package input

import "strconv"

// ListBinder describes the interface that anything that wants to present key value pairs needs to implement.
type ListBinder interface {
	ListKeyValuePairs() []ListKeyValuePair
}

type ListKeyValuePair struct {
	Key, Value string
}

// ListBindGenericSlice implements ListBinder for slices that are of some arbitrary type.
// For this to work, you need to supply a function that returns key value pairs for every slice entry.
type ListBindGenericSlice[T any] struct {
	Slice        *[]T
	KeyValueFunc func(index int, entry T) ListKeyValuePair
}

func (l ListBindGenericSlice[T]) ListKeyValuePairs() []ListKeyValuePair {
	if l.Slice == nil || l.KeyValueFunc == nil {
		return nil
	}

	result := make([]ListKeyValuePair, 0, len(*l.Slice))
	for i, entry := range *l.Slice {
		result = append(result, l.KeyValueFunc(i, entry))
	}
	return result
}

// ListBindSlice implements ListBinder for string slices.
// The list index (as a string) is used as a key.
type ListBindSlice struct {
	Slice *[]string
}

func (l ListBindSlice) ListKeyValuePairs() []ListKeyValuePair {
	if l.Slice == nil {
		return nil
	}

	result := make([]ListKeyValuePair, 0, len(*l.Slice))
	for i, entry := range *l.Slice {
		result = append(result, ListKeyValuePair{Key: strconv.Itoa(i), Value: entry})
	}
	return result
}