use talc_lang::{exception::{throw, Exception, Result}, symbol::SYM_TYPE_ERROR, value::Value, Vm};
use talc_macros::native_func;

use crate::{unpack_args, unpack_varargs};

#[native_func(1..)]
pub fn throw(_: &mut Vm, args: Vec<Value>) -> Result<Value> {
	let ([_, ty], varargs) = unpack_varargs!(args);
	let Value::Symbol(ty) = ty else {
		throw!(*SYM_TYPE_ERROR, "exception type must be a symbol")
	};
	Err(match &*varargs {
		[] | [Value::Nil]
			=> Exception::new(ty),
		[Value::Nil, data]
			=> Exception::new_with_data(ty, data.clone()),
		[Value::String(s)]
			=> Exception::new_with_msg(ty, s.clone()),
		[Value::String(s), data]
			=> Exception::new_with_msg_data(ty, s.clone(), data.clone()),
		[_] | [_,_] => throw!(*SYM_TYPE_ERROR, "wrong arguments for throw"),
		[_,_,_,..] => throw!(*SYM_TYPE_ERROR, "too many arguments for throw"),
	})
}

#[native_func(1)]
pub fn rethrow(_: &mut Vm, args: Vec<Value>) -> Result<Value> {
	let [_, table] = unpack_args!(args);
	if let Value::Table(table) = table {
		if let Some(e) = Exception::from_table(&table) {
			return Err(e)
		}
	}
	throw!(*SYM_TYPE_ERROR, "argument not a valid exception")
}

pub fn load(vm: &mut Vm) {
	vm.set_global_name("throw", throw().into());
	vm.set_global_name("rethrow", rethrow().into());
}