# Copyright 2019 The Matrix.org Foundation C.I.C.
#
# 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 typing import List, Optional

from parameterized import parameterized

from twisted.test.proto_helpers import MemoryReactor

from synapse.api.constants import EventTypes, RelationTypes
from synapse.api.room_versions import RoomVersion, RoomVersions
from synapse.rest import admin
from synapse.rest.client import login, room, sync
from synapse.server import HomeServer
from synapse.storage._base import db_to_json
from synapse.storage.database import LoggingTransaction
from synapse.types import JsonDict
from synapse.util import Clock

from tests.unittest import HomeserverTestCase, override_config


class RedactionsTestCase(HomeserverTestCase):
    """Tests that various redaction events are handled correctly"""

    servlets = [
        admin.register_servlets,
        room.register_servlets,
        login.register_servlets,
        sync.register_servlets,
    ]

    def make_homeserver(self, reactor: MemoryReactor, clock: Clock) -> HomeServer:
        config = self.default_config()

        config["rc_message"] = {"per_second": 0.2, "burst_count": 10}
        config["rc_admin_redaction"] = {"per_second": 1, "burst_count": 100}

        return self.setup_test_homeserver(config=config)

    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
        # register a couple of users
        self.mod_user_id = self.register_user("user1", "pass")
        self.mod_access_token = self.login("user1", "pass")
        self.other_user_id = self.register_user("otheruser", "pass")
        self.other_access_token = self.login("otheruser", "pass")

        # Create a room
        self.room_id = self.helper.create_room_as(
            self.mod_user_id, tok=self.mod_access_token
        )

        # Invite the other user
        self.helper.invite(
            room=self.room_id,
            src=self.mod_user_id,
            tok=self.mod_access_token,
            targ=self.other_user_id,
        )
        # The other user joins
        self.helper.join(
            room=self.room_id, user=self.other_user_id, tok=self.other_access_token
        )

    def _redact_event(
        self,
        access_token: str,
        room_id: str,
        event_id: str,
        expect_code: int = 200,
        with_relations: Optional[List[str]] = None,
        content: Optional[JsonDict] = None,
    ) -> JsonDict:
        """Helper function to send a redaction event.

        Returns the json body.
        """
        path = "/_matrix/client/r0/rooms/%s/redact/%s" % (room_id, event_id)

        request_content = content or {}
        if with_relations:
            request_content["org.matrix.msc3912.with_relations"] = with_relations

        channel = self.make_request(
            "POST", path, request_content, access_token=access_token
        )
        self.assertEqual(channel.code, expect_code)
        return channel.json_body

    def _sync_room_timeline(self, access_token: str, room_id: str) -> List[JsonDict]:
        channel = self.make_request("GET", "sync", access_token=access_token)
        self.assertEqual(channel.code, 200)
        room_sync = channel.json_body["rooms"]["join"][room_id]
        return room_sync["timeline"]["events"]

    def test_redact_event_as_moderator(self) -> None:
        # as a regular user, send a message to redact
        b = self.helper.send(room_id=self.room_id, tok=self.other_access_token)
        msg_id = b["event_id"]

        # as the moderator, send a redaction
        b = self._redact_event(self.mod_access_token, self.room_id, msg_id)
        redaction_id = b["event_id"]

        # now sync
        timeline = self._sync_room_timeline(self.mod_access_token, self.room_id)

        # the last event should be the redaction
        self.assertEqual(timeline[-1]["event_id"], redaction_id)
        self.assertEqual(timeline[-1]["redacts"], msg_id)

        # and the penultimate should be the redacted original
        self.assertEqual(timeline[-2]["event_id"], msg_id)
        self.assertEqual(timeline[-2]["unsigned"]["redacted_by"], redaction_id)
        self.assertEqual(timeline[-2]["content"], {})

    def test_redact_event_as_normal(self) -> None:
        # as a regular user, send a message to redact
        b = self.helper.send(room_id=self.room_id, tok=self.other_access_token)
        normal_msg_id = b["event_id"]

        # also send one as the admin
        b = self.helper.send(room_id=self.room_id, tok=self.mod_access_token)
        admin_msg_id = b["event_id"]

