//! `GET /_matrix/client/*/rooms/{roomId}/context/{eventId}`
//!
//! Get the events immediately preceding and following a given event.

pub mod v3 {
    //! `/v3/` ([spec])
    //!
    //! [spec]: https://spec.matrix.org/latest/client-server-api/#get_matrixclientv3roomsroomidcontexteventid

    use js_int::{uint, UInt};
    use ruma_common::{
        api::{request, response, Metadata},
        metadata,
        serde::Raw,
        OwnedEventId, OwnedRoomId,
    };
    use ruma_events::{AnyStateEvent, AnyTimelineEvent};

    use crate::filter::RoomEventFilter;

    const METADATA: Metadata = metadata! {
        method: GET,
        rate_limited: false,
        authentication: AccessToken,
        history: {
            1.0 => "/_matrix/client/r0/rooms/:room_id/context/:event_id",
            1.1 => "/_matrix/client/v3/rooms/:room_id/context/:event_id",
        }
    };

    /// Request type for the `get_context` endpoint.
    #[request(error = crate::Error)]
    pub struct Request {
        /// The room to get events from.
        #[ruma_api(path)]
        pub room_id: OwnedRoomId,

        /// The event to get context around.
        #[ruma_api(path)]
        pub event_id: OwnedEventId,

        /// The maximum number of context events to return.
        ///
        /// This limit applies to the sum of the `events_before` and `events_after` arrays. The
        /// requested event ID is always returned in `event` even if the limit is `0`.
        ///
        /// Defaults to 10.
        #[ruma_api(query)]
        #[serde(default = "default_limit", skip_serializing_if = "is_default_limit")]
        pub limit: UInt,

        /// A RoomEventFilter to filter returned events with.
        #[ruma_api(query)]
        #[serde(
            with = "ruma_common::serde::json_string",
            default,
            skip_serializing_if = "RoomEventFilter::is_empty"
        )]
        pub filter: RoomEventFilter,
    }

    /// Response type for the `get_context` endpoint.
    #[response(error = crate::Error)]
    #[derive(Default)]
    pub struct Response {
        /// A token that can be used to paginate backwards with.
        #[serde(skip_serializing_if = "Option::is_none")]
        pub start: Option<String>,

        /// A token that can be used to paginate forwards with.
        #[serde(skip_serializing_if = "Option::is_none")]
        pub end: Option<String>,

        /// A list of room events that happened just before the requested event,
        /// in reverse-chronological order.
        #[serde(default, skip_serializing_if = "Vec::is_empty")]
        pub events_before: Vec<Raw<AnyTimelineEvent>>,

        /// Details of the requested event.
        #[serde(skip_serializing_if = "Option::is_none")]
        pub event: Option<Raw<AnyTimelineEvent>>,

        /// A list of room events that happened just after the requested event,
        /// in chronological order.
        #[serde(default, skip_serializing_if = "Vec::is_empty")]
        pub events_after: Vec<Raw<AnyTimelineEvent>>,

        /// The state of the room at the last event returned.
        #[serde(default, skip_serializing_if = "Vec::is_empty")]
        pub state: Vec<Raw<AnyStateEvent>>,
    }

    impl Request {
        /// Creates a new `Request` with the given room id and event id.
        pub fn new(room_id: OwnedRoomId, event_id: OwnedEventId) -> Self {
            Self { room_id, event_id, limit: default_limit(), filter: RoomEventFilter::default() }
        }
    }

    impl Response {
        /// Creates an empty `Response`.
        pub fn new() -> Self {
            Default::default()
        }
    }

    fn default_limit() -> UInt {
        uint!(10)
    }

    #[allow(clippy::trivially_copy_pass_by_ref)]
    fn is_default_limit(val: &UInt) -> bool {
        *val == default_limit()
    }
}