# -*- coding: utf-8 -*-
# Copyright 2014-2016 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License 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.

import hashlib
from inspect import getcallargs
import urllib
import urlparse

from mock import Mock, patch
from twisted.internet import defer, reactor

from synapse.api.errors import CodeMessageException, cs_error
from synapse.federation.transport import server
from synapse.http.server import HttpServer
from synapse.server import HomeServer
from synapse.storage import PostgresEngine
from synapse.storage.engines import create_engine
from synapse.storage.prepare_database import prepare_database
from synapse.util.logcontext import LoggingContext
from synapse.util.ratelimitutils import FederationRateLimiter

# set this to True to run the tests against postgres instead of sqlite.
# It requires you to have a local postgres database called synapse_test, within
# which ALL TABLES WILL BE DROPPED
USE_POSTGRES_FOR_TESTS = False


@defer.inlineCallbacks
def setup_test_homeserver(name="test", datastore=None, config=None, **kargs):
    """Setup a homeserver suitable for running tests against. Keyword arguments
    are passed to the Homeserver constructor. If no datastore is supplied a
    datastore backed by an in-memory sqlite db will be given to the HS.
    """
    if config is None:
        config = Mock()
        config.signing_key = [MockKey()]
        config.event_cache_size = 1
        config.enable_registration = True
        config.macaroon_secret_key = "not even a little secret"
        config.expire_access_token = False
        config.server_name = name
        config.trusted_third_party_id_servers = []
        config.room_invite_state_types = []
        config.password_providers = []
        config.worker_replication_url = ""
        config.worker_app = None
        config.email_enable_notifs = False
        config.block_non_admin_invites = False
        config.federation_domain_whitelist = None
        config.user_directory_search_all_users = False

        # disable user directory updates, because they get done in the
        # background, which upsets the test runner.
        config.update_user_directory = False

    config.use_frozen_dicts = True
    config.ldap_enabled = False

    if "clock" not in kargs:
        kargs["clock"] = MockClock()

    if USE_POSTGRES_FOR_TESTS:
        config.database_config = {
            "name": "psycopg2",
            "args": {
                "database": "synapse_test",
                "cp_min": 1,
                "cp_max": 5,
            },
        }
    else:
        config.database_config = {
            "name": "sqlite3",
            "args": {
                "database": ":memory:",
                "cp_min": 1,
                "cp_max": 1,
            },
        }

    db_engine = create_engine(config.database_config)

    # we need to configure the connection pool to run the on_new_connection
    # function, so that we can test code that uses custom sqlite functions
    # (like rank).
    config.database_config["args"]["cp_openfun"] = db_engine.on_new_connection

    if datastore is None:
        hs = HomeServer(
            name, config=config,
            db_config=config.database_config,
            version_string="Synapse/tests",
            database_engine=db_engine,
            room_list_handler=object(),
            tls_server_context_factory=Mock(),
            **kargs
        )
        db_conn = hs.get_db_conn()
        # make sure that the database is empty
        if isinstance(db_engine, PostgresEngine):
            cur = db_conn.cursor()
            cur.execute("SELECT tablename FROM pg_tables where schemaname='public'")
            rows = cur.fetchall()
            for r in rows:
                cur.execute("DROP TABLE %s CASCADE" % r[0])
        yield prepare_database(db_conn, db_engine, config)
        hs.setup()
    else:
        hs = HomeServer(
            name, db_pool=None, datastore=datastore, config=config,
            version_string="Synapse/tests",
            database_engine=db_engine,
            room_list_handler=object(),
            tls_server_context_factory=Mock(),
            **kargs
        )

    # bcrypt is far too slow to be doing in unit tests
    # Need to let the HS build an auth handler and then mess with it
    # because AuthHandler's constructor requires the HS, so we can't make one
    # beforehand and pass it in to the HS's constructor (chicken / egg)
    hs.get_auth_handler().hash = lambda p: hashlib.md5(p).hexdigest()
    hs.get_auth_handler().validate_hash = lambda p, h: hashlib.md5(p).hexdigest() == h

    fed = kargs.get("resource_for_federation", None)
    if fed:
        server.register_servlets(
            hs,
            resource=fed,
            authenticator=server.Authenticator(hs),
            ratelimiter=FederationRateLimiter(
                hs.get_clock(),
                window_size=hs.config.federation_rc_window_size,
                sleep_limit=hs.config.federation_rc_sleep_limit,
                sleep_msec=hs.config.federation_rc_sleep_delay,
                reject_limit=hs.config.federation_rc_reject_limit,
                concurrent_requests=hs.config.federation_rc_concurrent
            ),
        )

    defer.returnValue(hs)


def get_mock_call_args(pattern_func, mock_func):
    """ Return the arguments the mock function was called with interpreted
    by the pattern functions argument list.
    """
    invoked_args, invoked_kargs = mock_func.call_args
    return getcallargs(pattern_func, *invoked_args, **invoked_kargs)


def mock_getRawHeaders(headers=None):
    headers = headers if headers is not None else {}

    def getRawHeaders(name, default=None):
        return headers.get(name, default)

    return getRawHeaders


# This is a mock /resource/ not an entire server
class MockHttpResource(HttpServer):

    def __init__(self, prefix=""):
        self.callbacks = []  # 3-tuple of method/pattern/function
        self.prefix = prefix

    def trigger_get(self, path):
        return self.trigger("GET", path, None)

    @patch('twisted.web.http.Request')
    @defer.inlineCallbacks
    def trigger(self, http_method, path, content, mock_request, federation_auth=False):
        """ Fire an HTTP event.

