use crate::*;

pub struct EventMap<'a, const N: usize, E, T, U>(
    pub [(E, &'a dyn Fn(T) -> U); N],
    pub Option<&'a dyn Fn(T) -> U>,
);

pub type KeyMapping<const N: usize, E, T, U> = [(E, &'static dyn Fn(&T)->U);N];

impl<'a, const N: usize, E: PartialEq, T, U> EventMap<'a, N, E, T, U> {
    pub fn handle (&self, context: T, event: &E) -> Option<U> {
        for (binding, handler) in self.0.iter() {
            if event == binding {
                return Some(handler(context))
            }
        }
        return None
    }
}

#[macro_export] macro_rules! event_map {
    ($events:expr) => {
        EventMap($events, None)
    };
    ($events:expr, $default: expr) => {
        EventMap($events, $default)
    };
}

#[macro_export] macro_rules! event_map_input_to_command {
    ($Engine:ty: $Model:ty: $Command:ty: $EventMap:expr) => {
        input_to_command!($Command: <$Engine>|state: $Model, input|{
            event_map!($EventMap).handle(state, input.event())?
        });
    }
}