package saccharine

import (
	"fmt"
	"strings"

	"git.maximhutz.com/max/lambda/pkg/saccharine/ast"
)

func stringifyAtom(n *ast.Atom) string {
	return n.Name
}

func stringifyAbstraction(n *ast.Abstraction) string {
	return "\\" + strings.Join(n.Parameters, " ") + "." + Stringify(n.Body)
}

func stringifyApplication(n *ast.Application) string {
	arguments := []string{Stringify(n.Abstraction)}

	for _, argument := range n.Arguments {
		arguments = append(arguments, Stringify(argument))
	}

	return "(" + strings.Join(arguments, " ") + ")"
}

func Stringify(n ast.Expression) string {
	switch n := n.(type) {
	case *ast.Atom:
		return stringifyAtom(n)
	case *ast.Abstraction:
		return stringifyAbstraction(n)
	case *ast.Application:
		return stringifyApplication(n)
	default:
		panic(fmt.Errorf("unknown expression type: %v", n))
	}
}