# -*- coding: utf-8 -*-
# Copyright 2014 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.

from tests import unittest
from twisted.internet import defer
from twisted.python.log import PythonLoggingObserver

from synapse.state import StateHandler
from synapse.storage.pdu import PduEntry
from synapse.federation.pdu_codec import encode_event_id
from synapse.federation.units import Pdu

from collections import namedtuple

from mock import Mock

import mock


ReturnType = namedtuple(
    "StateReturnType", ["new_branch", "current_branch"]
)


def _gen_get_power_level(power_level_list):
    def get_power_level(room_id, user_id):
        return defer.succeed(power_level_list.get(user_id, None))
    return get_power_level

class StateTestCase(unittest.TestCase):
    def setUp(self):
        self.persistence = Mock(spec=[
            "get_unresolved_state_tree",
            "update_current_state",
            "get_latest_pdus_in_context",
            "get_current_state_pdu",
            "get_pdu",
            "get_power_level",
        ])
        self.replication = Mock(spec=["get_pdu"])

        hs = Mock(spec=["get_datastore", "get_replication_layer"])
        hs.get_datastore.return_value = self.persistence
        hs.get_replication_layer.return_value = self.replication
        hs.hostname = "bob.com"

        self.state = StateHandler(hs)

    @defer.inlineCallbacks
    def test_new_state_key(self):
        # We've never seen anything for this state before
        new_pdu = new_fake_pdu("A", "test", "mem", "x", None, "u")

        self.persistence.get_power_level.side_effect = _gen_get_power_level({})

        self.persistence.get_unresolved_state_tree.return_value = (
            (ReturnType([new_pdu], []), None)
        )

        is_new = yield self.state.handle_new_state(new_pdu)

        self.assertTrue(is_new)

        self.persistence.get_unresolved_state_tree.assert_called_once_with(
            new_pdu
        )

        self.assertEqual(1, self.persistence.update_current_state.call_count)

        self.assertFalse(self.replication.get_pdu.called)

    @defer.inlineCallbacks
    def test_direct_overwrite(self):
        # We do a direct overwriting of the old state, i.e., the new state
        # points to the old state.

        old_pdu = new_fake_pdu("A", "test", "mem", "x", None, "u1")
        new_pdu = new_fake_pdu("B", "test", "mem", "x", "A", "u2")

        self.persistence.get_power_level.side_effect = _gen_get_power_level({
            "u1": 10,
            "u2": 5,
        })

        self.persistence.get_unresolved_state_tree.return_value = (
            (ReturnType([new_pdu, old_pdu], [old_pdu]), None)
        )

        is_new = yield self.state.handle_new_state(new_pdu)

        self.assertTrue(is_new)

        self.persistence.get_unresolved_state_tree.assert_called_once_with(
            new_pdu
        )

        self.assertEqual(1, self.persistence.update_current_state.call_count)

        self.assertFalse(self.replication.get_pdu.called)

    @defer.inlineCallbacks
    def test_overwrite(self):
        old_pdu_1 = new_fake_pdu("A", "test", "mem", "x", None, "u1")
        old_pdu_2 = new_fake_pdu("B", "test", "mem", "x", "A", "u2")
        new_pdu = new_fake_pdu("C", "test", "mem", "x", "B", "u3")

        self.persistence.get_power_level.side_effect = _gen_get_power_level({
            "u1": 10,
            "u2": 5,
            "u3": 0,
        })

        self.persistence.get_unresolved_state_tree.return_value = (
            (ReturnType([new_pdu, old_pdu_2, old_pdu_1], [old_pdu_1]), None)
        )

        is_new = yield self.state.handle_new_state(new_pdu)

        self.assertTrue(is_new)

        self.persistence.get_unresolved_state_tree.assert_called_once_with(
            new_pdu
        )

        self.assertEqual(1, self.persistence.update_current_state.call_count)

        self.assertFalse(self.replication.get_pdu.called)

    @defer.inlineCallbacks
    def test_power_level_fail(self):
        # We try to update the state based on an outdated state, and have a
        # too low power level.

        old_pdu_1 = new_fake_pdu("A", "test", "mem", "x", None, "u1")
        old_pdu_2 = new_fake_pdu("B", "test", "mem", "x", None, "u2")
        new_pdu = new_fake_pdu("C", "test", "mem", "x", "A", "u3")

        self.persistence.get_power_level.side_effect = _gen_get_power_level({
            "u1": 10,
            "u2": 10,
            "u3": 5,
        })

        self.persistence.get_unresolved_state_tree.return_value = (
            (ReturnType([new_pdu, old_pdu_1], [old_pdu_2, old_pdu_1]), None)
        )

        is_new = yield self.state.handle_new_state(new_pdu)

        self.assertFalse(is_new)

        self.persistence.get_unresolved_state_tree.assert_called_once_with(
            new_pdu
        )

        self.assertEqual(0, self.persistence.update_current_state.call_count)

        self.assertFalse(self.replication.get_pdu.called)