        # as a normal, try to redact the admin's event
        self._redact_event(
            self.other_access_token, self.room_id, admin_msg_id, expect_code=403
        )

        # now try to redact our own event
        b = self._redact_event(self.other_access_token, self.room_id, normal_msg_id)
        redaction_id = b["event_id"]

        # now sync
        timeline = self._sync_room_timeline(self.other_access_token, self.room_id)

        # the last event should be the redaction of the normal event
        self.assertEqual(timeline[-1]["event_id"], redaction_id)
        self.assertEqual(timeline[-1]["redacts"], normal_msg_id)

        # the penultimate should be the unredacted one from the admin
        self.assertEqual(timeline[-2]["event_id"], admin_msg_id)
        self.assertNotIn("redacted_by", timeline[-2]["unsigned"])
        self.assertTrue(timeline[-2]["content"]["body"], {})

        # and the antepenultimate should be the redacted normal
        self.assertEqual(timeline[-3]["event_id"], normal_msg_id)
        self.assertEqual(timeline[-3]["unsigned"]["redacted_by"], redaction_id)
        self.assertEqual(timeline[-3]["content"], {})

    def test_redact_nonexistent_event(self) -> None:
        # control case: an existing event
        b = self.helper.send(room_id=self.room_id, tok=self.other_access_token)
        msg_id = b["event_id"]
        b = self._redact_event(self.other_access_token, self.room_id, msg_id)
        redaction_id = b["event_id"]

        # room moderators can send redactions for non-existent events
        self._redact_event(self.mod_access_token, self.room_id, "$zzz")

        # ... but normals cannot
        self._redact_event(
            self.other_access_token, self.room_id, "$zzz", expect_code=404
        )

        # when we sync, we should see only the valid redaction
        timeline = self._sync_room_timeline(self.other_access_token, self.room_id)
        self.assertEqual(timeline[-1]["event_id"], redaction_id)
        self.assertEqual(timeline[-1]["redacts"], msg_id)

        # and the penultimate should be the redacted original
        self.assertEqual(timeline[-2]["event_id"], msg_id)
        self.assertEqual(timeline[-2]["unsigned"]["redacted_by"], redaction_id)
        self.assertEqual(timeline[-2]["content"], {})

    def test_redact_create_event(self) -> None:
        # control case: an existing event
        b = self.helper.send(room_id=self.room_id, tok=self.mod_access_token)
        msg_id = b["event_id"]
        self._redact_event(self.mod_access_token, self.room_id, msg_id)

        # sync the room, to get the id of the create event
        timeline = self._sync_room_timeline(self.other_access_token, self.room_id)
        create_event_id = timeline[0]["event_id"]

        # room moderators cannot send redactions for create events
        self._redact_event(
            self.mod_access_token, self.room_id, create_event_id, expect_code=403
        )

        # and nor can normals
        self._redact_event(
            self.other_access_token, self.room_id, create_event_id, expect_code=403
        )

    def test_redact_event_as_moderator_ratelimit(self) -> None:
        """Tests that the correct ratelimiting is applied to redactions"""

        message_ids = []
        # as a regular user, send messages to redact
        for _ in range(20):
            b = self.helper.send(room_id=self.room_id, tok=self.other_access_token)
            message_ids.append(b["event_id"])
            self.reactor.advance(10)  # To get around ratelimits

        # as the moderator, send a bunch of redactions
        for msg_id in message_ids:
            # These should all succeed, even though this would be denied by
            # the standard message ratelimiter
            self._redact_event(self.mod_access_token, self.room_id, msg_id)

    @override_config({"experimental_features": {"msc3912_enabled": True}})
    def test_redact_relations_with_types(self) -> None:
        """Tests that we can redact the relations of an event of specific types
        at the same time as the event itself.
        """
        # Send a root event.
        res = self.helper.send_event(
            room_id=self.room_id,
            type=EventTypes.Message,
            content={"msgtype": "m.text", "body": "hello"},
            tok=self.mod_access_token,
        )
        root_event_id = res["event_id"]

