#
# This file is licensed under the Affero General Public License (AGPL) version 3.
#
# Copyright (C) 2023 New Vector, Ltd
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# See the GNU Affero General Public License for more details:
# <https://www.gnu.org/licenses/agpl-3.0.html>.
#
# Originally licensed under the Apache License, Version 2.0:
# <http://www.apache.org/licenses/LICENSE-2.0>.
#
# [This file includes modifications made by New Vector Limited]
#
#

from typing import Iterable, List, Optional, Tuple, cast

from synapse.api.constants import EventTypes, Membership
from synapse.api.room_versions import RoomVersions
from synapse.events import EventBase, FrozenEvent
from synapse.push.presentable_names import calculate_room_name
from synapse.types import StateKey, StateMap

from tests import unittest


class MockDataStore:
    """
    A fake data store which stores a mapping of state key to event content.
    (I.e. the state key is used as the event ID.)
    """

    def __init__(self, events: Iterable[Tuple[StateKey, dict]]):
        """
        Args:
            events: A state map to event contents.
        """
        self._events = {}

        for i, (event_id, content) in enumerate(events):
            self._events[event_id] = FrozenEvent(
                {
                    "event_id": "$event_id",
                    "type": event_id[0],
                    "sender": "@user:test",
                    "state_key": event_id[1],
                    "room_id": "#room:test",
                    "content": content,
                    "origin_server_ts": i,
                },
                RoomVersions.V1,
            )

    async def get_event(
        self, event_id: str, allow_none: bool = False
    ) -> Optional[FrozenEvent]:
        assert allow_none, "Mock not configured for allow_none = False"

        # Decode the state key from the event ID.
        state_key = cast(Tuple[str, str], tuple(event_id.split("|", 1)))
        return self._events.get(state_key)

    async def get_events(self, event_ids: Iterable[StateKey]) -> StateMap[EventBase]:
        # This is cheating since it just returns all events.
        return self._events


class PresentableNamesTestCase(unittest.HomeserverTestCase):
    USER_ID = "@test:test"
    OTHER_USER_ID = "@user:test"

    def _calculate_room_name(
        self,
        events: Iterable[Tuple[Tuple[str, str], dict]],
        user_id: str = "",
        fallback_to_members: bool = True,
        fallback_to_single_member: bool = True,
    ) -> Optional[str]:
        # Encode the state key into the event ID.
        room_state_ids = {k[0]: "|".join(k[0]) for k in events}

        return self.get_success(
            calculate_room_name(
                MockDataStore(events),  # type: ignore[arg-type]
                room_state_ids,
                user_id or self.USER_ID,
                fallback_to_members,
                fallback_to_single_member,
            )
        )

    def test_name(self) -> None:
        """A room name event should be used."""
        events: List[Tuple[Tuple[str, str], dict]] = [
            ((EventTypes.Name, ""), {"name": "test-name"}),
        ]
        self.assertEqual("test-name", self._calculate_room_name(events))

        # Check if the event content has garbage.
        events = [((EventTypes.Name, ""), {"foo": 1})]
        self.assertEqual("Empty Room", self._calculate_room_name(events))

        events = [((EventTypes.Name, ""), {"name": 1})]
        self.assertEqual(1, self._calculate_room_name(events))

    def test_canonical_alias(self) -> None:
        """An canonical alias should be used."""
        events: List[Tuple[Tuple[str, str], dict]] = [
            ((EventTypes.CanonicalAlias, ""), {"alias": "#test-name:test"}),
        ]
        self.assertEqual("#test-name:test", self._calculate_room_name(events))

        # Check if the event content has garbage.
        events = [((EventTypes.CanonicalAlias, ""), {"foo": 1})]
        self.assertEqual("Empty Room", self._calculate_room_name(events))

        events = [((EventTypes.CanonicalAlias, ""), {"alias": "test-name"})]
        self.assertEqual("Empty Room", self._calculate_room_name(events))

    def test_invite(self) -> None:
        """An invite has special behaviour."""
        events: List[Tuple[Tuple[str, str], dict]] = [
            ((EventTypes.Member, self.USER_ID), {"membership": Membership.INVITE}),
            ((EventTypes.Member, self.OTHER_USER_ID), {"displayname": "Other User"}),
        ]
        self.assertEqual("Invite from Other User", self._calculate_room_name(events))
        self.assertIsNone(
            self._calculate_room_name(events, fallback_to_single_member=False)
        )
        # Ensure this logic is skipped if we don't fallback to members.
        self.assertIsNone(self._calculate_room_name(events, fallback_to_members=False))

