package naive

import "fmt"

type Effect[T any] struct {
	value     T
	listeners []func(newValue T)
}

var effects []interface{ clearListeners() }

func clearAllEffectListeners() {
	for _, eff := range effects {
		eff.clearListeners()
	}
}

func UseEffect[T any](value T) *Effect[T] {
	eff := &Effect[T]{value, nil}
	effects = append(effects, eff)
	return eff
}

func (eff *Effect[T]) Value() string {
	return fmt.Sprintf("%v", eff.value)
}

func (eff *Effect[T]) SetValue(newValue T) {
	eff.value = newValue
	for _, listener := range eff.listeners {
		listener(newValue)
	}
}

func (eff *Effect[T]) OnChange(listener func(newValue T)) {
	eff.listeners = append(eff.listeners, listener)
}

func (eff *Effect[T]) clearListeners() {
	eff.listeners = eff.listeners[:0]
}