# 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 logging
import random
from typing import TYPE_CHECKING, Optional

from synapse.api.errors import (
    AuthError,
    Codes,
    HttpResponseException,
    RequestSendFailed,
    StoreError,
    SynapseError,
)
from synapse.metrics.background_process_metrics import wrap_as_background_process
from synapse.types import (
    JsonDict,
    Requester,
    UserID,
    create_requester,
    get_domain_from_id,
)

if TYPE_CHECKING:
    from synapse.server import HomeServer

logger = logging.getLogger(__name__)

MAX_DISPLAYNAME_LEN = 256
MAX_AVATAR_URL_LEN = 1000


class ProfileHandler:
    """Handles fetching and updating user profile information.

    ProfileHandler can be instantiated directly on workers and will
    delegate to master when necessary.
    """

    PROFILE_UPDATE_MS = 60 * 1000
    PROFILE_UPDATE_EVERY_MS = 24 * 60 * 60 * 1000

    def __init__(self, hs: "HomeServer"):
        self.store = hs.get_datastore()
        self.clock = hs.get_clock()
        self.hs = hs

        self.federation = hs.get_federation_client()
        hs.get_federation_registry().register_query_handler(
            "profile", self.on_profile_query
        )

        self.user_directory_handler = hs.get_user_directory_handler()
        self.request_ratelimiter = hs.get_request_ratelimiter()

        if hs.config.worker.run_background_tasks:
            self.clock.looping_call(
                self._update_remote_profile_cache, self.PROFILE_UPDATE_MS
            )

    async def get_profile(self, user_id: str) -> JsonDict:
        target_user = UserID.from_string(user_id)

        if self.hs.is_mine(target_user):
            try:
                displayname = await self.store.get_profile_displayname(
                    target_user.localpart
                )
                avatar_url = await self.store.get_profile_avatar_url(
                    target_user.localpart
                )
            except StoreError as e:
                if e.code == 404:
                    raise SynapseError(404, "Profile was not found", Codes.NOT_FOUND)
                raise

            return {"displayname": displayname, "avatar_url": avatar_url}
        else:
            try:
                result = await self.federation.make_query(
                    destination=target_user.domain,
                    query_type="profile",
                    args={"user_id": user_id},
                    ignore_backoff=True,
                )
                return result
            except RequestSendFailed as e:
                raise SynapseError(502, "Failed to fetch profile") from e
            except HttpResponseException as e:
                if e.code < 500 and e.code != 404:
                    # Other codes are not allowed in c2s API
                    logger.info(
                        "Server replied with wrong response: %s %s", e.code, e.msg
                    )

                    raise SynapseError(502, "Failed to fetch profile")
                raise e.to_synapse_error()

    async def get_profile_from_cache(self, user_id: str) -> JsonDict:
        """Get the profile information from our local cache. If the user is
        ours then the profile information will always be correct. Otherwise,
        it may be out of date/missing.
        """
        target_user = UserID.from_string(user_id)
        if self.hs.is_mine(target_user):
            try:
                displayname = await self.store.get_profile_displayname(
                    target_user.localpart
                )
                avatar_url = await self.store.get_profile_avatar_url(
                    target_user.localpart
                )
            except StoreError as e:
                if e.code == 404:
                    raise SynapseError(404, "Profile was not found", Codes.NOT_FOUND)
                raise

            return {"displayname": displayname, "avatar_url": avatar_url}
        else:
            profile = await self.store.get_from_remote_profile_cache(user_id)
            return profile or {}

    async def get_displayname(self, target_user: UserID) -> Optional[str]:
        if self.hs.is_mine(target_user):
            try:
                displayname = await self.store.get_profile_displayname(
                    target_user.localpart
                )
            except StoreError as e:
                if e.code == 404:
                    raise SynapseError(404, "Profile was not found", Codes.NOT_FOUND)
                raise

            return displayname
        else:
            try:
                result = await self.federation.make_query(
                    destination=target_user.domain,
                    query_type="profile",
                    args={"user_id": target_user.to_string(), "field": "displayname"},
                    ignore_backoff=True,
                )
            except RequestSendFailed as e:
                raise SynapseError(502, "Failed to fetch profile") from e
            except HttpResponseException as e:
                raise e.to_synapse_error()

            return result.get("displayname")

    async def set_displayname(
        self,
        target_user: UserID,
        requester: Requester,
        new_displayname: str,
        by_admin: bool = False,
    ) -> None:
        """Set the displayname of a user

