use std::num::NonZero;

use hashbrown::HashMap;
use orchid_base::interner::intern;
use orchid_base::name::PathSlice;

use crate::api;

pub trait VirtFS: Send + Sync + 'static {
	fn load(&self, path: &PathSlice) -> api::OrcResult<api::Loaded>;
}

pub enum DeclFs {
	Lazy(&'static dyn VirtFS),
	Mod(&'static [(&'static str, DeclFs)]),
}
impl DeclFs {
	pub fn to_api_rec(&self, vfses: &mut HashMap<api::VfsId, &'static dyn VirtFS>) -> api::EagerVfs {
		match self {
			DeclFs::Lazy(fs) => {
				let vfsc: u16 = vfses.len().try_into().expect("too many vfses (more than u16::MAX)");
				let id = api::VfsId(NonZero::new(vfsc + 1).unwrap());
				vfses.insert(id, *fs);
				api::EagerVfs::Lazy(id)
			},
			DeclFs::Mod(children) => api::EagerVfs::Eager(
				children.iter().map(|(k, v)| (intern(*k).to_api(), v.to_api_rec(vfses))).collect(),
			),
		}
	}
}