// Copyright 2024 Matthew Rich <matthewrich.conf@gmail.com>. All rights reserved.

package ds

import (
	"log/slog"
)

type OrderedSet[Value comparable] struct {
	Values []*Value
	elements map[Value]int
}

func NewOrderedSet[Value comparable]() *OrderedSet[Value] {
	return &OrderedSet[Value]{ elements: make(map[Value]int), Values: make([]*Value, 0, 10) }
}

func (s *OrderedSet[Value]) Add(value Value) {
	slog.Info("OrderedSet.Add", "key", value, "s", s)
	s.Values = append(s.Values, &value)
	s.elements[value] = len(s.Values)
	slog.Info("OrderedSet.Add", "key", value, "s", s, "v", &s.Values)
}

func (s *OrderedSet[Value]) Delete(key Value) {
	slog.Info("OrderedSet.Delete", "key", key, "s", s, "size", len(s.Values))
	if i, ok := s.elements[key]; ok {
		i--
		s.Values[i] = nil
		delete(s.elements, key)
	}
}

func (s *OrderedSet[Value]) Contains(value Value) (result bool) {
	slog.Info("OrderedSet.Contains", "key", value, "s", s, "size", len(s.Values), "v", &s.Values)
	_, result = s.elements[value]
	return
}

func (s *OrderedSet[Value]) Len() int {
    return len(s.elements)
}

func (s *OrderedSet[Value]) AddItems(value []Value) {
	for _, v := range value {
		s.Add(v)
	}
}

func (s *OrderedSet[Value]) Items() []*Value {
	slog.Info("OrderedSet.Items - start", "s", s)
	result := make([]*Value, 0, len(s.elements) - 1)
	for _, v := range s.Values {
		slog.Info("OrderedSet.Items", "value", v)
		if v != nil {
			result = append(result, v)
			s.elements[*v] = len(result)
		}
	}
	slog.Info("OrderedSet.Items", "s", s, "result", result)
	s.Values = result
	return result
}