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

#[native_func(2)]
pub fn throw(_: &mut Vm, args: Vec<Value>) -> Result<Value> {
    let [_, ty, msg] = args.try_into().expect("bypassed arity check");
    let Value::Symbol(ty) = ty else {
        throw!(*SYM_TYPE_ERROR, "exception type must be a symbol")
    };
    match msg {
        Value::String(msg) => Err(Exception::new_with_msg(ty, msg)),
        Value::Nil => Err(Exception::new(ty)),
        _ => throw!(*SYM_TYPE_ERROR, "exception message must be a string")
    }
}

#[native_func(1)]
pub fn rethrow(_: &mut Vm, args: Vec<Value>) -> Result<Value> {
    let [_, table] = args.try_into().expect("bypassed arity check");
    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());
}