerializerPipeline):
            pytest.skip(f'Dependencies not installed for {serializer}')

        session = self.init_session(serializer=serializer)
        # Temporary workaround for this issue: https://github.com/kevin1024/pytest-httpbin/issues/60
        if response_format == 'json' and USE_PYTEST_HTTPBIN:
            session.allowable_codes = (200, 404)

        r1 = session.get(httpbin(response_format))
        r2 = session.get(httpbin(response_format))
        assert r1.from_cache is False
        assert r2.from_cache is True
        assert r1.content == r2.content

    @pytest.mark.parametrize('n_redirects', range(1, 5))
    @pytest.mark.parametrize('endpoint', ['redirect', 'absolute-redirect', 'relative-redirect'])
    def test_redirect_history(self, endpoint, n_redirects):
        """Test redirect caching (in separate `redirects` cache) with all types of redirect endpoints,
        using different numbers of consecutive redirects
        """
        session = self.init_session()
        session.get(httpbin(f'{endpoint}/{n_redirects}'))
        r2 = session.get(httpbin('get'))

        assert r2.from_cache is True
        assert len(session.cache.redirects) == n_redirects

    @pytest.mark.parametrize('endpoint', ['redirect', 'absolute-redirect', 'relative-redirect'])
    def test_redirect_responses(self, endpoint):
        """Test redirect caching (in main `responses` cache) with all types of redirect endpoints"""
        session = self.init_session(allowable_codes=(200, 302))
        r1 = session.head(httpbin(f'{endpoint}/2'))
        r2 = session.head(httpbin(f'{endpoint}/2'))

        assert r2.from_cache is True
        assert len(session.cache.redirects) == 0
        assert isinstance(r1.next, PreparedRequest) and r1.next.url.endswith('redirect/1')
        assert isinstance(r2.next, PreparedRequest) and r2.next.url.endswith('redirect/1')

    def test_cookies(self):
        session = self.init_session()

        def get_json(url):
            return json.loads(session.get(url).text)

        response_1 = get_json(httpbin('cookies/set/test1/test2'))
        with session.cache_disabled():
            assert get_json(httpbin('cookies')) == response_1
        # From cache
        response_2 = get_json(httpbin('cookies'))
        assert response_2 == get_json(httpbin('cookies'))
        # Not from cache
        with session.cache_disabled():
            response_3 = get_json(httpbin('cookies/set/test3/test4'))
            assert response_3 == get_json(httpbin('cookies'))

    @pytest.mark.parametrize('cache_control', [True, False])
    @pytest.mark.parametrize(
        'request_headers, expected_expiration',
        [
            ({}, 60),
            ({'Cache-Control': 'max-age=360'}, 360),
            ({'Cache-Control': 'no-store'}, None),
            ({'Expires': HTTPDATE_STR, 'Cache-Control': 'max-age=360'}, 360),
        ],
    )
    def test_cache_control_expiration(self, request_headers, expected_expiration, cache_control):
        """Test cache headers for both requests and responses. The `/cache/{seconds}` endpoint returns
        Cache-Control headers, which should be used unless request headers are sent.
        No headers should be used if `cache_control=False`.
        """
        session = self.init_session(cache_control=cache_control)
        now = datetime.utcnow()
        session.get(httpbin('cache/60'), headers=request_headers)
        response = session.get(httpbin('cache/60'), headers=request_headers)

        if expected_expiration is None or cache_control is False:
            assert response.expires is None
        else:
            assert_delta_approx_equal(now, response.expires, expected_expiration)

    @pytest.mark.parametrize(
        'cached_response_headers, expected_from_cache',
        [
            ({}, False),
            ({'ETag': ETAG}, True),
            ({'Last-Modified': LAST_MODIFIED}, True),
            ({'ETag': ETAG, 'Last-Modified': LAST_MODIFIED}, True),
        ],
    )
    def test_304_not_modified(self, cached_response_headers, expected_from_cache):
        """Test behavior of ETag and Last-Modified headers and 304 responses.

