use std::process::Command;

use proc_macro::TokenStream;
use quote::quote;

use crate::utils::get_crate_name;

pub(super) fn flags_capture(args: TokenStream) -> TokenStream {
	let Some(crate_name) = get_crate_name() else {
		return args;
	};

	let flag = std::env::args().collect::<Vec<_>>();
	let flag_len = flag.len();
	let ret = quote! {
		pub static RUSTC_FLAGS: [&str; #flag_len] = [#( #flag ),*];

		#[tuwunel_core::ctor]
		fn _set_rustc_flags() {
			tuwunel_core::info::rustc::FLAGS.lock().expect("locked").insert(#crate_name, &RUSTC_FLAGS);
		}

		// static strings have to be yanked on module unload
		#[tuwunel_core::dtor]
		fn _unset_rustc_flags() {
			tuwunel_core::info::rustc::FLAGS.lock().expect("locked").remove(#crate_name);
		}
	};

	ret.into()
}

pub(super) fn version(args: TokenStream) -> TokenStream {
	let Some(_) = get_crate_name() else {
		return args;
	};

	let rustc_path = std::env::args()
		.next()
		.expect("Path to rustc executable");

	let version = Command::new(rustc_path)
		.args(["-V"])
		.output()
		.map(|output| {
			str::from_utf8(&output.stdout)
				.map(str::trim)
				.map(String::from)
				.ok()
		})
		.ok()
		.flatten()
		.unwrap_or_default();

	let ret = quote! {
		static RUSTC_VERSION: &'static str = #version;
	};

	ret.into()
}