package events

import (
	"fmt"
	"reflect"
)

type EventType = string

type IEvent interface {
	Typ() EventType
	Data(ref any) error
}

func NewEvent[T any](typ EventType, data ...T) IEvent {
	var d T
	if len(data) > 0 {
		d = data[0]
	}
	ev := &event[T]{
		typ:  typ,
		data: d,
	}
	return ev
}

type event[T any] struct {
	typ  EventType
	data T
}

func (event *event[T]) Typ() EventType {
	return event.typ
}

func (event *event[T]) Data(ref any) error {
	val := reflect.ValueOf(ref)
	if val.Kind() != reflect.Ptr {
		return fmt.Errorf("need Pointer to get Event Data")
	}

	valElem := val.Elem()
	if !valElem.CanSet() {
		return fmt.Errorf("cannot set value of the provided pointer")
	}

	dataType := reflect.TypeOf(event.data)
	if valElem.Type() != dataType {
		return fmt.Errorf("type mismatch: expected %s, got %s", dataType.String(), valElem.Type().String())
	}

	valElem.Set(reflect.ValueOf(event.data))

	return nil
}