    @defer.inlineCallbacks
    def test_power_level_succeed(self):
        # We try to update the state based on an outdated state, but have
        # sufficient power level to force the update.

        old_pdu_1 = new_fake_pdu("A", "test", "mem", "x", None, "u1")
        old_pdu_2 = new_fake_pdu("B", "test", "mem", "x", None, "u2")
        new_pdu = new_fake_pdu("C", "test", "mem", "x", "A", "u3")

        self.persistence.get_power_level.side_effect = _gen_get_power_level({
            "u1": 10,
            "u2": 10,
            "u3": 15,
        })

        self.persistence.get_unresolved_state_tree.return_value = (
            (ReturnType([new_pdu, old_pdu_1], [old_pdu_2, old_pdu_1]), None)
        )

        is_new = yield self.state.handle_new_state(new_pdu)

        self.assertTrue(is_new)

        self.persistence.get_unresolved_state_tree.assert_called_once_with(
            new_pdu
        )

        self.assertEqual(1, self.persistence.update_current_state.call_count)

        self.assertFalse(self.replication.get_pdu.called)

    @defer.inlineCallbacks
    def test_power_level_equal_same_len(self):
        # We try to update the state based on an outdated state, the power
        # levels are the same and so are the branch lengths

        old_pdu_1 = new_fake_pdu("A", "test", "mem", "x", None, "u1")
        old_pdu_2 = new_fake_pdu("B", "test", "mem", "x", None, "u2")
        new_pdu = new_fake_pdu("C", "test", "mem", "x", "A", "u3")

        self.persistence.get_power_level.side_effect = _gen_get_power_level({
            "u1": 10,
            "u2": 10,
            "u3": 10,
        })

        self.persistence.get_unresolved_state_tree.return_value = (
            (ReturnType([new_pdu, old_pdu_1], [old_pdu_2, old_pdu_1]), None)
        )

        is_new = yield self.state.handle_new_state(new_pdu)

        self.assertTrue(is_new)

        self.persistence.get_unresolved_state_tree.assert_called_once_with(
            new_pdu
        )

        self.assertEqual(1, self.persistence.update_current_state.call_count)

        self.assertFalse(self.replication.get_pdu.called)

    @defer.inlineCallbacks
    def test_power_level_equal_diff_len(self):
        # We try to update the state based on an outdated state, the power
        # levels are the same but the branch length of the new one is longer.

        old_pdu_1 = new_fake_pdu("A", "test", "mem", "x", None, "u1")
        old_pdu_2 = new_fake_pdu("B", "test", "mem", "x", None, "u2")
        old_pdu_3 = new_fake_pdu("C", "test", "mem", "x", "A", "u3")
        new_pdu = new_fake_pdu("D", "test", "mem", "x", "C", "u4")

        self.persistence.get_power_level.side_effect = _gen_get_power_level({
            "u1": 10,
            "u2": 10,
            "u3": 10,
            "u4": 10,
        })

        self.persistence.get_unresolved_state_tree.return_value = (
            (
                ReturnType(
                    [new_pdu, old_pdu_3, old_pdu_1],
                    [old_pdu_2, old_pdu_1]
                ),
                None
            )
        )

        is_new = yield self.state.handle_new_state(new_pdu)

        self.assertTrue(is_new)

        self.persistence.get_unresolved_state_tree.assert_called_once_with(
            new_pdu
        )

        self.assertEqual(1, self.persistence.update_current_state.call_count)

        self.assertFalse(self.replication.get_pdu.called)

    @defer.inlineCallbacks
    def test_missing_pdu(self):
        # We try to update state against a PDU we haven't yet seen,
        # triggering a get_pdu request

        # The pdu we haven't seen
        old_pdu_1 = new_fake_pdu(
            "A", "test", "mem", "x", None, "u1", depth=0
        )

        old_pdu_2 = new_fake_pdu(
            "B", "test", "mem", "x", "A", "u2", depth=1
        )
        new_pdu = new_fake_pdu(
            "C", "test", "mem", "x", "A", "u3", depth=2
        )

        self.persistence.get_power_level.side_effect = _gen_get_power_level({
            "u1": 10,
            "u2": 10,
            "u3": 20,
        })

