package commands

import (
	"context"
	"errors"

	"git.loyso.art/frx/eway/internal/entity"
)

type chanIter[T any] struct {
	in   <-chan T
	err  error
	next T
}

var errChannelClosed = errors.New("channel closed")

func (i *chanIter[T]) Next() (ok bool) {
	if i.err != nil {
		return false
	}

	i.next, ok = <-i.in
	if !ok {
		i.err = errChannelClosed
	}

	return ok
}

func (i *chanIter[T]) Get() T {
	return i.next
}

func (i *chanIter[T]) Err() error {
	if errors.Is(i.err, errChannelClosed) {
		return nil
	}

	return i.err
}

func (i *chanIter[T]) Close() {
	for range i.in {
	}
}

func getItemsIter(ctx context.Context, r entity.GoodsItemRepository) *chanIter[entity.GoodsItem] {
	in, err := r.ListIter(ctx, 3)

	return &chanIter[entity.GoodsItem]{
		in:  in,
		err: err,
	}
}