        Args:
            target_user: the user whose displayname is to be changed.
            requester: The user attempting to make this change.
            new_displayname: The displayname to give this user.
            by_admin: Whether this change was made by an administrator.
        """
        if not self.hs.is_mine(target_user):
            raise SynapseError(400, "User is not hosted on this homeserver")

        if not by_admin and target_user != requester.user:
            raise AuthError(400, "Cannot set another user's displayname")

        if not by_admin and not self.hs.config.registration.enable_set_displayname:
            profile = await self.store.get_profileinfo(target_user.localpart)
            if profile.display_name:
                raise SynapseError(
                    400,
                    "Changing display name is disabled on this server",
                    Codes.FORBIDDEN,
                )

        if not isinstance(new_displayname, str):
            raise SynapseError(
                400, "'displayname' must be a string", errcode=Codes.INVALID_PARAM
            )

        if len(new_displayname) > MAX_DISPLAYNAME_LEN:
            raise SynapseError(
                400, "Displayname is too long (max %i)" % (MAX_DISPLAYNAME_LEN,)
            )

        displayname_to_set: Optional[str] = new_displayname
        if new_displayname == "":
            displayname_to_set = None

        # If the admin changes the display name of a user, the requesting user cannot send
        # the join event to update the displayname in the rooms.
        # This must be done by the target user himself.
        if by_admin:
            requester = create_requester(
                target_user,
                authenticated_entity=requester.authenticated_entity,
            )

        await self.store.set_profile_displayname(
            target_user.localpart, displayname_to_set
        )

        profile = await self.store.get_profileinfo(target_user.localpart)
        await self.user_directory_handler.handle_local_profile_change(
            target_user.to_string(), profile
        )

        await self._update_join_states(requester, target_user)

    async def get_avatar_url(self, target_user: UserID) -> Optional[str]:
        if self.hs.is_mine(target_user):
            try:
                avatar_url = await self.store.get_profile_avatar_url(
                    target_user.localpart
                )
            except StoreError as e:
                if e.code == 404:
                    raise SynapseError(404, "Profile was not found", Codes.NOT_FOUND)
                raise
            return avatar_url
        else:
            try:
                result = await self.federation.make_query(
                    destination=target_user.domain,
                    query_type="profile",
                    args={"user_id": target_user.to_string(), "field": "avatar_url"},
                    ignore_backoff=True,
                )
            except RequestSendFailed as e:
                raise SynapseError(502, "Failed to fetch profile") from e
            except HttpResponseException as e:
                raise e.to_synapse_error()

            return result.get("avatar_url")

    async def set_avatar_url(
        self,
        target_user: UserID,
        requester: Requester,
        new_avatar_url: str,
        by_admin: bool = False,
    ) -> None:
        """Set a new avatar URL for a user.

        Args:
            target_user: the user whose avatar URL is to be changed.
            requester: The user attempting to make this change.
            new_avatar_url: The avatar URL to give this user.
            by_admin: Whether this change was made by an administrator.
        """
        if not self.hs.is_mine(target_user):
            raise SynapseError(400, "User is not hosted on this homeserver")

        if not by_admin and target_user != requester.user:
            raise AuthError(400, "Cannot set another user's avatar_url")

        if not by_admin and not self.hs.config.registration.enable_set_avatar_url:
            profile = await self.store.get_profileinfo(target_user.localpart)
            if profile.avatar_url:
                raise SynapseError(
                    400, "Changing avatar is disabled on this server", Codes.FORBIDDEN
                )

        if not isinstance(new_avatar_url, str):
            raise SynapseError(
                400, "'avatar_url' must be a string", errcode=Codes.INVALID_PARAM
            )

        if len(new_avatar_url) > MAX_AVATAR_URL_LEN:
            raise SynapseError(
                400, "Avatar URL is too long (max %i)" % (MAX_AVATAR_URL_LEN,)
            )

        avatar_url_to_set: Optional[str] = new_avatar_url
        if new_avatar_url == "":
            avatar_url_to_set = None

        # Same like set_displayname
        if by_admin:
            requester = create_requester(
                target_user, authenticated_entity=requester.authenticated_entity
            )

        await self.store.set_profile_avatar_url(
            target_user.localpart, avatar_url_to_set
        )

        profile = await self.store.get_profileinfo(target_user.localpart)
        await self.user_directory_handler.handle_local_profile_change(
            target_user.to_string(), profile
        )

        await self._update_join_states(requester, target_user)

    async def on_profile_query(self, args: JsonDict) -> JsonDict:
        """Handles federation profile query requests."""