        Args:
            http_method : The HTTP method
            path : The HTTP path
            content : The HTTP body
            mock_request : Mocked request to pass to the event so it can get
                           content.
        Returns:
            A tuple of (code, response)
        Raises:
            KeyError If no event is found which will handle the path.
        """
        path = self.prefix + path

        # annoyingly we return a twisted http request which has chained calls
        # to get at the http content, hence mock it here.
        mock_content = Mock()
        config = {'read.return_value': content}
        mock_content.configure_mock(**config)
        mock_request.content = mock_content

        mock_request.method = http_method
        mock_request.uri = path

        mock_request.getClientIP.return_value = "-"

        headers = {}
        if federation_auth:
            headers["Authorization"] = ["X-Matrix origin=test,key=,sig="]
        mock_request.requestHeaders.getRawHeaders = mock_getRawHeaders(headers)

        # return the right path if the event requires it
        mock_request.path = path

        # add in query params to the right place
        try:
            mock_request.args = urlparse.parse_qs(path.split('?')[1])
            mock_request.path = path.split('?')[0]
            path = mock_request.path
        except Exception:
            pass

        for (method, pattern, func) in self.callbacks:
            if http_method != method:
                continue

            matcher = pattern.match(path)
            if matcher:
                try:
                    args = [
                        urllib.unquote(u).decode("UTF-8")
                        for u in matcher.groups()
                    ]

                    (code, response) = yield func(
                        mock_request,
                        *args
                    )
                    defer.returnValue((code, response))
                except CodeMessageException as e:
                    defer.returnValue((e.code, cs_error(e.msg, code=e.errcode)))

        raise KeyError("No event can handle %s" % path)

    def register_paths(self, method, path_patterns, callback):
        for path_pattern in path_patterns:
            self.callbacks.append((method, path_pattern, callback))


class MockKey(object):
    alg = "mock_alg"
    version = "mock_version"
    signature = b"\x9a\x87$"

    @property
    def verify_key(self):
        return self

    def sign(self, message):
        return self

    def verify(self, message, sig):
        assert sig == b"\x9a\x87$"


class MockClock(object):
    now = 1000

    def __init__(self):
        # list of lists of [absolute_time, callback, expired] in no particular
        # order
        self.timers = []
        self.loopers = []

    def time(self):
        return self.now

    def time_msec(self):
        return self.time() * 1000

    def call_later(self, delay, callback, *args, **kwargs):
        current_context = LoggingContext.current_context()

        def wrapped_callback():
            LoggingContext.thread_local.current_context = current_context
            callback(*args, **kwargs)

        t = [self.now + delay, wrapped_callback, False]
        self.timers.append(t)

        return t

    def looping_call(self, function, interval):
        self.loopers.append([function, interval / 1000., self.now])

    def cancel_call_later(self, timer, ignore_errs=False):
        if timer[2]:
            if not ignore_errs:
                raise Exception("Cannot cancel an expired timer")

        timer[2] = True
        self.timers = [t for t in self.timers if t != timer]

    # For unit testing
    def advance_time(self, secs):
        self.now += secs

        timers = self.timers
        self.timers = []

        for t in timers:
            time, callback, expired = t

            if expired:
                raise Exception("Timer already expired")

            if self.now >= time:
                t[2] = True
                callback()
            else:
                self.timers.append(t)

        for looped in self.loopers:
            func, interval, last = looped
            if last + interval < self.now:
                func()
                looped[2] = self.now

    def advance_time_msec(self, ms):
        self.advance_time(ms / 1000.)

    def time_bound_deferred(self, d, *args, **kwargs):
        # We don't bother timing things out for now.
        return d


def _format_call(args, kwargs):
    return ", ".join(
        ["%r" % (a) for a in args] +
        ["%s=%r" % (k, v) for k, v in kwargs.items()]
    )


class DeferredMockCallable(object):
    """A callable instance that stores a set of pending call expectations and
    return values for them. It allows a unit test to assert that the given set
    of function calls are eventually made, by awaiting on them to be called.
    """

    def __init__(self):
        self.expectations = []
        self.calls = []

    def __call__(self, *args, **kwargs):
        self.calls.append((args, kwargs))

        if not self.expectations:
            raise ValueError("%r has no pending calls to handle call(%s)" % (
                self, _format_call(args, kwargs))
            )

        for (call, result, d) in self.expectations:
            if args == call[1] and kwargs == call[2]:
                d.callback(None)
                return result

        failure = AssertionError("Was not expecting call(%s)" % (
            _format_call(args, kwargs)
        ))

        for _, _, d in self.expectations:
            try:
                d.errback(failure)
            except Exception:
                pass

        raise failure

    def expect_call_and_return(self, call, result):
        self.expectations.append((call, result, defer.Deferred()))

    @defer.inlineCallbacks
    def await_calls(self, timeout=1000):
        deferred = defer.DeferredList(
            [d for _, _, d in self.expectations],
            fireOnOneErrback=True
        )

        timer = reactor.callLater(
            timeout / 1000,
            deferred.errback,
            AssertionError("%d pending calls left: %s" % (
                len([e for e in self.expectations if not e[2].called]),
                [e for e in self.expectations if not e[2].called]
            ))
        )

        yield deferred

        timer.cancel()

        self.calls = []

    def assert_had_no_calls(self):
        if self.calls:
            calls = self.calls
            self.calls = []

            raise AssertionError(
                "Expected not to received any calls, got:\n" + "\n".join([
                    "call(%s)" % _format_call(c[0], c[1]) for c in calls
                ])
            )