        # The return_value of `get_unresolved_state_tree`, which changes after
        # the call to get_pdu
        tree_to_return = [(ReturnType([new_pdu], [old_pdu_2]), 0)]

        def return_tree(p):
            return tree_to_return[0]

        def set_return_tree(destination, pdu_origin, pdu_id, outlier=False):
            tree_to_return[0] = (
                ReturnType(
                    [new_pdu, old_pdu_1], [old_pdu_2, old_pdu_1]
                ),
                None
            )
            return defer.succeed(None)

        self.persistence.get_unresolved_state_tree.side_effect = return_tree

        self.replication.get_pdu.side_effect = set_return_tree

        self.persistence.get_pdu.return_value = None

        is_new = yield self.state.handle_new_state(new_pdu)

        self.assertTrue(is_new)

        self.replication.get_pdu.assert_called_with(
            destination=new_pdu.origin,
            pdu_origin=old_pdu_1.origin,
            pdu_id=old_pdu_1.pdu_id,
            outlier=True
        )

        self.persistence.get_unresolved_state_tree.assert_called_with(
            new_pdu
        )

        self.assertEquals(
            2, self.persistence.get_unresolved_state_tree.call_count
        )

        self.assertEqual(1, self.persistence.update_current_state.call_count)

    @defer.inlineCallbacks
    def test_missing_pdu_depth_1(self):
        # We try to update state against a PDU we haven't yet seen,
        # triggering a get_pdu request

        # The pdu we haven't seen
        old_pdu_1 = new_fake_pdu(
            "A", "test", "mem", "x", None, "u1", depth=0
        )

        old_pdu_2 = new_fake_pdu(
            "B", "test", "mem", "x", "A", "u2", depth=2
        )
        old_pdu_3 = new_fake_pdu(
            "C", "test", "mem", "x", "B", "u3", depth=3
        )
        new_pdu = new_fake_pdu(
            "D", "test", "mem", "x", "A", "u4", depth=4
        )

        self.persistence.get_power_level.side_effect = _gen_get_power_level({
            "u1": 10,
            "u2": 10,
            "u3": 10,
            "u4": 20,
        })

        # The return_value of `get_unresolved_state_tree`, which changes after
        # the call to get_pdu
        tree_to_return = [
            (
                ReturnType([new_pdu], [old_pdu_3]),
                0
            ),
            (
                ReturnType(
                    [new_pdu, old_pdu_1], [old_pdu_3]
                ),
                1
            ),
            (
                ReturnType(
                    [new_pdu, old_pdu_1], [old_pdu_3, old_pdu_2, old_pdu_1]
                ),
                None
            ),
        ]

        to_return = [0]

        def return_tree(p):
            return tree_to_return[to_return[0]]

        def set_return_tree(destination, pdu_origin, pdu_id, outlier=False):
            to_return[0] += 1
            return defer.succeed(None)

        self.persistence.get_unresolved_state_tree.side_effect = return_tree

        self.replication.get_pdu.side_effect = set_return_tree

        self.persistence.get_pdu.return_value = None

        is_new = yield self.state.handle_new_state(new_pdu)

        self.assertTrue(is_new)

        self.assertEqual(2, self.replication.get_pdu.call_count)

        self.replication.get_pdu.assert_has_calls(
            [
                mock.call(
                    destination=new_pdu.origin,
                    pdu_origin=old_pdu_1.origin,
                    pdu_id=old_pdu_1.pdu_id,
                    outlier=True
                ),
                mock.call(
                    destination=old_pdu_3.origin,
                    pdu_origin=old_pdu_2.origin,
                    pdu_id=old_pdu_2.pdu_id,
                    outlier=True
                ),
            ]
        )

        self.persistence.get_unresolved_state_tree.assert_called_with(
            new_pdu
        )

        self.assertEquals(
            3, self.persistence.get_unresolved_state_tree.call_count
        )

        self.assertEqual(1, self.persistence.update_current_state.call_count)

    @defer.inlineCallbacks
    def test_missing_pdu_depth_2(self):
        # We try to update state against a PDU we haven't yet seen,
        # triggering a get_pdu request

        # The pdu we haven't seen
        old_pdu_1 = new_fake_pdu(
            "A", "test", "mem", "x", None, "u1", depth=0
        )

        old_pdu_2 = new_fake_pdu(
            "B", "test", "mem", "x", "A", "u2", depth=2
        )
        old_pdu_3 = new_fake_pdu(
            "C", "test", "mem", "x", "B", "u3", depth=3
        )
        new_pdu = new_fake_pdu(
            "D", "test", "mem", "x", "A", "u4", depth=1
        )

        self.persistence.get_power_level.side_effect = _gen_get_power_level({
            "u1": 10,
            "u2": 10,
            "u3": 10,
            "u4": 20,
        })

