use crate::prelude::*;
use std::fmt::{Debug, Display};

pub struct Function {
    pub name: Rc<str>,
    pub arity: usize,
    pub variadic: bool,
    pub fun: InnerFunction
}

#[derive(Clone)]
pub enum InnerFunction {
    Compiled(Rc<Chunk>),
    Native(Rc<dyn Fn((&mut Vm, &mut StackFrame), Vec<Value>) -> Result<Value>>),
}

impl Debug for Function {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        use InnerFunction as F;
        match self.fun {
            F::Compiled(_) => {
                write!(f, "[Function {}]", self.name)
            },
            F::Native(_) => {
                write!(f, "[Builtin {}]", self.name)
            }
        }
    }
}

impl Display for Function {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        use InnerFunction as F;
        match self.fun {
            F::Compiled(_) => {
                write!(f, "[Function {}]", self.name)
            },
            F::Native(_) => {
                write!(f, "[Builtin {}]", self.name)
            }
        }
    }
}