package interpreter

import (
	"log"

	"git.adyxax.org/adyxax/gofunge/pkg/field"
	"git.adyxax.org/adyxax/gofunge/pkg/pointer"
)

type Interpreter struct {
	f *field.Field
	p *pointer.Pointer
}

func NewInterpreter(f *field.Field, p *pointer.Pointer) *Interpreter {
	return &Interpreter{f: f, p: p}
}

func (i *Interpreter) Run() {
	for i.p != nil {
		i.Step()
	}
}

func (i *Interpreter) Step() {
	var prev *pointer.Pointer = nil
	for p := i.p; p != nil; p = p.Next {
		c := p.Get(*i.f)
		switch c {
		case '@':
			if prev == nil {
				i.p = p.Next
			} else {
				prev.Next = p.Next
			}
			break
		case '#':
			p.Step(*i.f)
		default:
			if !p.Redirect(c) {
				log.Fatalf("Non implemented instruction code %d : %c", c, c)
			}
		}
		p.Step(*i.f)
	}
}