        # Send an edit to this root event.
        res = self.helper.send_event(
            room_id=self.room_id,
            type=EventTypes.Message,
            content={
                "body": " * hello world",
                "m.new_content": {
                    "body": "hello world",
                    "msgtype": "m.text",
                },
                "m.relates_to": {
                    "event_id": root_event_id,
                    "rel_type": RelationTypes.REPLACE,
                },
                "msgtype": "m.text",
            },
            tok=self.mod_access_token,
        )
        edit_event_id = res["event_id"]

        # Also send a threaded message whose root is the same as the edit's.
        res = self.helper.send_event(
            room_id=self.room_id,
            type=EventTypes.Message,
            content={
                "msgtype": "m.text",
                "body": "message 1",
                "m.relates_to": {
                    "event_id": root_event_id,
                    "rel_type": RelationTypes.THREAD,
                },
            },
            tok=self.mod_access_token,
        )
        threaded_event_id = res["event_id"]

        # Also send a reaction, again with the same root.
        res = self.helper.send_event(
            room_id=self.room_id,
            type=EventTypes.Reaction,
            content={
                "m.relates_to": {
                    "rel_type": RelationTypes.ANNOTATION,
                    "event_id": root_event_id,
                    "key": "👍",
                }
            },
            tok=self.mod_access_token,
        )
        reaction_event_id = res["event_id"]

        # Redact the root event, specifying that we also want to delete events that
        # relate to it with m.replace.
        self._redact_event(
            self.mod_access_token,
            self.room_id,
            root_event_id,
            with_relations=[
                RelationTypes.REPLACE,
                RelationTypes.THREAD,
            ],
        )

        # Check that the root event got redacted.
        event_dict = self.helper.get_event(
            self.room_id, root_event_id, self.mod_access_token
        )
        self.assertIn("redacted_because", event_dict, event_dict)

        # Check that the edit got redacted.
        event_dict = self.helper.get_event(
            self.room_id, edit_event_id, self.mod_access_token
        )
        self.assertIn("redacted_because", event_dict, event_dict)

        # Check that the threaded message got redacted.
        event_dict = self.helper.get_event(
            self.room_id, threaded_event_id, self.mod_access_token
        )
        self.assertIn("redacted_because", event_dict, event_dict)

        # Check that the reaction did not get redacted.
        event_dict = self.helper.get_event(
            self.room_id, reaction_event_id, self.mod_access_token
        )
        self.assertNotIn("redacted_because", event_dict, event_dict)

    @override_config({"experimental_features": {"msc3912_enabled": True}})
    def test_redact_all_relations(self) -> None:
        """Tests that we can redact all the relations of an event at the same time as the
        event itself.
        """
        # Send a root event.
        res = self.helper.send_event(
            room_id=self.room_id,
            type=EventTypes.Message,
            content={"msgtype": "m.text", "body": "hello"},
            tok=self.mod_access_token,
        )
        root_event_id = res["event_id"]

        # Send an edit to this root event.
        res = self.helper.send_event(
            room_id=self.room_id,
            type=EventTypes.Message,
            content={
                "body": " * hello world",
                "m.new_content": {
                    "body": "hello world",
                    "msgtype": "m.text",
                },
                "m.relates_to": {
                    "event_id": root_event_id,
                    "rel_type": RelationTypes.REPLACE,
                },
                "msgtype": "m.text",
            },
            tok=self.mod_access_token,
        )
        edit_event_id = res["event_id"]

        # Also send a threaded message whose root is the same as the edit's.
        res = self.helper.send_event(
            room_id=self.room_id,
            type=EventTypes.Message,
            content={
                "msgtype": "m.text",
                "body": "message 1",
                "m.relates_to": {
                    "event_id": root_event_id,
                    "rel_type": RelationTypes.THREAD,
                },
            },
            tok=self.mod_access_token,
        )
        threaded_event_id = res["event_id"]

        # Also send a reaction, again with the same root.
        res = self.helper.send_event(
            room_id=self.room_id,
            type=EventTypes.Reaction,
            content={
                "m.relates_to": {
                    "rel_type": RelationTypes.ANNOTATION,
                    "event_id": root_event_id,
                    "key": "👍",
                }
            },
            tok=self.mod_access_token,
        )
        reaction_event_id = res["event_id"]

