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#![recursion_limit = "256"]

use quote::quote;
use syn::parse_macro_input;

#[proc_macro_attribute]
pub fn mobile_entry_point(
    _args: proc_macro::TokenStream,
    input: proc_macro::TokenStream,
) -> proc_macro::TokenStream {
    let func = parse_macro_input!(input as syn::ItemFn);
    let name = &func.sig.ident;

    let expanded = quote! {
        fn stop_unwind<F: FnOnce() -> T, T>(f: F) -> T {
            match std::panic::catch_unwind(std::panic::AssertUnwindSafe(f)) {
                Ok(t) => t,
                Err(err) => {
                    eprintln!("attempt to unwind out of `rust` with err: {:?}", err);
                    std::process::abort()
                }
            }
        }

        #[cfg_attr(target_os = "android", ndk_glue::main(
            backtrace = "on",
            ndk_glue = "ndk_glue",
        ))]
        fn _start_app() {
            #func
            stop_unwind(|| #name());
        }

        #[cfg(not(target_os = "android"))]
        #[no_mangle]
        #[inline(never)]
        pub extern "C" fn start_app() {
            _start_app()
        }
    };
    //panic!("{}", expanded.to_string());
    expanded.into()
}