use crate::context::Context;

use super::vector3::Vector3;
use super::cframe::CFrame;

pub struct Runner{
	lua:mlua::Lua,
}
#[derive(Debug)]
pub enum Error{
	Lua(mlua::Error),
	Script(crate::script::Error),
	/// If the lua.remove_app_data function fails
	RemoveAppData,
}
impl Error{
	pub fn print(self){
		match self{
			Self::Lua(mlua::Error::RuntimeError(s))=>{
				println!("lua error: {s}");
			},
			other=>println!("{:?}",other),
		}
	}
}

fn init(lua:&mlua::Lua)->mlua::Result<()>{
	lua.sandbox(true)?;

	//global environment
	let globals=lua.globals();

	//Vector3
	{
		let vector3_table=lua.create_table()?;

		//Vector3.new
		vector3_table.raw_set("new",
			lua.create_function(|ctx,(x,y,z):(f32,f32,f32)|
				Ok(ctx.create_userdata(Vector3::new(x,y,z)))
			)?
		)?;

		globals.set("Vector3",vector3_table)?;
	}

	//CFrame
	{
		let cframe_table=lua.create_table()?;

		//CFrame.new
		cframe_table.raw_set("new",
			lua.create_function(|ctx,(x,y,z):(f32,f32,f32)|
				Ok(ctx.create_userdata(CFrame::new(x,y,z)))
			)?
		)?;

		//CFrame.Angles
		cframe_table.raw_set("Angles",
			lua.create_function(|ctx,(x,y,z):(f32,f32,f32)|
				Ok(ctx.create_userdata(CFrame::angles(x,y,z)))
			)?
		)?;

		globals.set("CFrame",cframe_table)?;
	}

	Ok(())
}

impl Runner{
	pub fn new()->mlua::Result<Self>{
		let runner=Self{
			lua:mlua::Lua::new(),
		};
		init(&runner.lua)?;
		Ok(runner)
	}
	pub fn run_script(&self,script:crate::script::Script,context:&mut Context)->Result<(),Error>{
		let yoink=script.name_source(context);
		//this makes set_app_data shut up about the lifetime
		self.lua.set_app_data::<&'static mut rbx_dom_weak::WeakDom>(unsafe{core::mem::transmute(&mut context.dom)});
		let (name,source)=yoink.map_err(Error::Script)?;
			self.lua.globals().set("script",super::instance::Instance::from(script)).map_err(Error::Lua)?;
		self.lua.load(source)
		.set_name(name)
		.exec().map_err(Error::Lua)?;
		self.lua.remove_app_data::<&'static mut rbx_dom_weak::WeakDom>();
		Ok(())
	}
}