        # Redact the root event, specifying that we also want to delete all events that
        # relate to it.
        self._redact_event(
            self.mod_access_token,
            self.room_id,
            root_event_id,
            with_relations=["*"],
        )

        # Check that the root event got redacted.
        event_dict = self.helper.get_event(
            self.room_id, root_event_id, self.mod_access_token
        )
        self.assertIn("redacted_because", event_dict, event_dict)

        # Check that the edit got redacted.
        event_dict = self.helper.get_event(
            self.room_id, edit_event_id, self.mod_access_token
        )
        self.assertIn("redacted_because", event_dict, event_dict)

        # Check that the threaded message got redacted.
        event_dict = self.helper.get_event(
            self.room_id, threaded_event_id, self.mod_access_token
        )
        self.assertIn("redacted_because", event_dict, event_dict)

        # Check that the reaction got redacted.
        event_dict = self.helper.get_event(
            self.room_id, reaction_event_id, self.mod_access_token
        )
        self.assertIn("redacted_because", event_dict, event_dict)

    @override_config({"experimental_features": {"msc3912_enabled": True}})
    def test_redact_relations_no_perms(self) -> None:
        """Tests that, when redacting a message along with its relations, if not all
        the related messages can be redacted because of insufficient permissions, the
        server still redacts all the ones that can be.
        """
        # Send a root event.
        res = self.helper.send_event(
            room_id=self.room_id,
            type=EventTypes.Message,
            content={
                "msgtype": "m.text",
                "body": "root",
            },
            tok=self.other_access_token,
        )
        root_event_id = res["event_id"]

        # Send a first threaded message, this one from the moderator. We do this for the
        # first message with the m.thread relation (and not the last one) to ensure
        # that, when the server fails to redact it, it doesn't stop there, and it
        # instead goes on to redact the other one.
        res = self.helper.send_event(
            room_id=self.room_id,
            type=EventTypes.Message,
            content={
                "msgtype": "m.text",
                "body": "message 1",
                "m.relates_to": {
                    "event_id": root_event_id,
                    "rel_type": RelationTypes.THREAD,
                },
            },
            tok=self.mod_access_token,
        )
        first_threaded_event_id = res["event_id"]

        # Send a second threaded message, this time from the user who'll perform the
        # redaction.
        res = self.helper.send_event(
            room_id=self.room_id,
            type=EventTypes.Message,
            content={
                "msgtype": "m.text",
                "body": "message 2",
                "m.relates_to": {
                    "event_id": root_event_id,
                    "rel_type": RelationTypes.THREAD,
                },
            },
            tok=self.other_access_token,
        )
        second_threaded_event_id = res["event_id"]

        # Redact the thread's root, and request that all threaded messages are also
        # redacted. Send that request from the non-mod user, so that the first threaded
        # event cannot be redacted.
        self._redact_event(
            self.other_access_token,
            self.room_id,
            root_event_id,
            with_relations=[RelationTypes.THREAD],
        )

        # Check that the thread root got redacted.
        event_dict = self.helper.get_event(
            self.room_id, root_event_id, self.other_access_token
        )
        self.assertIn("redacted_because", event_dict, event_dict)

        # Check that the last message in the thread got redacted, despite failing to
        # redact the one before it.
        event_dict = self.helper.get_event(
            self.room_id, second_threaded_event_id, self.other_access_token
        )
        self.assertIn("redacted_because", event_dict, event_dict)

        # Check that the message that was sent into the tread by the mod user is not
        # redacted.
        event_dict = self.helper.get_event(
            self.room_id, first_threaded_event_id, self.other_access_token
        )
        self.assertIn("body", event_dict["content"], event_dict)
        self.assertEqual("message 1", event_dict["content"]["body"])

    @override_config({"experimental_features": {"msc3912_enabled": True}})
    def test_redact_relations_txn_id_reuse(self) -> None:
        """Tests that redacting a message using a transaction ID, then reusing the same
        transaction ID but providing an additional list of relations to redact, is
        effectively a no-op.
        """
        # Send a root event.
        res = self.helper.send_event(
            room_id=self.room_id,
            type=EventTypes.Message,
            content={
                "msgtype": "m.text",
                "body": "root",
            },
            tok=self.mod_access_token,
        )
        root_event_id = res["event_id"]