        # Check if the event content has garbage.
        events = [
            ((EventTypes.Member, self.USER_ID), {"membership": Membership.INVITE}),
            ((EventTypes.Member, self.OTHER_USER_ID), {"foo": 1}),
        ]
        self.assertEqual("Invite from @user:test", self._calculate_room_name(events))

        # No member event for sender.
        events = [
            ((EventTypes.Member, self.USER_ID), {"membership": Membership.INVITE}),
        ]
        self.assertEqual("Room Invite", self._calculate_room_name(events))

    def test_no_members(self) -> None:
        """Behaviour of an empty room."""
        events: List[Tuple[Tuple[str, str], dict]] = []
        self.assertEqual("Empty Room", self._calculate_room_name(events))

        # Note that events with invalid (or missing) membership are ignored.
        events = [
            ((EventTypes.Member, self.OTHER_USER_ID), {"foo": 1}),
            ((EventTypes.Member, "@foo:test"), {"membership": "foo"}),
        ]
        self.assertEqual("Empty Room", self._calculate_room_name(events))

    def test_no_other_members(self) -> None:
        """Behaviour of a room with no other members in it."""
        events = [
            (
                (EventTypes.Member, self.USER_ID),
                {"membership": Membership.JOIN, "displayname": "Me"},
            ),
        ]
        self.assertEqual("Me", self._calculate_room_name(events))

        # Check if the event content has no displayname.
        events = [
            ((EventTypes.Member, self.USER_ID), {"membership": Membership.JOIN}),
        ]
        self.assertEqual("@test:test", self._calculate_room_name(events))

        # 3pid invite, use the other user (who is set as the sender).
        events = [
            ((EventTypes.Member, self.OTHER_USER_ID), {"membership": Membership.JOIN}),
        ]
        self.assertEqual(
            "nobody", self._calculate_room_name(events, user_id=self.OTHER_USER_ID)
        )

        events = [
            ((EventTypes.Member, self.OTHER_USER_ID), {"membership": Membership.JOIN}),
            ((EventTypes.ThirdPartyInvite, self.OTHER_USER_ID), {}),
        ]
        self.assertEqual(
            "Inviting email address",
            self._calculate_room_name(events, user_id=self.OTHER_USER_ID),
        )

    def test_one_other_member(self) -> None:
        """Behaviour of a room with a single other member."""
        events = [
            ((EventTypes.Member, self.USER_ID), {"membership": Membership.JOIN}),
            (
                (EventTypes.Member, self.OTHER_USER_ID),
                {"membership": Membership.JOIN, "displayname": "Other User"},
            ),
        ]
        self.assertEqual("Other User", self._calculate_room_name(events))
        self.assertIsNone(
            self._calculate_room_name(events, fallback_to_single_member=False)
        )

        # Check if the event content has no displayname and is an invite.
        events = [
            ((EventTypes.Member, self.USER_ID), {"membership": Membership.JOIN}),
            (
                (EventTypes.Member, self.OTHER_USER_ID),
                {"membership": Membership.INVITE},
            ),
        ]
        self.assertEqual("@user:test", self._calculate_room_name(events))

    def test_other_members(self) -> None:
        """Behaviour of a room with multiple other members."""
        # Two other members.
        events = [
            ((EventTypes.Member, self.USER_ID), {"membership": Membership.JOIN}),
            (
                (EventTypes.Member, self.OTHER_USER_ID),
                {"membership": Membership.JOIN, "displayname": "Other User"},
            ),
            ((EventTypes.Member, "@foo:test"), {"membership": Membership.JOIN}),
        ]
        self.assertEqual("Other User and @foo:test", self._calculate_room_name(events))

        # Three or more other members.
        events.append(
            ((EventTypes.Member, "@fourth:test"), {"membership": Membership.INVITE})
        )
        self.assertEqual("Other User and 2 others", self._calculate_room_name(events))
