extern crate proc_macro;

use proc_macro::TokenStream;
use proc_macro2::Span;
use quote::quote;

/// Wraps function using `procspawn` to allocate a new temporary directory,
/// make it the process' working directory, and run the function.
#[proc_macro_attribute]
pub fn itest(attrs: TokenStream, input: TokenStream) -> TokenStream {
    let attrs = syn::parse_macro_input!(attrs as syn::AttributeArgs);
    if attrs.len() > 0 {
        return syn::Error::new_spanned(&attrs[0], "itest takes no attributes")
            .to_compile_error()
            .into();
    }
    let func = syn::parse_macro_input!(input as syn::ItemFn);
    let fident = func.sig.ident.clone();
    let varident = quote::format_ident!("ITEST_{}", fident);
    let fidentstrbuf = format!(r#"{}"#, fident);
    let fidentstr = syn::LitStr::new(&fidentstrbuf, Span::call_site());
    let output = quote! {
        #[linkme::distributed_slice(TESTS)]
        #[allow(non_upper_case_globals)]
        static #varident : Test = Test {
            name: #fidentstr,
            f: #fident,
        };
        #func
    };
    output.into()
}