use yrs::updates::decoder::Decode;
use yrs::{Doc, GetString, Options, ReadTxn, StateVector, Text, Transact, Update};

#[test]
fn partially_known_delete_range_remains_deleted_when_tail_arrives() {
    check_missing_tail(false, false);
}

#[test]
fn partially_known_delete_range_survives_snapshot_before_tail_arrives() {
    check_missing_tail(true, false);
}

#[test]
fn deletion_received_before_any_source_update_is_preserved() {
    check_missing_tail(false, true);
}

#[test]
fn unknown_client_deletion_survives_snapshot_before_source_arrives() {
    check_missing_tail(true, true);
}

fn check_missing_tail(reload: bool, deletion_first: bool) {
    let sender = Doc::with_options(Options::with_guid_and_client_id(
        "delete-tail-review".into(),
        111,
    ));
    let text = sender.get_or_insert_text("text");
    text.insert(&mut sender.transact_mut(), 0, "abcdef");
    let first = sender
        .transact()
        .encode_state_as_update_v1(&StateVector::default());
    let before_tail = sender.transact().state_vector();
    text.insert(&mut sender.transact_mut(), 6, "ghij");
    let delayed = sender.transact().encode_state_as_update_v1(&before_tail);
    let before_delete = sender.transact().state_vector();
    text.remove_range(&mut sender.transact_mut(), 2, 8);
    let deletion = sender.transact().encode_state_as_update_v1(&before_delete);
    let mut receiver = Doc::with_options(Options::with_guid_and_client_id(
        "delete-tail-review".into(),
        222,
    ));
    let updates = if deletion_first {
        [deletion, first]
    } else {
        [first, deletion]
    };
    for (index, update) in updates.into_iter().enumerate() {
        receiver
            .transact_mut()
            .apply_update(Update::decode_v1(&update).unwrap())
            .unwrap();
        if reload && index == if deletion_first { 0 } else { 1 } {
            let snapshot = receiver
                .transact()
                .encode_state_as_update_v1(&StateVector::default());
            receiver = Doc::with_options(Options::with_guid_and_client_id(
                "delete-tail-review".into(),
                333,
            ));
            receiver
                .transact_mut()
                .apply_update(Update::decode_v1(&snapshot).unwrap())
                .unwrap();
        }
    }
    receiver
        .transact_mut()
        .apply_update(Update::decode_v1(&delayed).unwrap())
        .unwrap();
    let received = receiver.get_or_insert_text("text");
    assert_eq!(text.get_string(&sender.transact()), "ab");
    assert_eq!(
        received.get_string(&receiver.transact()),
        "ab",
        "A deletion covering an unseen suffix must survive until that suffix arrives"
    );
}