use std::rc::Rc;
use std::error::Error;
use crate::ast::*;
use crate::ast::walker;

//TODO maybe these functions should take closures that return a KeepRecursing | StopHere type,
//or a tuple of (T, <that type>)

//TODO default implmentations should call walk methods - then I can test printing
pub trait ASTVisitor: Sized {
  fn visit(&mut self, ast: &AST) {
    println!("FUCK");
    walker::ast(self, ast);
  }

  fn block(&mut self, statements: &Vec<Statement>) {
    println!("oi");
    walker::block(self, statements);
  }

  fn statement(&mut self, statement: &Statement) {
    println!("stmt");
    walker::statement(self, statement);
  }

  fn declaration(&mut self, declaration: &Declaration) {
    walker::declaration(self, declaration);
  }

  fn signature(&mut self, signature: &Signature) {
  }

  fn binding(&mut self, name: &Rc<String>, constant: bool, type_anno: Option<&TypeIdentifier>, expr: &Expression) {
    walker::maybe_type_identifier(self, type_anno);
    walker::expression(self, expr);
  }

  fn expression(&mut self, expression: &Expression) {
    println!("expr yo");
    walker::expression(self, expression);
  }

  fn expression_kind(&mut self, kind: &ExpressionKind) {
    walker::expression_kind(self, kind);
  }

  fn maybe_type_identifier(&mut self, type_anno: Option<&TypeIdentifier>) {
    walker::maybe_type_identifier(self, type_anno);
  }

  fn named_struct(&mut self, name: &QualifiedName, fields: &Vec<(Rc<String>, Expression)>) {
    self.qualified_name(name);
    for (_, expr) in fields.iter() {
      walker::expression(self, expr);
    }
  }

  fn import(&mut self, import: &ImportSpecifier) {}
  fn qualified_name(&mut self, name: &QualifiedName) {}
  fn nat_literal(&mut self, n: u64) {}
  fn float_literal(&mut self, f: f64) {}
  fn string_literal(&mut self, s: &Rc<String>) {}
  fn bool_literal(&mut self, b: bool) {}
  fn binexp(&mut self, op: &BinOp, lhs: &Expression, rhs: &Expression) {
    walker::expression(self, lhs);
    walker::expression(self, rhs);
  }

  fn prefix_exp(&mut self, op: &PrefixOp, arg: &Expression) {
    walker::expression(self, arg);
  }
}