use crate::Stack;
use libloading::{Library, Symbol};

static mut STACKPTR: *mut Stack = 0 as *mut Stack;

#[no_mangle]
unsafe extern fn stack_pop_callback() -> u16  { 
    (*STACKPTR).memory.pop()
}

#[no_mangle]
unsafe extern fn stack_push_callback(data: u16) { 
    (*STACKPTR).memory.push(data) 
}

#[no_mangle]
unsafe extern fn stack_len_callback() -> usize { 
    (*STACKPTR).memory.len()
}


pub unsafe fn native(stack: &mut Stack, arg: String) {
    STACKPTR = stack as *mut Stack;
    #[cfg(not(target_family = "windows"))]
    let libsuf: String = ".so".to_owned();

    #[cfg(target_family = "windows")]
    let libsuf: String = ".dll".to_owned();

    let module = Library::new(format!("./{}{}", arg, libsuf)).unwrap();
    // C libraries should use 
    // void (*labashka)(unsigned short (*pop)(void), void (*push)(unsigned short), size_t (*len)(void), size_t max_size);
    let func: Symbol<unsafe extern "C" fn(unsafe extern fn() -> u16, unsafe extern fn(u16), unsafe extern fn() -> usize, usize)> = module.get(b"labashka").unwrap();
    func(stack_pop_callback,stack_push_callback,stack_len_callback, stack.memory.size());
}