lyra-engine/lyra-scripting/src/lib.rs

#[cfg(feature = "lua")]
pub mod lua;

pub mod world;
use std::any::TypeId;

use lyra_ecs::{Component, ResourceObject};
pub use world::*;

pub mod wrap;
pub use wrap::*;

pub mod host;
pub use host::*;

pub mod script;
pub use script::*;

use lyra_game::game::Game;

// required for some proc macros :(
#[allow(unused_imports)]
pub(crate) mod lyra_engine {
    pub use lyra_ecs as ecs;
    pub use lyra_reflect as reflect;
}

use lyra_reflect::{ReflectedComponent, Reflect, FromType, ReflectedResource};

#[derive(Clone)]
pub enum ReflectBranch {
    Component(ReflectedComponent),
    Resource(ReflectedResource),
}

impl ReflectBranch {
    /// Gets self as a [`ReflectedComponent`]. 
    /// 
    /// # Panics
    /// If `self` is not a variant of [`ReflectBranch::Component`].
    pub fn as_component_unchecked(&self) -> &ReflectedComponent {
        match self {
            ReflectBranch::Component(c) => c,
            _ => panic!("`self` is not an instance of `ReflectBranch::Component`")
        }
    }

    /// Returns a boolean indicating if `self` is a reflection of a Component.
    pub fn is_component(&self) -> bool {
        matches!(self, ReflectBranch::Component(_))
    }

    /// Gets self as a [`ReflectedResource`]. 
    /// 
    /// # Panics
    /// If `self` is not a variant of [`ReflectBranch::Resource`].
    pub fn as_resource_unchecked(&self) -> &ReflectedResource {
        match self {
            ReflectBranch::Resource(v) => v,
            _ => panic!("`self` is not an instance of `ReflectBranch::Component`")
        }
    }

    /// Returns a boolean indicating if `self` is a reflection of a Resource.
    pub fn is_resource(&self) -> bool {
        matches!(self, ReflectBranch::Resource(_))
    }

    /// Returns the type id of the reflected thing
    pub fn reflect_type_id(&self) -> TypeId {
        match self {
            ReflectBranch::Component(c) => c.type_id,
            ReflectBranch::Resource(r) => r.type_id,
        }
    }
}

pub struct ScriptBorrow {
    reflect_branch: ReflectBranch,
    data: Option<Box<dyn Reflect>>,
}

impl Clone for ScriptBorrow {
    fn clone(&self) -> Self {
        let data = self.data.as_ref().map(|b| b.clone_inner());

        Self {
            reflect_branch: self.reflect_branch.clone(),
            data,
        }
    }
}

impl ScriptBorrow {
    /// Creates a ScriptBorrow from a Component
    pub fn from_component<T>(data: Option<T>) -> Self
    where
        T: Reflect + Component + Default + 'static
    {
        let data = data.map(|d| Box::new(d) as Box<(dyn Reflect + 'static)>);

        Self {
            reflect_branch: ReflectBranch::Component(<ReflectedComponent as FromType<T>>::from_type()),
            data,
        }
    }

    /// Creates a ScriptBorrow from a Resource.
    pub fn from_resource<T>(data: Option<T>) -> Self
    where
        T: Reflect + ResourceObject + Default + 'static
    {
        let data = data.map(|d| Box::new(d) as Box<(dyn Reflect + 'static)>);

        Self {
            reflect_branch: ReflectBranch::Resource(<ReflectedResource as FromType<T>>::from_type()),
            data,
        }
    }
}

/// An extension trait that adds some helpful methods that makes it easier to do scripting things
pub trait GameScriptExt {
    /// A helper method for adding a ScriptApiProvider into the world.
    fn add_script_api_provider<T, P>(&mut self, provider: P)
    where
        T: ScriptHost,
        P: ScriptApiProvider<ScriptContext = T::ScriptContext> + 'static;
}

impl GameScriptExt for Game {
    fn add_script_api_provider<T, P>(&mut self, mut provider: P)
    where
        T: ScriptHost,
        P: ScriptApiProvider<ScriptContext = T::ScriptContext> + 'static
    {
        let world = self.world();
        provider.prepare_world(world);
        let mut providers = world.get_resource_mut::<ScriptApiProviders<T>>();
        providers.add_provider(provider);
    }
}