// Copyright 2024 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.

use matrix_sdk_base::read_receipts::RoomReadReceipts;

use super::{super::RoomListItem, Filter};

type IsMarkedUnread = bool;

fn matches<F>(read_receipts_and_unread: F, room: &RoomListItem) -> bool
where
    F: Fn(&RoomListItem) -> (RoomReadReceipts, IsMarkedUnread),
{
    let (read_receipts, is_marked_unread) = read_receipts_and_unread(room);

    read_receipts.num_notifications > 0 || is_marked_unread
}

/// Create a new filter that will filter out rooms that have no unread
/// notifications (different from unread messages), or is not marked as unread.
pub fn new_filter() -> impl Filter {
    let read_receipts_and_unread =
        |room: &RoomListItem| (room.read_receipts(), room.is_marked_unread());

    move |room_list_entry| -> bool { matches(read_receipts_and_unread, room_list_entry) }
}

#[cfg(test)]
mod tests {
    use std::ops::Not;

    use matrix_sdk::test_utils::mocks::MatrixMockServer;
    use matrix_sdk_base::read_receipts::RoomReadReceipts;
    use matrix_sdk_test::async_test;
    use ruma::room_id;

    use super::{super::new_rooms, *};

    #[async_test]
    async fn test_has_unread_notifications() {
        let server = MatrixMockServer::new().await;
        let client = server.client_builder().build().await;
        let [room] = new_rooms([room_id!("!a:b.c")], &client, &server).await;

        for is_marked_as_unread in [true, false] {
            let read_receipts_and_unread = |_: &RoomListItem| {
                let read_receipts = RoomReadReceipts {
                    num_unread: 42,
                    num_notifications: 42,
                    ..Default::default()
                };

                (read_receipts, is_marked_as_unread)
            };

            assert!(matches(read_receipts_and_unread, &room));
        }
    }

    #[async_test]
    async fn test_has_unread_messages_but_no_unread_notifications_and_is_not_marked_as_unread() {
        let server = MatrixMockServer::new().await;
        let client = server.client_builder().build().await;
        let [room] = new_rooms([room_id!("!a:b.c")], &client, &server).await;

        let read_receipts_and_unread = |_: &RoomListItem| {
            let read_receipts =
                RoomReadReceipts { num_unread: 42, num_notifications: 0, ..Default::default() };

            (read_receipts, false)
        };

        assert!(matches(read_receipts_and_unread, &room).not());
    }

    #[async_test]
    async fn test_has_unread_messages_but_no_unread_notifications_and_is_marked_as_unread() {
        let server = MatrixMockServer::new().await;
        let client = server.client_builder().build().await;
        let [room] = new_rooms([room_id!("!a:b.c")], &client, &server).await;

        let read_receipts_and_unread = |_: &RoomListItem| {
            let read_receipts =
                RoomReadReceipts { num_unread: 42, num_notifications: 0, ..Default::default() };

            (read_receipts, true)
        };

        assert!(matches(read_receipts_and_unread, &room));
    }

    #[async_test]
    async fn test_has_no_unread_notifications_and_is_not_marked_as_unread() {
        let server = MatrixMockServer::new().await;
        let client = server.client_builder().build().await;
        let [room] = new_rooms([room_id!("!a:b.c")], &client, &server).await;

        let read_receipts_and_unread = |_: &RoomListItem| (RoomReadReceipts::default(), false);

        assert!(matches(read_receipts_and_unread, &room).not());
    }

    #[async_test]
    async fn test_has_no_unread_notifications_and_is_marked_as_unread() {
        let server = MatrixMockServer::new().await;
        let client = server.client_builder().build().await;
        let [room] = new_rooms([room_id!("!a:b.c")], &client, &server).await;

        let read_receipts_and_unread = |_: &RoomListItem| (RoomReadReceipts::default(), true);

        assert!(matches(read_receipts_and_unread, &room));
    }
}