        if not self.hs.config.federation.allow_profile_lookup_over_federation:
            raise SynapseError(
                403,
                "Profile lookup over federation is disabled on this homeserver",
                Codes.FORBIDDEN,
            )

        user = UserID.from_string(args["user_id"])
        if not self.hs.is_mine(user):
            raise SynapseError(400, "User is not hosted on this homeserver")

        just_field = args.get("field", None)

        response = {}
        try:
            if just_field is None or just_field == "displayname":
                response["displayname"] = await self.store.get_profile_displayname(
                    user.localpart
                )

            if just_field is None or just_field == "avatar_url":
                response["avatar_url"] = await self.store.get_profile_avatar_url(
                    user.localpart
                )
        except StoreError as e:
            if e.code == 404:
                raise SynapseError(404, "Profile was not found", Codes.NOT_FOUND)
            raise

        return response

    async def _update_join_states(
        self, requester: Requester, target_user: UserID
    ) -> None:
        if not self.hs.is_mine(target_user):
            return

        await self.request_ratelimiter.ratelimit(requester)

        # Do not actually update the room state for shadow-banned users.
        if requester.shadow_banned:
            # We randomly sleep a bit just to annoy the requester.
            await self.clock.sleep(random.randint(1, 10))
            return

        room_ids = await self.store.get_rooms_for_user(target_user.to_string())

        for room_id in room_ids:
            handler = self.hs.get_room_member_handler()
            try:
                # Assume the target_user isn't a guest,
                # because we don't let guests set profile or avatar data.
                await handler.update_membership(
                    requester,
                    target_user,
                    room_id,
                    "join",  # We treat a profile update like a join.
                    ratelimit=False,  # Try to hide that these events aren't atomic.
                )
            except Exception as e:
                logger.warning(
                    "Failed to update join event for room %s - %s", room_id, str(e)
                )

    async def check_profile_query_allowed(
        self, target_user: UserID, requester: Optional[UserID] = None
    ) -> None:
        """Checks whether a profile query is allowed. If the
        'require_auth_for_profile_requests' config flag is set to True and a
        'requester' is provided, the query is only allowed if the two users
        share a room.

        Args:
            target_user: The owner of the queried profile.
            requester: The user querying for the profile.

        Raises:
            SynapseError(403): The two users share no room, or ne user couldn't
                be found to be in any room the server is in, and therefore the query
                is denied.
        """

        # Implementation of MSC1301: don't allow looking up profiles if the
        # requester isn't in the same room as the target. We expect requester to
        # be None when this function is called outside of a profile query, e.g.
        # when building a membership event. In this case, we must allow the
        # lookup.
        if (
            not self.hs.config.server.limit_profile_requests_to_users_who_share_rooms
            or not requester
        ):
            return

        # Always allow the user to query their own profile.
        if target_user.to_string() == requester.to_string():
            return

        try:
            requester_rooms = await self.store.get_rooms_for_user(requester.to_string())
            target_user_rooms = await self.store.get_rooms_for_user(
                target_user.to_string()
            )

            # Check if the room lists have no elements in common.
            if requester_rooms.isdisjoint(target_user_rooms):
                raise SynapseError(403, "Profile isn't available", Codes.FORBIDDEN)
        except StoreError as e:
            if e.code == 404:
                # This likely means that one of the users doesn't exist,
                # so we act as if we couldn't find the profile.
                raise SynapseError(403, "Profile isn't available", Codes.FORBIDDEN)
            raise

    @wrap_as_background_process("Update remote profile")
    async def _update_remote_profile_cache(self) -> None:
        """Called periodically to check profiles of remote users we haven't
        checked in a while.
        """
        entries = await self.store.get_remote_profile_cache_entries_that_expire(
            last_checked=self.clock.time_msec() - self.PROFILE_UPDATE_EVERY_MS
        )

        for user_id, displayname, avatar_url in entries:
            is_subscribed = await self.store.is_subscribed_remote_profile_for_user(
                user_id
            )
            if not is_subscribed:
                await self.store.maybe_delete_remote_profile_cache(user_id)
                continue

            try:
                profile = await self.federation.make_query(
                    destination=get_domain_from_id(user_id),
                    query_type="profile",
                    args={"user_id": user_id},
                    ignore_backoff=True,
                )
            except Exception:
                logger.exception("Failed to get avatar_url")

                await self.store.update_remote_profile_cache(
                    user_id, displayname, avatar_url
                )
                continue

            new_name = profile.get("displayname")
            if not isinstance(new_name, str):
                new_name = None
            new_avatar = profile.get("avatar_url")
            if not isinstance(new_avatar, str):
                new_avatar = None

            # We always hit update to update the last_check timestamp
            await self.store.update_remote_profile_cache(user_id, new_name, new_avatar)
