use crate::dynamic_data::Event;
use crate::ffi::BorrowedPtr;

/// Wrapper class for easier use of an external function pointer.
#[repr(C)]
pub(super) struct NativeEventHook {
    /// The actual C function to be called.
    f: extern "C" fn(BorrowedPtr<Event>),
}

impl NativeEventHook {
    /// Calls the actual wrapped function in the correct format.
    fn call_self(&self, b: &&Event<'_>) {
        (self.f)(*b as *const Event)
    }
}

/// A tuple with the arguments of the event hook function
type EventHookArgs<'a, 'b, 'c> = (&'a Box<&'b Event<'c>>,);

impl FnMut<EventHookArgs<'_, '_, '_>> for NativeEventHook {
    extern "rust-call" fn call_mut(&mut self, args: EventHookArgs<'_, '_, '_>) -> Self::Output {
        self.call_self(args.0)
    }
}

impl FnOnce<EventHookArgs<'_, '_, '_>> for NativeEventHook {
    type Output = ();

    extern "rust-call" fn call_once(self, args: EventHookArgs<'_, '_, '_>) -> Self::Output {
        self.call_self(args.0)
    }
}

impl Fn<EventHookArgs<'_, '_, '_>> for NativeEventHook {
    extern "rust-call" fn call(&self, args: EventHookArgs<'_, '_, '_>) -> Self::Output {
        self.call_self(args.0)
    }
}