PkmnLib_rs/src/script_implementations/wasm/script_function_cache.rs

use std::sync::Arc;

use parking_lot::RwLock;
use paste::paste;
use wasmer::NativeFunc;

use crate::dynamic_data::{DynamicLibrary, TurnChoice};
use crate::script_implementations::wasm::extern_ref::{ExternRef, VecExternRef};
use crate::script_implementations::wasm::script_resolver::WebAssemblyEnvironmentData;
use crate::static_data::EffectParameter;
use crate::StringKey;

macro_rules! script_function_cache {
    (
        $(
            $name:ident -> $return:ty
        )*
    ) => {
        #[derive(Default)]
        pub struct ScriptFunctionCache {
            $(
                $name: RwLock<Option<$return>>,
            )*
        }

        impl ScriptFunctionCache {
            $(
                paste! {
                    #[cold]
                    fn [<initialize_ $name>](&self, env: &Arc<WebAssemblyEnvironmentData>) {
                        let exported = env.exported_functions();
                        let f = exported.get::<StringKey>(&stringify!([< script_ $name >]).into());
                        if let Some(f) = f {
                            let func: $return = f.native().unwrap();
                            let _ = self.$name.write().insert(func);
                        }
                    }


                    pub(crate) fn [<$name>](
                        &self,
                        env: &Arc<WebAssemblyEnvironmentData>,
                    ) -> Option<$return> {
                        {
                            let read_lock = self.$name.read();
                            if let Some(f) = read_lock.as_ref() {
                                return Some(f.clone());
                            }
                        }
                        self.[<initialize_ $name>](env);
                        self.$name.read().as_ref().cloned()
                    }
                }
            )*
        }
    }
}

script_function_cache! {
    on_initialize -> NativeFunc<(u32, ExternRef<DynamicLibrary>, VecExternRef<EffectParameter>), ()>
    on_before_turn -> NativeFunc<(u32, ExternRef<TurnChoice>), ()>
}