package ast

import (
	"fmt"
	"golox/parser"
)

type Printer struct {
}

func New() *Printer {
	return &Printer{}
}

func (ap *Printer) Print(expr parser.Expr) string {
	return expr.Accept(ap).(string)
}

func (ap *Printer) VisitBinaryExpr(expr *parser.BinaryExpr) any {
	return ap.parenthesize(expr.Operator.Lexeme, expr.Left, expr.Right)
}

func (ap *Printer) VisitGroupingExpr(expr *parser.GroupingExpr) any {
	return ap.parenthesize("group", expr.Expression)
}

func (ap *Printer) VisitLiteralExpr(expr *parser.LiteralExpr) any {
	if expr.Value == nil {
		return "nil"
	}
	return fmt.Sprint(expr.Value)
}

func (ap *Printer) VisitUnaryExpr(expr *parser.UnaryExpr) any {
	return ap.parenthesize(expr.Operator.Lexeme, expr.Right)
}

func (ap *Printer) VisitErrorExpr(expr *parser.ErrorExpr) any {
	return expr.Value
}

func (ap *Printer) parenthesize(name string, exprs ...parser.Expr) string {
	str := "(" + name

	for _, expr := range exprs {
		str += " " + expr.Accept(ap).(string)
	}

	return str + ")"
}