use std::borrow::Cow;

use orchid_api_derive::{Coding, Hierarchy};
use orchid_api_traits::Request;
use orchid_base::{NameLike, ReqHandleExt, Sym, es, is, mk_errv};
use orchid_extension::gen_expr::new_atom;
use orchid_extension::tree::{GenMember, fun, prefix};
use orchid_extension::{
	Atomic, Expr, ExprHandle, OwnedAtom, OwnedVariant, Supports, TAtom, sys_req,
};

use crate::std::std_system::StdReq;
use crate::std::string::str_atom::IntStrAtom;
use crate::std::string::to_string::ToStringMethod;
use crate::{HomoTpl, StdSystem, api};

#[derive(Clone, Coding)]
pub struct SymAtomData(pub api::TStrv);
#[derive(Clone)]
pub struct SymAtom(pub(crate) Sym);
impl Atomic for SymAtom {
	type Data = SymAtomData;
	type Variant = OwnedVariant;
}
impl OwnedAtom for SymAtom {
	type Refs = ();
	async fn val(&self) -> Cow<'_, Self::Data> { Cow::Owned(SymAtomData(self.0.tok().to_api())) }
}
impl Supports<ToStringMethod> for SymAtom {
	async fn handle<'a>(
		&self,
		hand: Box<dyn orchid_base::ReqHandle<'a> + '_>,
		req: ToStringMethod,
	) -> std::io::Result<orchid_base::Receipt<'a>> {
		hand.reply(&req, &self.0.to_string()).await
	}
}

#[derive(Clone, Debug, Coding, Hierarchy)]
#[extends(StdReq)]
pub struct CreateSymAtom(pub api::TStrv);
impl Request for CreateSymAtom {
	type Response = api::ExprTicket;
}

pub async fn sym_expr(sym: Sym) -> Expr {
	Expr::from_handle(ExprHandle::deserialize(
		sys_req::<StdSystem, _>(CreateSymAtom(sym.to_api())).await,
	))
}

pub async fn gen_sym_lib() -> Vec<GenMember> {
	prefix("std::refl::sym", [
		fun(true, "from_str", async move |str: TAtom<IntStrAtom>| {
			match Sym::parse(&es(*str).await).await {
				Ok(sym) => Ok(new_atom(SymAtom(sym))),
				Err(_) => Err(mk_errv(
					is("Cannot parse sym from empty string").await,
					"Empty string passed to std::refl::sym::from_str",
					[str.pos()],
				)),
			}
		}),
		fun(true, "to_tpl", async move |sym: TAtom<SymAtom>| {
			HomoTpl(sym.own().await.0.segs().map(|seg| new_atom(IntStrAtom(seg))).collect())
		}),
	])
}