use turkos_os_shell_input::{Epoch, Error, Input};

#[test]
fn os_shell_input_cancel_invalidates_stale_commit_and_allows_new_line() {
    let mut input = Input::<16>::new();
    let first = input.epoch();
    input.push(first, "hel").unwrap();
    input.push(first, "lo").unwrap();
    let second = input.cancel(first).unwrap();
    assert_eq!(input.len(), 0);
    assert_eq!(input.commit(first).err(), Some(Error::StaleEpoch));
    assert_eq!(input.push(first, "old"), Err(Error::StaleEpoch));
    input.push(second, "new").unwrap();
    let command = input.commit(second).unwrap();
    assert_eq!(command.as_str(), "new");
    assert_eq!(command.epoch, second);
    assert_eq!(input.len(), 0);
}

#[test]
fn os_shell_input_capacity_nul_and_utf8_are_atomic() {
    let mut input = Input::<5>::new();
    let epoch = input.epoch();
    input.push(epoch, "ç").unwrap();
    assert_eq!(input.len(), 2);
    assert_eq!(input.push(epoch, "abcd"), Err(Error::Full));
    assert_eq!(input.push(epoch, "\0"), Err(Error::Nul));
    assert_eq!(input.len(), 2);
    input.push(epoch, "ay").unwrap();
    assert_eq!(input.commit(epoch).unwrap().as_str(), "çay");
}

#[test]
fn os_shell_input_rejects_wrong_epoch_without_mutation() {
    let mut input = Input::<8>::new();
    let epoch = input.epoch();
    input.push(epoch, "run").unwrap();
    assert_eq!(input.cancel(Epoch(9)), Err(Error::StaleEpoch));
    assert_eq!(input.commit(Epoch(9)).err(), Some(Error::StaleEpoch));
    assert_eq!(input.len(), 3);
    assert_eq!(input.commit(epoch).unwrap().as_str(), "run");
}