use std::rc::Rc;
use std::fmt::Debug;
use crate::ast::types::{Identity, Value};

/// A generic AST Node wrapper to preserve identity and metadata
#[derive(Debug, Clone)]
pub struct Node<K, T = ()> {
    pub identity: Identity,
    pub kind: K,
    pub ty: T,
}

/// The base for custom node types (extensions)
pub trait CustomNode: Debug {
    fn display_name(&self) -> &'static str;
}

#[derive(Debug)]
pub enum UntypedKind {
    Nop,
    Constant(Value),
    Identifier(Rc<str>),
    If {
        cond: Box<Node<UntypedKind>>,
        then_br: Box<Node<UntypedKind>>,
        else_br: Option<Box<Node<UntypedKind>>>,
    },
    Def {
        name: Rc<str>,
        value: Box<Node<UntypedKind>>,
    },
    Assign {
        target: Box<Node<UntypedKind>>,
        value: Box<Node<UntypedKind>>,
    },
    Lambda {
        params: Vec<Rc<str>>,
        body: Rc<Node<UntypedKind>>,
    },
    Call {
        callee: Box<Node<UntypedKind>>,
        args: Vec<Node<UntypedKind>>,
    },
    Block {
        exprs: Vec<Node<UntypedKind>>,
    },
    Tuple {
        elements: Vec<Node<UntypedKind>>,
    },
    Map {
        entries: Vec<(Node<UntypedKind>, Node<UntypedKind>)>,
    },
    Extension(Box<dyn CustomNode>),
}