        # The return_value of `get_unresolved_state_tree`, which changes after
        # the call to get_pdu
        tree_to_return = [
            (
                ReturnType([new_pdu], [old_pdu_3]),
                1,
            ),
            (
                ReturnType(
                    [new_pdu], [old_pdu_3, old_pdu_2]
                ),
                0,
            ),
            (
                ReturnType(
                    [new_pdu, old_pdu_1], [old_pdu_3, old_pdu_2, old_pdu_1]
                ),
                None
            ),
        ]

        to_return = [0]

        def return_tree(p):
            return tree_to_return[to_return[0]]

        def set_return_tree(destination, pdu_origin, pdu_id, outlier=False):
            to_return[0] += 1
            return defer.succeed(None)

        self.persistence.get_unresolved_state_tree.side_effect = return_tree

        self.replication.get_pdu.side_effect = set_return_tree

        self.persistence.get_pdu.return_value = None

        is_new = yield self.state.handle_new_state(new_pdu)

        self.assertTrue(is_new)

        self.assertEqual(2, self.replication.get_pdu.call_count)

        self.replication.get_pdu.assert_has_calls(
            [
                mock.call(
                    destination=old_pdu_3.origin,
                    pdu_origin=old_pdu_2.origin,
                    pdu_id=old_pdu_2.pdu_id,
                    outlier=True
                ),
                mock.call(
                    destination=new_pdu.origin,
                    pdu_origin=old_pdu_1.origin,
                    pdu_id=old_pdu_1.pdu_id,
                    outlier=True
                ),
            ]
        )

        self.persistence.get_unresolved_state_tree.assert_called_with(
            new_pdu
        )

        self.assertEquals(
            3, self.persistence.get_unresolved_state_tree.call_count
        )

        self.assertEqual(1, self.persistence.update_current_state.call_count)

    @defer.inlineCallbacks
    def test_no_common_ancestor(self):
        # We do a direct overwriting of the old state, i.e., the new state
        # points to the old state.

        old_pdu = new_fake_pdu("A", "test", "mem", "x", None, "u1")
        new_pdu = new_fake_pdu("B", "test", "mem", "x", None, "u2")

        self.persistence.get_power_level.side_effect = _gen_get_power_level({
            "u1": 5,
            "u2": 10,
        })

        self.persistence.get_unresolved_state_tree.return_value = (
            (ReturnType([new_pdu], [old_pdu]), None)
        )

        is_new = yield self.state.handle_new_state(new_pdu)

        self.assertTrue(is_new)

        self.persistence.get_unresolved_state_tree.assert_called_once_with(
            new_pdu
        )

        self.assertEqual(1, self.persistence.update_current_state.call_count)

        self.assertFalse(self.replication.get_pdu.called)

    @defer.inlineCallbacks
    def test_new_event(self):
        event = Mock()
        event.event_id = "12123123@test"

        state_pdu = new_fake_pdu("C", "test", "mem", "x", "A", 20)

        snapshot = Mock()
        snapshot.prev_state_pdu = state_pdu
        event_id = "pdu_id@origin.com"

        def fill_out_prev_events(event):
            event.prev_events = [event_id]
            event.depth = 6
        snapshot.fill_out_prev_events = fill_out_prev_events

        yield self.state.handle_new_event(event, snapshot)

        self.assertLess(5, event.depth)

        self.assertEquals(1, len(event.prev_events))

        prev_id = event.prev_events[0]

        self.assertEqual(event_id, prev_id)

        self.assertEqual(
            encode_event_id(state_pdu.pdu_id, state_pdu.origin),
            event.prev_state
        )


def new_fake_pdu(pdu_id, context, pdu_type, state_key, prev_state_id,
                 user_id, depth=0):
    new_pdu = Pdu(
        pdu_id=pdu_id,
        pdu_type=pdu_type,
        state_key=state_key,
        user_id=user_id,
        prev_state_id=prev_state_id,
        origin="example.com",
        context="context",
        origin_server_ts=1405353060021,
        depth=depth,
        content_json="{}",
        unrecognized_keys="{}",
        outlier=True,
        is_state=True,
        prev_state_origin="example.com",
        have_processed=True,
        content={},
    )

    return new_pdu