        # Send a first threaded message.
        res = self.helper.send_event(
            room_id=self.room_id,
            type=EventTypes.Message,
            content={
                "msgtype": "m.text",
                "body": "I'm in a thread!",
                "m.relates_to": {
                    "event_id": root_event_id,
                    "rel_type": RelationTypes.THREAD,
                },
            },
            tok=self.mod_access_token,
        )
        threaded_event_id = res["event_id"]

        # Send a first redaction request which redacts only the root event.
        channel = self.make_request(
            method="PUT",
            path=f"/rooms/{self.room_id}/redact/{root_event_id}/foo",
            content={},
            access_token=self.mod_access_token,
        )
        self.assertEqual(channel.code, 200)

        # Send a second redaction request which redacts the root event as well as
        # threaded messages.
        channel = self.make_request(
            method="PUT",
            path=f"/rooms/{self.room_id}/redact/{root_event_id}/foo",
            content={"org.matrix.msc3912.with_relations": [RelationTypes.THREAD]},
            access_token=self.mod_access_token,
        )
        self.assertEqual(channel.code, 200)

        # Check that the root event got redacted.
        event_dict = self.helper.get_event(
            self.room_id, root_event_id, self.mod_access_token
        )
        self.assertIn("redacted_because", event_dict)

        # Check that the threaded message didn't get redacted (since that wasn't part of
        # the original redaction).
        event_dict = self.helper.get_event(
            self.room_id, threaded_event_id, self.mod_access_token
        )
        self.assertIn("body", event_dict["content"], event_dict)
        self.assertEqual("I'm in a thread!", event_dict["content"]["body"])

    @parameterized.expand(
        [
            # Tuples of:
            #   Room version
            #   Boolean: True if the redaction event content should include the event ID.
            #   Boolean: true if the resulting redaction event is expected to include the
            #            event ID in the content.
            (RoomVersions.V10, False, False),
            (RoomVersions.V11, True, True),
            (RoomVersions.V11, False, True),
        ]
    )
    def test_redaction_content(
        self, room_version: RoomVersion, include_content: bool, expect_content: bool
    ) -> None:
        """
        Room version 11 moved the redacts property to the content.

        Ensure that the event gets created properly and that the Client-Server
        API servers the proper backwards-compatible version.
        """
        # Create a room with the newer room version.
        room_id = self.helper.create_room_as(
            self.mod_user_id,
            tok=self.mod_access_token,
            room_version=room_version.identifier,
        )

        # Create an event.
        b = self.helper.send(room_id=room_id, tok=self.mod_access_token)
        event_id = b["event_id"]

        # Ensure the event ID in the URL and the content must match.
        if include_content:
            self._redact_event(
                self.mod_access_token,
                room_id,
                event_id,
                expect_code=400,
                content={"redacts": "foo"},
            )

        # Redact it for real.
        result = self._redact_event(
            self.mod_access_token,
            room_id,
            event_id,
            content={"redacts": event_id} if include_content else {},
        )
        redaction_event_id = result["event_id"]

        # Sync the room, to get the id of the create event
        timeline = self._sync_room_timeline(self.mod_access_token, room_id)
        redact_event = timeline[-1]
        self.assertEqual(redact_event["type"], EventTypes.Redaction)
        # The redacts key should be in the content and the redacts keys.
        self.assertEqual(redact_event["content"]["redacts"], event_id)
        self.assertEqual(redact_event["redacts"], event_id)

        # But it isn't actually part of the event.
        def get_event(txn: LoggingTransaction) -> JsonDict:
            return db_to_json(
                main_datastore._fetch_event_rows(txn, [redaction_event_id])[
                    redaction_event_id
                ].json
            )

        main_datastore = self.hs.get_datastores().main
        event_json = self.get_success(
            main_datastore.db_pool.runInteraction("get_event", get_event)
        )
        self.assertEqual(event_json["type"], EventTypes.Redaction)
        if expect_content:
            self.assertNotIn("redacts", event_json)
            self.assertEqual(event_json["content"]["redacts"], event_id)
        else:
            self.assertEqual(event_json["redacts"], event_id)
            self.assertNotIn("redacts", event_json["content"])