///
/// Declare your arguments using this macro.
/// ```
/// # use badargs::arg;
/// arg!(Force: "force", 'f' -> bool);
/// ```
/// is a shorthand for
/// ```
/// # use badargs::{arg, CliArg};
/// struct Force;
///
/// impl CliArg for Force {
///     type Content = bool;
///
///     fn long() -> &'static str {
///         "force"
///     }
///
///     fn short() -> Option<char> {
///         Some('f')
///     }
/// }
/// ```
#[macro_export]
macro_rules! arg {
    // implicit optional
    ($name:ident: $long:literal, $short:literal -> $result:ty) => {
        arg!(@$name: ($long, ::std::option::Option::Some($short)) -> $result);
    };
    ($name:ident: $long:literal -> $result:ty) => {
        arg!(@$name: ($long, ::std::option::Option::None) -> $result);
    };
    (@$name:ident: ($long:literal, $short:expr) -> $result:ty) => {
        #[derive(Default)]
        struct $name;

        impl $crate::CliArg for $name {
            type Content = $result;

            fn long() -> &'static str {
                $long
            }

            fn short() -> Option<char> {
                $short
            }
        }
    };
}

///
/// A shorthand for calling the [`badargs::badargs`] main function
/// This macro lets you specify your arguments in a flat list, and then converts them into
/// nested tuples for you, since that's what's internally used.
/// ```
/// # use badargs::arg;
/// # arg!(Force: "force", 'f' -> bool);
/// # arg!(OutFile: "outfile", 't' -> bool);
/// # arg!(SetUpstream: "set-upstream", 'x' -> bool);
/// # fn main() {
/// let args = badargs::badargs!(Force, OutFile, SetUpstream);
/// # }
/// ```
/// will be expanded into
/// ```
/// # use badargs::arg;
/// # arg!(Force: "force", 'f' -> bool);
/// # arg!(OutFile: "outfile", 't' -> bool);
/// # arg!(SetUpstream: "set-upstream", 'x' -> bool);
/// let args = badargs::badargs::<(Force, (OutFile, SetUpstream))>();
/// ```
/// This only provides a minor benefit for programs with a small amount of args, but is
/// very useful for larger arg amounts.
#[macro_export]
macro_rules! badargs {
    (@inner $head:ty) => {
        $head
    };
    (@inner $head:ty, $($tail:ty),+) => {
        ($head, $crate::badargs!(@inner $($tail),+))
    };
    ($($tail:ty),+) => {
        {
            #[allow(unused_parens)] // allow this because there might only be one arg
            {

                $crate::badargs::<($crate::badargs!(@inner $($tail),+))>()
            }
        }
    };
}