use turkos_os_shell_dispatch::{decide, Builtin, Error, Route};
use turkos_os_shell_words::Words;

#[test]
fn os_shell_dispatch_exact_builtin_names_and_external_prefixes() {
    let cd = Words::<32, 3>::parse("cd /tmp").unwrap();
    assert_eq!(decide(&cd).unwrap().route, Route::Builtin(Builtin::Cd));
    let exit = Words::<32, 3>::parse("exit 0").unwrap();
    assert_eq!(decide(&exit).unwrap().route, Route::Builtin(Builtin::Exit));
    let help = Words::<32, 3>::parse("help").unwrap();
    assert_eq!(decide(&help).unwrap().route, Route::Builtin(Builtin::Help));
    let helpful = Words::<32, 3>::parse("helpful arg").unwrap();
    assert_eq!(decide(&helpful).unwrap().route, Route::External("helpful"));
    let path = Words::<32, 3>::parse("/bin/echo hi").unwrap();
    assert_eq!(decide(&path).unwrap().route, Route::External("/bin/echo"));
}

#[test]
fn os_shell_dispatch_rejects_missing_and_invalid_names() {
    let empty = Words::<8, 2>::parse(" \t ").unwrap();
    assert_eq!(decide(&empty), Err(Error::MissingCommand));
    let quoted_empty = Words::<8, 2>::parse("''").unwrap();
    assert_eq!(decide(&quoted_empty), Err(Error::InvalidName));
}

#[test]
fn os_shell_dispatch_enforces_builtin_arity() {
    for input in ["cd", "cd a b", "exit 0 1", "help extra"] {
        let words = Words::<32, 4>::parse(input).unwrap();
        assert_eq!(decide(&words), Err(Error::BuiltinArity), "{input}");
    }
}