use proc_macro_crate::{FoundCrate, crate_name};
use proc_macro2::{Span, TokenStream};
use quote::{format_ident, quote};

pub struct CrateIdent {
	gcore: syn::Result<TokenStream>,
	gcore_shaders: syn::Result<TokenStream>,
	raster_types: syn::Result<TokenStream>,
	wgpu_executor: syn::Result<TokenStream>,
}

impl CrateIdent {
	pub fn gcore(&self) -> syn::Result<&TokenStream> {
		self.gcore.as_ref().map_err(Clone::clone)
	}

	pub fn gcore_shaders(&self) -> syn::Result<&TokenStream> {
		self.gcore_shaders.as_ref().map_err(Clone::clone)
	}

	pub fn raster_types(&self) -> syn::Result<&TokenStream> {
		self.raster_types.as_ref().map_err(Clone::clone)
	}

	pub fn wgpu_executor(&self) -> syn::Result<&TokenStream> {
		self.wgpu_executor.as_ref().map_err(Clone::clone)
	}
}

impl Default for CrateIdent {
	fn default() -> Self {
		let find_crate = |orig_name| match crate_name(orig_name) {
			Ok(FoundCrate::Itself) => Ok(quote!(crate)),
			Ok(FoundCrate::Name(name)) => {
				let name = format_ident!("{}", name);
				Ok(quote!(::#name))
			}
			Err(e) => Err(syn::Error::new(Span::call_site(), format!("Could not find dependency on `{orig_name}`:\n{e}"))),
		};

		let gcore = find_crate("core-types");
		let gcore_shaders = find_crate("no-std-types").or_else(|eshaders| gcore.clone().map_err(|ecore| syn::Error::new(Span::call_site(), format!("{ecore}\n\nFallback: {eshaders}"))));
		let raster_types = find_crate("raster-types");
		let wgpu_executor = find_crate("wgpu-executor");
		Self {
			gcore,
			gcore_shaders,
			raster_types,
			wgpu_executor,
		}
	}
}