use std::ffi::CStr;

use crate::State;

use mlua_sys as lua;

pub unsafe fn ensure_type(state: &State, typ: i32, idx: i32) -> crate::Result<()> {
    let s = state.state_ptr();

    let lua_type = lua::lua_type(s, idx);
    
    if lua_type == typ {
        Ok(())
    } else {
        let exp_tyname = lua::lua_typename(s, typ);
        let exp_cstr = CStr::from_ptr(exp_tyname);
        let exp_s = exp_cstr.to_str()
            .expect("Lua type has invalid bytes!");

        let tyname = lua::lua_typename(s, lua_type);
        let cstr = CStr::from_ptr(tyname);
        let s = cstr.to_str()
            .expect("Lua type has invalid bytes!");

        Err(crate::Error::UnexpectedType(exp_s.to_string(), s.to_string()))
    }
}