        When a cached response contains one of these headers, corresponding request headers should
        be added. The `/cache` endpoint returns a 304 if one of these request headers is present.
        When this happens, the previously cached response should be returned.
        """
        response = requests.get(httpbin('cache'))
        response.headers = cached_response_headers

        session = self.init_session(cache_control=True)
        session.cache.save_response(response, expires=EXPIRED_DT)

        response = session.get(httpbin('cache'))
        assert response.from_cache == expected_from_cache

    @pytest.mark.parametrize('stream', [True, False])
    def test_response_decode(self, stream):
        """Test that gzip-compressed raw responses (including streamed responses) can be manually
        decompressed with decode_content=True
        """
        session = self.init_session()
        response = session.get(httpbin('gzip'), stream=stream)
        assert b'gzipped' in response.content
        if stream is True:
            assert b'gzipped' in response.raw.read(None, decode_content=True)
        response.raw._fp = BytesIO(response.content)

        cached_response = CachedResponse.from_response(response)
        assert b'gzipped' in cached_response.content
        assert b'gzipped' in cached_response.raw.read(None, decode_content=True)

    def test_multipart_upload(self):
        session = self.init_session()
        session.post(httpbin('post'), files={'file1': BytesIO(b'10' * 1024)})
        for i in range(5):
            assert session.post(httpbin('post'), files={'file1': BytesIO(b'10' * 1024)}).from_cache

    def test_remove_expired_responses(self):
        session = self.init_session(expire_after=0.01)

        # Populate the cache with several responses that should expire immediately
        for response_format in HTTPBIN_FORMATS:
            session.get(httpbin(response_format))
        session.get(httpbin('redirect/1'))
        sleep(0.01)

        # Cache a response + redirects, which should be the only non-expired cache items
        session.get(httpbin('get'), expire_after=-1)
        session.get(httpbin('redirect/3'), expire_after=-1)
        session.cache.remove_expired_responses()

        assert len(session.cache.responses.keys()) == 2
        assert len(session.cache.redirects.keys()) == 3
        assert not session.cache.has_url(httpbin('redirect/1'))
        assert not any([session.cache.has_url(httpbin(f)) for f in HTTPBIN_FORMATS])

    @pytest.mark.parametrize('iteration', range(N_ITERATIONS))
    def test_multithreaded(self, iteration):
        """Run a multi-threaded stress test for each backend"""
        session = self.init_session()
        start = time()
        url = httpbin('anything')

        def send_requests():
            for i in range(N_ITERATIONS):
                session.get(url, params={f'key_{i}': f'value_{i}'})

        threads = [Thread(target=send_requests) for i in range(N_THREADS)]
        for t in threads:
            t.start()
        for t in threads:
            t.join()

        elapsed = time() - start
        average = (elapsed * 1000) / (N_ITERATIONS * N_THREADS)
        print(
            f'{self.backend_class}: Ran {N_ITERATIONS} iterations with {N_THREADS} threads each in {elapsed} s'
        )
        print(f'Average time per request: {average} ms')

        for i in range(N_ITERATIONS):
            assert session.cache.has_url(f'{url}?key_{i}=value_{i}')

    @pytest.mark.parametrize('method', HTTPBIN_METHODS)
    def test_filter_request_headers(self, method):
        url = httpbin(method.lower())
        session = self.init_session(ignored_parameters=['Authorization'])
        response = session.request(method, url, headers={"Authorization": "<Secret Key>"})
        assert response.from_cache is False
        response = session.request(method, url, headers={"Authorization": "<Secret Key>"})
        assert response.from_cache is True
        assert response.request.headers.get('Authorization') is None

    @pytest.mark.parametrize('method', HTTPBIN_METHODS)
    def test_filter_request_query_parameters(self, method):
        url = httpbin(method.lower())
        session = self.init_session(ignored_parameters=['api_key'])
        response = session.request(method, url, params={"api_key": "<Secret Key>"})
        assert response.from_cache is False
        response = session.request(method, url, params={"api_key": "<Secret Key>"})
        assert response.from_cache is True
        query = urlparse(response.request.url).query
        query_dict = parse_qs(query)
        assert 'api_key' not in query_dict

    @pytest.mark.parametrize('post_type', ['data', 'json'])
    def test_filter_request_post_data(self, post_type):
        method = 'POST'
        url = httpbin(method.lower())
        session = self.init_session(ignored_parameters=['api_key'])
        response = session.request(method, url, **{post_type: {"api_key": "<Secret Key>"}})
        assert response.from_cache is False
        response = session.request(method, url, **{post_type: {"api_key": "<Secret Key>"}})
        assert response.from_cache is True
        if post_type == 'data':
            body = parse_qs(response.request.body)
            assert "api_key" not in body
        elif post_type == 'json':
            body = json.loads(response.request.body)
            assert "api_key" not in body