package set

import (
	"cmp"
	"slices"
)

type OrderedSet[O cmp.Ordered] struct {
	Set[O]
	order []O
}

func NewOrdered[O cmp.Ordered]() *OrderedSet[O] {
	return &OrderedSet[O]{
		Set:   New[O](),
		order: []O{},
	}
}

// Creates an ordered set from each item in a slice.
func OrderedFromSlice[S ~[]O, O cmp.Ordered](slice S) *OrderedSet[O] {
	set := NewOrdered[O]()
	set.Add(slice...)
	return set
}

// Creates an ordered set from each key in a map.
func OrderedFromMap[M ~map[O]V, O cmp.Ordered, V any](m M) *OrderedSet[O] {
	return OrderedFromSlice(mapKeys(m))
}

// Convert an unordered set to ordered set.
func OrderedFromSet[O cmp.Ordered](set Set[O]) *OrderedSet[O] {
	return OrderedFromSlice(set.ToSlice())
}

// Convert the ordered set to an unordered set.
func (ordered *OrderedSet[O]) ToSet() Set[O] {
	return ordered.Set
}

// Returns an ordered slice of the members in a set.
func (ordered *OrderedSet[O]) ToSlice() []O {
	return ordered.order
}

// Adds members to the ordered set.
func (ordered *OrderedSet[O]) Add(items ...O) {
	for _, item := range items {
		if !ordered.HasMember(item) {
			ordered.Set.Add(item)
			idx, _ := slices.BinarySearch(ordered.order, item)
			ordered.order = slices.Insert(ordered.order, idx, item)
		}
	}
}

// Removes members from the ordered set, if they exists.
func (ordered *OrderedSet[O]) Remove(items ...O) {
	ordered.Set.Remove(items...)
	ordered.order = slices.DeleteFunc(ordered.order, func(item O) bool {
		return !ordered.HasMember(item)
	})
}