//! Implementation of [MSC4185](https://github.com/matrix-org/matrix-spec-proposals/pull/4185)

use ruma::{
    api::{request, response, Metadata},
    metadata, OwnedEventId, OwnedRoomId, OwnedUserId,
};

use crate::{services, Ar, Ra, Result};

const METADATA: Metadata = metadata! {
    method: GET,
    rate_limited: true,
    authentication: AccessToken,

    history: {
        unstable => "/_matrix/client/unstable/net.tadzik/can_user_see_event/:room_id/:user_id/:event_id",
    },
};

#[request]
#[allow(clippy::struct_field_names)]
pub(crate) struct Request {
    #[ruma_api(path)]
    pub(crate) room_id: OwnedRoomId,

    #[ruma_api(path)]
    pub(crate) user_id: OwnedUserId,

    #[ruma_api(path)]
    pub(crate) event_id: OwnedEventId,
}

#[response]
pub(crate) struct Response {
    #[ruma_api(body)]
    pub(crate) is_visible: bool,
}

pub(crate) async fn can_user_see_event_route(
    body: Ar<Request>,
) -> Result<Ra<Response>> {
    let Ok(true) = services().rooms.state_accessor.user_can_see_event(
        body.sender_user.as_ref().expect("user is authenticated"),
        &body.room_id,
        &body.event_id,
    ) else {
        return Err(crate::Error::BadRequest(
            ruma::api::client::error::ErrorKind::Unauthorized,
            "event is not visible to requesting user",
        ));
    };

    Ok(Ra(Response {
        is_visible: services().rooms.state_accessor.user_can_see_event(
            &body.user_id,
            &body.room_id,
            &body.event_id,
        )?,
    }))
}